WO2012098908A1

WO2012098908A1 - Radiation phase image-capturing device

Info

Publication number: WO2012098908A1
Application number: PCT/JP2012/000353
Authority: WO
Inventors: 拓司多田
Original assignee: 富士フイルム株式会社
Priority date: 2011-01-20
Filing date: 2012-01-20
Publication date: 2012-07-26

Abstract

[Problem] To provide a radiation phase image-capturing device for obtaining a phase-contrast image by using two gratings, wherein a plurality of fringe images for obtaining the phase-contrast image is obtained using a single round of imaging. [Solution] A moiré is generated by the superposition of a second grating with a periodic pattern image from a first grating. An image signal read from a pixel group arranged at a spacing of at least one pixel with respect to a predetermined direction serving as a cross direction other than a direction parallel or perpendicular to the direction of the period of the moiré is obtained on the basis of an image signal of the moiré. With respect to the predetermined direction, the image signals of at least two lines of adjacent pixel groups are used as mutually different fringe image signals to generate an image signal of a single complex pixel and thereby generate a radiation image of a complex pixel unit thereof. The complex pixel is shifted and set by a pixel unit in the predetermined direction, thus generating a plurality of radiation images. A composite image is generated on the basis of the plurality of radiation images.

Description

Radiation phase imaging device

The present invention relates to a radiation phase image photographing apparatus using a lattice.

X-rays are used as a probe for seeing through the inside of a subject because they have characteristics such as attenuation depending on the atomic numbers of elements constituting the substance and the density and thickness of the substance. X-ray imaging is widely used in fields such as medical diagnosis and non-destructive inspection.

In a general X-ray imaging system, a subject is placed between an X-ray source that emits X-rays and an X-ray image detector that detects an X-ray image, and a transmission image of the subject is captured. In this case, each X-ray radiated from the X-ray source toward the X-ray image detector has characteristics (atomic number, density, thickness) of the substance constituting the subject existing on the path to the X-ray image detector. ), The light is incident on the X-ray image detector. As a result, an X-ray transmission image of the subject is detected and imaged by the X-ray image detector. As an X-ray image detector, a flat panel detector (FPD: Flat Panel Detector) using a semiconductor circuit is widely used in addition to a combination of an X-ray intensifying screen and a film and a stimulable phosphor.

However, the X-ray absorptivity becomes lower as a substance composed of an element having a smaller atomic number, and the difference in the X-ray absorptivity is small in a soft tissue or soft material of a living body. Therefore, a sufficient image density as an X-ray transmission image is obtained. There is a problem that (contrast) cannot be obtained. For example, most of the components of the cartilage part constituting the joint of the human body and the joint fluid in the vicinity thereof are water, and the difference in the amount of X-ray absorption between the two is small, so that it is difficult to obtain image contrast.

In recent years, research on X-ray phase imaging that obtains a phase contrast image based on a phase change of X-rays due to a difference in refractive index of a subject instead of a change in X-ray intensity due to a difference in absorption coefficient of the subject has been performed. Yes. In X-ray phase imaging using this phase difference, a high-contrast image can be acquired even for a weakly absorbing object with low X-ray absorption ability.

As such X-ray phase imaging, for example, in Patent Document 1 and Patent Document 2, two gratings of a first grating and a second grating are arranged in parallel at a predetermined interval, and a Talbot by the first grating is used. A radiation phase imaging apparatus is proposed that forms a self-image of the first grating at the position of the second grating by the interference effect, and obtains a radiation phase contrast image by intensity-modulating the self-image with the second grating. ing.

In the radiation phase image capturing apparatus described in Patent Document 1 or Patent Document 2, the second grating is disposed substantially parallel to the surface of the first grating with respect to the first grating, and the first grating Alternatively, the second grating is relatively translated by a predetermined amount finer than the grating pitch in a direction substantially perpendicular to the grating direction, and a plurality of images are taken by taking images for each translation movement. On the basis of the plurality of images, a fringe scanning method for acquiring the amount of X-ray phase change (phase shift differential amount) generated by the interaction with the subject is performed. A phase contrast image of the subject can be acquired based on the phase shift differential amount.

International Publication WO2008 / 102654 JP 2010-190777 A

However, in the radiation phase image capturing apparatuses described in Patent Document 1 and Patent Document 2, as described above, it is necessary to move the first or second grating with a finer pitch than the grating pitch. The grating pitch is typically several μm, and the feeding accuracy of the grating is required to be higher, so that a very high-precision moving mechanism is required. As a result, the mechanism becomes complicated and the cost increases. In addition, when imaging is performed for each movement of the lattice, the positional relationship between the subject and the imaging system is shifted due to factors such as subject movement and apparatus vibration between a series of imaging for acquiring a phase contrast image. There is a problem that the phase change of the X-ray generated by the interaction with the subject cannot be correctly guided, and as a result, a good phase contrast image cannot be obtained.

In view of the above circumstances, an object of the present invention is to provide a radiation phase image photographing apparatus capable of obtaining a good phase contrast image by one photographing without requiring a highly accurate moving mechanism. To do.

The radiographic imaging device of the present invention includes a radiation source, a grating structure periodically arranged, a first grating that forms a periodic pattern image by passing radiation emitted from the radiation source, and the grating structure is periodic. A second grating on which a periodic pattern image formed by the first grating is incident, and a radiation image detector in which pixels that detect radiation transmitted through the second grating are two-dimensionally arranged The first and second gratings generate moiré by overlapping the periodic pattern image formed by the first grating and the second grating. Based on the moire image signal detected by the radiation image detector, at least one pixel is arranged in a predetermined direction that is parallel to or orthogonal to the moire periodic direction. A radiographic image of a composite pixel unit is obtained by acquiring an image signal read from the read pixel group and generating an image signal of the composite pixel based on the image signal of the adjacent pixel group of at least two rows in the predetermined direction. A composite image generation unit that generates and generates a plurality of radiation images by shifting the composite pixel in the predetermined direction in units of pixels and generating a composite image based on the generated plurality of radiation images. It is characterized by.
In the radiographic image capturing apparatus of the present invention, the first grating and the second grating are arranged such that the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating are relative to each other. It can arrange so that it may incline.
In addition, the first grating and the second grating can be configured such that the moire period T satisfies the following formula.

Where Z ₁ is the distance between the focal point of the radiation source and the first grating, Z ₂ is the distance between the first grating and the second grating, L is the distance between the focal point of the radiation source and the radiation image detector, P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the first grating, and the extending direction of the second grating It is the angle made by.
In addition, a plurality of radiation shielding members that shield radiation are extended at a predetermined pitch, and are arranged between the radiation source and the first grating to absorb the radiation irradiated from the radiation source in a region-selective manner. A multi-slit made of a mold grating is further provided, and the first grating and the second grating can be configured such that the moire period T is a value satisfying the following expression.

Where Z ₁ is the distance between the focal point of the radiation source and the first grating, Z ₂ is the distance between the first grating and the second grating, L is the distance between the focal point of the radiation source and the radiation image detector, P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the first grating, and the extending direction of the second grating It is the angle made by.
Further, the pitch P ₃ of the multi-slit may be configured to a value that satisfies the following expression.

Where Z ₃ is the distance between the multi-slit and the first grating, Z ₂ is the distance from the first grating to the second grating, and P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating. .
Further, the relative inclination angle θ between the periodic pattern image formed by the first grating and the second grating can be set to a value satisfying the following expression.

Where P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating, D is the number of pixels constituting the composite pixel M × the size of the pixel in the predetermined direction, and n is an integer excluding 0 and a multiple of M is there.
Further, the inclination θ1 of the self-image of the first grating with respect to the predetermined direction and the inclination θ2 of the second grating with respect to the predetermined direction can be set to values satisfying the following expression.

Where P ₁ ′ is the pitch of the first periodic pattern image at the position of the second lattice, D is the size of the composite pixel composed of M pixels in the predetermined direction, and n is an integer excluding 0 and a multiple of M. is there.
Further, the first grating, and a phase modulation type grating or amplitude modulation type grating providing a phase modulation of 90 °, the pitch P ₂ of the pitch P _{1 'and} the second grating periodic pattern image at the position of the second grating Can be configured to satisfy the following formula.

Where P ₁ is the grating pitch of the _first grating, Z ₁ is the distance from the focal point of the radiation source to the first grating, and Z ₂ is the distance from the first grating to the second grating.
Further, the first grating, and a phase modulation type grating that provides a phase modulation of 180 °, the pitch P _{1 'and} the pitch P ₂ of the second grating periodic pattern image at the position of the second grating, the formula It can be configured to satisfy the value.

Where P ₁ is the grating pitch of the _first grating, Z ₁ is the distance from the focal point of the radiation source to the first grating, and Z ₂ is the distance from the first grating to the second grating.
Further, as a radiation image detector, a pixel in which pixels are two-dimensionally arranged in the first and second directions orthogonal to each other is used, and a periodic pattern image formed by the first grating or the extension of the second grating The direction and the first direction can be parallel.
Further, the phase image generation unit sets a predetermined number of pixels in the first direction according to a relative inclination between the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating. Based on the read image signal, a radiation image in units of composite pixels can be acquired.
In addition, the pixel signal of each pixel constituting the composite pixel within the width in the predetermined direction of one composite pixel is n (n is an integer excluding 0 and a multiple of M, and M is the pixel constituting the composite pixel. Number) The other of the first and second gratings can be tilted so that the period changes.
Further, the first grating and the second grating can be configured such that the pitch of the periodic pattern image at the position of the second grating is different from the pitch of the second grating.
Moreover, the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating can be made parallel.
In addition, the first grating and the second grating can be configured such that the moire period T satisfies the following formula.

Where Z ₁ is the distance between the focal point of the radiation source and the first grating, Z ₂ is the distance between the first grating and the second grating, L is the distance between the focal point of the radiation source and the radiation image detector, P ₂ is the pitch of the second grating, P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating, and Dsub is the size of the pixel in the predetermined direction.
In addition, a plurality of radiation shielding members that shield radiation are extended at a predetermined pitch, and are arranged between the radiation source and the first grating to absorb the radiation irradiated from the radiation source in a region-selective manner. A multi-slit made of a mold grating is further provided, and the first grating and the second grating can be configured such that the moire period T is a value satisfying the following expression.

Where Z ₁ is the distance between the focal point of the radiation source and the first grating, Z ₂ is the distance between the first grating and the second grating, L is the distance between the focal point of the radiation source and the radiation image detector, P ₂ is the pitch of the second grating, P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating, and Dsub is the size of the pixel in the predetermined direction.
The pitch P ₃ of the multi-slit may be configured to a value that satisfies the following expression.

Where Z ₃ is the distance between the multi-slit and the first grating, Z ₂ is the distance from the first grating to the second grating, and P ₁ ′ is the pitch of the periodic pattern image at the position of the second grating. .
Further, the first grating is a phase modulation type grating or amplitude modulation type grating that applies 90 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image at the position of the second grating is a value that satisfies the following expression. It can be constituted as follows.

Where P ₁ is the grating pitch of the _first grating, Z ₁ is the distance from the focal point of the radiation source to the first grating, and Z ₂ is the distance from the first grating to the second grating.
The first grating is a phase modulation type grating that applies 180 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image at the position of the second grating is configured to satisfy the following expression. Can do.

Where P ₁ is the grating pitch of the grating, Z ₁ is the distance from the focal point of the radiation source to the first grating, and Z ₂ is the distance from the first grating to the second grating.
Further, the first grating and the second grating are configured so that the pitch of the periodic pattern image at the position of the second grating is different from the pitch of the second grating, and the period formed by the first grating. It can arrange | position so that the extending | stretching direction of a pattern image and the extending | stretching direction of a 2nd grating | lattice may incline relatively.
In addition, as the radiation image detector, a pixel in which pixels provided with a switch element for reading an image signal are two-dimensionally arranged can be used.

Also, a linear reading light source that emits linear reading light may be provided, and the radiographic image detector may read an image signal by scanning the linear reading light source.

Further, the second grating can be arranged at a position of the Talbot interference distance from the first grating, and intensity modulation can be applied to the periodic pattern image formed by the Talbot interference effect of the first grating.

Further, the first grating is an absorption grating that forms a periodic pattern image by passing radiation as a projected image, and the second grating is intensity-modulated into a periodic pattern image as a projected image that has passed through the first grating. Can be given.

Also, the second grating can be arranged at a distance shorter than the minimum Talbot interference distance from the first grating.

Also, the size of the composite pixel in the direction orthogonal to the predetermined direction can be made smaller than the size of the composite pixel in the predetermined direction.

Further, the composite image generation unit can generate at least one of a phase contrast image, a small angle scattered image, and an absorption image as a radiation image.

Further, it is possible to provide a rotation mechanism that rotates the first and second gratings by 90 ° from the extending direction of the gratings around the rotation axis orthogonal to the centers of the lattice planes of the first and second gratings.

Also, the first and second gratings can have a two-dimensional grating structure.

The radiographic image capturing apparatus of the present invention includes a radiation source, a grating in which a grating structure is periodically arranged, a grating that forms a periodic pattern image by passing radiation emitted from the radiation source, and a periodic pattern image formed by the grating. A first electrode layer that transmits light, a photoconductive layer that generates charges upon irradiation of a periodic pattern image transmitted through the first electrode layer, a charge storage layer that stores charges generated in the photoconductive layer, Radiation image detection in which a second electrode layer in which a large number of linear electrodes that transmit reading light are arranged is stacked in this order, and an image signal for each pixel corresponding to each linear electrode is read by scanning with the reading light And the charge storage layer is formed in a lattice pattern with a pitch smaller than the arrangement pitch of the linear electrodes, and the lattice and the charge storage layer are formed of a periodic pattern image and a charge formed by the lattice. It is configured to generate an image signal representing moire by superimposing with an array pattern of layers, and based on the image signal representing moire detected by the radiation image detector, with respect to the periodic direction of moire An image signal read from a group of pixels arranged with an interval between at least one pixel is obtained in a predetermined direction which is a cross direction other than a parallel or orthogonal direction, and at least two rows adjacent to each other in the predetermined direction. A composite pixel unit radiation image is generated by generating a composite pixel image signal based on a pixel group image signal, and a plurality of radiation images are generated by setting the composite pixel by shifting the pixel unit in the predetermined direction. And a composite image generation unit that generates a composite image based on the plurality of generated radiation images.
In the radiographic image capturing apparatus of the present invention, the grid and the radiographic image detector can be arranged so that the extending direction of the lattice and the extending direction of the lattice pattern of the charge storage layer are relatively inclined.
Further, the lattice and the charge storage layer can be configured such that the moire period T satisfies the following formula.

Where P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the grating, and the extending direction of the charge storage layer. Is the horn made by.
In addition, a plurality of radiation shielding members for shielding radiation are extended at a predetermined pitch, arranged between the radiation source and the grating, and from an absorption type grating that selectively shields radiation irradiated from the radiation source. The multi-slit can be further provided, and the lattice and the charge storage layer can be configured such that the moire period T satisfies the following formula.

Where P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the grating, and the extending direction of the charge storage layer. Is the horn made by.
The pitch P ₃ of the multi-slit may be configured to a value that satisfies the following expression.

Here, Z ₃ is the distance between the multi-slit and the grating, Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector, and P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector.
Further, the relative inclination angle θ between the periodic pattern image formed by the grating and the charge storage layer can be set to a value satisfying the following expression.

Here, P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector, D is the number of fringe images M × the size of the pixels in the predetermined direction, and n is an integer excluding 0 and a multiple of M.
Further, the inclination θ of the self-image of the lattice with respect to the extending direction of the lattice structure of the charge storage layer can be set to a value satisfying the following expression.

However, P 1 _'is the pitch of the periodic pattern image of the grating at the position of the lattice structure and the charge storage layer of the charge storage layer, D is the predetermined direction of the size of the composite pixels of M pixels, n represents 0 and M It is an integer excluding multiples.
Further, the grating is a phase modulation type grating or amplitude modulation type grating that applies 90 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image at the position of the radiation image detector and the arrangement pitch P ₂ of the grating structure of the charge storage layer. 'Can be configured to satisfy:

Here, P ₁ is the grating pitch of the grating, Z ₁ is the distance from the focal point of the radiation source to the grating, and Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector.
In addition, the grating is a phase modulation type grating that applies 180 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image and the arrangement pitch P ₂ ′ of the grating structure of the charge storage layer at the position of the radiation image detector are Can be configured to satisfy.

Here, P ₁ is the grating pitch of the grating, Z ₁ is the distance from the focal point of the radiation source to the grating, and Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector.
Further, the grid and the charge storage layer can be configured such that the pitch of the periodic pattern image at the position of the radiation image detector is different from the arrangement pitch of the grid structure of the charge storage layer.
In addition, the extending direction of the periodic pattern image at the position of the radiation image detector can be made parallel to the extending direction of the lattice structure of the charge storage layer.
Further, the lattice and the charge storage layer can be configured such that the moire period T satisfies the following formula.

Here, P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector, P ₂ ′ is the arrangement pitch of the lattice structure of the charge storage layer, and Dsub is the size of the pixel in the predetermined direction.
In addition, a plurality of radiation shielding members for shielding radiation are extended at a predetermined pitch, arranged between the radiation source and the grating, and from an absorption type grating that selectively shields radiation irradiated from the radiation source. The multi-slit can be further provided, and the lattice and the charge storage layer can be configured such that the moire period T satisfies the following formula.

However, P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector, P ₂ ′ is the arrangement pitch of the lattice structure of the charge storage layer, Dsub is the size of the pixel in the predetermined direction, and the multi-slit pitch P ₃ Can be configured to satisfy the following formula.

Where Z ₃ is the distance between the multi-slit and the grating, Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector, and P ₁ ′ is the pitch of the periodic pattern image at the position of the radiation image detector. .
Further, the grating may be a phase modulation type grating or an amplitude modulation type grating that applies 90 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image at the position of the radiation image detector may be configured to satisfy the following expression. it can.

Here, P ₁ is the grating pitch of the grating, Z ₁ is the distance from the focal point of the radiation source to the grating, and Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector.
Further, the grating may be a phase modulation type grating that applies 180 ° phase modulation, and the pitch P ₁ ′ of the periodic pattern image at the position of the radiation image detector may be configured to satisfy the following expression.

Here, P ₁ is the grating pitch of the grating, Z ₁ is the distance from the focal point of the radiation source to the grating, and Z ₂ ′ is the distance from the grating to the detection surface of the radiation image detector.
Further, the grid and the charge storage layer are configured such that the pitch of the periodic pattern image at the position of the radiation image detector is different from the arrangement pitch of the grid structure of the charge storage layer, and the extension direction of the grid and the grid of the charge storage layer It can arrange | position so that the extending | stretching direction of a pattern may incline relatively.

Also, the lattice structure of the charge storage layer can be formed so as to be parallel to the linear electrode.

Further, the thickness of the charge storage layer in the stacking direction can be set to 2 μm or less.

In addition, the dielectric constant of the charge storage layer can be set to be within 2 times or more than 1/2 the dielectric constant of the photoconductive layer.

Also, the radiation image detector can be arranged at a position of the Talbot interference distance from the grating, and intensity modulation can be applied to the periodic pattern image formed by the Talbot interference effect of the grating.

Further, the grating can be an absorption grating that forms a periodic pattern image by passing radiation as a projection image, and the radiation image detector can modulate intensity of the periodic pattern image as a projection image that has passed through the grating.

Also, the radiation image detector can be arranged at a distance shorter than the minimum Talbot interference distance from the grating.

The radiographic imaging device of the present invention includes a radiation source, a grating structure periodically arranged, a first grating that forms a periodic pattern image by passing radiation emitted from the radiation source, and the grating structure is periodic. A second grating on which a periodic pattern image formed by the first grating is incident, and a radiation image detector in which pixels that detect radiation transmitted through the second grating are two-dimensionally arranged A plurality of radiation shielding members that shield radiation, and are arranged between the radiation source and the first grating and irradiated from the radiation source. A multi-slit composed of an absorption-type grating that selectively shields radiation; and the multi-slit, the first grating, and the second grating include a slit image formed by the multi-slit, the first grating, and the first grating. The image signal representing the moire is generated by superimposing the lattice pattern of the grating on the basis of the image signal representing the moire detected by the radiation image detector with respect to the periodic direction of the moire. Image signals read from a group of pixels arranged at an interval of at least one pixel in a predetermined direction that is a crossing direction other than a parallel or orthogonal direction, and adjacent to at least two rows in the predetermined direction A composite pixel unit radiation image is generated by generating a composite pixel image signal based on a pixel group image signal, and a plurality of radiation images are generated by setting the composite pixel by shifting the pixel unit in the predetermined direction. And a composite image generation unit that generates a composite image based on the plurality of generated radiation images.
In the radiographic image capturing apparatus of the present invention, the multi-slit can be arranged so that the extending direction of the multi-slit and the extending directions of the first and second gratings are relatively inclined.
In addition, the multi-slit and the first grating can be configured such that the pitch of the slit image at the position of the first grating is different from the pitch of the grating pattern of the first grating.

The radiographic imaging device of the present invention includes a radiation source, a grating structure that is periodically arranged, a grating that forms a periodic pattern image by passing radiation emitted from the radiation source, and a periodic pattern image that is formed by the grating. A first electrode layer that transmits light, a photoconductive layer that generates charges upon irradiation of a periodic pattern image transmitted through the first electrode layer, and a charge storage layer that stores charges generated in the photoconductive layer And a second electrode layer in which a large number of linear electrodes that transmit the reading light are stacked in this order, and the image signal for each pixel corresponding to each linear electrode is read by scanning with the reading light. A radiographic imaging device comprising an image detector, wherein a plurality of radiation shielding members for shielding radiation are extended at a predetermined pitch, and are arranged between a radiation source and a grating, and are irradiated from the radiation source. A multi-slit made of an absorption-type lattice that selectively shields the emitted radiation, and the charge storage layer is formed in a lattice shape with a pitch smaller than the arrangement pitch of the linear electrodes, and the multi-slit And the grating are configured to generate an image signal representing the moire by superimposing the slit image formed by the multi-slit and the grating pattern of the grating, and the moire detected by the radiation image detector is generated. An image signal read from a group of pixels arranged with an interval between at least one pixel in a predetermined direction that is parallel to or orthogonal to the moiré periodic direction based on the image signal that is represented. Acquiring and generating an image signal of a composite pixel based on image signals of adjacent pixel groups in at least two rows in the predetermined direction Therefore, a radiographic image is generated in units of composite pixels, and a plurality of radiographic images are generated by setting the composite pixels to be shifted in units of pixels in the predetermined direction, and a composite image is generated based on the generated radiographic images. A composite image generating unit is provided.
Further, the multi-slit can be arranged so that the extending direction of the multi-slit and the extending direction of the lattice pattern of the lattice and the charge storage layer are relatively inclined.
Further, the multi-slit and the grating can be configured so that the pitch of the slit image at the position of the grating is different from the pitch of the grating pattern of the grating.

