JPS58123488A - Radiation detector - Google Patents

Abstract

PURPOSE:To achieve a higher spatial resolution along with a higher assembly accuracy by integrating a plurality of scintillator elements for converting incident radiation into phosphor outside the incident range thereof. CONSTITUTION:A number of grooves 11a piercing a multi-segment scintillator element 11 from the top to the bottom are cut through parallel with the shorter side l thereof 11 in such a manner that the length of the grooves 11a corresponds to the width of an X ray fan beam irradiated from an X ray tube and hence, the part between the groove 11a and the groove 11a serves as a scintillator element in the conventional equipment. The width l of the groove 11a is determined to enable the insertion of a collimeter plate 13. The groove 11a is formed, for example, with a diamond cutter or a wire saw. The interval between one groove 11a of the element 11 and the adjacent one thereof 11a can be made smaller than 2mm. to allow a higher resolution of a detector 10. The dimensional accuracy of the element 11 in the detector 10 only depends on the working accuracy in forming the groove 11a. The working accuracy is extremely high.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention belongs to the technical field of radiation tomography apparatuses, and relates to a radiation detector equipped in a radiation tomography apparatus. ] Radiation tomography equipment For example, an X@CT device has an X-ray tube that rotates around the subject around the subject's body axis, and an X-ray tube that is placed opposite the X-ray tube across the space in which the subject is placed. and a detector for detecting the X-rays emitted from the X-ray tube and transmitted through the subject, and rotates the X and g tubes by, for example, 0.6 degrees around the center of the body axis of the subject. X* is emitted onto the subject while moving, and image reconstruction processing is performed based on a large number of projection data at 0 and 6° intervals output from the detector that detects XIII passing through the subject. It is configured so that it can be reconstructed into nine tomographic images and displayed. For example, a doctor or the like makes a medical judgment regarding the health condition of a subject, such as a patient, and the probability of a lesion, based on the tomographic image obtained by the X11ICT device. Therefore, to enable accurate medical judgment, X-ray CT
The tomographic images obtained by the apparatus are required to have extremely high quality. Factors that affect the quality of tomographic images
The performance of the detector can be mentioned as follows. Conventionally, a detector in an X-edge CT apparatus is configured as follows, for example. That is, as shown in FIG. 1, the detector is a rectangular parallelepiped with a length t of 20 to 25-5, a width W of about 2 cm, and a flatness t of about 4 cm. (Cs i ; Tt), bismuth kermanate CBi4GmsOn>, fin/cadmium stenate (CjWDJ, zinc tungstate (2%
WO4), magnesium tungstate (Mg WO
Detection consisting of a scintillator element 1 made of a substance such as a), and nine photoelectric conversion single elements 6, such as photodiodes or phototransistors, bonded to the bottom surface of the scintillator element 1 via an adhesive 2 with good optical transparency. As shown in FIG. 2, a large number of blocks are arranged on a support member 8 in the transverse direction of the detection blocks, and collimator plates made of a substance with a large atomic number, such as tungsten or tantalum, are arranged between the detection blocks. 6 is inserted so that a part of the collimator plate 6 protrudes from the upper surface of the detection block. As shown in FIG. 2, when the X-ray flux emitted from the XII tube (not shown) is incident on the upper surface of the scintillator element 1, the scintillator element 1 converts the X-rays into light, and the light emitted by the scintillator element 1 is converted into light by a photodiode. 6, it is detected and photoelectrically converted, and a current proportional to the amount of incident Xi is output.

However, one of the factors that affects the image quality of tomographic images is the dimensional accuracy of the scintillator element 1 and the assembly accuracy when arranging the detection blocks. It is extremely difficult to form a rectangular parallelepiped, and even if the scintillator element 1 is formed into a rectangular parallelepiped having exactly the above dimensions, the photoelectric conversion element 2 is glued to the scintillator element 1, and then the collimator plate 6
It is difficult to precisely arrange the detection blocks by inserting them, and errors in the assembly accuracy of the detector are inevitable. If the arrangement of the scintillator elements 1 is out of alignment, response fluctuations will occur, which will adversely affect the quality of the tomographic image. Moreover, the above assembly method is complicated. Furthermore, scintillator element 1 by cutting process
The zero width WK is 69 degrees, and the spatial resolution is limited because the width W of the scintillator element 10 cannot be made as small as desired.

[Purpose of the invention]

The object of the present invention is to provide a multi-element radiation detector that can be manufactured with high assembly accuracy through simple assembly work and has high spatial resolution. [Summary of the Invention] The above. To achieve the object, the present invention provides a radiation detector which includes at least a plurality of scintillator elements for converting incident radiation into fluorescent light, and a photoelectric conversion element for photoconverting the emitted fluorescent light from the scintillator elements. The scintillator element is characterized in that each scintillator element is integrally coupled outside the radiation incident range.

