JP2000098040A - Method of manufacturing solid state detector for CT - Google Patents

Abstract

(57) Abstract: Provided is a method for manufacturing a solid state detector for CT using an inexpensive scintillator crystal by improving the arrangement accuracy of a detector array. In a step (a), a rod-shaped scintillator crystal having a square cross section is bonded onto a base with an optical adhesive. (B)
In the process, a large number of grooves 4 are cut at a predetermined pitch in parallel with the bar-shaped scintillator crystal 1 with a multi-wire saw, a diamond cutter, or the like to form each scintillator element 1a having a predetermined shape. At this time, the groove 4 to be cut is formed up to the lower end of the rectangular cross-section bar-shaped scintillator crystal 1 or the depth of the optical adhesive 2, and no cut is made any more. In the step (c), the reflecting material 8 with the shielding plate 7 as the center.
Then, it is inserted into the groove 4 and fixed so that both sides thereof are sandwiched. In the step (d), on the scintillator element 1a,
Further, the photodiode array 5 is bonded and fixed via the optical adhesive 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid state detector for CT used in an X-ray CT apparatus or the like.

[0002]

2. Description of the Related Art An X-ray CT apparatus emits X-rays from an X-ray tube, is focused on a fan-shaped X-ray beam by a collimator at an emission port, and is opposed to the X-ray tube with respect to a subject. An arc-shaped collimator and a detector arranged in a rotating manner are rotated, the detector captures X-ray information transmitted through the subject, and the signal is processed by a computer to obtain an X-ray tomographic image of the subject. . The collimator is positioned so that it converges in the X-ray tube focal direction.
The line shielding plate is arranged together with the detector using a thin hard metal plate made of a material that is hardly transparent to X-rays. The detector has a function of causing only a direct transmission line in the X-ray tube focal direction transmitted through the subject to enter the detector, and removing other scattered radiation. The detector is composed of a scintillator that emits light when irradiated with X-rays on the front surface, and a photodiode that receives light and converts it into an electric signal on the back surface, and is arranged in an arc of about 500 to 1000 channels. It has become. This detector has an X-ray shielding plate between each scintillator and is placed behind a collimator. The positional accuracy of the collimator and the detector is set accurately, and the detection of each detector is performed. The sensitivity is made uniform and maximum. Due to the mechanical arrangement, 8 to 30 scintillators and photodiodes combined by optical bonding are arranged on a substrate to form one module. The solid-state detector for CT is configured by being arranged in a substantially arc shape continuously with the collimator and being combined with a collimator. A conventional solid-state detector for CT is configured as shown in FIG. 4 and includes a scintillator element 41 and a photoelectric conversion element 43 such as a photodiode adhered to the lower surface of the scintillator element 41 via an adhesive 42 having a high light transmittance. The radiation detector consisting of
And a radiation detector array is formed on the support member 44. Radiation is scintillator element 41
When the light enters the upper surface of the device, the radiation is converted into light in the scintillator element 41, and the emitted light is detected by the photoelectric conversion element 43, converted into an electric signal, and a signal proportional to the amount of incident radiation is extracted.

[0003]

The conventional solid-state detector for CT is constructed as described above, but after cutting each scintillator element 41 from a plate-shaped rectangular scintillator crystal, the photoelectric conversion element 43 is bonded. Generally, the scintillator crystal is made of an expensive material such as a CdWO ₄ crystal or a Gd ₂ O ₂ S ceramic scintillator, but a plate-shaped rectangular parallelepiped scintillator crystal as in the related art is generally used. The yield is low for manufacturing non-defective products, and when processing plate-shaped products, the number of non-defective products is reduced and the products are expensive. Then, the radiation detectors S are precisely arranged on the support member 44 so that the shielding plate 45 can be inserted. However, it is difficult to form the scintillator elements 41 to the same size in this process. With each radiation detector S
However, there is a problem that it is not easy to precisely arrange the components, and the assembling accuracy is deviated. The present invention has been made in view of such circumstances, and it is possible to easily control the interval between each channel of the detector array, improve the arrangement accuracy, and use inexpensive scintillator crystals without waste. An object of the present invention is to provide a method for manufacturing a solid state detector for CT that can be used.