Also, the radiation source and the radiation image detector can be arranged opposite to each other in the horizontal direction so that the subject can be photographed while standing.

Also, the radiation source and the radiation image detector can be arranged to face each other in the vertical direction so that the subject can be photographed in the supine position.

Also, the radiation source and the radiation image detector can be held by a swivel arm so that the subject can be photographed in a standing position and a standing position.

Also, a mammography apparatus configured to be able to photograph a breast as a subject can be provided.

Further, the radiation source is moved to a first position where the radiation image detector is irradiated with radiation from the first direction and a second position where radiation is irradiated from a second direction different from the first direction. A moving mechanism is provided, and the composite image generation unit generates the composite image based on the image signals detected by the radiation image detector for the first and second positions, and the composite image corresponding to the first position And a stereo image forming unit that forms a stereo image based on the combined image corresponding to the second position can be provided.

In addition, a circulation mechanism that circulates the radiation source and the radiation image detector around the subject is provided, and the composite image generation unit is configured to detect the rotation image for each rotation angle based on the image signal detected by the radiation image detector at each rotation angle. It is assumed that a composite image is generated, and a 3D image configuration unit that configures a 3D image based on the composite image for each rotation angle can be provided.

According to the radiographic imaging device of the present invention, moire is generated by superimposing the periodic pattern image formed by the first grating and the second grating, and based on the moire image signal detected by the radiographic image detector. Then, an image signal read from a pixel group arranged at an interval of at least one pixel is obtained in a predetermined direction which is a crossing direction other than a parallel or orthogonal direction to the moiré periodic direction, and the predetermined signal is acquired. Since a composite pixel unit phase contrast image is generated by generating an image signal of one composite pixel using image signals of adjacent pixel groups in at least two rows in the direction as different stripe image signals. Phase contrast can be obtained by a single shooting without the need for a highly accurate moving mechanism that moves the second grating as in the prior art. It is possible to obtain a plurality of fringe images to obtain an image.

Further, the composite pixel is generated by shifting the pixel unit in the predetermined direction to generate a plurality of radiation images, and the composite image is generated based on the generated plurality of radiation images. In contrast, an edge having a gentle slope can be clearly shown on the composite image. This effect will be described in detail later.

1 is a schematic configuration diagram of a first embodiment of a radiation phase imaging apparatus of the present invention. 1 is a top view of the radiation phase image capturing apparatus shown in FIG. Schematic configuration diagram of the first grating Schematic configuration diagram of second grating The perspective view which shows schematic structure of the radiographic image detector of an optical reading system XZ plane sectional view of the radiation image detector shown in FIG. 5A YZ plane sectional view of the radiation image detector shown in FIG. 5A The figure which shows the arrangement | positioning relationship of the pixel of a self-image of a 1st grating | lattice, a 2nd grating | lattice, and a radiographic image detector. The figure for demonstrating the method of setting the inclination-angle of the self-image of the 1st grating | lattice with respect to a 2nd grating | lattice. The figure for demonstrating the adjustment method of the inclination angle of the self-image of the 1st grating | lattice with respect to a 2nd grating | lattice. The figure for demonstrating the effect | action of a recording of the radiographic image detector of an optical reading system The figure for demonstrating the effect | action of a recording of the radiographic image detector of an optical reading system The figure for demonstrating the effect | action of the reading of the radiographic image detector of an optical reading system The figure for demonstrating the effect | action which acquires several fringe images based on the image signal read from the radiographic image detector of an optical reading system The figure for demonstrating the effect | action which acquires several fringe images based on the image signal read from the radiographic image detector of an optical reading system The figure for demonstrating the method to acquire five different fringe image signals for producing | generating a 2nd phase contrast image. The figure which illustrates the path | route of one radiation refracted according to phase shift distribution (PHI) (x) regarding the X direction of a subject. The figure for demonstrating the method to produce | generate a phase contrast image The figure which shows an example of arrangement | positioning relationship between the phase differential value of a to-be-photographed object's edge, and the pixel of a detector. The figure for demonstrating the reason which synthesize | combines two phase contrast images and produces | generates a synthesized image The figure for demonstrating the reason which synthesize | combines two phase contrast images and produces | generates a synthesized image The figure showing the self-image of the 1st grating | lattice which has an inclination with respect to a pixel row | line | column, and the 2nd grating | lattice which has an inclination with respect to a pixel row | line. The figure which showed typically the direction of the self-image with respect to a pixel row direction, and the extending | stretching direction of the 2nd grating | lattice with respect to a pixel row direction The figure which shows an example of the relationship between the sub-pixel read out as an image signal which comprises the fringe image which differs from the moire produced by superposition of the self-image of a 1st grating | lattice, and a 2nd grating | lattice. In the case where the extending direction of the self-image of the first grating and the extending direction of the second grating are made parallel to each other and the second grating having a pitch different from the pitch of the self-image of the first grating is used, The figure which shows an example of the relationship between the sub-pixel read out as an image signal which comprises a different fringe image, and the moire produced by superposition of the self-image of the grating | lattice of a 2nd, and a 2nd grating | lattice By moving the second grating away from the position where the pitch of the self-image of the first grating and the pitch of the second grating coincide with each other, the pitch of the self-image of the first grating at the position of the second grating and the second The figure which shows an example at the time of making the pitch of the grating | lattice different In the case where a second lattice having a pitch different from the pitch of the self-image of the first lattice is used while being inclined relative to the extending direction of the self-image of the first lattice and the extending direction of the second lattice, The figure which shows an example of the relationship between the sub-pixel read out as an image signal which comprises a different fringe image, and the moire produced by superposition of the self-image of the grating | lattice of a 2nd, and a 2nd grating | lattice In the case where a second lattice having a pitch different from the pitch of the self-image of the first lattice is used while being inclined relative to the extending direction of the self-image of the first lattice and the extending direction of the second lattice, The figure which shows the other example of the relationship between the moiré produced by the superimposition of the self-image of the grating | lattice of 2nd, and the 2nd grating | lattice, and the subpixel read as an image signal which comprises a different fringe image In the case where a second lattice having a pitch different from the pitch of the self-image of the first lattice is used while being inclined relative to the extending direction of the self-image of the first lattice and the extending direction of the second lattice, The figure which shows the other example of the relationship between the moiré produced by the superimposition of the self-image of the grating | lattice of 2nd, and the 2nd grating | lattice, and the subpixel read as an image signal which comprises a different fringe image The figure which shows an example of the 1st grating | lattice and the 2nd grating | lattice which made the grating | lattice surface concave-surfaced The figure which shows the arrangement | positioning relationship between the radiographic image detector using a TFT switch, and the 1st and 2nd grating | lattice The figure which shows schematic structure of the radiographic image detector using a CMOS sensor. The figure which shows the structure of one pixel circuit of the radiographic image detector using a CMOS sensor. The figure which shows the arrangement | positioning relationship between the radiographic image detector using a CMOS sensor, and the 1st and 2nd grating | lattice. The figure which shows schematic structure of the X-ray imaging system which can be image | photographed in the standing position using one Embodiment of this invention 1 is a block diagram showing a schematic configuration of an X-ray imaging system capable of imaging in an upright state using an embodiment of the present invention. The figure which shows schematic structure of the X-ray imaging system which can be image | photographed in the supine state using one Embodiment of this invention The figure which shows schematic structure of the X-ray imaging system which can be image | photographed in the standing state and the supine state using one Embodiment of this invention The figure which shows schematic structure of the X-ray imaging system which can be image | photographed in the standing state and the supine state using one Embodiment of this invention The figure which shows schematic structure of the mammography apparatus using one Embodiment of this invention. The figure which shows schematic structure of the mammography apparatus using one Embodiment of this invention. The figure which shows schematic structure of the mammography apparatus using one Embodiment of this invention, Comprising: The grating | lattice has arrange | positioned between the radiation source and the subject. The figure which shows schematic structure of the mammography apparatus in which expansion imaging | photography is possible using one Embodiment of this invention. The figure which shows the other schematic structure of the mammography apparatus in which expansion imaging | photography is possible using one Embodiment of this invention. 1 is a diagram showing a schematic configuration of an X-ray imaging system capable of imaging in an upright state using an embodiment of the present invention, in which a multi-slit is provided in a radiation source. The figure which shows schematic structure of the X-ray imaging system which can be image | photographed long length using one Embodiment of this invention 1 is a schematic configuration diagram of a CT imaging apparatus using an embodiment of the present invention. 1 is a schematic configuration diagram of a stereo photographing apparatus using an embodiment of the present invention. Diagram for explaining a method for generating an absorption image and a small angle scattered image The figure for demonstrating the method of producing | generating an absorption image Diagram for explaining another method of generating an absorption image The figure which shows an example of the sine curve of the signal of five subpixels The figure for demonstrating the structure which rotates the 1st and 2nd grating | lattice 90 degrees The figure for demonstrating the example at the time of making a 1st and 2nd grating | lattice into a two-dimensional grating | lattice The figure which shows an example of the radiographic image detector which has a function of a 2nd grating | lattice XZ plane sectional view of the radiation image detector shown in FIG. 51A YZ plane sectional view of the radiation image detector shown in FIG. 51A The figure for demonstrating the effect | action of recording of the radiographic image in the radiographic image detector shown in FIG. The figure for demonstrating the effect | action of recording of the radiographic image in the radiographic image detector shown in FIG. The figure for demonstrating the effect | action of reading of the radiographic image in the radiographic image detector shown in FIG. The figure which shows the other example of the radiographic image detector which has a function of a 2nd grating | lattice. The figure for demonstrating the effect | action of recording of the radiographic image in the radiographic image detector shown in FIG. The figure for demonstrating the effect | action of recording of the radiographic image in the radiographic image detector shown in FIG. The figure for demonstrating the effect | action of reading of the radiographic image in the radiographic image detector shown in FIG. The figure which shows the other shape of the electric charge storage layer in the radiographic image detector shown in FIG.

Hereinafter, a radiation phase image capturing apparatus using the first embodiment of the radiation image capturing apparatus of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of the radiation phase image capturing apparatus of the first embodiment. FIG. 2 shows a top view (XZ sectional view) of the radiation phase image capturing apparatus shown in FIG. The thickness direction in FIG. 2 is the Y direction in FIG.

As shown in FIG. 1, the radiation phase imaging apparatus of the present embodiment forms a periodic pattern image by passing a radiation source 1 that irradiates radiation toward a subject 10 and radiation emitted from the radiation source 1. The first grating 2 and the grating structure are arranged periodically, and a periodic pattern image formed by the first grating 2 (hereinafter referred to as a self-image G1 of the first grating 2) is incident thereon. A fringe image is acquired based on the grating 3, a radiation image detector 4 that detects radiation that has passed through the second grating 3, and an image signal detected by the radiographic image detector 4, and based on the acquired fringe image And a phase contrast image generation unit 5 for generating a phase contrast image.

The radiation source 1 emits radiation toward the subject 10 and has spatial coherence sufficient to generate a Talbot interference effect when the first grating 2 is irradiated with radiation. For example, a microfocus X-ray tube or a plasma X-ray source having a small radiation emission point size can be used.

As shown in FIG. 3, the first grating 2 includes a substrate 21 that mainly transmits radiation, and a plurality of members 22 provided on the substrate 21. Each of the plurality of members 22 is a linear member that extends in one direction in the plane orthogonal to the optical axis of radiation (Y direction orthogonal to the X direction and Z direction, the thickness direction in FIG. 3). The plurality of members 22 are arranged with a predetermined interval d ₁ from each other at a constant period P ₁ in the X direction. As a material of the member 22, for example, a metal such as gold or platinum can be used. Further, the first grating 2 is desirably a so-called phase modulation type grating that gives a phase modulation of about 90 ° or about 180 ° to the irradiated radiation. The thickness h ₁ of the member 22 is preferably set according to the energy of radiation used for imaging, but the X-ray energy region used in normal medical image diagnosis is 30 to 120 eV. In view of this, for example, when the member 22 is made of gold, the required gold thickness h ₁ is about 1 μm to 10 μm. As the first grating 2, an amplitude modulation type grating can be used. However, in the case of the amplitude modulation type grating, the member 22 needs to have a thickness that sufficiently absorbs radiation. For example, when the member 22 is made of gold, the gold thickness h ₁ required in the X-ray energy region is about 10 μm to several hundreds of μm.

As shown in FIG. 4, the second grating 3 includes a substrate 31 that mainly transmits radiation and a plurality of members 32 provided on the substrate 31, as in the first grating 2. The plurality of members 32 shield radiation, and all of them extend in one direction in the plane orthogonal to the optical axis of the radiation (the Y direction orthogonal to the X direction and the Z direction, the thickness direction in FIG. 4). It is a linear member. The plurality of members 32 are arranged with a predetermined interval d ₂ from each other at a constant period P ₂ in the X direction. As a material of the plurality of members 32, for example, a metal such as gold or platinum can be used. The second grating 3 is preferably an amplitude modulation type grating. The thickness h ₂ of the member 32, but are preferably set in accordance with the energy of the radiation to be used for shooting, this time, member 32 is necessary thickness to sufficiently absorb the radiation. For example, when the member 32 and the gold, the thickness _{h 2} of gold required in the X-ray energy range is about 10 [mu] m ~ number 100 [mu] m.

In general, the radiation irradiated from the radiation source 1 is not a parallel beam but a cone beam that propagates with a predetermined angle spread from the focal point of the radiation. Therefore, the self-image G1 of the first grating 2 formed by the radiation irradiated from the radiation source 1 passing through the first grating 2 is enlarged in proportion to the distance from the focal point of the radiation source 1. For this reason, in the present embodiment, the grating pitch P ₂ of the second grating 3 is set so that the slit portion of the second grating 3 takes into account the enlargement of the self-image G 1 due to the distance from the focal point of the radiation source 1. Is determined so as to substantially coincide with the periodic pattern of the bright part of the self-image G1 of the first grating 2 at the position. That is, when the distance from the focal point of the radiation source 1 to the first grating 2 is Z ₁ and the distance from the first grating 2 to the second grating 3 is Z ₂ (see FIG. 2), the second grating The pitch P ₂ is determined so as to satisfy the relationship of the following formula (1) when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation.

In the case where the first grating 2 is a phase modulation type grating that applies 180 ° phase modulation, the pitch of the self-image G1 of the first grating 2 formed through the first grating 2 is In view of the fact that the lattice pitch P ₁ of the lattice 2 of ₁ is 1/2, it is desirable that the second lattice pitch P ₂ satisfies the relationship of the following equation (2) instead of the above equation (1). .

When the radiation irradiated from the radiation source 1 is a parallel beam, the self-image G1 of the first grating 2 formed through the first grating 2 corresponds to the distance from the radiation source 1. Therefore, when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that gives a phase modulation of 90 °, P ₂ = P ₁ and the first grating 2 has a phase of 180 °. In the case of a phase modulation type grating that applies modulation, P ₂ = P _1/2 .

The radiation image detector 4 detects an image in which a self-image of the first grating 2 formed by radiation incident on the first grating 2 is intensity-modulated by the second grating 3 as an image signal. In this embodiment, the radiation image detector 4 is a direct-conversion type radiation image detector, in which an image signal is read out by scanning with linear reading light. A radiation image detector is used.

5A is a perspective view of the radiological image detector 4 of the present embodiment, FIG. 5B is a cross-sectional view of the XZ plane of the radiographic image detector shown in FIG. 5A, and FIG. 5C is a cross-sectional view of the radiographic image detector shown in FIG. It is.

As shown in FIGS. 5A to 5C, the radiation image detector 4 of the present embodiment is charged with a first electrode layer 41 that transmits radiation and irradiation with radiation that has passed through the first electrode layer 41. Of the generated charges in the recording photoconductive layer 42 and the recording photoconductive layer 42, the charge of one polarity acts as an insulator, and the charge of the other polarity acts as a conductor. The charge storage layer 43, the reading photoconductive layer 44 that generates charges when irradiated with the reading light, and the second electrode layer 45 are laminated in this order. Each of the above layers is formed in order from the second electrode layer 45 on the glass substrate 46.

The first electrode layer 41 may be any material that transmits radiation. For example, Nesa film (SnO ₂ ), ITO (Indium Tin Oxide), IZO (Indium)
Zinc Oxide), IDIXO (Idemitsu Indium X-metal Oxide; Idemitsu Kosan Co., Ltd.), which is an amorphous light-transmitting oxide film, can be used with a thickness of 50 to 200 nm, and 100 nm thick Al, Au, etc. Can also be used.

The recording photoconductive layer 42 only needs to generate charges when irradiated with radiation, and is excellent in that it has a relatively high quantum efficiency with respect to radiation and a high dark resistance. A material mainly composed of Se is used. The thickness is suitably 10 μm or more and 1500 μm or less. In particular, when it is used for mammography, it is preferably 150 μm or more and 250 μm or less, and when used for general photographing, it is preferably 500 μm or more and 1200 μm or less.

The charge storage layer 43 may be a film that is insulative with respect to the charge of polarity to be stored, such as an acrylic organic resin, polyimide, BCB, PVA, acrylic, polyethylene, polycarbonate, polyetherimide, or a polymer such as As ₂ S. ₃ , sulfides such as Sb ₂ S ₃ and ZnS, oxides and fluorides. Furthermore, it is more preferable that it is insulative with respect to the charge of the polarity to be accumulated and that it is conductive with respect to the charge of the opposite polarity, and the product of mobility × life is 3 digits or more depending on the polarity of the charge. Substances with differences are preferred.

Preferred compounds include As ₂ Se ₃ , As ₂ Se ₃ doped with Cl, Br, and I from 500 ppm to 20000 ppm, and As ₂ Se ₃ with Se ₂ substituted to about 50% _by Te. _1-x ) ₃ (0.5 <x <1), As ₂ Se ₃ with Se replaced to about 50%, As _x Se with As concentration changed by about ± 15% from As ₂ Se ₃ _y (x + y = 100, 34 ≦ x ≦ 46), amorphous Se—Te system and Te of 5-30 wt%.

In addition, as a material of the charge storage layer 43, in order to prevent the electric lines of force formed between the first electrode layer 41 and the second electrode layer 45 from being bent, the dielectric constant thereof is a recording light. It is desirable to use a conductive layer 42 and a photoconductive layer 44 for reading having a dielectric constant that is ½ to 2 times the dielectric constant.

The reading photoconductive layer 44 may be any material that exhibits conductivity when irradiated with reading light. For example, a-Se, Se-Te, Se-As-Te, metal-free phthalocyanine, metal phthalocyanine, A photoconductive substance mainly composed of at least one of MgPc (Magnesiumtalphtalocyanine), VoPc (phase II of Vanadyl phthalocyanine), CuPc (Copper phthalocyanine) and the like is preferable. A thickness of about 5 to 20 μm is appropriate.

The second electrode layer 45 includes a plurality of transparent linear electrodes 45a that transmit the reading light and a plurality of light shielding linear electrodes 45b that shield the reading light. The transparent linear electrode 45a and the light shielding linear electrode 45b extend linearly continuously from one end of the image forming region of the radiation image detector 4 to the other end. Then, as shown in FIGS. 5A and 5B, the transparent linear electrodes 45a and the light shielding linear electrodes 45b are alternately arranged in parallel at a predetermined interval.

The transparent linear electrode 45a transmits reading light and is made of a conductive material. For example, as with the first electrode layer 41, ITO, IZO, or IDIXO can be used. The thickness is about 100 to 200 nm.

The light shielding linear electrode 45b shields the reading light and is made of a conductive material. For example, the above transparent conductive material and a color filter can be used in combination. The thickness of the transparent conductive material is about 100 to 200 nm.

In the radiation image detector 4 of the present embodiment, as will be described in detail later, an image signal is read out using a pair of adjacent transparent linear electrodes 45a and light shielding linear electrodes 45b. That is, as shown in FIG. 5B, an image signal of one pixel is read out by a pair of transparent linear electrodes 45a and light shielding linear electrodes 45b. In the present embodiment, the transparent linear electrode 45a and the light shielding linear electrode 45b are arranged so that one pixel is approximately 50 μm.

Then, the radiation phase imaging apparatus of the present embodiment, as shown in FIG. 5A, linear reading that extends in a direction (X direction) orthogonal to the extending direction of the transparent linear electrode 45a and the light shielding linear electrode 45b. A light source 50 is provided. The linear reading light source 50 according to the present embodiment includes a light source such as an LED (Light Emitting Diode) or LD (Laser Diode) and a predetermined optical system, and the extending direction of the transparent linear electrode 46a and the light shielding linear electrode 46b. The radiation image detector 4 is irradiated with linear reading light having a width of about 10 μm in a direction parallel to the direction (Y direction). The linear reading light source 50 is moved in the Y direction by a predetermined moving mechanism (not shown), and the radiation image detector is detected by the linear reading light emitted from the linear reading light source 50 by this movement. 4 is scanned to read the image signal. The operation of reading the image signal will be described in detail later.

The radiation source 1, the first grating 2, the second grating 3, and the radiation image detector 4 constitute a radiation phase image capturing apparatus capable of acquiring a radiation phase contrast image. This configuration is used as a Talbot interferometer. In order to function, a few additional conditions must be nearly met. The conditions will be described below. Here, “substantially satisfy” means that, under various conditions described later, the energy of the radiation emitted from the radiation source, that is, the wavelength has a width rather than a single width, and therefore there is an allowable width for the energy width of the radiation. This means that the performance such as the image quality is inferior because it is not optimal, but there is an allowable range in which at least a phase contrast image can be obtained in the present embodiment.

First, the grid plane of the first grid 2 and the second grid 3 needs to be parallel to the XY plane shown in FIG.

Further, the distance Z ₂ between the first grating 2 and the second grating 3 should substantially satisfy the following condition when the first grating 2 is a phase modulation type grating that applies 90 ° phase modulation. I must.

