JPH0621037U - Radiation image information reader - Google Patents

Abstract

(57) [Abstract] [Purpose] In a device for reading radiation image information stored and recorded in a storage-type radiation image conversion panel, a light-collecting device that guides stimulated emission obtained by scanning the panel with excitation light to a photodetector. Shorten the distance between the body (light guide) and the photodetector. A light collector (optical fiber) 18 that guides stimulated emission to a photodetector 17, and an optical filter 22 that passes only the stimulated emission and a light blocking member 21 on the optical path between the photodetector 17. Is selectively inserted. Here, the light blocking member 21 and the optical filter 22 are arranged side by side on the same plane. Therefore, when the light blocking member 21 is placed on the optical path, the optical filter 22 retracts, and conversely, when the optical filter 22 is placed on the optical path, the light blocking member 21 retracts. Therefore, the light blocking member 21 and the optical filter 22
The distance between the condenser 18 and the photodetector 17 can be narrowed compared to the case where and are simultaneously inserted in the optical path.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a radiation image information reading device, and more particularly, to a device for reading radiation image information stored and recorded in a storage type radiation image conversion panel.

[0002]

[Prior art]

 For example, when a photostimulable phosphor is irradiated with radiation such as X-rays, a part of the energy of this radiation is accumulated in the phosphor, and when the phosphor is subsequently irradiated with excitation light, the accumulated energy is accumulated. In response to this, the phosphor emits stimulated emission. A radiation image conversion panel is a panel having such a stimulable phosphor layer (hereinafter, simply referred to as a "panel" except for special cases), and this stimulable phosphor is an X-ray image of a human body or the like. Can be recorded as a latent image, and when this latent image portion is irradiated with excitation light such as a laser beam, stimulated luminescence with an intensity corresponding to the energy of the latent image occurs. Therefore, if the stimulated emission is detected and processed by a photodetector such as a photomultiplier tube, a recorded X-ray image can be obtained (Japanese Patent Laid-Open Nos. 63-110442 and 63-104242). No. 62-119537).

By the way, in the photodetector, there is a possibility that problems such as deterioration of the photocathode and seizure of the anode may occur in general when light of high energy enters. For this reason, during the period other than the image reading period, that is, when the latent image remaining by the erasing lamp is erased or during radiation exposure, the optical path between the panel and the photodetector is made of a material such as lead. It was designed to be blocked by the light shielding member.

In order to improve the accuracy of image reading, an optical filter that absorbs excitation light and passes only light in the stimulated emission wavelength range is provided in the optical path between the panel and the photodetector. I am trying.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, when the light blocking member and the optical filter are provided in the optical path between the panel and the photodetector, conventionally, as shown in FIG. A light blocking member 33 and an optical filter 34 are placed back and forth on the optical path between the optical fiber (light guide) 31 that guides the panel to the photo detector and the photo detector 32, and only the light blocking member 33 is required. Depending on the situation, it was placed in the optical path or retracted.

As described above, in order to allow the light shielding member 33 and the optical filter 34 to be inserted back and forth on the optical path between the optical fiber 31 and the photodetector 32 at the same time, the optical fiber 31 There is a problem that the distance between the end surface of the photodetector and the photodetector 32 becomes large, and in order to receive all the light emitted from the optical fiber 31, it is necessary to increase the diameter of the light receiving surface of the photodetector.

The present invention has been made in view of the above problems, and the distance between the end surface of the light guide and the photodetector can be minimized, so that the light collection efficiency can be increased without increasing the light receiving surface of the photodetector. It is an object of the present invention to provide a radiation image information reading device capable of improving the image quality.

[0008]

[Means for Solving the Problems]

 Therefore, the radiation image information reading apparatus according to the present invention accumulates and records radiation image information by irradiating the accumulation type radiation image conversion panel with the radiation that has passed through the subject, and the accumulation type radiation image conversion panel is excited by the excitation light. A radiation image information reading apparatus configured to read the radiation image information by guiding the stimulated emission obtained by scanning to a photodetector by a light guide and detecting the stimulated emission by the photodetector. Only one of the light blocking member and the optical filter is selectively inserted in the optical path between the light guide and the photodetector.

[0009]

[Action]

 According to this structure, both the light blocking member and the optical filter are not inserted in the optical path at the same time, so it is necessary to secure the space required for inserting the light blocking member and the optical filter in the optical path at the same time. However, it is sufficient if there is a space in which only one of the light blocking member and the optical filter can be inserted, and the distance between the light guide and the photodetector can be shortened.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a radiation image information reading apparatus of this embodiment, and a light shielding material for shielding the entire apparatus from outside light is omitted in the drawing. In FIG. 1, radiation image information is accumulated and recorded as a latent image on the radiation image conversion panel 1 described above, and the panel 1 is set in a frame 4 constituting an outer frame of the apparatus main body. An excitation / reading unit 5 movably provided on the frame 4 scans the panel 1 with excitation light 2 and detects stimulated emission generated by the excitation. .