[0004]

In order to achieve the above object, a method for manufacturing a solid state detector for CT according to the present invention comprises a scintillator element which is arranged in an array and emits light by radiation, and a photoelectric sensor which detects light emission by the scintillator element. In the method of manufacturing a solid state detector for CT provided with a conversion element, a rod-shaped scintillator having a square cross section is closely placed and fixed on a radiation-transmissive substrate or a film, and a number of grooves are formed in parallel with the rod-shaped scintillator. A scintillator element row divided into an array is formed by cutting, a radiation-impermeable shielding plate having a light reflecting material on both sides is inserted into the groove, and then the scintillator element row on the side opposite to the substrate or film is formed. The photoelectric conversion element is bonded and fixed to the surface. Further, another method of manufacturing a solid state detector for CT according to the present invention is that, after a rod-shaped scintillator having a square cross section is tightly arranged and fixed on a radiation-transmissive substrate or a film, a large number of the rod-shaped scintillators are perpendicular to the rod-shaped scintillator. Is cut into grooves to form an array of scintillator elements divided into an array, and a radiopaque shielding plate having light reflecting materials on both surfaces is inserted into the grooves, and then the scintillator on the opposite side of the substrate or film is formed. The photoelectric conversion element is bonded and fixed to the surface of the element row.

The method for manufacturing a solid state detector for CT according to the present invention comprises:
An inexpensive scintillator with a rectangular cross section and a good yield is placed and fixed on a substrate or film, and then a number of grooves are cut at the required pitch to form a scintillator element row. Since a radiopaque shielding plate having a reflecting material is inserted, and then the photoelectric conversion element is bonded and fixed to the surface of the scintillator element row, the arrangement accuracy of the detector can be improved and the manufacturing cost can be reduced. .

[0006]

FIG. 1 shows a method for manufacturing a solid state detector for CT according to the present invention, and FIG. 2 shows a detailed sectional view of the solid state detector for CT after completion. The solid state detector for CT of the present invention includes a block-shaped scintillator element 1a as a phosphor for converting incident radiation into light, optical adhesives 2 and 6 having radiation and light transmittance, and a support material as a support. A radiation-transparent base 3 having a function and made of plastic, for example, polyester, a shielding plate 7 having poor radiation transmissivity having a reflective material 8 inserted into the cut groove 4, and a scintillator element 1a. And a photodiode array 5 serving as a photoelectric conversion element for converting fluorescence into an electric signal. The base 3 may be a radiation transmissive film.
The manufacturing method includes the following four steps (a), (b),
This is performed in (c) and (d). In the step (a), the scintillator crystal 1 having a square cross section is bonded onto a film or a base 3 with an optical adhesive 2. Next, in the step (b), a large number of grooves 4 are cut at a predetermined pitch in parallel with the bar-shaped scintillator crystal 1 with a multi-wire saw or a diamond cutter to form each scintillator element 1a having a predetermined shape. . At this time, the groove 4 to be cut
Is to the lower end of the square cross-section scintillator crystal 1 or to the depth of the optical adhesive 2, and no more cuts are made. In this manner, rows of scintillator elements 1a which are completely divided into an array at a predetermined pitch are formed.
Next, in the step (c), the shielding material 7 is inserted into and fixed to the groove 4 such that both sides of the shielding material 7 are sandwiched by the reflector 8. The reflector 8 may be any reflector that efficiently reflects the light emitted by the scintillator element 1a on the shielding plate 7. For example, the shielding plate 7 may be formed by depositing aluminum or the like on the surface and coating the surface. Next, in the step (d), the photodiode array 5 is further adhered and fixed on the scintillator element 1a via the optical adhesive 6.
In this step, a solid state detector for CT is completed. As can be seen from the detailed sectional view of FIG. 2, the scintillator element 1a is completely separated into each channel, and the shielding plate 7 and the reflecting material 8 are inserted between each scintillator element 1a. The light emitted in the scintillator element 1a excited by the radiation can be prevented from entering the adjacent scintillator element 1a, and crosstalk is prevented.