Where λ is the wavelength of radiation (usually, the effective wavelength of radiation incident on the first grating 2), m is 0 or a positive integer, P ₁ is the grating pitch of the first grating 2 described above, and P ₂ is described above. This is the lattice pitch of the second lattice 3.

In addition, when the first grating 2 is a phase modulation type grating that gives 180 ° phase modulation, the following condition must be substantially satisfied.

Further, when the first grating 2 is an amplitude modulation type grating, the following condition must be substantially satisfied.

Where λ is the wavelength of radiation (usually the effective wavelength of radiation incident on the first grating 2), m ′ is a positive integer, P ₁ is the grating pitch of the first grating 2 described above, and P ₂ is described above. This is the grating pitch of the second grating 3.

The above formulas (3), (4), and (5) are for the case where the radiation irradiated from the radiation source 1 is a cone beam, and when the radiation is a parallel beam, the above formula (3) Instead, the following expression (6), the above expression (4) is replaced by the following expression (7), and the above expression (5) is replaced by the following expression (8).

Further, as shown in FIG. 3, the first grating 2 of the member 22 is formed with a thickness h _1, although member 32 of the second grating 3 is formed with a thickness h _2, the thickness h ₁ and the thickness h ₂ Is excessively thick, it becomes difficult for radiation incident obliquely to the first grating 2 and the second grating 3 to pass through the slit portion, so-called vignetting occurs, and the direction perpendicular to the extending direction of the members 22 and 32 ( There is a problem that the effective visual field in the X direction becomes narrow. For this reason, it is preferable to define the upper limits of the thicknesses h ₁ and h ₂ from the viewpoint of securing a visual field. In order to ensure the effective field length V in the X direction on the detection surface of the radiation image detector 4, the thicknesses h ₁ and h ₂ are set so as to satisfy the following expressions (9) and (10). It is preferable. Here, L is the distance from the focal point of the radiation source 1 to the detection surface of the radiation image detector 4 (see FIG. 2).

Further, in the radiation phase imaging apparatus of the present embodiment, as shown in FIG. 6, the first grating 2 and the second grating 3 are disposed so as to be relatively inclined to each other. The extending direction of the self-image G1 and the extending direction of the second lattice 3 are relatively inclined. In the present embodiment, the main scanning direction of each pixel of the image signal detected by the radiation image detector 4 with respect to the first grating 2 and the third grating 3 arranged in this way (FIG. 5). The main pixel size Dx in the X direction) and the sub-pixel size Dy in the sub-scanning direction have a relationship as shown in FIG. In the present embodiment, it is assumed that the extending direction of the second lattice 3 and the pixel column direction are the same. However, the configuration is not limited to this, and the extending direction of the first lattice 2 and the pixel column direction may be the same.

The main pixel size Dx is determined by the arrangement pitch of the transparent linear electrodes 45a and the light shielding linear electrodes 45b of the radiation image detector 4 as described above, and is set to 50 μm in this embodiment. . The sub-pixel size Dy is determined by the width of the linear reading light irradiated to the radiation image detector 4 by the linear reading light source 50, and is set to 10 μm in this embodiment. .

Here, in the present embodiment, a plurality of fringe images are acquired and a phase contrast image is generated based on the plurality of fringe images. If the number of the obtained fringe images is M, M subpixels are obtained. The first grating 2 is tilted with respect to the second grating 3 so that the size Dy is one pixel size in the sub-scanning direction of the phase contrast image, that is, the image resolution D. The M × subpixels corresponds to a composite pixel in the claims.

Specifically, as shown in FIG. 7, the pitch of the second grating 3 and the pitch of the self-image G1 formed at the position of the second grating 3 by the first grating 2 are P ₁ ′, When the relative rotation angle in the XY plane of the self-image of the first grating 2 with respect to the grating 3 is θ and the image resolution in the sub-scanning direction of the phase contrast image is D (= Dy × M), the rotation angle θ Is set so as to satisfy the following expression (11), the phase of the self-image G1 of the first grating 2 and the second grating 3 corresponds to n periods with respect to the length of the image resolution D in the sub-scanning direction. It will shift. FIG. 7 shows the case where M = 5 and n = 1.

Therefore, the image signal obtained by dividing the intensity modulation for n periods of the self-image of the first grating 2 by M can be detected by each pixel of Dx × Dy obtained by dividing the image resolution D of the phase contrast image in the sub-scanning direction by M. Become. In the example shown in FIG. 7, since n = 1, the phase of the self-image G1 of the first grating 2 and the second grating 3 is shifted by one period with respect to the length of the image resolution D in the sub-scanning direction. It will be. More simply, the region that passes through the second grating 3 in one period of the self-image G1 of the first grating 2 changes over the length of the image resolution D in the sub-scanning direction, whereby the first The intensity of the self-image G1 of the grating 2 is modulated in the sub-scanning direction.

Since M = 5, an image signal obtained by dividing the intensity modulation of one period of the self-image of the first grating 2 into 5 can be detected by each pixel of Dx × Dy, that is, each pixel of Dx × Dy. Thus, it is possible to detect image signals of five different fringe images. The method for acquiring the image signals of the five striped images will be described in detail later.

In the present embodiment, as described above, since Dx = 50 μm, Dy = 10 μm, and M = 5, the image resolution Dx in the main scanning direction and the image resolution D in the sub-scanning direction D = Dy × M of the phase contrast image. However, it is not always necessary to match the image resolution Dx in the main scanning direction and the image resolution D in the sub scanning direction, and an arbitrary main / sub ratio may be used.

Further, in this embodiment, M = 5, but M may be 3 or more, and may be other than 5. In the above description, n = 1, but n may be an integer other than 1 as long as n is an integer other than 0. That is, when n is a negative integer, the rotation is opposite to that in the above-described example, and n may be an intensity modulation for n periods with n being an integer other than ± 1. However, when n is a multiple of M, the phases of the self-image G1 of the first grating 2 and the second grating 3 are equal between a set of M sub-scanning direction pixels Dy, and M different numbers Since it is not a striped image, it is excluded.

As for the rotation angle θ of the self-image of the first grating 2 with respect to the second grating 3, for example, after fixing the relative rotation angle between the radiation image detector 4 and the second grating 3, the first grating 2 is fixed. This can be done by rotating.

For example, if P ₁ ′ = 5 μm, D = 50 μm, and n = 1 in the above equation (11), the rotation angle θ is about 5.7 °. Then, the actual rotation angle θ ′ of the self-image G1 of the first grating 2 with respect to the second grating 3 is detected by, for example, the self-image G1 of the first grating and the moire pitch by the second grating 3. Can do.

Specifically, as shown in FIG. 8, when the actual rotation angle is θ ′ and the pitch P ′ of the apparent self-image G1 in the X direction generated by the rotation is, the observed moire pitch Pm is
1 / Pm = | 1 / P′−1 / P ₁ ′ |
Therefore, the actual rotation angle θ ′ can be obtained by substituting P ′ = P ₁ ′ / cos θ ′ into the above equation. The moire pitch Pm may be obtained based on the image signal detected by the radiation image detector 4.

Then, the rotation angle θ determined by the above equation (11) is compared with the actual rotation angle θ ′, and the rotation angle of the first grating 2 is adjusted automatically or manually only by the difference. Good.

The phase contrast image generation unit 5 generates one phase contrast image based on image signals of M kinds of different fringe images acquired by the respective pixels of Dx × Dy described above in the radiation image detector 4, and the phase A plurality of phase contrast images are generated by shifting the positions of the M sub-pixels Dy constituting one pixel of the contrast image in the Y direction, and a combined image is generated by combining the plurality of phase contrast images. A method for generating a phase contrast image and a method for generating a composite image will be described in detail later.

Next, the operation of the radiation phase imaging apparatus of this embodiment will be described.

First, as shown in FIG. 1, after the subject 10 is arranged between the radiation source 1 and the first grating 2, radiation is emitted from the radiation source 1. The radiation passes through the subject 10 and is then applied to the first grating 2. The radiation irradiated on the first grating 2 is diffracted by the first grating 2 to form a Talbot interference image at a predetermined distance from the first grating 2 in the optical axis direction of the radiation.

This is called the Talbot effect. When a light wave passes through the first grating 2, a self-image G1 of the first grating 2 is formed at a predetermined distance from the first grating 2. For example, when the first grating 2 is a phase modulation type grating that gives 90 ° phase modulation, the above equation (3) or the above equation (6) (in the case of a 180 ° phase modulation type grating, the above equation (4)). or the above equation (7), while forming a first grating 2 self image G1 at a distance Z ₂ given by the above equation (5) or equation (8)) in the case of intensity modulation type grating, the subject 10 As a result, the wavefront of the radiation incident on the first grating 2 is distorted, and the self-image G1 of the first grating 2 is deformed accordingly.

Subsequently, the radiation passes through the second grating 3. As a result, the deformed self-image G1 of the first grating 2 is intensity-modulated by being superimposed on the second grating 3, and is detected by the radiation image detector 4 as an image signal reflecting the wavefront distortion. Is done.

Here, the operation of image detection and readout in the radiation image detector 4 will be described.

First, as shown in FIG. 9A, in a state where a negative voltage is applied to the first electrode layer 41 of the radiation image detector 4 by the high-voltage power source 101, the self-image of the first grating 2 and the second grating 3 The radiation whose intensity is modulated by the superposition is irradiated from the first electrode layer 41 side of the radiation image detector 4.

The radiation applied to the radiation image detector 4 passes through the first electrode layer 41 and is applied to the recording photoconductive layer 42. Then, a charge pair is generated in the recording photoconductive layer 42 by the irradiation of the radiation, and the positive charge is combined with the negative charge charged in the first electrode layer 41 and disappears, and the negative charge is a latent image. The charge is accumulated in the charge accumulation layer 43 (see FIG. 9B).

Next, as shown in FIG. 10, in the state where the first electrode layer 41 is grounded, the linear reading light L1 emitted from the linear reading light source 50 is irradiated from the second electrode layer 45 side. . The reading light L1 passes through the transparent linear electrode 45a and is applied to the reading photoconductive layer 44, and the positive charge generated in the reading photoconductive layer 44 due to the irradiation of the reading light L1 is a latent image in the charge storage layer 43. The negative charge is combined with the positive charge charged on the light-shielding linear electrode 45b through the charge amplifier 200 connected to the transparent linear electrode 45a.

A current flows through the charge amplifier 200 due to the combination of the negative charge generated in the read photoconductive layer 44 and the positive charge charged in the light shielding linear electrode 45b, and this current is integrated and detected as an image signal. The

Then, the radiation image detector 4 is scanned by the linear reading light L1 as the linear reading light source 50 moves in the sub-scanning direction, and the operation described above is performed for each reading line irradiated with the linear reading light L1. Thus, the image signals are sequentially detected, and the detected image signals for each reading line are sequentially input to the phase contrast image generation unit 5 and stored.

Then, the entire surface of the radiation image detector 4 is scanned with the reading light L 1, and the image signal of one frame is stored in the phase contrast image generation unit 5.

The phase contrast image generation unit 5 generates a plurality of phase contrast images as described above based on the stored radiographic image signal. First, the first phase contrast image among the plurality of phase contrast images is generated. For generation, the five sub-pixels Dy constituting one pixel of the first phase contrast image are set at predetermined first positions, and the pixel signals of the respective sub-pixels Dy are respectively acquired to be different from each other. Image signals of five stripe images are acquired.

Specifically, in the present embodiment, as shown in FIG. 7, the image resolution D in the sub-scanning direction of the phase contrast image is divided into five, and the intensity modulation for one period of the self-image G1 of the first grating 2 is performed. Since the self-image G1 of the first grating 2 is tilted with respect to the second grating 3 so that an image signal divided into five can be detected, reading from the 1-1 reading line is performed as shown in FIG. The obtained image signal is acquired as the first fringe image signal M1, and the image signal read out from the 1-2 reading line is acquired as the second fringe image signal M2, and read out from the 1-3 reading line. The acquired image signal is acquired as the third fringe image signal M3, and the image signal read out from the 1-4 reading line is acquired as the fourth fringe image signal M4 and read out from the 1-5 reading line. The obtained image signal is the fifth fringe image signal M5. Is obtained. Note that each of the widths 1-1 to 1-5 shown in FIG. 11 in the sub-scanning direction corresponds to the sub-pixel Dy shown in FIG.

In FIG. 11, only the Dx × (Dy × 5) range of one pixel of the first phase contrast image is shown, but the first to fifth stripes are also applied to the other ranges in the same manner as described above. An image signal is acquired.

That is, five subpixels Dy constituting one pixel of the first phase contrast image are set at the first position as shown in FIG. 12, and pixel rows (reading lines) every four pixel intervals in the subscanning direction. ) Is acquired, and one stripe image signal of one frame is acquired. More specifically, the image signal of the pixel row group of the 1-1 reading line shown in FIG. 12 is acquired, the first fringe image signal of 1 frame is acquired, and the pixel row group of the 1-2 reading line is acquired. Image signal is acquired to acquire a second fringe image signal of one frame, an image signal of a pixel row group of the first to third reading lines is acquired to acquire a third fringe image signal of one frame, The image signal of the pixel row group of the first to fourth reading lines is acquired to acquire the fourth striped image signal of one frame, and the image signal of the pixel row group of the first to fifth reading lines is acquired to acquire one frame of A fifth fringe image signal is acquired.

As described above, different first to fifth fringe image signals for generating the first phase contrast image are obtained.

Next, the phase contrast image generation unit 5 obtains five different fringe image signals for generating the second phase contrast image, so that the five sub-pixels Dy constituting one pixel of the phase contrast image are obtained. As shown in FIG. 13, the position is shifted by 2 pixels in the sub-scanning direction (Y direction) from the first position described above, and set to the second position, and the pixel signal of each sub-pixel Dy is acquired. To obtain image signals of the sixth to tenth fringe images for generating the second phase contrast image.

Specifically, the image signal of the pixel row group of the 2-1 reading line shown in FIG. 13 is acquired, the sixth striped image signal of one frame is acquired, and the pixel row group of the 2-2 reading line is acquired. An image signal is acquired to acquire a seventh stripe image signal of one frame, an image signal of a pixel row group of the second to third reading lines is acquired, and an eighth stripe image signal of one frame is acquired. The image signal of the pixel row group of the 2-4 reading line is acquired and the ninth striped image signal of one frame is acquired, and the image signal of the pixel row group of the 2-5 reading line is acquired and the first frame of the first frame is acquired. Ten fringe image signals are acquired.

As described above, the sixth to tenth fringe image signals different from each other for generating the second phase contrast image are acquired.

In the present embodiment, the fringe image signal for generating the first phase contrast image and the fringe image signal for generating the second phase contrast image are shifted by two pixels in the Y direction. However, the number is not limited to two pixels, and may be one pixel or more smaller than the number of stripe image signals for generating one phase contrast image.

Next, a method of generating the first and second phase contrast images in the phase contrast image generation unit 5 will be described. First, the principle of the method of generating a phase contrast image in the present embodiment will be described.

FIG. 14 illustrates one radiation path refracted according to the phase shift distribution Φ (x) in the X direction of the subject 10. Reference numeral X1 indicates a path of radiation that travels straight when the subject 10 is not present, and the radiation that travels along the path X1 passes through the first and

second gratings

2 and 3 to the radiation image detector 4. Incident. Reference numeral X2 indicates a path of the radiation refracted and deflected by the subject 10 when the subject 10 exists. The radiation traveling along the path X2 passes through the first grating 2 and is then shielded by the second grating 3.

The phase shift distribution Φ (x) of the subject 10 is expressed by the following equation (12), where n (x, z) is the refractive index distribution of the subject 10 and z is the direction in which the radiation travels. Here, the y-coordinate is omitted for simplification of description.

The self-image G1 formed at the position from the first grating 2 to the third grating 3 is displaced in the x direction by an amount corresponding to the refraction angle ψ due to the refraction of radiation at the subject 10. This displacement amount Δx is approximately expressed by the following equation (13) based on the fact that the refraction angle ψ of radiation is very small.

Here, the refraction angle ψ is expressed by the following equation (14) using the wavelength λ of radiation and the phase shift distribution Φ (x) of the subject 10.

Thus, the displacement amount Δx of the self-image G1 due to the refraction of the radiation at the subject 10 is related to the phase shift distribution Φ (x) of the subject 10. This displacement amount Δx is the amount of phase shift Ψ of the intensity modulation signal of each pixel detected by the radiation image detector 4 (the phase shift of the intensity modulation signal of each pixel with and without the subject 10). The amount is related to the following equation (15).

Therefore, by obtaining the phase shift amount ψ of the intensity modulation signal of each pixel, the refraction angle ψ is obtained from the above equation (15), and the differential amount of the phase shift distribution Φ (x) is obtained using the above equation (14). . By integrating this differential amount with respect to x, the phase shift distribution Φ (x) of the subject 10, that is, the phase contrast image of the subject 10 can be generated. In the present embodiment, the phase shift amount Ψ is calculated using a fringe scanning method based on the first to fifth fringe image signals (sixth to tenth fringe image signals) described above.

In the present embodiment, since the image resolution D in the sub-scanning direction of the phase contrast image is divided into five, five types of first to fifth fringe image signals are acquired for each pixel of the phase contrast image. ing. Hereinafter, a method of calculating the phase shift amount Ψ of the intensity modulation signal of each pixel of the phase contrast image from the five types of first to fifth stripe image signals will be described. Here, the method of calculating the phase shift amount Ψ based on M types of stripe image signals is described without being limited to the five types of stripe image signals.

First, the pixel signal Ik (x) of each pixel arranged in the main scanning direction of the radiation image detector 4 in the kth reading line as shown in FIG. 11 is expressed by the following equation (16).

Here, x is a coordinate in the x direction of the pixel, A ₀ is the intensity of the incident radiation, and _An is a value corresponding to the contrast of the intensity modulation signal (where n is a positive integer). ). Also, ψ (x) represents the refraction angle ψ as a function of the coordinate x of the pixel of the radiation image detector 4.

Next, using the relational expression of the following expression (17), the refraction angle ψ (x) is expressed as the expression (18).

Here, arg [] means extraction of declination and corresponds to the phase shift amount Ψ of each pixel of the phase contrast image. Therefore, by calculating the phase shift amount ψ of the intensity modulation signal of each pixel of the phase contrast image from the pixel signals of the M stripe image signals acquired for each pixel of the phase contrast image, based on Expression (16). The refraction angle ψ (x) is obtained.

Specifically, as shown in FIG. 15, the M pixel signals respectively acquired for the M subpixels Dy constituting each pixel of the phase contrast image are read line positions (subpixel Dy positions). On the other hand, it periodically changes in a cycle of M × subpixel Dy. Therefore, the M pixel signal sequences of the sub-pixel Dy are fitted with, for example, a sine wave, and the phase shift amount Ψ of the fitting curve when the subject is present and when there is no subject is obtained. , (15) calculates the differential amount of the phase shift distribution Φ (x), and integrates this differential amount with respect to x, thereby obtaining the phase shift distribution Φ (x) of the subject 10, that is, the phase contrast image of the subject 10. Generate.

For the fitting curve, a sine wave can be typically used as described above, but a rectangular wave or a triangular wave shape may be used.

As described above, the first phase contrast image is generated using the first to fifth fringe image signals, and the second phase contrast image is generated using the sixth to tenth fringe image signals. Then, the phase contrast image generation unit 5 combines the two phase contrast images to generate a combined image. Here, the reason for combining the two phase contrast images in this way will be described.

First, the phase differential value calculated based on the fringe image signal corresponding to the edge portion of the subject 10 changes as shown in FIG. On the other hand, for example, when the relationship between the five sub-pixels Dy constituting one pixel of the phase contrast image and the edge of the subject 10 that gently tilts in the Y direction is as shown in FIG. 17, the two pixels (a set of five subpixels) that are painted black in the first and second columns from the right use the signals of the five subpixels from the edge of the subject 10 toward the subject side. In this arrangement relationship shown in FIG. 16, the phase differential value is obtained based on the signals detected by the 6th to 10th sub-pixels, which is a strong signal.

In addition, the two pixels painted black in the third and fourth columns from the right shown in FIG. 17 are the signals detected by the second to sixth sub-pixels in the arrangement relationship shown in FIG. The phase differential value is obtained based on the above, and the signal of the edge of the subject 10 can be detected only by one or two subpixels, so that the signal becomes weak. However, for the two pixels arranged on the two pixels, a signal near the edge of the subject 10 is detected by each of the five sub-pixels, so that a relatively strong signal is detected. . Therefore, the edge signals detected by the four pixels in the third and fourth columns from the right shown in FIG. 17 are intermediate signals as a whole.

Further, the two thinly painted pixels in the fifth and sixth columns from the right shown in FIG. 17 are based on the signals detected by the third to seventh subpixels in the arrangement relationship shown in FIG. Thus, the phase differential value is obtained, and since the edge signal of the subject 10 can be detected only by 2 to 3 subpixels, it becomes a weak signal. The two pixels arranged on the thinly painted two pixels in the fifth and sixth columns from the right are also separated from the edge of the subject, so that a medium signal is detected. Therefore, the edge signals detected by the four pixels in the fifth and sixth columns from the right shown in FIG. 17 are weak signals as a whole.

In addition, the two pixels painted in black in the first to fourth columns from the left shown in FIG. 17 are detected because the edge signal of the subject 10 is detected by the 3 to 5 subpixels. It becomes a strong signal.

Therefore, as a result, as shown in FIG. 17, the phase contrast image of the edge of the subject 10 looks relatively strong in the range of R1 and R3, but looks relatively weak in the range of R2, and the density Unevenness occurs.

Therefore, in the present embodiment, as described above, the positions of the five subpixels Dy constituting one pixel of the phase contrast image are shifted by 2 pixels in the subscanning direction (Y direction), and another phase contrast image is obtained. It is trying to generate.

Specifically, as shown in FIG. 18, the five sub-pixels Dy constituting one pixel of the phase contrast image are set by shifting by two pixels in the Y direction. In this case, considering the same as above, the two thinly-painted pixels in the first and second columns from the right shown in FIG. Since it can only be detected with a signal, the signal is relatively weak.

In addition, the three pixels painted black in the third to fifth columns from the right shown in FIG. 18 are strong signals because the edge signal of the subject 10 is detected by the 4 to 5 subpixels.