The entire excitation / reading unit 5 is fixed to the moving plate 6. A female screw body 7 is fixed to the moving plate 6, and the female screw body 7 is screwed onto a male screw rod 9 which is rotated by a motor 8 attached to the frame 4. Therefore, the moving plate 6 can be moved in the direction of the arrow Y in the figure or in the opposite direction by driving the motor 8.

The moving mechanism may be configured by a wire, a roller, or the like, or by using a belt, but a feed mechanism using a ball screw or a roller screw is more preferable. An opening 4a is formed on the lower surface of the moving range of the moving plate 6 in the frame 4.

A temperature controller 10 is fixed to the moving plate 6, and a light emission source 11 such as a laser light source is mounted on the temperature controller 10. A light beam 12 from the light emission source 11 passes through an optical system (not shown) such as a beam expander that shapes (expands) the beam diameter, and then a galvanometer mirror or polygon mirror (in the figure, a galvanometer mirror is used). Of the excitation light 2 after being reflected by the deflector 13 into a fan-shaped scanning light 14 and passing through a condenser lens 15 such as an fθ lens for focus adjustment and a reflection mirror 16 changing the optical path downward. And

The panel 1 is fixed below the moving range of the excitation / reading unit 5, that is, on the bottom portion 4 b of the frame 4, and the excitation light 2 scans the panel 1 along the scanning line 3. To be done. The stimulated emission emitted from the panel 1 by the scanning is detected by the photodetector 17 fixed to the lower surface of the moving plate 6. The photodetector 17 is a photomultiplier tube (photomultiplier) or the like, and at the light input portion thereof, an optical fiber bundle, an acrylic sheet, or the like, the tip of which is arranged in parallel with the scanning line 3 near the scanning line 3. (The optical fiber bundle is preferable in terms of light guiding efficiency and workability.) A condenser 18 (light guide) is attached.

In the main scanning in the X direction on the panel 1, the light beam emitted from the light emitting source 11 is deflected (scanned) by the deflector 13 and focused on the panel 1 surface by the condenser lens 15. Done. On the other hand, the sub-scanning in the Y direction is performed by moving the moving plate 6 in the Y direction, that is, moving the exciting / reading unit 5 itself.

Therefore, the panel 1 can be two-dimensionally scanned with the excitation light 2, and when stimulated emission corresponding to the energy of the latent image is generated in the portion scanned with the excitation light 2, the emission is The light is collected by the light collector 18 and guided to the photodetector 17, which is detected by the photodetector 17 and becomes an electrical signal. Then, by processing this electric signal in synchronization with the main scanning and the sub-scanning, the image recorded as a latent image on the panel 1 can be reproduced.

Since the panel 1 is fixed in the apparatus of the present embodiment, its application range is extremely wide. In particular, when a latent image is formed on the panel 1, a radiation imaging apparatus is integrated with this apparatus, a radiation image can be directly recorded on the fixed panel 1, and then this image can be read by the mechanism described above. it can. That is, the panel 1 can be used repeatedly.

By the way, in order to enable repeated use of the panel 1 without removing it from the frame 4 as described above, it is necessary to erase the latent image remaining after the reading. Since this erasing can be performed by irradiating the panel 1 with strong light, as shown in FIG. 2, the rod-shaped erasing lamp 19 is attached to the tip of the condenser 18 in the sub-scanning direction (direction of arrow Y). ) Is provided on the opposite side to the light collector 18 substantially in parallel, and the erasing lamp 19 is fixed to the moving plate 6. Further, the erasing lamp 19 is covered with a reflecting plate 20 in order to efficiently irradiate the erasing light to the panel 1.

In this embodiment, since the condenser 18 and the erasing lamp 19 are integrated, it is possible to sequentially erase the read-completed portions while the image is being read. When incident on the condensing body 18 or irradiating the scanning line 3 which is currently being read, a large noise occurs, which causes a problem of being detected by the photodetector 17. Therefore, it is preferable to adopt a process in which reading is performed during sub-scanning in the direction of arrow Y and erasing is performed when returning in the opposite direction.