The method for manufacturing a solid state detector for CT according to the present invention comprises:
Another embodiment is shown in FIG. The manufacturing method is performed in the following four steps (a), (b), (c), and (d). The difference from the above-described manufacturing method lies in the cutting direction of the groove 4 in the step (b). In the above, parallel cutting was performed on the square scintillator crystal 1 using a multi-wire saw or a diamond cutter, but in this embodiment, a large number of grooves 4 were vertically cut at a predetermined pitch to obtain a predetermined shape. The scintillator element 1a is formed. In this case, several square-section rod-shaped scintillator crystals 1 are arranged in one channel, but the sensitivity of the detector is the same as that of the above-mentioned manufacturing method. The manufacturing method is also similar to the following four steps (a),
This is performed in (b), (c), and (d). In the step (a), the scintillator crystal 1 having a rectangular cross section is adhered onto the base 3 with an optical adhesive 2. Next, in the step (b), a large number of grooves 4 are cut at a predetermined pitch perpendicular to the bar-shaped scintillator crystal 1 with a multi-wire saw or a diamond cutter to form each scintillator element 1a having a predetermined shape. . At this time, the groove 4 to be cut is formed up to the lower end of the rectangular cross-section bar-shaped scintillator crystal 1 or the depth of the optical adhesive 2, and no cut is made any more. In this way, rows of scintillator elements 1a which are completely divided into an array at a predetermined pitch are formed, and several square-section rod-shaped scintillator crystals 1 are arranged in one channel. Next, in the step (c), the reflector 8 is sandwiched on both sides thereof with the shielding plate 7 as a center.
Insert into the groove 4 and fix. The reflector 8 may be any reflector that efficiently reflects the light emitted by the scintillator element 1a on the shield plate 7. For example, the shield plate 7 may be formed by evaporating aluminum or the like and coating the surface. Then (d)
In the process, the photodiode array 5 is further adhered and fixed on the scintillator element 1a via the optical adhesive 6. In this step, a solid state detector for CT is completed. By using such an inexpensive rectangular cross-section rod-shaped scintillator crystal 1, the groove for inserting the shielding plate 7 having the reflecting material 8 can be precisely formed by machining, and the photodiode array 5 is coated with the optical adhesive 6. Since it is a manufacturing method of bonding and fixing through the steps, the manufacturing cost can be reduced, and a solid state detector for CT with high accuracy is completed.

[0008]

The method for manufacturing a solid state detector for CT according to the present invention is constructed as described above, and has a rectangular cross-section rod-shaped production yield on a radiation-transmissive substrate or film arranged in the radiation incident direction. After placing a good and cheap scintillator in close contact with the surface opposite to the radiation incidence direction and fixing it,
A number of grooves are cut at the required pitch to separate and form a scintillator element row, a non-radiation shielding plate having a light reflecting material is inserted into the groove, and then photoelectric conversion is performed on the surface of the scintillator element row. A manufacturing method for bonding and fixing elements,
The spacing between the channels can be easily controlled, the arrangement accuracy of the detector can be improved, and the manufacturing cost can be reduced by using a rod-shaped scintillator crystal.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a method of manufacturing a solid-state detector for CT of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing a solid-state detector for CT according to the present invention.

FIG. 3 is a view showing another embodiment of the method for producing a solid state detector for CT according to the present invention.

FIG. 4 is a view showing a method for manufacturing a conventional solid-state detector for CT.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Square-shaped bar-shaped scintillator crystal 2 ... Optical adhesive 3 ... Base 4 ... Groove 5 ... Photodiode array 6 ... Optical adhesive 7 ... Shielding plate 8 ... Reflector 41 ... Scintillator element 42 ... Adhesive 43 ... Photoelectric conversion element 44: support member 45: shielding plate S: radiation detector

Claims (2)

[Claims] 1. A method for manufacturing a solid-state detector for CT comprising a scintillator element arranged in an array and emitting light by radiation and a photoelectric conversion element for detecting light emission by the scintillator element, the method comprising the steps of: After closely attaching and fixing a rod-shaped scintillator having a square cross section, a number of grooves are cut in parallel with the rod-shaped scintillator to form a scintillator element row divided into an array,
A CT is characterized in that a radiation-impermeable shielding plate having a light reflecting material on both sides is inserted into the groove, and then a photoelectric conversion element is bonded and fixed to the surface of the scintillator element row opposite to the substrate or the film. Manufacturing method for solid state detector. 2. A method of manufacturing a solid-state detector for CT comprising a scintillator element arranged in an array and emitting light by radiation and a photoelectric conversion element detecting light emitted by the scintillator element, the method comprising the steps of: After sticking and fixing a rod-shaped scintillator having a square cross section in close contact, a number of grooves are cut at right angles to the rod-shaped scintillator to form scintillator element rows divided into an array,
A CT is characterized in that a radiation-impermeable shielding plate having a light reflecting material on both sides is inserted into the groove, and then a photoelectric conversion element is bonded and fixed to the surface of the scintillator element row opposite to the substrate or the film. Manufacturing method for solid state detector.