Further, the three pixels in the third to fifth columns from the left shown in FIG. 18 are weak signals because the edge signal of the subject 10 can be detected only by the 1-2 subpixels. . However, for the three pixels arranged on the three pixels, a signal near the edge of the subject 10 is detected by each of the five sub-pixels, so that a relatively strong signal is detected. . Therefore, the edge signals detected by the six pixels in the third to fifth columns from the left shown in FIG. 18 are intermediate signals as a whole.

Further, the two thinly painted pixels in the first and second columns from the left shown in FIG. 18 are relatively weak signals because the edge signal of the subject 10 can be detected only by the three subpixels. .

Therefore, as a result, as shown in FIG. 18, the phase contrast image of the edge of the subject 10 looks relatively strong in the range of R2 ′, but looks relatively weak in the range of R1 ′ and R3 ′. Become.

That is, since the range in which the edge is not clearly shown in the phase contrast shown in FIG. 17 can be supplemented by the range in which the edge is clearly shown in the phase contrast image shown in FIG. 18, these phase contrast images complement each other. It becomes a relationship.

For the reasons described above, in the present embodiment, the first phase contrast image is generated as the phase contrast image shown in FIG. 17, and the second phase contrast image is generated as the phase contrast image shown in FIG. ing.

Then, for example, the phase contrast image generation unit 5 calculates a simple average of the first phase contrast image and the second phase contrast image, or adds the first phase contrast image and the second phase contrast image. To generate a composite image.

In the present embodiment, two phase contrast images are acquired to generate a composite image. However, the present invention is not limited to this, and three or more phase contrast images are acquired to generate a composite image. May be.

In the above description, the y-coordinate regarding the y-direction of the pixel of the phase contrast image is not taken into consideration. However, by performing the same calculation for each y-coordinate, the refraction angle two-dimensional distribution ψ (x, y) is By obtaining this and integrating it along the x-axis, a two-dimensional phase shift distribution Φ (x, y) can be obtained.

Further, instead of the two-dimensional distribution ψ (x, y) of the refraction angle, the phase contrast image is generated by integrating the two-dimensional distribution ψ (x, y) of the phase shift amount along the x-axis. Also good.

The two-dimensional distribution of refraction angles ψ (x, y) and the phase shift amount ψ (x, y) correspond to the differential values of the phase shift distribution Φ (x, y) and are called phase differential images. This phase differential image may be generated as a phase contrast image.

In the above-described embodiment, the configuration in which the pixel column of the radiation image detector 4 and the grid member of the second grid 3 are arranged in parallel as illustrated in FIG. 6 has been described. It is not necessary that the grid 3 or the pixel column and the first grid 2 are arranged in parallel, and the second grid 3 or the first grid 2 and the pixel column may have an inclination. The conditions of the angle θ1 formed by the extending direction of the first lattice 2 and the pixel column direction and the angle θ2 formed by the extending direction of the second lattice 3 and the pixel column direction will be described below.

FIG. 19A is a diagram illustrating a self-image G1 of the first grating 2 having an inclination θ1 with respect to the pixel column and a second grating 3 having an inclination θ2 with respect to the pixel column. Five squares arranged in the vertical direction shown in FIG. 19A are pixel rows. The diagram shown in FIG. 19B schematically shows the direction of the self-image G1 with respect to the pixel column direction and the extending direction of the second grating 3 with respect to the pixel column direction.

Here, as a condition of θ1 and θ2, the distance between AB and the distance between the intersections of the self-image G1 and the second grating 3 may be within the range of D = M × Dy.

Since the distance L AB between the _ABs can be expressed as the following expression (19), the condition that the distance L _AB is just in the range of D is the following expression (20). Note that P ₁ ′ in Expression (19) is the pitch of the self-image G1 formed at the position of the second grating 3 by the first grating 2 as in the above Expression (11).

On the other hand, since the distance LAC between _ACs can be expressed as the following formula (21), the condition that this distance _LAC is just in the range of D is the following formula (22).

Therefore, the conditional expression of θ1 and θ2 can be expressed as the following expression (23). Since the following formula (23) is a formula when the phase of the self-image G1 of the first grating 2 and the phase of the second grating 3 is shifted by one period with respect to D, as shown in FIG. If it is shifted by the period, it can be expressed by the following formula (24). Note that n and P ₁ ′ in the following equation (24) are the same as those in the above equation (11).

In the first embodiment, as shown in FIG. 6, the extending direction of the second grating 3 is parallel to the Y direction, and the extending direction of the self-image G1 of the first grating 2 is set to the Y direction. However, conversely, the extending direction of the self-image G1 of the first grating 2 is parallel to the Y direction, and the extending direction of the second grating 3 is inclined by θ with respect to the Y direction. You may do it.
Further, the relative rotation angle θ in the XY plane between the self-image G1 of the first grating 2 and the second grating 3 is not only expressed by the above equations (11) and (24). From the relationship between the moire period T generated by the self-image G1 of the first grating 2 and the second grating 3 and the sub-pixel size Dsub, it can also be expressed by the following equation (25). However, Z ₁ in the formula (25) distance from the focal point of the radiation source 1 to the first grid 2, Z ₂ is a distance from the first grating 2 to the second grating 3, L is the radiation source 1 The distance from the focal point to the radiation image detector 4, P ₁ ′, is the arrangement pitch of the self-image G 1 of the first grating 2 formed at the position of the second grating 3.
In the description of the above formula (11), the sub-pixel size is referred to as Dy. This is because the arrangement direction of five pixels for acquiring image signals constituting different stripe images is the Y direction. It is. As described above, the arrangement direction of the five pixels is not necessarily limited to the Y direction, and may be any other direction. Therefore, the subpixel size in Expression (25) is referred to as Dsub. Dy and Dsub are the same in terms of subpixel size. Therefore, the image resolution D in Expression (11) can also be expressed as the number M of stripe images × subpixel size Dsub, and the direction of the subpixel size is not limited to the Y direction.

Further, as described above, the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 when the extending direction of the self-image G1 of the first grating 2 and the extending direction of the second grating 3 are relatively inclined. When the first and the grating pitch P ₁ of the grating 2 grating pitch P ₂ and the relationship should satisfy the second grating 3, the phase modulation type grating or amplitude modulation type first grating 2 gives a phase modulation of 90 ° In the case of a grating, the following expression (26) is obtained, and in the case where the first grating 2 is a phase modulation type grating that applies 180 ° phase modulation, the following expression (27) is obtained.

When the self-image G1 of the first grating 2 and the second grating 3 are arranged as shown in FIG. 20, a moire having a periodic direction in the Y direction as shown in the rightmost part of FIG. 20 is generated. However, as shown by a dotted square in FIG. 20, for example, if image signals of pixels arranged in parallel to the periodic direction of the moire are acquired, each other, as in the first embodiment, Five different fringe image signals can be acquired. Even in this case, as in the first embodiment, the position of the sub-pixel Dsub is shifted by, for example, two pixels with respect to the moire periodic direction, and the pixel signal of each sub-pixel Dsub at the shifted position is changed. By acquiring each, it is possible to acquire five fringe image signals for generating the second phase contrast image.
The above is the description of the first embodiment of the radiation phase imaging apparatus of the present invention.

Next, a radiation phase image capturing apparatus using the second embodiment of the radiation image capturing apparatus of the present invention will be described. In the radiation phase imaging apparatus of the first embodiment, the type of the first grating 2 and the radiation source 1 are set so that the distance Z2 from the first grating 2 to the second grating 3 becomes the Talbot interference distance. One of the above formulas (3) to (8) is satisfied according to the divergence angle of the radiated radiation. However, in the radiation phase imaging apparatus of the second embodiment, the first grating 2 projects a large portion of incident radiation without diffracting, so that a projection image projected through the first grating 2 is obtained in a similar manner at a position behind the first grating 2. the distance Z ₂ from the first grating 2 to the second grating 3, in which to be able to be set independently of the Talbot distance.

Specifically, in the radiation phase imaging apparatus of the second embodiment, the first grating 2 and the second grating 3 are both configured as absorption (amplitude modulation type) gratings and have Talbot interference. Regardless of the presence or absence of the effect, the radiation passing through the slit portion is geometrically projected. More specifically, first the spacing d ₁ of the grating 2 and the spacing d ₂ of the second grating 3, by a sufficiently large value than the effective wavelength of the radiation emitted from the radiation source 1, the illumination radiation Mostly, the self-image G1 of the first grating 2 can be formed behind the first grating 2 without being diffracted by the slit portion. For example, when tungsten is used as the target of the radiation source and the tube voltage is 50 kV, the effective wavelength of radiation is about 0.4 mm. In this case, the radiation image first with the distance d ₁ of the grating 2 the distance d ₂ of the second grating 3, the radiation that has passed through the slit portion be about 1 [mu] m ~ 10 [mu] m to form ignores the effects of diffraction The self-image G1 of the first grating 2 is geometrically projected behind the first grating 2 as much as possible.

The first and the grating pitch P ₁ of the grating 2 for the relationship between the lattice pitch P ₂ of the second grating 3 is the same as in the first embodiment. Further, the relation of the relative inclination between the self-image G1 of the first grating 2 and the second grating 3 is the same as the equation (11) in the first embodiment.

In the second embodiment, the distance Z ₂ between the first grating 2 and the second grating 3 is set to a value shorter than the minimum Talbot interference distance when m = 1 in the above equation (5). Can be set. That is, the distance Z ₂ is set to a value in the range satisfying the following equation (28).

The member 22 of the first grating 2 and the member 32 of the second grating 3 preferably shield (absorb) radiation completely in order to generate a periodic pattern image with high contrast. Even if a material excellent in radiation absorption (gold, platinum, etc.) is used, there is a considerable amount of radiation that is transmitted without being absorbed. For this reason, in order to improve the radiation shielding property, it is preferable that the thicknesses h ₁ and h ₂ of the

members

22 and 32 be as thick as possible. The

members

22 and 32 are preferably capable of shielding 90% or more of the irradiation radiation, and the materials and thicknesses h1 and h2 of the

members

22 and 32 are set by the energy of the irradiation radiation. For example, when tungsten is used as the target of the radiation source 1 and the tube voltage is 50 kV, the thicknesses h ₁ and h ₂ are preferably 100 μm or more in terms of gold (Au).

However, in the second embodiment as well, the thickness of the member 22 of the first grating 2 and the member 32 of the second grating 3 has a problem of so-called radiation vignetting as in the first embodiment. It is preferable to limit the lengths h ₁ and h ₂ .

Also in the radiation phase imaging apparatus of the second embodiment, as shown in FIG. 1, after the subject 10 is disposed between the radiation source 1 and the first grating 2, Radiation is emitted. The radiation passes through the subject 10 and is then applied to the first grating 2.

Then, the projected image projected through the first grating 2 passes through the second grating 3, and as a result, the projected image is subjected to intensity modulation by superimposing with the second grating 3, and the image The signal is detected by the radiation image detector 4 as a signal.

Then, the image signal detected by the radiation image detector 4 is read out in the same manner as in the first embodiment, and the image signal of one whole frame is stored in the phase contrast image generation unit 5 and then the phase contrast. Based on the stored image signal, the image generation unit 5 generates first and second phase contrast images in the same manner as in the first embodiment. Then, the phase contrast image generation unit 5 combines the first phase contrast image and the second phase contrast image to generate a combined image.

The operation of generating the first and second phase contrast images and the operation of generating the composite image in the phase contrast image generation unit 5 are the same as those in the first embodiment.

According to the radiation phase imaging apparatus of the second embodiment, since the distance Z2 between the first grating 2 and the second grating 3 can be made shorter than the Talbot interference distance, a constant Talbot interference distance is ensured. Compared with the radiation phase imaging apparatus of the first embodiment that must be performed, the imaging apparatus can be made thinner.
The above is the description of the second embodiment of the radiation phase image capturing apparatus of the present invention.

Further, in the radiation phase imaging apparatus of the first embodiment and the second embodiment, the distance from the radiation source 1 to the radiation image detector 4 is set at a distance set in a general hospital imaging room. When the focal point size of the radiation source 1 is, for example, about 0.1 mm to 1 mm, which is typical, the Talbot interference of the first grating 2 or the first grating 2 There is a possibility that the self-image G1 is blurred due to the projection and the image quality of the phase contrast image is deteriorated.

Therefore, when the radiation source 1 having the above-described focal size is used, it is conceivable to effectively reduce the focal point size by installing a pinhole immediately after the focal point of the radiation source 1. If the opening area of the pinhole is reduced in order to reduce the focal point size, the radiation intensity is reduced.

Therefore, instead of providing the pinhole as described above, a multi-slit may be arranged immediately after the focal point of the radiation source 1 in the radiation phase imaging apparatus of the first and second embodiments.

Here, the multi-slit is an absorption type grating having the same configuration as the first and

second gratings

2 and 3 of the second embodiment, and a plurality of radiation shielding portions extending in a predetermined direction are periodically formed. It is what is arranged. The arrangement direction of the radiation shielding portions arranged in the multi-slit is preferably the same as either the arrangement direction of the members 22 of the first grating 2 or the members 32 of the second grating 3, but the phase contrast image Are not necessarily the same from the viewpoint of obtaining. In the present embodiment, as an example of the most preferable form among them, it is assumed that the arrangement direction of the radiation shielding portions arranged in the multi slit is the same as the arrangement direction (X direction) of the members 22 of the first lattice 2 To do.
That is, in this case, the multi-slit can partially reduce the effective focus size in the X direction by partially shielding the radiation emitted from the focus of the radiation source 1. A large number of microfocus light sources divided in the X direction can be formed.

The multi-slit lattice pitch P ₃ needs to be set to satisfy the following equation (29), where Z ₃ is the distance from the multi-slit to the first lattice 2. P ₁ ′ is the arrangement pitch of the self-image G1 of the first grating 2 at the position of the second grating 3.

When there is a multi-slit that satisfies the equation (29), the pitch of the self-image G1 of the first grating 2 is a pitch that takes the position of the multi-slit as the starting point of enlargement. Therefore, the grating pitch P ₂ of the second grating 3 satisfies the relationship of the following equation (30) when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation. To be determined. Z ₃ is the distance from the multi slit to the first grating 2 as described above.

When the first grating 2 is a phase modulation type grating that applies 180 ° phase modulation, it is determined so as to satisfy the relationship of the following equation (31).

Further, in order to secure the effective field length V in the X direction on the detection surface of the radiation image detector 4, if the distance from the focal point of the radiation source 1 to the radiation image detector 4 is L, the first grating 2. the thickness h ₁ of the member 22 and the thickness h ₂ of the second grating 3 members, the following equation (32) and following equation (33) are preferably determined so as to satisfy.

In the above equation (29), the plurality of self-images G1 formed by the Talbot interference or projection of the first grating 2 by the radiation emitted from each micro-focus light source pseudo-dispersed and formed by the multi-slit This is a geometric condition for overlapping the self-image G1 of the first grating 2 at the position of the second grating 3 by shifting by one pitch. In this way, the plurality of microfocus light sources formed by the multi-slits are formed, and the self-images G1 of the plurality of first gratings 2 formed by the Talbot interference or the projection are regularly superimposed on each other. The image quality of the phase contrast image can be improved without reducing the intensity.
As described above, when the multi-slit is used in the radiation phase imaging apparatus of the first and second embodiments, the relative rotation angle θ between the self-image G1 of the first grating 2 and the second grating 3 is used. And the equation indicating the relationship between the moire period T generated by the self-image G1 of the first grating 2 and the second grating 3 and the sub-pixel size Dsub is similar to the following expression (25): It can be expressed as (34). In the following equation (34), Z ₁ is the distance from the focal point of the radiation source 1 to the first grating 2, Z ₂ is the distance between the first grating 2 and the second grating 3, and L is from the focal point of the radiation source 1. This is the distance to the radiation image detector 4.

In the first and second embodiments, the first grating 2 and the second grating 3 are relatively inclined. However, when the multi-slit described above is provided, The first lattice 2 and the second lattice 3 are arranged so that the extending directions of the

lattice members

22 and 32 are parallel to each other, and the extending direction of the

lattice members

22 and 32 and the extending direction of the multi-slit are relatively It may be tilted. This is because, even in this configuration, the stretching direction of the self-image G1 of the first grating 2 and the stretching direction of the second grating can be relatively inclined, and moire can be generated. This is because a fringe image signal similar to that of the form can be acquired. In addition, about the inclination | tilt angle of the extending | stretching direction of the

lattice members

22 and 32 and the extending | stretching direction of a multi slit, similarly to the 1st and 2nd embodiment, the above Formula (11), the above Formula (24), or the above Formula The setting may be made based on (25).
In the description of the radiation phase imaging apparatus of the first and second embodiments, the self-image G1 of the first grating 2 and the second grating 3 are relatively inclined, but this is not necessarily the case. For example, the self-image G1 of the first grating 2 and the second grating 3 are parallel to each other, and the arrangement pitch of the self-image G1 of the first grating 2 is different. You may make it use the 2nd grating | lattice 3 of arrangement pitch.
When such first grating 2 and second grating 3 are used, a moire in the Y direction as shown in FIG. 21, that is, a moire having a periodic direction in the X direction is generated. Therefore, for example, as shown by a dotted square in FIG. 21, if the image signals of five pixels arranged in parallel with the periodic direction of the moire are acquired, the same as in the first embodiment. The image signals constituting the five different fringe images can be respectively acquired.
When the second grating 3 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2 is used as described above, the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 and the second The arrangement pitch P ₂ of the grating 3, the moire period T, and the sub-pixel size Dsub may satisfy the following expression (35).

At this time, the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 is expressed by the following formula (1) when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that applies 90 ° phase modulation. 36), and when the first grating 2 is a phase modulation type grating giving 180 ° phase modulation, the following expression (37) may be satisfied.

Also in the embodiment in which the multi-slit described above is provided for the radiation phase imaging apparatus of the first and second embodiments, the arrangement pitch of the self-image G1 of the first grating 2 is as described above. It can be set as the structure using the 2nd grating | lattice 3 of a different arrangement pitch. In the case of using the multi-slit also arranged a pitch P _{1 'of} the first grating 2 self image G1, the arrangement pitch P ₂ of the second grating 3, the period T of the moire, the sub-pixel size Dsub is The following equation (38) may be satisfied. In the following equation (38), Z ₁ is the distance from the focal point of the radiation source 1 to the first grating 2, Z ₂ is the distance between the first grating 2 and the second grating 3, and L is from the focal point of the radiation source 1. This is the distance to the radiation image detector 4.

At this time, the relational expression to be satisfied by the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 is an expression in which Z ₁ in the above expression (36) and the above expression (37) is replaced with Z _3. It is necessary to satisfy the above formula (29).
Further, in the above description, the arrangement pitch of the self-image G1 of the first grating 2 and the arrangement pitch of the second grating 3 are different from each other. If radiation is a cone beam, as shown in FIG. 22, using the second grating 3 as the same arrangement pitch as the array pitch of the first grating 2 self image G1 at the position of Z _2, The self-image of the first grating 3 enlarged by disposing the second grating 3 at a position where Z ₂ is made larger (or by moving to a position where Z ₂ is made smaller, although not shown). The arrangement pitch of G1 may be different from the arrangement pitch of the second grating 3. Even in this configuration, the above expression (35), the above expression (36), or the above expression (37) is satisfied, and When using a multi slit, The above equation in place of equation (35) to the al (38), it is necessary to satisfy the above equation (29). However, in these formulas, the P 1 _'position of the second grating 3 after the movement the first arrangement pitch P ₁ of the self image G1 grid 2 ', Z _2, the distance between the first grating 2 and the second grating 3 after the movement, to be replaced with.
Further, as described above, the second grating 3 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2 is used, and the self-image G1 and the second image of the first grating 2 are further used as described above. The grating 3 may be relatively tilted.
With such a configuration, it is possible to generate moire having a period in an oblique direction (a direction not parallel to the X direction and the Y direction) as shown in FIG. Therefore, for example, as shown by a dotted square in FIG. 23, if image signals of five pixels arranged in parallel to the Y direction are acquired, five different from each other as in the first embodiment. Each of the fringe image signals can be acquired.
In FIG. 23, the image signals of five pixels arranged in parallel to the Y direction are acquired. However, the present invention is not limited to this, and as shown in FIG. 24, 5 pixels arranged in parallel to the X direction. You may make it acquire the image signal of one pixel. In short, the pixels may be arranged in any direction as long as the image signals of the pixels arranged in the crossing direction other than the direction parallel to or orthogonal to the moire periodic direction are acquired.
In the above description, the periodic direction of the self-image G1 of the first grating 2 or the periodic direction of the second grating 3 is either one of the orthogonal directions in which the pixels of the radiation image detector 4 are arranged. However, the present invention is not limited to this. As shown in FIG. 25, image signals of five pixels arranged in an oblique direction (a direction not parallel to the X direction and the Y direction) can be acquired. Further, the relative angle between the periodic direction of the first and

second gratings

2 and 3 and the arrangement direction of the pixels of the radiation image detector 4 may be shifted.
In short, if the image signals of a plurality of pixels arranged in a predetermined direction which is a cross direction other than the parallel or orthogonal direction to the moiré periodic direction are acquired as image signals constituting different fringe images, the first The relationship between the periodic direction of the

second gratings

2 and 3 and the arrangement direction of the pixels of the radiation image detector 4 may be any relationship. Due to this relationship, the subpixel size in the above equation (11), the above equation (24), the above equation (25), the above equation (34), the above equation (35), and the above equation (38) is in the Y direction. The size of the pixel in the predetermined direction is not limited.
Even in the cases shown in FIGS. 21 to 25, as in the first embodiment, the position of the sub-pixel Dsub is shifted by, for example, two pixels with respect to the periodic direction of the moire, and at the shifted position. The five fringe image signals for generating the second phase contrast image can be acquired by acquiring the pixel signal of each of the sub-pixels Dsub.

In the above description, the first and

second gratings

2 and 3 are configured such that the periodic arrangement direction of the

members

22 and 32 is linear (that is, the grating surface is planar). In all the embodiments described above, instead of this, as shown in FIG. 26, it is more preferable to use a first grating 450 and a second grating 460 in which the grating surface is concaved into a curved surface.