Further, in this embodiment, in order to prevent the photocathode of the photodetector 17 from being deteriorated by the erasing lamp 19 due to the light at the time of erasing or the exposure at the time of radiation imaging, the end portion of the light collector 18 is prevented. A plate-shaped light shielding member 21 made of a material such as lead can be selectively inserted on the optical path between the light detector 17 and the photodetector 17. In this way, it is possible to block the light of the erasing lamp and harmful energy from entering the photodetector 17, which makes it possible to prolong the life of the photodetector 17 and reduce obstacles to the next reading. It

The above-mentioned light blocking member 21 is inserted in the optical path except when an image is read, and blocks unnecessary light from entering the photodetector 17. Further, even when the image is read, it is originally desired that only the stimulated emission is incident on the photodetector 17, but the excitation light may be input to the photodetector 17 together with the stimulated emission. Therefore, in order to block unnecessary light from entering during such reading, an optical filter 22 that allows only the frequency component of stimulated emission to pass during reading is provided at the end of the condenser 18 and the photodetector 17 as well. It is designed so that it can be placed on the optical path between and.

Here, the light shielding member 21 and the optical filter 22 are not required at the same time, and the optical filter 22 may be inserted at the time of reading, and the light shielding member 21 may be inserted on the optical path except at the time of reading. In this embodiment, only one of the light blocking member 21 and the optical filter 22 is selectively inserted in the optical path only when necessary.

That is, as shown in FIG. 3, a filter / light-shielding unit 23 in which an optical filter 22 and a light-shielding member 21 are arranged side by side on the same plane is movably supported in a direction orthogonal to the optical path axis. I am doing it. For example, if the filter / light-shielding unit 23 is moved upward in FIG. 3, the optical filter 22 that has been placed on the optical path until then retracts, and instead, the light-shielding member 21 is placed on the optical path. . If the optical filter 22 is moved so that it is inserted in the optical path from the state where the light shielding member 21 is inserted in the optical path, the light shielding member 21 retracts from the optical path and the optical filter 22 is replaced. It is placed in the optical path.

The movement of the filter / light-shielding unit 23 may be parallel movement or rotational movement about an axis parallel to the optical path axis. As described above, if only one of the light blocking member 21 and the optical filter 22 is inserted in the optical path, the gap between the light collector 18 and the photodetector 17 is set to the light blocking member 21. The width can be made narrower than the case where the optical filter 22 and the optical filter 22 are set so that they can be inserted at the same time. As a result, the light emitted from the end of the light collector 18 can be made incident on the light receiving surface of the photodetector 17 before it spreads so much. Therefore, for example, when an optical fiber is used as the light collector 18, if the diameter of the light receiving surface of the photodetector 17 is fixed, a thicker optical fiber can be used to improve the light collection efficiency. As the distance between the fiber and the photodetector 17 becomes narrower, the aperture of the light receiving surface can be made smaller to downsize the photodetector 17.

In particular, when an acrylic sheet is used as the light collector 18, the emission angle becomes larger than that when an optical fiber is used, and thus the distance between the light collector 18 and the photodetector 17 is set as described above. If they can be brought closer, a larger effect can be obtained.

[0026]

[Effect of device]

 As described above, according to the present invention, the stimulated emission obtained by scanning the storage-type radiation image conversion panel with the excitation light is guided to the photodetector by the light guide, and the radiation image information stored and recorded in the panel. In the reading device, an optical filter that allows only photostimulated light to pass during reading and a light blocking member that blocks light from entering the photodetector except during reading are placed in the optical path only when necessary. Since the distance between the light guide and the photodetector can be narrowed, there is an effect that the photodetector can be downsized and the light collection efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mechanism of a radiation image reading apparatus to which the present invention is applied.

FIG. 2 is a diagram showing a front end of an image reading unit in FIG.

FIG. 3 is a diagram showing an embodiment of a structure for inserting an optical filter and a light shielding member.

FIG. 4 is a diagram showing a conventional structure for inserting an optical filter and a light shielding member.

[Explanation of symbols]

 1 Radiation image conversion panel 2 Excitation light 3 Scanning line 4 Frame 5 Excitation / reading unit 6 Moving plate 7 Female screw body 8 Motor 9 Male screw rod 10 Temperature controller 11 Light emission source 12 Rays 13 Deflector 14 Scanning light 15 Condenser lens 16 Reflection Mirror 17 Photodetector 18 Condenser (light guide) 19 Erase lamp 20 Reflector 21 Light-shielding member 22 Optical filter 23 Filter / light-shielding unit

Claims (1)

[Scope of utility model registration request] 1. A stimulable luminescence obtained by irradiating a storage type radiation image conversion panel with radiation that has passed through an object to store and record radiation image information and scanning the storage type radiation image conversion panel with excitation light. In the radiation image information reading device configured to read the radiation image information by guiding the light to the photodetector by the light guide and detecting stimulated emission by the light detector, the light between the light guide and the photodetector is detected. A radiation image information reading device, characterized in that only one of the light blocking member and the optical filter is selectively placed on the road.