The first grating 450, the radiation permeable and curved surfaces of the substrate 450a, a plurality of members 450b are periodically arranged at a predetermined pitch P _1. Each member 450b extends linearly in the Y direction, as in the first and second embodiments, and the lattice plane of the first grating 450 passes through the focal point of the radiation source 1 and extends of the member 450b. It has a shape along a cylindrical surface with a straight line extending in the direction as the central axis. Similarly, the second grating 460, the radiation permeable and curved surfaces of the substrate 460a, a plurality of members 460b are periodically arranged at a predetermined pitch P _2. Each member 460b extends linearly in the Y direction, and the lattice plane of the second grating 460 passes through the focal point of the radiation source 1 and is on a cylindrical surface with a straight line extending in the extending direction of the member 460b as a central axis. It is a shape along.

When the distance from the focal point of the radiation source 1 to the first grating 450 is Z ₁ and the distance from the first grating 450 to the second grating 460 is Z ₂ , the grating pitch P ₁ and the grating pitch P ₂ are , It is determined so as to satisfy the relationship of the above formula (1) or the above formula (2).

Thus, by making the grating surfaces of the first and

second gratings

450 and 460 cylindrical, the radiation irradiated from the focal point of the radiation source 1 is all the grating surfaces when the subject 10 does not exist. Therefore, there is no upper limit on the thickness of the member 450b and the thickness of the member 460b, and the above equations (9) and (10) need not be considered.

Furthermore, in the case of the embodiment in which the multi slit described above is provided, it is preferable that the multi slit is configured similarly to the second grating 460.

The first and

second gratings

450 and 460 may be configured by joining a plurality of planar small gratings. Further, the

substrates

450a and 460a of the first and

second gratings

450 and 132 may be flexible.

Also, the radiation image detector 60 is made flexible, an SID changing mechanism that changes the distance (SID) from the focal point of the radiation source 1 to the detection surface of the radiation image detector 60, and a curvature that changes the curvature according to the SID. An adjustment mechanism may be provided. For example, based on the SID value input from a predetermined input device, the SID changing mechanism and the curvature adjusting mechanism are controlled, the position of the radiation source 1 or the radiation image detector 60 is adjusted, and radiation is incident on the detection surface. The curvature of the radiation image detector 60 may be changed so that the angle is substantially vertical.

Further, when the distances Z ₁ and Z ₂ change with the change of the SID in the SID changing mechanism, the curvatures of the first and

second gratings

450 and 460 are changed according to the distances Z ₁ and Z _2. You may make it provide the mechanism to change. However, when the changes in the distances Z ₁ and Z ₂ are large, the grating pitches P ₁ and P ₂ cannot fully correspond even if the curvatures of the first and

second gratings

450 and 460 are changed. The

second gratings

450 and 460 may be interchangeable with those having appropriate curvature and grating pitches P ₁ and P ₂ .

In the above description, the first and

second gratings

450 and 460 are configured by disposing the

members

450b and 460b in a direction orthogonal to the bending direction of the

substrates

450a and 460a, respectively. Although the restriction on the thickness is eliminated, the

members

450b and 460b may be disposed along the bending method of the

substrates

450a and 460a.

In the above description, as the radiation image detector 4, a so-called optical reading type radiation image detector in which an image signal is read out by scanning linear reading light emitted from the linear reading light source 50 is used. However, the present invention is not limited to this, and in all of the above-described embodiments, for example, a number of TFT switches are arranged in a two-dimensional manner as described in JP-A-2002-26300, and the TFT switches are turned on / off. Thus, a radiation image detector using a TFT switch from which an image signal is read out, a radiation image detector using a CMOS sensor, or the like may be used.

Specifically, a radiation image detector using a TFT switch is collected by, for example, a pixel electrode 71 and a pixel electrode 71 that collect charges photoelectrically converted in a semiconductor film by radiation irradiation, as shown in FIG. A plurality of pixel circuits 70 each having a TFT switch 72 for reading out the charged charges as image signals are arranged in a two-dimensional manner. The radiation image detector using the TFT switch is provided for each pixel circuit row, and is provided for each of the pixel circuit columns and a large number of gate electrodes 73 to which a gate scanning signal for turning on and off the TFT switch 72 is output. And a plurality of data electrodes 74 to which the charge signal read from each pixel circuit 70 is output. The detailed layer configuration of each pixel circuit 70 is the same as the layer configuration described in JP-A-2002-26300.

For example, when the second grid 3 and the pixel circuit array (data electrode) are installed in parallel, one pixel circuit array corresponds to the main pixel size Dx described in the above embodiment. One pixel circuit row corresponds to the sub-pixel size Dy described in the above embodiment. Note that the main pixel size Dx and the sub-pixel size Dy can be set to 50 μm, for example.

Similarly to the above-described embodiment, when M striped images are used to generate a phase contrast image, M pixel circuit rows have one image resolution D in the sub-scanning direction of the phase contrast image. Thus, the self-image G 1 of the first grating 2 is tilted with respect to the second grating 3. As for the specific rotation angle of the self-image G1 of the first grating 2, the above equation (11), the above equation (24), the above equation (25), the above equation (34), It is calculated by the above equation (35) or the above equation (38).

In the above equation (11), for example, when the rotation angle θ of the self-image G1 of the first grating 2 is set with M = 5 and n = 1, one pixel circuit 70 in FIG. An image signal obtained by dividing the intensity modulation of one period of the self image into five can be detected, that is, five different fringe images depending on five pixel circuit rows connected to the five gate electrodes 73 shown in FIG. Each of the image signals can be detected. In FIG. 27, one second grating 3 and a self-image G1 are shown corresponding to one pixel circuit array, but in actuality, one pixel circuit array is shown. Many second gratings 3 and self-images G1 may be present, and FIG. 27 is not shown.

Therefore, the image signal read from the pixel circuit row connected to the first read line gate electrode G11 is acquired as the first stripe image signal M1, and the pixel circuit connected to the second read line gate electrode G12. The image signal read from the row is acquired as the second stripe image signal M2, and the image signal read from the pixel circuit row connected to the third read line gate electrode G13 is the third stripe image signal M3. The image signal read from the pixel circuit row connected to the fourth read line gate electrode G14 is acquired as the fourth stripe image signal M4 and connected to the fifth read line gate electrode G15. The image signal read from the pixel circuit row is acquired as the fifth fringe image signal M5.

Further, similarly to the above embodiment, in order to obtain five different fringe image signals for generating the second phase contrast image, the positions of the five pixel circuit rows constituting one pixel of the phase contrast image Are set to be shifted by two lines in the sub-scanning direction (Y direction), and image signals of the sixth to tenth fringe images for generating the second phase contrast image are acquired.

Specifically, the image signal read from the pixel circuit row connected to the third read line gate electrode G13 is acquired as the sixth stripe image signal M6 and connected to the fourth read line gate electrode G14. The image signal read from the pixel circuit row is acquired as the seventh stripe image signal M7, and the image signal read from the pixel circuit row connected to the fifth read line gate electrode G15 is the eighth stripe image signal M7. The image signal acquired as the image signal M8 and read from the pixel circuit row connected to the sixth reading line gate electrode G16 is acquired as the ninth fringe image signal M9, and is applied to the seventh reading line gate electrode G17. An image signal read from the connected pixel circuit row is acquired as a tenth fringe image signal M10.

Similar to the above embodiment, the first phase contrast image is generated based on the first to fifth fringe image signals, and the second phase contrast image is generated based on the sixth to tenth fringe image signals. Are generated, and a composite image is generated based on the first and second phase contrast images.

As described above, when the size of one pixel circuit 70 in the main scanning direction and the sub scanning direction is 50 μm, the image resolution in the main scanning direction of the phase contrast image is 50 μm, and the image resolution in the sub scanning direction is 50 μm × 5 = 250 μm.

The extending direction of the gate electrode and the data electrode of the radiographic image detector is not limited to the example shown in FIG. 27. For example, the radiographic image detector is arranged so that the gate electrode is in the vertical direction on the paper and the data line is in the horizontal direction on the paper. It may be arranged.
In addition, the self-image G1 of the first grating 2 and the second grating 3 may be rotated by 90 ° with respect to the arrangement of the radiation image detectors as shown in FIG. In this case, by acquiring the image signal read from the pixel circuit 70 arranged in the direction parallel to the gate electrode, the image signal constituting the different fringe images is acquired as in the above embodiment. Can do.
Further, the shape of each pixel and the shape of the pixel grid of the radiation image detector are not limited to a square, and may be, for example, a rectangle or a parallelogram. Alternatively, a pixel array in which the pixel grid is rotated 45 degrees may be used.
Even when the above-described radiation image detector using the TFT switch is used, the self-image G1 of the first grating 2 and the second grating 3 are made parallel to each other, and the first grating 2 Moire is generated by using the second grating 3 having an arrangement pitch different from the arrangement pitch of the self-image G1, or the second grating having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2. 3 may be used, and the self image G1 of the first grating 2 and the second grating 3 may be relatively inclined to generate moire.
Even when the above-described radiation image detector using the TFT switch is used, as described above, the periodic direction of the self-image G1 of the first grating 2 or the periodic direction of the second grating 3, and the radiation It is not always necessary to coincide with one of the orthogonal directions in which the pixel circuits 70 of the image detector are arranged. As described above, the image signals of the pixels arranged in the crossing direction other than the direction parallel or orthogonal to the periodic direction of the moire generated by the self-image G1 of the first grating 2 and the second grating 3 If it is the structure which can acquire (2), the relationship between the periodic direction of the 1st and 2nd grating |

lattices

2 and 3 and the arrangement direction of the pixel circuit 70 of a radiographic image detector may be made into any relationship.
As a radiation image detector using a CMOS sensor, for example, a pixel circuit 80 that generates visible light upon receiving radiation and photoelectrically converts the visible light to detect a charge signal is shown in FIG. As shown, a plurality of two-dimensional arrays can be used. The radiation image detector using the CMOS sensor is provided for each pixel circuit row, and includes a large number of gate electrodes 82 and reset electrodes from which drive signals for driving a signal readout circuit included in the pixel circuit 80 are output. 84, and a plurality of data electrodes 83 provided for each pixel circuit column and to which a charge signal read from the signal reading circuit of each pixel circuit 80 is output. The gate electrode 82 and the reset electrode 84 are connected to a row selection scanning unit 85 that outputs a drive signal to the signal readout circuit, and the data electrode 83 performs predetermined processing on the charge signal output from each pixel circuit. A signal processing unit 86 to be applied is connected.

As shown in FIG. 29, each pixel circuit 80 includes a lower electrode 806 formed above the substrate 800 via an insulating film 803, a photoelectric conversion film 807 formed on the lower electrode 806, and a photoelectric conversion film 807. An upper electrode 808 formed above, a protective film 809 formed on the upper electrode 808, and a radiation conversion film 810 formed on the protective film 809 are provided.

The radiation conversion film 810 is made of, for example, CsI: TI that emits light having a wavelength of 550 nm when irradiated with radiation. The thickness is preferably about 500 μm.

The upper electrode 808 is made of a conductive material that is transparent to the incident light because it is necessary to make light having a wavelength of 550 nm incident on the photoelectric conversion film 807. The lower electrode 806 is a thin film divided for each pixel circuit 80, and is formed of a transparent or opaque conductive material.

The photoelectric conversion film 807 is formed of, for example, a photoelectric conversion material that absorbs light having a wavelength of 550 nm and generates a charge corresponding to the light. As such a photoelectric conversion material, for example, an organic semiconductor, an organic material containing an organic dye, a material in which an inorganic semiconductor crystal having a direct transition type band gap and a large absorption coefficient, or the like is used alone or in combination.

Then, by applying a predetermined bias voltage between the upper electrode 808 and the lower electrode 806, one of the charges generated in the photoelectric conversion film 807 moves to the upper electrode 808 and the other moves to the lower electrode 806. .

In the substrate 800 below the lower electrode 806, a charge accumulating portion 802 for accumulating the charges transferred to the lower electrode 806 corresponding to the lower electrode 806, and the charges accumulated in the charge accumulating portion 802. And a signal readout circuit 801 for converting the signal into a voltage signal and outputting it.

The charge storage portion 802 is electrically connected to the lower electrode 806 by a conductive material plug 804 formed through the insulating film 803. The signal readout circuit 801 is configured by a known CMOS circuit.

When the radiation image detector using the CMOS sensor as described above is installed so that the second grid 3 and the pixel circuit array (data electrode) are parallel as shown in FIG. The pixel circuit column corresponds to the main pixel size Dx described in the above embodiment, and one pixel circuit row corresponds to the sub pixel size Dy described in the above embodiment. Note that the main pixel size Dx and the sub-pixel size Dy can be set to 10 μm, for example, in the case of a radiation image detector using a CMOS sensor.

Similarly to the above-described embodiment, when M striped images are used to generate a phase contrast image, M pixel circuit rows have one image resolution D in the sub-scanning direction of the phase contrast image. Thus, the self-image G 1 of the first grating 2 is tilted with respect to the second grating 3. As for the specific rotation angle of the self-image 1 of the first grating 2, the above equation (11), the above equation (24), the above equation (25), the above equation (34), It is calculated by the above equation (35) or the above equation (38).

In the above equation (11), for example, when the rotation angle θ of the self-image G1 of the first grating 2 is set with M = 5 and n = 1, one pixel circuit 80 in FIG. It is possible to detect an image signal obtained by dividing intensity modulation of one period of a self image into five, that is, five stripe images different from each other depending on five pixel circuit rows connected to the five gate electrodes 82 shown in FIG. Each of the image signals can be detected. In FIG. 30, one second grating 3 and the self-image G1 are shown corresponding to one pixel circuit array. However, in actuality, one pixel circuit array corresponds to one pixel circuit array. Many second gratings 3 and self-images G1 may exist, and FIG. 30 is not shown.

Accordingly, as in the case of the radiation image detector using the TFT switch, the image signal read from the pixel circuit row connected to the first read line gate electrode G11 is acquired as the first fringe image signal M1. An image signal read from the pixel circuit row connected to the second read line gate electrode G12 is acquired as the second stripe image signal M2, and is connected to the third read line gate electrode G13. The image signal read from is acquired as the third fringe image signal M3, and the image signal read from the pixel circuit row connected to the fourth read line gate electrode G14 is used as the fourth stripe image signal M4. The acquired image signal read from the pixel circuit row connected to the fifth read line gate electrode G15 is acquired as the fifth fringe image signal M5.

Similar to the above embodiment, the first phase contrast image is generated based on the first to fifth fringe image signals, and the second phase contrast image is generated based on the sixth to tenth fringe image signals. Are generated, and a composite image is generated based on the first and second phase contrast images.
As in the case of the radiation image detector using the TFT switch, the extending direction of the gate electrode and the data electrode of the radiation image detector is not limited to the example shown in FIG. You may make it arrange | position a radiographic image detector so that a data line may become a paper surface horizontal direction.
Further, the self-image G1 of the first grating 2 and the second grating 3 may be rotated by 90 ° with respect to the arrangement of the radiation image detectors as shown in FIG. In this case, by acquiring the image signals read from the pixel circuits 80 arranged in the direction parallel to the gate electrode, the image signals constituting the different fringe images are acquired as in the above embodiment. Can do.
Further, the shape of each pixel and the shape of the pixel grid of the radiation image detector are not limited to a square, and may be, for example, a rectangle or a parallelogram. Alternatively, a pixel array in which the pixel grid is rotated 45 degrees may be used.
Similarly to the case of using the radiation image detector using the TFT switch described above, the self-image G1 of the first grating 2 and the second grating 3 are made parallel to each other, and the first grating 2 is used. Moire is generated using the second grating 3 having an arrangement pitch different from the arrangement pitch of the self-image G1, or the second arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2 is used. While using the grating 3, the moire may be generated such that the self-image G 1 of the first grating 2 and the second grating 3 are relatively inclined.
Similarly to the case of using the radiographic image detector using the TFT switch described above, the periodic direction of the self-image G1 of the first grating 2 or the periodic direction of the second grating 3, and the pixel circuit of the radiographic image detector It is not always necessary to coincide with any one of the orthogonal directions in which 70 is arranged. As described above, the image signals of the pixels arranged in the crossing direction other than the parallel or orthogonal direction to the periodic direction of the moire generated by the self-image G1 of the first grating 2 and the second grating 3 If it is the structure which can acquire, the relationship between the periodic direction of the 1st and 2nd grating |

lattices

2 and 3 and the arrangement direction of the pixel circuit 80 of a radiographic image detector may be made into any relationship.

As described above, when the size of one pixel circuit 80 in the main scanning direction and the sub scanning direction is 10 μm, the image resolution in the main scanning direction of the phase contrast image is 10 μm, and the image resolution in the sub scanning direction is 10 μm × 5 = 50 μm.

As described above, a radiographic image detector using a TFT switch or a radiographic image detector using a CMOS sensor can be used. However, since these radiographic image detectors have square pixels, the present invention is not limited thereto. When applied, the resolution in the sub-scanning direction is worse than the resolution in the main scanning direction. On the other hand, in the optical reading type radiographic image detector described in the first and second embodiments, the resolution Dx is limited in the main scanning direction by the width of the linear electrode (direction perpendicular to the extending direction). However, in the sub-scanning direction, the resolution Dy is a product of the width of the reading light of the linear reading light source 50 in the sub-scanning direction, the accumulation time of the charge amplifier 200 per line and the moving speed of the linear reading light source 50. It will be decided. Both the main and sub resolutions are typically several tens of μm, but it is possible to increase the sub scanning direction resolution while maintaining the main scanning direction resolution. For example, it can be realized by reducing the width of the linear reading light source 50 or slowing the moving speed, and the radiation image detector of the optical reading system described in the first and second embodiments is more advantageous. It is a simple configuration.

In addition, since a plurality of fringe image signals can be acquired in one shooting, not only the semiconductor detector that can be used immediately and repeatedly as described above, but also a stimulable phosphor sheet or silver salt film can be used. can do. In this case, the reading pixel when reading the stimulable phosphor sheet or the developed silver salt film corresponds to the pixel in the claims.

The basic configuration of the radiation phase imaging apparatus of the present invention has been described above. Next, a specific system configuration using this basic configuration will be described. In the system described below, all the embodiments described above can be used.

The X-ray imaging system 100 shown in FIGS. 31 and 32 is obtained by applying the radiation phase imaging apparatus of the above embodiment to an X-ray diagnostic apparatus that images a subject H in a standing position.

Specifically, the X-ray imaging system 100 includes a radiation source 1 that irradiates a subject H with X-rays, and an X-ray that is disposed opposite to the radiation source 1 and is emitted from the radiation source 1 and transmitted through the subject H. The imaging unit 12 that detects and generates image data, controls the exposure operation of the radiation source 1 and the imaging operation of the imaging unit 12 based on the operation of the operator, and calculates the image signal acquired by the imaging unit 12 And a console 13 for processing to generate a phase contrast image.

The radiation source 1 is held movably in the vertical direction (X direction) by an X-ray source holding device 14 suspended from the ceiling. The photographing unit 12 is held by a standing stand 15 installed on the floor so as to be movable in the vertical direction.

The radiation source 1 includes an X-ray tube 18 that generates X-rays according to a high voltage applied from the high voltage generator 16 and an X-ray emitted from the X-ray tube 18 based on the control of the X-ray source control unit 17. It is comprised from the collimator unit 19 provided with the movable collimator 19a which restrict | limits an irradiation field so that the part which does not contribute to the test | inspection area | region of the subject H among the lines may be shielded. The X-ray tube 18 is of an anode rotating type, and emits an electron beam from a filament (not shown) as an electron emission source (cathode) and collides with a rotating anode 18a rotating at a predetermined speed, thereby causing X-rays. Is generated. The colliding portion of the rotating anode 18a with the electron beam becomes the X-ray focal point 18b.

The X-ray source holding device 14 includes a carriage unit 14a configured to be movable in a horizontal direction (Z direction) by a ceiling rail (not shown) installed on the ceiling, and a plurality of support column units 14b connected in the vertical direction. It consists of. The carriage unit 14a is provided with a motor (not shown) that extends and contracts the support column unit 14b to change the position of the radiation source 1 in the vertical direction.

The standing stand 15 includes a main body 15a installed on the floor, and a holding portion 15b that holds the photographing unit 12 is attached to be movable in the vertical direction. The holding portion 15b is connected to an endless belt 15d that is suspended between two pulleys 15c that are spaced apart in the vertical direction, and is driven by a motor (not shown) that rotates the pulley 15c. This motor drive is controlled by the control device 20 of the console 13 to be described later based on the setting operation by the operator.

Further, the standing stand 15 is provided with a position sensor (not shown) such as a potentiometer that detects the position of the photographing unit 12 in the vertical direction by measuring the movement amount of the pulley 15c or the endless belt 15d. . The detection value of this position sensor is supplied to the X-ray source holding device 14 by a cable or the like. The X-ray holding device 14 expands and contracts the support column 14 b based on the supplied detection value, and moves the radiation source 1 so as to follow the vertical movement of the imaging unit 12.

The console 13 is provided with a control device 200 including a CPU, a ROM, a RAM, and the like. The control device 200 includes an input device 201 through which an operator inputs a photographing instruction and the content of the instruction, and an arithmetic processing unit 202 that performs arithmetic processing on the image signal acquired by the photographing unit 12 to generate a phase contrast image and a composite image. An image storage unit 203 for storing a phase contrast image and a composite image, a monitor 204 for displaying the composite image and the like, and an interface (I / F) 205 connected to each unit of the X-ray imaging system 100 via a bus 206 Connected through. The arithmetic processing unit 202 corresponds to the phase contrast image generation unit 5 described in the above embodiment.

As the input device 201, for example, a switch, a touch panel, a mouse, a keyboard, or the like can be used. By operating the input device 201, X-ray imaging conditions such as X-ray tube voltage and X-ray irradiation time, imaging timing, and the like. Is entered. The monitor 204 includes a liquid crystal display and displays characters such as X-ray imaging conditions and a phase contrast image under the control of the control device 200.

The imaging unit 12 is provided with the first grating 2, the second grating 3, and the radiation image detector 4 described in the above embodiment. The radiation image detector 4 is arranged so that its detection surface is orthogonal to the optical axis A of X-rays emitted from the radiation source 1. Further, as described in the above embodiment, the first grid 2 and the second grid 3 are installed such that the extending directions of the

members

22 and 23 are relatively inclined.

Next, an X-ray imaging system 110 shown in FIG. 33 is obtained by applying the radiation phase imaging apparatus of the above embodiment to an X-ray diagnostic apparatus that images a subject H in a prone state.

The X-ray system 110 includes a bed 61 on which the subject H is placed in addition to the radiation source 1 and the imaging unit 12 of the X-ray imaging system 100. Since the radiation source 1 and the imaging unit 12 have the same configuration as that of the X-ray imaging system 100, the same reference numerals as those of the X-ray imaging system 100 are given to the respective components. Only differences from the X-ray imaging system 100 will be described below. Since other configurations and operations are the same as those of the X-ray imaging system 100, description thereof is omitted.

The X-ray imaging system 110 is attached to the lower surface side of the top plate 62 so that the imaging unit 12 faces the radiation source 1 through the subject H. On the other hand, the radiation source 1 is held by an X-ray source holding device 14, and the X-ray irradiation direction is set downward by an angle changing mechanism (not shown) of the radiation source 1. In this state, the radiation source 1 irradiates the subject H lying on the top plate 62 of the bed 16 with X-rays. The X-ray source holding device 14 adjusts the distance from the X-ray focal point 18b to the detection surface of the radiation image detector 3 by moving the radiation source 1 up and down by extending and contracting the support 14b. be able to.

For example, when the configuration of the radiological phase imaging apparatus of the second embodiment is adopted as the configuration of the imaging unit 12, the distance between the grating 2 and the radiographic image detector 3 may be shortened. In addition, since the thickness can be reduced, the leg 63 supporting the top plate 62 of the bed 61 can be shortened, and the position of the top plate 62 can be lowered. For example, it is preferable that the imaging unit 12 is thinned and the top plate 62 is positioned high enough to allow the subject H to sit down (for example, about 40 cm above the floor). In addition, it is preferable to lower the position of the top plate 62 in order to secure a sufficient distance from the radiation source 1 to the imaging unit 12.

Contrary to the positional relationship between the radiation source 1 and the imaging unit 12, the radiation source 1 is attached to the bed 61, and the imaging unit 12 is installed on the ceiling side, so that the subject H is photographed in the supine position. It is also possible.

As in the case of the X-ray imaging system 110, it is possible to photograph the lumbar vertebrae, the hip joints, etc., in which the subject H is difficult to shoot, by enabling the position contrast imaging of the phase contrast image. In addition, by using an appropriate fixture for fixing the subject H to the bed 61, it is possible to reduce deterioration of the phase contrast image due to body movement.

Next, the X-ray imaging system 120 shown in FIGS. 34 and 35 is obtained by applying the radiation phase imaging apparatus of the above embodiment to an X-ray diagnostic apparatus that images the subject H in a standing position and a standing position. It is.

In the X-ray system 110, the radiation source 1 and the imaging unit 12 are held by a turning arm 121. The turning arm 121 is connected to the base 122 so as to be turnable. Since the radiation source 1 and the imaging unit 12 have the same configuration as that of the X-ray imaging system 100, the same reference numerals as those of the X-ray imaging system 100 are given to the respective components. Only differences from the X-ray imaging system 100 will be described below. Since other configurations and operations are the same as those of the X-ray imaging system 100, description thereof is omitted.

The swivel arm 121 includes a U-shaped portion 121a having a substantially U-shape and a linear straight portion 121b connected to one end of the U-shaped portion 121a. The photographing part 12 is attached to the other end of the U-shaped part 121a. A first groove 123 is formed in the linear portion 121b along the extending direction, and the radiation source 1 is slidably attached to the first groove 123. The radiation source 1 and the imaging unit 12 are opposed to each other, and the distance from the X-ray focal point 18b to the detection surface of the radiation image detector 3 is adjusted by moving the radiation source 1 along the first groove 123. be able to.

In addition, the base 172 is formed with a second groove 124 extending in the vertical direction. The swivel arm 121 is movable in the vertical direction along the second groove 124 by a coupling mechanism 175 provided at a connection portion between the U-shaped portion 121a and the linear portion 121b. Further, the turning arm 121 can be turned around the rotation axis C along the y direction by the connecting mechanism 125. 35, the swivel arm 121 is rotated 90 ° clockwise around the rotation axis C from the standing position shown in FIG. 35, and the imaging unit 12 is placed under the bed (not shown) on which the subject H is placed. By arranging, it is possible to shoot the supine position. Note that the turning arm 121 is not limited to 90 ° rotation, and can rotate at any angle, and shooting in a direction other than standing-up shooting (horizontal direction) and lying-down shooting (vertical direction). Is possible.

In the X-ray imaging system 120, the imaging unit 12 is arranged in the U-shaped part 121a, and the radiation source 1 is arranged in the linear part 121b. However, like the X-ray diagnostic apparatus using a so-called C-arm. In addition, the imaging unit 12 may be disposed at one end of the C arm, and the radiation source 1 may be disposed at the other end.

Next, the mammography apparatus 130 shown in FIGS. 36 and 37 is obtained by applying the radiation phase image imaging apparatus of the above embodiment to mammography (X-ray mammography).

The mammography apparatus 130 is an apparatus that captures a phase contrast image of the breast B as a subject. The mammography apparatus 130 is disposed at the other end of the support 131 and the X-ray source storage section 132 disposed at one end of the support 131 that is pivotally connected to a base (not shown). An imaging table 133 and a compression plate 134 configured to be movable in the vertical direction with respect to the imaging table 133 are provided.

The X-ray source storage unit 132 stores the radiation source 1, and the imaging table 133 stores the imaging unit 12. The radiation source 1 and the imaging unit 12 are arranged to face each other. The compression plate 134 is moved by a compression plate moving mechanism (not shown), and the breast B is sandwiched between the imaging table 133 and compressed. The X-ray imaging described above is performed in this compressed state.

Since the radiation source 1 and the imaging unit 12 have the same configuration as that of the X-ray imaging system 100, the same reference numerals as those of the X-ray imaging system 100 are given to the respective components. Since other configurations and operations are the same as those of the X-ray imaging system 100, description thereof is omitted.

Next, a modification of the mammography device is shown. A mammography apparatus 140 shown in FIG. 38 is different from the mammography apparatus 130 only in that the first grating 2 is disposed between the radiation source 1 and the compression plate 134. The first grid 2 is stored in a grid storage unit 91 connected to the support unit 131. The imaging unit 92 includes the second grating 3 and the radiation image detector 4 without including the first grating 2.

Thus, even when the subject (breast) B is located between the first grating 2 and the radiation image detector 4, the self-image of the first grating 2 detected by the radiation image detector 4. G1 is deformed by the subject B. Therefore, even in this case, the radiation image detector 3 can detect the fringe image modulated due to the subject B. That is, even with the configuration of the mammography apparatus 140, a phase contrast image of the subject B can be obtained based on the principle described above.

Note that the configuration in which the subject is arranged between the first grating 2 and the second grating 3 is not limited to the mammography apparatus, and can be applied to other X-ray imaging systems.

Next, in FIG. 39, a mammography apparatus 150 capable of enlarging the subject B is shown. The mammography apparatus 150 includes an interlocking mechanism 151 that moves the X-ray source storage unit 132 and the imaging unit 12 in an interlocking manner. The interlocking mechanism 151 is controlled by the control device 200 described above, and the X-ray source storage unit 132 and the imaging unit 12 are moved to the Z direction while the relative positions of the radiation source 1, the grating 2, and the radiation image detector 3 are kept the same. Move in the direction.

The position of the subject B is fixed by the imaging stand 133 and the compression plate 134. By moving the X-ray source storage unit 132 and the imaging table 12 downward, the subject B approaches the radiation source 11 and the subject B is magnified. This enlargement ratio can be input from the input device 201 described above. When an enlargement factor is input from the input device 201, the control device 200 controls the interlocking movement mechanism 151 so that the distance from the subject B to the imaging stage 133 is a distance corresponding to the enlargement factor. The storage unit 132 and the photographing unit 12 are moved.

For example, in the diagnosis of breast cancer, the positional relationship with calcification, mass, and mammary gland structure is important, and when it is desired to diagnose a suspicious lesion more precisely, it is necessary to increase the resolution of the image. The magnified photography used is effective. Since other configurations and operations are the same as those of the mammography apparatus 130, description thereof will be omitted.

Next, FIG. 40 shows a mammography apparatus 160 according to another embodiment that enables enlargement of the subject B. The mammography apparatus 160 includes a detector moving mechanism 161 that moves the radiation image detector 4 in the Z direction. As the radiation image detector 4 is moved away from the radiation source 1, the image incident on the radiation image detector 4 spreads, and the subject B is magnified. The detector moving mechanism 161 is controlled by the control device 200 described above, and moves the radiation image detector 4 to a position corresponding to the enlargement ratio input from the input device 201 described above. Since other configurations and operations are the same as those of the mammography apparatus 130, description thereof will be omitted.

Next, the X-ray imaging system 170 shown in FIG. 41 differs from the X-ray imaging system 100 in that a multi-slit 173 is provided in the collimator unit 172 of the radiation source 121. Since other configurations are the same as those of the X-ray imaging system 100, description thereof will be omitted. The effects of the multi-slit 173 and the configuration conditions thereof are as described above.

In each of the above systems, a single composite image is obtained by positioning a radiation source and an imaging unit and performing a series of imaging, but the radiation source and the imaging unit are connected to the optical axis of the X-ray. A plurality of composite images partially overlapping each other may be obtained by performing the series of photographing a plurality of times while being translated in any direction orthogonal to A. In this case, it is possible to generate a long image that is larger than the size of the detection surface of the radiation image detector by connecting the obtained composite images.

For example, in the above-described standing X-ray imaging system 100, as shown in FIG. 42, the X-ray source holding device 14 and the standing stand 15 are controlled, and the radiation source 1 and the imaging unit 12 are interlocked. By moving up and down, parallel movement in the X direction orthogonal to the optical axis A of the X-ray is possible.

Further, in the X-ray imaging system 120 capable of the above-described standing position imaging and standing position imaging, the above-mentioned parallel movement is possible by moving the turning arm 121 up and down along the groove 124 of the base 122. In addition, in the case of the X-ray imaging system 110, since there is no mechanism for translating the radiation source 1 and the imaging unit 12, a mechanism for translating in the direction orthogonal to the optical axis A may be provided as described above. .

Furthermore, it is also preferable to generate a long image in which the composite image is connected in the two-dimensional direction by performing two-dimensional movement in two directions, the X direction and the Y direction, with the radiation source and the imaging unit.

In the above embodiment, an example in which a two-dimensional composite image is acquired is shown. Synthetic images composed of phase contrast images enable the visualization of soft tissues such as muscle tendons and blood vessels that were difficult to visualize with conventional X-ray imaging. It is possible that this will occur.

Therefore, the present invention can also be applied to a radiation phase CT apparatus that acquires a three-dimensional image so as to separate the obstacle shadow and enable accurate diagnosis and interpretation. Specifically, as shown in FIG. 43, the object 10 disposed between the radiation source 1 and the imaging unit 12 including the first and

second gratings

2 and 3 and the radiation image detector 4 is placed on the subject 10. On the other hand, a rotational movement mechanism 170 that rotates the radiation source 1 and the imaging unit 12 in the direction of the arrow in FIG. A three-dimensional image of the subject 10 may be configured by the three-dimensional image configuration unit 171 based on the composite image. The method for constructing a three-dimensional image based on a plurality of images is the same as that of a conventional X-ray CT apparatus. Further, even when applied to a radiation phase CT apparatus, the subject 10 may be disposed between the first grating 2 and the second grating 3. Further, instead of the radiation source 1, a radiation source having the multi-slit described above may be used.

In addition, it is also preferable to apply the present invention to stereo photography for obtaining a stereo image that can be stereoscopically viewed so as to separate the obstacle shadow and enable accurate diagnosis and interpretation. Specifically, as shown in FIG. 44, a position changing mechanism 190 is provided for changing the position of the radiation source 1 with respect to the subject H and the imaging unit 12 in the arrow direction (Y direction) in FIG. Based on the two synthesized images of the subject H obtained by the imaging unit 12 at the first and second positions changed by the above, the stereo image construction unit 191 constructs a stereo image of the subject H.

It is preferable to adjust the collimator 19a so that the X-ray irradiation region of the radiation source 1 coincides with the image receiving unit of the imaging unit 12 at the first and second positions. It is also preferable to match the X-ray irradiation area with the image receiving section by changing the angle of the radiation source 1 between the first position and the second position (so-called swinging).

The method for constructing a stereo image based on the two images is the same as that of a conventional stereo photographing apparatus. In this configuration as well, the subject H may be disposed between the first lattice 2 and the second lattice 3.

In addition, according to this structure, since the position of the radiation source 1 is changed along the Y direction (the extending direction of the

members

22 and 32 of the first and second gratings 2 and 3), the position of the radiation source 1 is changed. There is an advantage that the vignetting of radiation due to the change does not occur.

According to the system as described above, the phase contrast image can be generated by one shooting as compared with the method of generating a phase contrast image by performing a plurality of shootings by translating the conventional grating. Further, it is possible to prevent deterioration of the image quality of the phase contrast image due to the vibration of the apparatus, and further, the apparatus can be simplified and the cost can be reduced because a highly accurate lattice moving mechanism is unnecessary.

In addition, since a plurality of phase contrast images are generated as described above, and a composite image is generated based on the generated plurality of phase contrast images, for example, an edge having a gentle slope is clearly displayed on the composite image. Can appear.

Further, in the above embodiment, an image that has been difficult to draw can be obtained by acquiring a phase contrast image. However, since conventional X-ray diagnostic imaging is based on an absorption image, Corresponding absorption images can help interpretation. For example, it is effective to supplement the portion where the absorption image cannot be expressed by superimposing the absorption image and the phase contrast image by appropriate processing such as weighting, gradation, and frequency processing, with the information of the phase contrast image.

However, taking an absorption image separately from a phase contrast image makes it difficult to superimpose a good image due to the shift of the limbs between the phase contrast image and the absorption image. Increasing the burden on the subject. In recent years, small-angle scattered images have attracted attention in addition to phase contrast images and absorption images. The small-angle scattered image can express tissue properties resulting from the fine structure inside the subject tissue, and is expected as a new expression method for image diagnosis in fields such as cancer and cardiovascular diseases.

Therefore, the arithmetic processing unit 202 is further provided with an absorption image generation unit that generates an absorption image and a small angle scattering image generation unit that generates a small angle scattering image from a plurality of striped images acquired to generate a phase contrast image. May be. The arithmetic processing unit 202 can generate at least one of a phase contrast image, a small angle scattered image, and an absorption image.

The absorption image generation unit generates an absorption image by averaging the pixel signal Ik (x, y) obtained for each pixel with respect to k as shown in FIG. is there. The average value may be calculated by simply averaging the pixel signal Ik (x, y) with respect to k. However, when M is small, the error increases, so the pixel signal Ik (x, y) After fitting y) with a sine wave, an average value of the fitted sine wave may be obtained. In addition to a sine wave, a rectangular wave or a triangular wave shape may be used.

Further, the generation of the absorption image is not limited to the average value, and an addition value obtained by adding the pixel signal Ik (x, y) with respect to k can be used as long as the amount corresponds to the average value.

Further, a method for generating an absorption image by calculating an average value of the pixel signal Ik (x, y) as described above and imaging it will be described more specifically. For example, as shown on the left side of FIG. If the pixel signal Ik (x, y) is detected by each sub-pixel, the pixel signal of the absorption image can be calculated based on the following equation (39), but the absorption image is as shown on the right side of FIG. In order to obtain an absorption image that is compressed by 5 pixels and is easy to see, it is necessary to extend it to 5 pixels in the y direction.

Therefore, for example, when a pixel signal Ik (x, y) as shown on the left side of FIG. 47 is detected by each subpixel, an absorption image is generated by calculating a moving average of the pixel signals of five subpixels. You may do it. That is, the absorption image may be calculated based on the following formula (40) to generate an absorption image as shown on the right side of FIG.

As shown in FIG. 48, even if a set of 5 pixels are shifted by one pixel, the cycle of the sin curve is exactly one cycle, so that the center of amplitude can be obtained by taking an average value. The average value of the amplitude can be obtained from the set of I (1,1) to I (1,5) and the set of I (1,2) to I (1,6).

The small-angle scattered image generation unit generates a small-angle scattered image by calculating and imaging the amplitude value of the pixel signal Ik (x, y) obtained for each pixel. The amplitude value may be calculated by obtaining a difference between the maximum value and the minimum value of the pixel signal Ik (x, y). However, when M is small, the error increases, and therefore the pixel signal Ik. After fitting (x, y) with a sine wave, the amplitude value of the fitted sine wave may be obtained. In addition, the generation of the small-angle scattered image is not limited to the amplitude value, and a dispersion value, a standard deviation, or the like can be used as an amount corresponding to the variation centered on the average value.

The phase contrast image is based on the X-ray refraction component in the periodic arrangement direction (X direction) of the

members

22 and 32 of the first and

second gratings

2 and 3, and the extending direction (Y The direction (refractive component) is not reflected. That is, a part outline along a direction intersecting the X direction (or Y direction when orthogonal) is drawn as a phase contrast image based on a refractive component in the X direction via a lattice plane that is an XY plane. A part contour that does not intersect the direction and extends along the X direction is not drawn as a phase contrast image in the X direction. That is, there is a part that cannot be depicted depending on the shape and orientation of the part to be the subject H. For example, when the direction of the load surface of the articular cartilage such as the knee is aligned with the Y direction in the XY direction which is the in-plane direction of the lattice, the part contour near the load surface (YZ surface) substantially along the Y direction is sufficiently depicted. However, it is considered that the depiction of tissue around the cartilage (tendon, ligament, etc.) that intersects the load surface and extends substantially along the X direction is insufficient. By moving the subject H, it is possible to recapture a region that is not fully visualized, but in addition to increasing the burden on the subject H and the operator, position reproducibility with the recaptured image is ensured. There is a problem that it is difficult to do.

Therefore, as another example, as shown in FIG. 49, the first and second imaginary lines (X-ray optical axis A) orthogonal to the centers of the lattice planes of the first and

second gratings

2 and 3 are centered. 2 is provided with a rotation mechanism 180 that rotates the

grids

2 and 3 at an arbitrary angle from the first orientation as shown in the upper diagram of FIG. 49 to have the second orientation as shown in the lower diagram of FIG. It is also preferable that the first and second phase contrast images and the composite image are generated in each of the first direction and the second direction.

In this way, the above-described problem of position reproducibility can be eliminated. 49 shows the first direction of the first and

second gratings

2 and 3 such that the extending direction of the member 32 of the second grating 3 is the direction along the Y direction. In the lower diagram of 49, the first and

second gratings

2, 3 are rotated 90 degrees from the state of the upper diagram of FIG. 49 so that the extending direction of the member 32 of the second grating 3 is in the direction along the X direction. However, if the inclination relation between the first grating 2 and the second grating 3 is maintained, the rotation angle of the first and

second gratings

2 and 3 is arbitrary. It is. Further, in addition to the first direction and the second direction, two or more rotation operations such as the third direction and the fourth direction are performed, and the first and second phase contrast images in the respective directions. And a composite image may be generated.

The rotation mechanism 180 may be configured to rotate only the first and

second gratings

2 and 3 separately from the radiation image detector 4, or the first and

second gratings

2 and 2. 3 and the radiation image detector 4 may be rotated together. Furthermore, the generation of the phase contrast image in the first and second directions using the rotation mechanism 180 can be applied to any of the above examples. When the multi-slit described above is provided, the multi-slit may be rotated in the same direction as the first grating 2.
FIG. 49 shows an example in which the first grating 2 and the second grating 3 are relatively inclined. However, the present invention is not limited to this, and the first grating at the position of the second grating 3 described above is used. A mode in which the pitch of the self-image G1 of the grating 2 and the pitch of the second grating 3 are different from each other is also applicable, and the first grating 2 and the second grating 3 having such a relationship are the same as described above. You may make it rotate 90 degree. Also in this case, the first grating 2 and the second grating 3 are relatively inclined, and the pitch of the self-image G1 of the first grating 2 at the position of the second grating 3 and the second grating 3 The pitch may be different from the pitch.

Further, as described above, instead of rotating the first and

second gratings

2 and 3 which are one-dimensional gratings, the

members

2 and 3 of the first and

second gratings

2 and 2 are set to 2 respectively. It is good also as a structure of the two-dimensional lattice extended in the dimension direction. FIG. 50 shows a self-image G1 of the first grating 2 configured as a two-dimensional grating and a second grating 3 configured as a two-dimensional grating. The rotation angle θ of the first grating 2 with respect to the second grating 3 is the same as in the above embodiment, the above equation (11), the above equation (24), the above equation (25), the above equation (34), It is set based on the equation (35) or the above equation (38).

In this case, the above equation (11), the above equation (24), the above equation (25), the above equation (34), the above equation (35), or the above equation (38) is defined for the subpixel size. However, not only the subpixel size but also the pixel size in the direction orthogonal to the subpixel size, the above equation (11), the above equation (24), the above equation (25), the above equation (34), the above equation Θ is set so as to satisfy (35) or the above equation (38). For example, if the number of fringe images for obtaining a phase contrast image is M, M pixel sizes Dx in the X direction as well as the Y direction are one image resolution D in the main scanning direction of the phase contrast image. Thus, the first grating 2 is tilted with respect to the second grating 3, and different stripe images are acquired for each pixel Dx also in the X direction.

By configuring in this way, phase contrast images in the first direction and the second direction can be obtained with one imaging as compared with a configuration in which a one-dimensional grating is rotated. There is no influence of the apparatus vibration and the position reproducibility between the phase contrast images in the first and second directions is better. Further, by eliminating the rotation mechanism, the apparatus can be simplified and the cost can be reduced.
FIG. 50 shows an example in which the first grating 2 and the second grating 3 configured by a two-dimensional grating are relatively inclined, but the present invention is not limited to this, and the second grating 3 described above A mode in which the pitch of the self-image G1 of the first grating 2 at the position and the pitch of the second grating 3 are different from each other is also applicable. In this case, for example, the pitch in the X direction of the self-image G1 of the first grating 2 at the position of the second grating 3 is different from the pitch in the X direction of the second grating 3, and the self-image G1 The pitch in the Y direction and the pitch in the Y direction of the second grating 3 are different from each other. Also in this case, the first grating 2 and the second grating 3 are relatively inclined, and the pitch of the self-image G1 of the first grating 2 at the position of the second grating 3 and the second grating 3 The pitch may be different from the pitch.

In the radiation phase imaging apparatus of the first and second embodiments, two gratings of the first grating 2 and the second grating 3 are used, but the function of the second grating 3 is used. Can be prevented from using the second grating 3. Hereinafter, the configuration of the radiation image detector having the function of the second grating 3 will be described.

The radiation image detector having the function of the second grating 3 detects a self-image of the first grating 2 formed by the first grating 2 by passing the radiation through the first grating 2 and A fringe image is generated by intensity modulation of the self-image by accumulating charge signals corresponding to the self-image in a charge storage layer divided into a lattice shape, which will be described later, and outputting the generated fringe image as an image signal It is.

51A is a perspective view of the radiation image detector 400 having the function of the second grating 3, FIG. 51B is a cross-sectional view of the XZ plane of the radiation image detector shown in FIG. 51A, and FIG. 5151C is the radiation image detector shown in FIG. FIG.

As shown in FIGS. 51A to 51C, the radiation image detector 400 is a first electrode layer 41 that transmits radiation, and is used for recording that generates charges when irradiated with radiation that has passed through the first electrode layer 41. Among the charges generated in the photoconductive layer 42 and the recording photoconductive layer 42, a charge storage layer that acts as an insulator for charges of one polarity and acts as a conductor for charges of the other polarity 43, a photoconductive layer for reading 44 that generates charges when irradiated with reading light, and a second electrode layer 45 are laminated in this order. Each of the above layers is formed in order from the second electrode layer 45 on the glass substrate 46.

The radiation image detector 400 having the function of the second grating 3 includes a first electrode layer 41, a recording photoconductive layer 42, a charge storage layer 43, a reading photoconductive layer 44, and a second electrode layer 45. These materials are the same as those of the first electrode layer 41, the recording photoconductive layer 42, the charge storage layer 43, the reading photoconductive layer 44, and the second electrode layer 45 of the radiation image detector 4 in the above embodiment. is there.

And the radiation image detector 400 having the function of the second grating 3 is different in the shape of the charge storage layer 43 from the radiation image detector 4 of the first and second embodiments. As shown in FIGS. 51A to 51C, the charge storage layer 43 of the radiation image detector 400 is a line that is parallel to the extending direction of the transparent linear electrode 45a and the light shielding linear electrode 45b of the second electrode layer 45. It is divided into shapes.

The charge storage layer 43 is divided at a pitch finer than the arrangement pitch of the transparent linear electrodes 45a or the light shielding linear electrodes 45b. The arrangement pitch P ₂ ′ is the same as that of the second lattice 3 of the above embodiment. It is the same as conditions. That is, when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation, it is determined so as to satisfy the relationship of the following expression (41), and the first grating 2 is 180 ° In the case of a phase modulation type grating that provides phase modulation, it is determined so as to satisfy the relationship of the following equation (42). In the following equations (41) and (42), P ₁ is the grating pitch of the first grating 2, Z ₁ is the distance from the focal point of the radiation source 1 to the first grating 2, and Z ₂ ′ is the first grating. 2 to the detection surface of the radiation image detector 400.

The charge storage layer 43 is formed with a thickness of 2 μm or less in the stacking direction (Z direction).

The charge storage layer 43 can be formed, for example, by resistance heating vapor deposition using the above-described material and a mask formed of a metal mask or a fiber having a hole in a metal plate. Further, it may be formed using photolithography.

Regarding the distance condition between the first grating 2 and the radiation image detector 400 for functioning as a Talbot interferometer, the radiation image detector 400 functions as the second grating 3. This is the same as the condition of the distance between the lattice 2 and the second lattice 3. In addition, as in the second embodiment, the first grating 2 projects incident radiation without diffracting, and the distance Z ₂ from the first grating 2 to the radiation image detector 400 is set to the Talbot interference distance. May be set independently of each other, or may be a distance satisfying the above equation (28).

Next, the operation of the radiation image detector 400 configured as described above will be described.

First, as shown in FIG. 52A, in a state where a negative voltage is applied to the first electrode layer 41 of the radiation image detector 400 by the high-voltage power supply 101, a self-image of the first lattice 2 formed by the Talbot effect is represented by G1. The carried radiation is irradiated from the first electrode layer 41 side of the radiation image detector 400.

The radiation applied to the radiation image detector 400 passes through the first electrode layer 41 and is applied to the recording photoconductive layer 42. Then, a charge pair is generated in the recording photoconductive layer 42 by the irradiation of the radiation, and the positive charge is combined with the negative charge charged in the first electrode layer 41 and disappears, and the negative charge is a latent image. Charges are accumulated in the charge accumulation layer 43 (see FIG. 52B).

Here, since the charge storage layer 43 is linearly divided at the arrangement pitch as described above, of the charges generated according to the self-image G1 of the first lattice 2 in the recording photoconductive layer 42, Only the charges that are present immediately below the charge storage layer 43 are trapped and stored by the charge storage layer 43, and other charges pass between the linear charge storage layers 43 and pass through the reading photoconductive layer 44. After that, it flows out to the transparent linear electrode 45a and the light shielding linear electrode 45b.

Of the charges generated in the recording photoconductive layer 42 in this way, only the charges in which the linear charge storage layer 43 exists immediately below are stored. By this action, the self-image G1 of the first grating 2 is intensity-modulated by superposition with the linear pattern of the charge storage layer 43, and the image signal of the fringe image reflecting the distortion of the wavefront of the self-image by the subject. Is stored in the charge storage layer 43. That is, the charge storage layer 43 performs the same function as the second lattice 3 of the above embodiment.

Then, as shown in FIG. 53, in the state where the first electrode layer 41 is grounded, the linear reading light L1 emitted from the linear reading light source 50 is irradiated from the second electrode layer 45 side. Is done. The reading light L1 passes through the transparent linear electrode 45a and is applied to the reading photoconductive layer 44, and the positive charge generated in the reading photoconductive layer 44 due to the irradiation of the reading light L1 is a latent image in the charge storage layer 43. The negative charge is combined with the positive charge charged on the light-shielding linear electrode 45b through the charge amplifier 200 connected to the transparent linear electrode 45a.

Then, when the linear reading light source 50 moves in the sub-scanning direction (Y direction), the radiation image detector 400 is scanned by the linear reading light L1, and each reading line irradiated with the linear reading light L1 is scanned. In addition, the image signals are sequentially detected by the above-described operation, and the detected image signals for each reading line are sequentially input and stored in the phase contrast image generation unit 5.

Then, the entire surface of the radiation image detector 400 is scanned with the reading light L 1, and the image signal of the entire frame is stored in the phase contrast image generation unit 5.

In the same manner as in the above embodiment, the first and second phase contrast images are generated based on the image signal stored in the phase contrast image generation unit 5, and the first phase contrast image and the second phase are generated. The contrast image and the contrast image are combined to generate a combined image.

In the radiation image detector 400 having the function of the second grating 3 described above, the recording photoconductive layer 42, the charge storage layer 43, and the reading photoconductive layer 44 are provided between the electrodes. However, this layer configuration is not necessarily required. For example, as shown in FIG. 54, the transparent linear electrode 45a and the light-shielding linear electrode of the second electrode layer are provided without providing the reading photoconductive layer 44. A linear charge storage layer 43 may be provided so as to be in direct contact with 45b, and a recording photoconductive layer 42 may be provided on the charge storage layer 43. The recording photoconductive layer 42 also functions as a reading photoconductive layer.

The radiation image detector 500 has a structure in which the charge storage layer 43 is provided directly on the second electrode layer 45 without the reading photoconductive layer 44, and the linear charge storage layer 43 is formed by vapor deposition. Therefore, the linear charge storage layer 43 can be easily formed. In the vapor deposition process, a metal mask or the like is used to selectively form a linear pattern. In the configuration in which the linear charge accumulation layer 43 is provided on the reading photoconductive layer 44, a step of setting a metal mask for forming the linear charge accumulation layer 43 by vapor deposition after vapor deposition of the reading photoconductive layer 44 is performed. Therefore, the reading photoconductive layer 44 is deteriorated or foreign matter is mixed between the photoconductive layers due to an operation in the air between the reading photoconductive layer 44 vapor deposition step and the recording photoconductive layer 42 vapor deposition step. May cause deterioration of quality. On the other hand, by adopting a structure in which the above-described reading photoconductive layer 44 is not provided, it is possible to reduce the operation in the air after vapor deposition of the photoconductive layer, thereby reducing the above-described concern about the quality deterioration.

The materials of the recording photoconductive layer 42 and the charge storage layer 43 are the same as those of the radiation image detector 400 described above. The linear configuration of the charge storage layer 43 is the same as that of the above-described radiation image detector.

Hereinafter, the operation of recording and reading out the radiation image of the radiation image detector 500 will be described.

First, as shown in FIG. 55A, in a state where a negative voltage is applied to the first electrode layer 41 of the radiation image detector 500 by the high-voltage power source 101, the radiation carrying the self-image G1 of the first grating 2 is radiation. Irradiation is performed from the first electrode layer 41 side of the image detector 4.

The radiation applied to the radiation image detector 4 passes through the first electrode layer 41 and is applied to the recording photoconductive layer 42. Then, a charge pair is generated in the recording photoconductive layer 42 by the irradiation of the radiation, and the positive charge is combined with the negative charge charged in the first electrode layer 41 and disappears, and the negative charge is a latent image. Charges are accumulated in the charge accumulation layer 43 (see FIG. 55B). Since the linear charge storage layer 43 in contact with the second electrode layer 45 is an insulating film, the charges reaching the charge storage layer 43 are captured there and go to the second electrode layer 45. Can't, and stays accumulated.

Also here, as in the case of the radiation image detector 400 described above, out of the charges generated in the recording photoconductive layer 42, only the charges in which the linear charge storage layer 43 exists immediately below are stored. By this action, the self-image G1 of the first lattice 2 is intensity-modulated by superimposition with the linear pattern of the charge storage layer 43, and a fringe image reflecting the distortion of the wavefront of the self-image G1 by the subject. A signal is accumulated in the charge accumulation layer 43.

Then, as shown in FIG. 56, in the state where the first electrode layer 41 is grounded, the linear reading light L1 emitted from the linear reading light source 50 is irradiated from the second electrode layer 45 side. The reading light L1 passes through the transparent linear electrode 45a and is irradiated to the recording photoconductive layer 42 in the vicinity of the charge storage layer 43, and positive charges generated by the irradiation of the reading light L1 are linear charge storage layer 43. Attracted to recombine. The other negative charge is attracted to the transparent linear electrode 45a, and the light shielding linear electrode is connected to the positive charge charged in the transparent linear electrode 45a and the charge amplifier 200 connected to the transparent linear electrode 45a. Combines with the positive charge charged in 45b. As a result, a current flows through the charge amplifier 200, and this current is integrated and detected as an image signal.

Further, in the above-described

radiographic image detectors

400 and 500, the charge storage layer 43 is formed by being completely separated into a linear shape. However, the present invention is not limited to this. As in 600, the lattice-shaped charge storage layer 43 may be formed by forming a linear pattern on a flat plate shape.

Even in the case where the

radiation image detectors

400, 500, and 600 having the function of the second grating 3 as described above are used, the first grating in the radiation phase imaging apparatus of the first and second embodiments is used. In the same manner as the direction in which the second self-image G1 extends and the direction in which the second grating 3 extends relatively, the direction in which the first image G1 extends in the first grating 2 and the radiation image detector 400, What is necessary is just to make it incline relatively with the extending | stretching direction of the linear charge storage layer 43 of 500,600.

Specifically, for example, the inclination θ of the extending direction of the self-image of the first lattice 2 with respect to the extending direction of the lattice structure of the charge storage layer 43 can be set to a value satisfying the following expression (43). The following formula (43) is obtained by setting the above formula (24) as θ1 = θ and θ2 = 0.

Here, P ₁ ′ is the lattice structure of the charge storage layer 43 and the pitch of the self-image of the first lattice 2 at the position of the charge storage layer 43, and D and n are the same as in the above equation (24).
In addition to the above equation (43), the self-image G1 of the first grating 2 and the

radiation image detectors

400 and 500 based on the above equation (11) or the above equation (25), as in the above embodiment. , 600 linear charge storage layer 43 may be inclined relative to each other. However, since L = Z ₁ + Z ₂ in the above equation (25), it is represented by the following equation (44).

Further, in the case where the extending direction of the self-image G1 of the first grating 2 and the extending direction of the linear charge storage layer 43 of the

radiation image detectors

400, 500, and 600 are relatively inclined as described above, a radiation image is obtained. first grating 2 of the self image G1 pitch _{P 1} 'and the grating pitch _{P 1} of the first grating 2 arrangement pitch _{P 2} of the lattice structure of the charge storage layer 43' and in the position of the

detector

400, 500, 600 Is satisfied when the first grating 2 is a phase modulation type grating or an amplitude modulation type grating that applies 90 ° phase modulation, and the first grating 2 is 180 ° phase modulation. In the case of a phase modulation type grating that gives the following equation (46): In the following equations (45) and (46), Z ₁ is the distance from the focal point of the radiation source 1 to the first grating 2, and Z ₂ ′ is the distance from the first grating 2 to the detection surface of the radiation image detector 400. Distance.

Even when the

radiation image detectors

400, 500, and 600 having the function of the second grating 3 are used, the above-described multi-slit is provided between the radiation source 1 and the first grating 2. Also good. In this case, the multi-slit grating pitch P ₃ needs to be set to satisfy the following equation (47), where Z ₃ is the distance from the multi-slit to the first grating 2. P ₁ ′ is an arrangement pitch of the self-image G1 of the first grating 2 at the position of the

radiation image detectors

400, 500, and 600, and Z ₂ ′ is the radiation image detector 400 from the first grating 2. , 500, 600 to the detection surface. In the case where a multi slit is provided, the above equation (45) and the above equation (46) are equations in which Z ₁ is replaced with Z ₃ (distance between the multi slit and the first lattice 2).

When the multi-slit is used as described above, the relative rotation angle θ between the stretching direction of the self-image G1 of the first lattice 2 and the stretching direction of the charge storage layer 43, and the self-image of the first lattice 2 The equation showing the relationship between the moire period T generated by G1 and the lattice pattern of the charge storage layer 43 and the subpixel size Dsub is the same as the equation (44). At this time, P ₁ ′ in the above equation (44) is the pitch of the self-image G1 of the first grating 2 at the position of the

radiation image detectors

400, 500, 600.

When the multi-slit described above is provided, the first lattice 2 and the charge storage layer 43 are arranged so that the extending directions of the lattice patterns are parallel to each other, and the lattice member 22 of the first lattice 2 and The extending direction of the lattice pattern of the charge storage layer 43 and the extending direction of the multi slits may be relatively inclined. With this configuration, the same fringe image signal as in the first and second embodiments can be acquired.
In addition, the first grid 2 and the linear charge storage layer 43 of the

radiation image detectors

400, 500, and 600 are not relatively inclined, for example, the extension direction and the line of the self-image G1 of the first grid 2 The charge storage layer 43 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first lattice 2 may be formed so that the extending direction of the charge storage layer 43 is parallel.
In the case of using the first lattice 2 and the charge storage layer 43 as described above, as in the first and second embodiments, an image signal representing a moire having a periodic direction in the X direction as shown in FIG. Can be detected. Therefore, for example, as shown by dotted squares in FIG. 20, if image signals of five pixels arranged in parallel to the moiré periodic direction are acquired, the first and second embodiments described above. Similarly to the above, it is possible to acquire image signals constituting five different fringe images.
When the charge storage layer 43 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2 is formed as described above, the

radiation image detectors

400, 500, 600 of the self-image G1 of the first grating 2 are formed. The relationship among the arrangement pitch P ₁ ′, the arrangement pitch P ₂ ′ of the charge storage layer 43, the moire period T, and the sub-pixel size Dsub is the first lattice in the first and second embodiments. Similarly to the relationship between 2 and the second grating 3, the following equation (48) may be satisfied. The following formula (48) is obtained by setting L = Z ₁ + Z ₂ in the above formula (35).

At this time, the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 at the position of the

radiation image detectors

400, 500, and 600 is a phase modulation type grating in which the first grating 2 applies 90 ° phase modulation. Alternatively, in the case of an amplitude modulation type grating, the following expression (49) is satisfied, and in the case where the first grating 3 is a phase modulation type grating giving 180 ° phase modulation, the above expression (50) is satisfied. do it. In the following equations (49) and (50), P ₁ is the arrangement pitch of the first grating 2, Z ₁ is the distance from the focal point of the radiation source 1 to the first grating 2, and Z ₂ ′ is the first grating 2 and radiation. This is the distance from the detection surface of the

image detector

400, 500, 600.

In the embodiment provided with the multi-slit described above, the charge storage layer 43 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first grating 2 can be used as described above. In the case of using the multi-slit also, _'the arrangement pitch P ₂ of the charge storage layer _43' arrangement pitch P ₁ of the first grating 2 self image G1 and the period T of the moire, the sub-pixel size Dsub is The above equation (48) may be satisfied.
At this time, the relational expression to be satisfied by the arrangement pitch P ₁ ′ of the self-image G1 of the first grating 2 is Z ₁ in the above expression (49) and the above expression (50) as Z ₃ (multi-slit and first It is necessary to satisfy the conditions expressed by the above formula (47).
In the above description, the arrangement pitch of the self-image G1 of the first grating 2 is different from the arrangement pitch of the charge storage layer 43. However, the arrangement pitch is not limited to this, and for example, radiation emitted from the radiation source 1 is used. Is a cone beam, as in the second grating 3 of the first and second embodiments, as shown in FIG. 22, the self-image G1 of the first grating 2 at the position of Z ₂ A charge storage layer 43 having the same arrangement pitch as the arrangement pitch is formed, and the

radiation image detectors

400, 500, and 600 having the charge storage layer 43 are made larger than Z ₂ (or although not shown, by arranging to move the Z ₂ in smaller position), or the arrangement pitch of the first grating 2 self image G1, which is enlarged and the array pitch of the charge storage layer 43 have different configuration. Even in this configuration, the above equation (48), the above equation (49), or the above equation (50) is satisfied, and when using a multi slit, the above equation (47) must be further satisfied. In these equations, P ₁ ′ is the arrangement pitch of the self-image G1 of the first grating 2 at the position of the

radiation image detectors

400, 500, and 600 after movement, Z ₂ ′, and the first grating 2 The distance to the

radiographic image detectors

400, 500, and 600 after the movement is read.
Further, as described above, the charge accumulation layer 43 having an arrangement pitch different from the arrangement pitch of the self-image G1 of the first lattice 2 is formed, and further, as described above, the self-image G1 and the charge accumulation of the first lattice 2 are accumulated. The layer 43 may be tilted relatively.
By adopting such a configuration, as in the first and second embodiments, an image signal representing a moire having a period in an oblique direction (a direction not parallel to the X direction and the Y direction) as shown in FIG. Can be detected. Therefore, for example, as shown by a dotted square in FIG. 23, if image signals of five pixels arranged in parallel in the Y direction are acquired, they are different from each other as in the first and second embodiments. Image signals constituting five stripe images can be acquired.
In FIG. 23, the image signals of five pixels arranged in parallel to the Y direction are acquired. However, the present invention is not limited to this, and as shown in FIG. 24, 5 pixels arranged in parallel to the X direction. You may make it acquire the image signal of one pixel. In short, the pixels may be arranged in any direction as long as the image signals of the pixels arranged in the crossing direction other than the direction parallel to or orthogonal to the moire periodic direction are acquired.
In the above description, the periodic direction of the self-image G1 of the first grating 2 or the periodic direction of the charge storage layer 43 is the orthogonal direction in which the pixels of the

radiation image detectors

400, 500, and 600 are arranged. Although the case where it coincides with one of the directions has been described, the present invention is not limited to this, and as shown in FIG. 25, image signals of five pixels arranged in an oblique direction (a direction not parallel to the X direction and the Y direction) are displayed. The relative angle between the periodic direction of the first lattice 2 and the charge storage layer 43 and the arrangement direction of the pixels of the

radiation image detectors

400, 500, 600 may be shifted so as to be acquired.
In short, as described above, the image signals of a plurality of pixels arranged in a predetermined direction that is parallel to or orthogonal to the moiré periodic direction are acquired as image signals constituting different fringe images. If so, the relationship between the periodic direction of the first lattice 2 and the charge storage layer 43 and the arrangement direction of the pixels of the radiation image detector may be any relationship. Here, the arrangement direction of the pixels of the

radiation image detectors

400, 500, and 600 refers to the arrangement direction of the linear electrodes or the scanning direction of the reading light in the

radiation image detectors

400, 500, and 600. Due to such a relationship, the subpixel size in the above equation (11), the above equation (43), the above equation (44), or the above equation (48) is not limited to the Y direction, but the pixel in the predetermined direction. It will be the size of.

Further, similarly to the second grating 3 in the above-described embodiment, the

radiation image detectors

400, 500, and 600 having the function of the second grating 3 are rotated by 90 ° to generate a composite image in each direction. Alternatively, the first grating 2 and the charge storage layer 43 of the

radiation image detectors

400, 500, and 600 may have a two-dimensional grating structure. The structure of the two-dimensional lattice of the charge storage layer 43 is the same as the structure of the two-dimensional lattice of the second lattice 3 described above. Further, when the charge storage layer 43 is configured as a two-dimensional lattice, the pitch of the self-image G1 of the first lattice 2 at the position of the charge storage layer 43 and the charge storage layer 43 are similar to those of the second lattice 3. A form in which the arrangement pitch of the lattice structure is different from the pitch is also applicable. In this case, for example, the pitch in the X direction of the self-image G1 of the lattice 2 at the position of the charge storage layer 43 is different from the arrangement pitch in the X direction of the lattice structure of the charge storage layer 43. The pitch in the Y direction is different from the arrangement pitch in the Y direction of the lattice structure of the charge storage layer 43.

Claims

A radiation source;
A first grating in which a grating structure is periodically arranged to pass a radiation emitted from the radiation source to form a periodic pattern image;
A second grating in which a grating structure is periodically arranged and a periodic pattern image formed by the first grating is incident;
A radiographic imaging device comprising a radiographic image detector in which pixels that detect radiation transmitted through the second grating are two-dimensionally arranged,
The first grating and the second grating generate moiré by overlapping the periodic pattern image formed by the first grating and the second grating,
Based on the image signal of the moire detected by the radiation image detector, at least one pixel is spaced in a predetermined direction which is a cross direction other than a direction parallel to or orthogonal to the periodic direction of the moire. An image signal read from the arranged pixel group is acquired, and an image signal of the composite pixel is generated based on the image signal of the adjacent pixel group of at least two rows in the predetermined direction. A composite image that generates a radiographic image, generates a plurality of radiographic images by setting the composite pixel to be shifted in the pixel unit in the predetermined direction, and generates a composite image based on the generated radiographic images A radiographic imaging apparatus comprising a generation unit.
The first grating and the second grating are arranged so that the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating are relatively inclined. The radiographic image capturing apparatus according to claim 1, wherein:
The radiographic image capturing apparatus according to claim 2, wherein the first grating and the second grating are configured such that a period T of the moire satisfies a value satisfying the following expression.

Where Z 1 is the distance between the focal point of the radiation source and the first grating, Z 2 is the distance between the first grating and the second grating, and L is the focal point of the radiation source and the radiation image detection. P 1 ′ is the pitch of the periodic pattern image at the position of the second grating, Dsub is the size of the pixel in the predetermined direction, and θ is the periodic pattern image formed by the first grating. Angle formed by the stretching direction and the stretching direction of the second lattice
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the first grating to selectively shield the radiation emitted from the radiation source. Further comprising a multi-slit consisting of an absorbing grating that
The radiographic image capturing apparatus according to claim 2, wherein the first grating and the second grating are configured such that a period T of the moire satisfies a value satisfying the following expression.

Where Z 1 is the distance between the focal point of the radiation source and the first grating, Z 2 is the distance between the first grating and the second grating, and L is the focal point of the radiation source and the radiation image detection. P 1 ′ is the pitch of the periodic pattern image at the position of the second grating, Dsub is the size of the pixel in the predetermined direction, and θ is the periodic pattern image formed by the first grating. Angle formed by the stretching direction and the stretching direction of the second lattice
The pitch P 3 of the multi-slit, the radiation imaging apparatus according to claim 4, characterized in that configured to a value that satisfies the following expression.

Where Z 3 is the distance between the multi-slit and the first grating, Z 2 is the distance from the first grating to the second grating, and P 1 ′ is the period at the position of the second grating. Pitch of pattern image
The relative inclination angle θ between the periodic pattern image formed by the first grating and the second grating is set to a value satisfying the following expression. Radiation imaging device.

Where P 1 ′ is the pitch of the periodic pattern image at the position of the second grating, D is the number M of the pixels constituting the composite pixel × the size of the pixel in the predetermined direction, and n is 0 and M An integer excluding multiples
The inclination θ1 of the self-image of the first grating with respect to the predetermined direction and the inclination θ2 of the second grating with respect to the predetermined direction are set to values satisfying the following expression: Item 3. The radiographic image capturing apparatus according to Item 2.

Where P 1 ′ is the pitch of the first periodic pattern image at the position of the second grating, D is the size of the composite pixel composed of M pixels, and n is a multiple of 0 and M An integer excluding
The first grating is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation;
Wherein said second pitch P 1 'and the pitch P 2 of the second grating of the periodic pattern image at the position of the grating, characterized in that it is one that is configured to a value that satisfies the formula Item 8. The radiographic image capturing apparatus according to any one of Items 2, 3, 6, and 7.

Where P 1 is the grating pitch of the first grating, Z 1 is the distance from the focal point of the radiation source to the first grating, and Z 2 is the distance from the first grating to the second grating.
The first grating is a phase modulation type grating that applies 180 ° phase modulation;
Wherein said second pitch P 1 'and the pitch P 2 of the second grating of the periodic pattern image at the position of the grating, characterized in that it is one that is configured to a value that satisfies the formula Item 8. The radiographic image capturing apparatus according to any one of Items 2, 3, 6, and 7.

Where P 1 is the grating pitch of the first grating, Z 1 is the distance from the focal point of the radiation source to the first grating, and Z 2 is the distance from the first grating to the second grating.
The radiation image detector is a pixel in which the pixels are two-dimensionally arranged in first and second directions orthogonal to each other,
The radiographic imaging according to claim 2, wherein the periodic pattern image formed by the first grating or the extending direction of the second grating is parallel to the first direction. apparatus.
The phase image generation unit has a predetermined number in the first direction according to a relative inclination between the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating. The radiographic image capturing apparatus according to claim 10, wherein the radiographic image of the composite pixel unit is acquired based on an image signal obtained by reading out pixels.
The pixel signal of each pixel constituting the composite pixel within the width of one composite pixel in the predetermined direction is n (n is an integer excluding 0 and a multiple of M, and M is a pixel constituting the composite pixel. The radiographic imaging device according to any one of claims 2 to 11, wherein the other of the first grating and the second grating is inclined so as to change in period. .
The first grating and the second grating are configured such that the pitch of the periodic pattern image at the position of the second grating is different from the pitch of the second grating. The radiographic imaging apparatus according to claim 1.
The radiographic image capturing apparatus according to claim 13, wherein the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating are parallel to each other.
15. The radiographic imaging according to claim 13, wherein the first grating and the second grating are configured such that the moire period T is a value satisfying the following expression: 15. apparatus.

Where Z 1 is the distance between the focal point of the radiation source and the first grating, Z 2 is the distance between the first grating and the second grating, and L is the focal point of the radiation source and the radiation image detection. P 2 is the pitch of the second grating, P 1 ′ is the pitch of the periodic pattern image at the position of the second grating, and Dsub is the size of the pixel in the predetermined direction
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the first grating to selectively shield the radiation emitted from the radiation source. Further comprising a multi-slit consisting of an absorbing grating that
15. The radiographic imaging according to claim 13, wherein the first grating and the second grating are configured such that the moire period T is a value satisfying the following expression: 15. apparatus.

Where Z 1 is the distance between the focal point of the radiation source and the first grating, Z 2 is the distance between the first grating and the second grating, and L is the focal point of the radiation source and the radiation image detection. P 2 is the pitch of the second grating, P 1 ′ is the pitch of the periodic pattern image at the position of the second grating, and Dsub is the size of the pixel in the predetermined direction
The radiographic imaging apparatus according to claim 16, wherein the multi-slit pitch P 3 is configured to satisfy a value satisfying the following expression.

Where Z 3 is the distance between the multi-slit and the first grating, Z 2 is the distance from the first grating to the second grating, and P 1 ′ is the period at the position of the second grating. Pitch of pattern image
The first grating is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation;
The pitch P 1 ′ of the periodic pattern image at the position of the second grating is configured to be a value satisfying the following expression: 16 to 15, Radiation imaging device.

Where P 1 is the grating pitch of the first grating, Z 1 is the distance from the focal point of the radiation source to the first grating, and Z 2 is the distance from the first grating to the second grating.
The first grating is a phase modulation type grating that applies 180 ° phase modulation;
The pitch P 1 ′ of the periodic pattern image at the position of the second grating is configured to be a value satisfying the following expression: 16 to 15, Radiation imaging device.

Where P 1 is the grating pitch of the grating, Z 1 is the distance from the focal point of the radiation source to the first grating, and Z 2 is the distance from the first grating to the second grating.
The first grating and the second grating are arranged so that the extending direction of the periodic pattern image formed by the first grating and the extending direction of the second grating are relatively inclined. The radiographic imaging apparatus according to claim 13, wherein
21. The radiographic image according to any one of claims 1 to 20, wherein the radiographic image detector is configured such that the pixels including a switch element for reading out the image signal are two-dimensionally arranged. Shooting device.
A linear reading light source that emits linear reading light;
21. The radiographic image capturing apparatus according to claim 1, wherein the radiographic image detector reads the image signal by scanning the linear reading light source.
The second grating is disposed at a Talbot interference distance from the first grating;
23. The radiographic image capturing apparatus according to claim 1, wherein intensity modulation is applied to the periodic pattern image formed by the Talbot interference effect of the first grating.
The first grating is an absorption grating that forms the periodic pattern image by passing the radiation as a projection image;
23. The second grating, wherein the periodic pattern image as the projection image that has passed through the first grating gives intensity modulation to the periodic pattern image. The radiographic imaging apparatus of any one of Claims.
25. The radiographic image capturing apparatus according to claim 24, wherein the second grating is disposed at a distance shorter than a minimum Talbot interference distance from the first grating.
26. The radiographic image capturing apparatus according to claim 1, wherein a size of the composite pixel in a direction orthogonal to the predetermined direction is smaller than a size of the composite pixel in the predetermined direction.
27. The radiation according to any one of claims 1 to 26, wherein the composite image generation unit generates at least one of a phase contrast image, a small angle scattered image, and an absorption image as the radiation image. Image shooting device.
A rotation mechanism that rotates the first and second gratings by 90 ° from the extending direction of the gratings around a rotation axis that is orthogonal to the centers of the lattice planes of the first and second gratings is provided. The radiographic imaging apparatus according to any one of claims 1 to 27, wherein
28. The radiographic image capturing apparatus according to claim 1, wherein the first and second gratings have a two-dimensional grating structure.
A radiation source and a grating in which a grating structure is periodically arranged to pass a radiation emitted from the radiation source to form a periodic pattern image;
A first electrode layer that transmits a periodic pattern image formed by the lattice; a photoconductive layer that generates an electric charge upon irradiation of the periodic pattern image transmitted through the first electrode layer; and the photoconductive layer. A charge accumulation layer for accumulating the charges generated in step 1 and a second electrode layer in which a large number of linear electrodes that transmit the reading light are stacked in this order, and each linear electrode is scanned by the reading light. A radiographic image capturing device including a radiographic image detector that reads out an image signal for each pixel corresponding to
The charge storage layer is formed in a lattice shape with a pitch finer than the arrangement pitch of the linear electrodes,
The lattice and the charge storage layer are configured to generate an image signal representing moiré by superimposing a periodic pattern image formed by the lattice and an array pattern of the charge storage layer,
Based on an image signal representing the moire detected by the radiological image detector, at least one pixel is spaced in a predetermined direction that is parallel to or orthogonal to the periodic direction of the moire. The composite pixel unit by acquiring an image signal read from the pixel group arranged in a row and generating an image signal of the composite pixel based on the image signal of the adjacent pixel group in at least two rows in the predetermined direction Generating a plurality of radiation images by generating the plurality of radiation images by setting the composite pixel to be shifted in the pixel unit in the predetermined direction, and generating a composite image based on the generated plurality of radiation images A radiographic imaging apparatus comprising an image generation unit.
31. The lattice and the radiation image detector are arranged so that the extending direction of the lattice and the extending direction of the lattice pattern of the charge storage layer are relatively inclined. Radiographic imaging device.
32. The radiographic imaging apparatus according to claim 31, wherein the lattice and the charge storage layer are configured such that the period T of the moire satisfies a value that satisfies the following expression.

Where P 1 ′ is the pitch of the periodic pattern image at the position of the radiation image detector, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the grating and the charge accumulation. The angle made by the stretching direction of the layer
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the grating, and are an absorption type that selectively shields radiation emitted from the radiation source. It is further equipped with a multi slit consisting of a lattice
32. The radiographic imaging apparatus according to claim 31, wherein the lattice and the charge storage layer are configured such that the period T of the moire satisfies a value that satisfies the following expression.

Where P 1 ′ is the pitch of the periodic pattern image at the position of the radiation image detector, Dsub is the size of the pixel in the predetermined direction, θ is the extending direction of the periodic pattern image formed by the grating and the charge accumulation. The angle made by the stretching direction of the layer
The pitch P 3 of the multi-slit, the radiation image photographing apparatus according to claim 33, wherein a is one that is configured to a value that satisfies the following expression.

Where Z 3 is the distance between the multi-slit and the grating, Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector, and P 1 ′ is the periodic pattern image at the position of the radiation image detector. Pitch of
32. The radiographic imaging apparatus according to claim 31, wherein a relative inclination angle [theta] between the periodic pattern image formed by the lattice and the charge storage layer is set to a value satisfying the following expression. .

Where P 1 ′ is the pitch of the periodic pattern image at the position of the radiation image detector, D is the number M of the fringe images × the size of the pixel in the predetermined direction, and n is an integer excluding 0 and a multiple of M
32. The radiographic image capturing apparatus according to claim 31, wherein the inclination [theta] of the self-image of the lattice with respect to the extending direction of the lattice structure of the charge storage layer is set to a value satisfying the following expression.

Where P 1 ′ is the lattice structure of the charge storage layer and the pitch of the periodic pattern image of the lattice at the position of the charge storage layer, D is the size of the composite pixel composed of M pixels in the predetermined direction, n Is an integer excluding multiples of 0 and M
The grating is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation;
The pitch P 1 ′ of the periodic pattern image at the position of the radiation image detector and the arrangement pitch P 2 ′ of the lattice structure of the charge storage layer are configured to satisfy the following expression: Item 37. The radiographic image capturing apparatus according to any one of Items 31, 32, 35, and 36.

Where P 1 is the grating pitch of the grating, Z 1 is the distance from the focal point of the radiation source to the grating, and Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector.
The grating is a phase modulation type grating that gives 180 ° phase modulation;
The pitch P 1 ′ of the periodic pattern image at the position of the radiation image detector and the arrangement pitch P 2 ′ of the lattice structure of the charge storage layer are configured to satisfy the following formula: 37. A radiographic imaging apparatus according to any one of claims 31, 32, 35 and 36.

Where P 1 is the grating pitch of the grating, Z 1 is the distance from the focal point of the radiation source to the grating, and Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector.
The lattice and the charge storage layer are configured such that the pitch of the periodic pattern image at the position of the radiation image detector is different from the arrangement pitch of the lattice structure of the charge storage layer. The radiographic imaging apparatus according to claim 30.
40. The radiographic image capturing apparatus according to claim 39, wherein the extending direction of the periodic pattern image at the position of the radiation image detector is parallel to the extending direction of the lattice structure of the charge storage layer.
41. The radiographic image capturing apparatus according to claim 39, wherein the lattice and the charge storage layer are configured such that a period T of the moire satisfies a value satisfying the following expression.

Where P 1 ′ is the pitch of the periodic pattern image at the position of the radiation image detector, P 2 ′ is the arrangement pitch of the lattice structure of the charge storage layer, and Dsub is the size of the pixel in the predetermined direction.
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the grating, and are an absorption type that selectively shields radiation emitted from the radiation source. It is further equipped with a multi slit consisting of a lattice
41. The radiographic image capturing apparatus according to claim 39, wherein the lattice and the charge storage layer are configured such that a period T of the moire satisfies a value satisfying the following expression.

Where P 1 ′ is the pitch of the periodic pattern image at the position of the radiation image detector, P 2 ′ is the arrangement pitch of the lattice structure of the charge storage layer, and Dsub is the size of the pixel in the predetermined direction.
The pitch P 3 of the multi-slit, the radiation image photographing apparatus according to claim 42, wherein a is one that is configured to a value that satisfies the following expression.

Where Z 3 is the distance between the multi-slit and the grating, Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector, and P 1 ′ is the periodic pattern image at the position of the radiation image detector. Pitch,
The grating is a phase modulation type grating or an amplitude modulation type grating that gives 90 ° phase modulation;
The radiographic imaging according to any one of claims 39 to 41, wherein a pitch P 1 ′ of the periodic pattern image at a position of the radiological image detector is configured to satisfy the following expression: apparatus.

Where P 1 is the grating pitch of the grating, Z 1 is the distance from the focal point of the radiation source to the grating, and Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector.
The grating is a phase modulation type grating that gives 180 ° phase modulation;
The radiographic imaging according to any one of claims 39 to 41, wherein a pitch P 1 ′ of the periodic pattern image at a position of the radiological image detector is configured to satisfy the following expression: apparatus.

Where P 1 is the grating pitch of the grating, Z 1 is the distance from the focal point of the radiation source to the grating, and Z 2 ′ is the distance from the grating to the detection surface of the radiation image detector.
38. The lattice and the radiation image detector are arranged so that the extending direction of the lattice and the extending direction of the lattice pattern of the charge storage layer are relatively inclined. Radiographic imaging device.
The radiographic imaging apparatus according to any one of claims 30 to 46, wherein a lattice structure of the charge storage layer is formed to be parallel to the linear electrode.
48. The radiographic image capturing apparatus according to claim 30, wherein a thickness of the charge storage layer in the stacking direction is 2 μm or less.
49. The radiographic imaging apparatus according to claim 30, wherein a dielectric constant of the charge storage layer is within twice and a half or more of a dielectric constant of the photoconductive layer.
The radiation image detector is disposed at a Talbot interference distance from the grating;
50. The radiographic image capturing apparatus according to claim 30, wherein intensity modulation is applied to the periodic pattern image formed by the Talbot interference effect of the grating.
The grating is an absorptive grating that forms the periodic pattern image by passing the radiation as a projection image;
50. The radiation image detector according to any one of claims 30 to 37, 39 to 44, and 46 to 49, wherein the radiation pattern detector applies intensity modulation to the periodic pattern image as the projection image that has passed through the grating. The radiographic imaging device described in the item.
52. The radiographic image capturing apparatus according to claim 51, wherein the radiographic image detector is disposed at a distance shorter than a minimum Talbot interference distance from the lattice.
A radiation source and a first grating in which a grating structure is periodically arranged to pass the radiation emitted from the radiation source to form a periodic pattern image;
A second grating in which a grating structure is periodically arranged and a periodic pattern image formed by the first grating is incident;
A radiographic imaging device comprising a radiographic image detector in which pixels that detect radiation transmitted through the second grating are two-dimensionally arranged,
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the first grating to selectively shield the radiation emitted from the radiation source. Equipped with multi-slits made of absorbing lattice
The multi-slit, the first grating, and the second grating are image signals that express moire by superposition of the slit image formed by the multi-slit and the grating patterns of the first grating and the second grating. Is configured to generate
Based on an image signal representing the moire detected by the radiological image detector, at least one pixel is spaced in a predetermined direction that is parallel to or orthogonal to the periodic direction of the moire. The composite pixel unit by acquiring an image signal read from the pixel group arranged in a row and generating an image signal of the composite pixel based on the image signal of the adjacent pixel group in at least two rows in the predetermined direction Generating a plurality of radiation images by generating the plurality of radiation images by setting the composite pixel to be shifted in the pixel unit in the predetermined direction, and generating a composite image based on the generated plurality of radiation images A radiographic imaging apparatus comprising an image generation unit.
54. The multi-slit is arranged such that an extending direction of the multi-slit and an extending direction of the first lattice and the second lattice are relatively inclined. Radiation imaging device.
The multi-slit and the first grating are configured such that the pitch of the slit image at the position of the first grating is different from the pitch of the grating pattern of the first grating. 55. The radiographic imaging apparatus according to claim 53 or 54.
A radiation source and a grating in which a grating structure is periodically arranged to pass a radiation emitted from the radiation source to form a periodic pattern image;
A first electrode layer that transmits a periodic pattern image formed by the lattice; a photoconductive layer that generates an electric charge upon irradiation of the periodic pattern image transmitted through the first electrode layer; and the photoconductive layer. A charge accumulation layer for accumulating the charges generated in step 1 and a second electrode layer in which a large number of linear electrodes that transmit the reading light are stacked in this order, and each linear electrode is scanned by the reading light. A radiographic image capturing device including a radiographic image detector that reads out an image signal for each pixel corresponding to
A plurality of radiation shielding members that shield the radiation are extended at a predetermined pitch, and are arranged between the radiation source and the grating, and an absorption type that selectively shields radiation emitted from the radiation source. It has a multi slit made of a lattice,
The charge storage layer is formed in a lattice shape with a pitch smaller than the arrangement pitch of the linear electrodes,
The multi-slit and the grating are configured to generate an image signal representing moiré by superimposing a slit image formed by the multi-slit and a grating pattern of the grating,
Based on an image signal representing the moire detected by the radiological image detector, at least one pixel is spaced in a predetermined direction that is parallel to or orthogonal to the periodic direction of the moire. The composite pixel unit by acquiring an image signal read from the pixel group arranged in a row and generating an image signal of the composite pixel based on the image signal of the adjacent pixel group in at least two rows in the predetermined direction Generating a plurality of radiation images by generating the plurality of radiation images by setting the composite pixel to be shifted in the pixel unit in the predetermined direction, and generating a composite image based on the generated plurality of radiation images A radiographic imaging apparatus comprising an image generation unit.
57. The radiation according to claim 56, wherein the multi-slits are arranged such that the extending direction of the multi-slit and the extending direction of the lattice pattern of the lattice and the charge storage layer are relatively inclined. Image shooting device.
The radiation according to claim 56 or 57, wherein the multi-slit and the grating are configured such that a pitch of the slit image at the position of the grating is different from a pitch of a grating pattern of the grating. Image shooting device.
59. Radiation according to any one of claims 1 to 58, wherein the radiation source and the radiation image detector are arranged opposite to each other in the horizontal direction so as to be capable of standing imaging of a subject. Image shooting device.
59. Radiation according to any one of claims 1 to 58, wherein the radiation source and the radiation image detector are arranged opposite to each other in the vertical direction so as to be able to photograph the subject's supine position. Image shooting device.
The said radiation source and the said radiographic image detector are hold | maintained by the turning arm, and it is comprised so that the standing-up imaging | photography of a subject and a supine position imaging | photography are possible. The radiation phase image photographing apparatus described.
59. The radiation phase image photographing apparatus according to any one of claims 1 to 58, wherein the radiation phase image photographing apparatus is a mammography apparatus configured to be capable of photographing a breast as a subject.
The radiation source is placed at a first position where the radiation is irradiated from a first direction to the radiation image detector and a second position where the radiation image detector is irradiated from a second direction different from the first direction. Equipped with a moving mechanism to move,
The composite image generation unit generates the composite image based on the image signals detected by the radiation image detector for the first and second positions,
59. The apparatus according to claim 1, further comprising a stereo image configuration unit configured to form a stereo image based on a composite image corresponding to the first position and a composite image corresponding to the second position. The radiation phase image photographing apparatus described.
Comprising a circling mechanism for circling the radiation source and the radiological image detector around a subject;
The composite image generation unit generates the composite image for each rotation angle based on the image signal detected by the radiation image detector at each rotation angle,
59. The radiographic image capturing apparatus according to claim 1, further comprising a three-dimensional image forming unit configured to form a three-dimensional image based on the combined image for each rotation angle.