[Embodiments of the invention]

FIG. 3 is a schematic perspective view showing an embodiment of the present invention,
FIG. 4 is a schematic top view showing a multi-segment scintillator element according to an embodiment of the present invention. As shown in FIG. 085,
The detector 10 according to the present invention includes a scintillator element of XI
It includes at least a multi-segment scintillator element 11, a photoelectric conversion element 12, a collimator plate 13, and a support substrate 14 which are coupled together outside the incident range of I. The multi-segment scintillator element 11 is formed of the same material as the conventional scintillator element 1, and as shown in FIG. In FIG. 4, the length tl of the groove 11g corresponds to the width of the X-ray beam emitted from the X-ray tube. / Corresponds to the beam width of the beam. Therefore, in the multi-divided scintillator element 11, the portion sandwiched between the grooves 11@ and grooves 11.corresponds to the scintillator element in the conventional device. Further, the width of groove No. 11 is determined so that the collimator plate 16 can be inserted therein.

Groove 111! can be formed, for example, with a diamond cutter or a wire saw.Also, the distance between the groove 11α and the adjacent groove 11a can be determined as appropriate,
In order to obtain high resolution, it is preferable to make the spacing as narrow as possible. The length W of the multi-division scintillator element 11 is
The appropriately determined 0-element electric conversion element 12 is made of the same material as the conventional one, has a length equal to the short side t of the multi-division scintillator element 11, and has a width equal to the width of the multi-division scintillator element 11.
It is formed into a flat plate equal to the distance between the #11 field and the adjacent groove 11s, and is interposed on the lower surface of the multi-segment scintillator element 11 between the groove 11a and the adjacent groove 116 via an adhesive. It is glued like this. The collimating plate 13 is inserted into the valley groove 11G of the multi-segment scintillator element 11 having the photoelectric conversion cords 12, and its upper side protrudes from the upper surface of the multi-segment scintillator element 11, and its lower side extends to each photoelectric converter element 11. The conversion elements 12 are separated from each other.

Then, a collimating plate 15 is inserted into the valley groove 11, and a plurality of multi-segment scintillator elements 11 to which a large number of photoelectric conversion cables 12 are adhered to the lower surface are arranged on a support substrate 14, An arc-shaped X on the top surface! l
I! The detector 10 according to the present invention is constructed such that an incident surface is formed. is the multi-division scintillator element 1
The incident X-rays are incident on a surface sandwiched by collimating plates 16 on the upper surface of 1, and the incident X-rays are converted into particles of an amount proportional to the amount of incident XIs for each scintillator element divided by the collimating plates 16, and the converted dimension is It is converted into a current value proportional to the incident X-ray dose by the photoelectric conversion element 12 separated at the lower side of the collimating plate 16. When the detection 1110 is configured as described above, the groove 11@ is cut with a diamond cutter or wire saw, for example. Since it is easy to form, the distance between the grooves 11- and the adjacent grooves 11- of the multi-division scintillator element 11 can be narrowed by more than 2cm, and the resolution of the detector 100 can be increased. . Further, the dimensional accuracy of the multi-segment scintillator element 11 in this detector 10 depends on the machining accuracy of forming the groove 116.

a,.

No deviation occurs in the dimensions of the divided scintillator elements 110. In addition, it is possible to prevent errors in assembly accuracy that occur when arranging and assembling individual scintillator elements as in the past, and it is also multi-divided, which is equivalent to combining conventional individual scintillator elements into one. The collimating plate 16 is inserted into the groove 116 of the scintillator element 11, and the detector 1
0, its manufacture is extremely simple.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without changing the gist of the present invention.

For example, as shown in FIG. 4, a substantially rectangular parallelepiped scintillator element body having a flat long side and a short side t, and a photoelectric conversion element plate having a flat long side and a short side tl are prepared,
Align the - of the long side of the scintillator element body with the - of the long side of the charge conversion element plate (make sure that the longitudinal side surface of the scintillator element body and the longitudinal side surface of the photoelectric conversion element plate are on the same plane). ) Glue the photoelectric conversion element plate to the bottom surface of the 7-inch V-scintillator element body via adhesive, and then cut the scintillator element body and photoelectric conversion element plate to the same length using a diamond cutter, for example, from the same longitudinal side. One example is a detector in which a large number of tl grooves are formed, a collimating plate is inserted into the round can groove, and finally these are placed on a support substrate.If the detector is constructed in this way, Furthermore, the dimensional accuracy and processing accuracy can be improved. Constructing the detector using a zero light reflector, which may be filled with barium sulfate (BaSO4), etc., further simplifies manufacturing and reduces manufacturing costs.

〔Effect of the invention〕

According to the invention described in detail above, the following effects can be achieved. In other words, compared to conventional detectors constructed by arranging individual scintillator elements one by one, the present invention can be easily configured by forming a plurality of grooves in the scintillator element body. The components that make up the detector are formed. Therefore, the problem of improper placement of scintillator elements that has occurred in the past can be solved. That is, the accuracy of the shape of each scintillator element in a multi-division scintillator element only depends on the processing accuracy of forming the grooves, and the present invention makes it possible to manufacture a highly accurate detector. Furthermore, since the distance between the grooves can be made narrower, a detector with high resolution can be manufactured. t'#:...According to the present invention, since the method of constructing the detector is simple, the manufacturing cost of the detector can be significantly reduced. According to the present invention, it is possible to provide a radiation tomography apparatus capable of configuring nine tomographic images with excellent image quality.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional unit detection block, FIG. 2 is a schematic perspective view showing a conventional detector, FIG. 6 is a schematic perspective view showing an embodiment of the present invention, and FIG. FIG. 1 is a schematic top view showing a multi-segment scintillator element in an embodiment of the present invention.

Claims (2)

[Claims] (1) In a radiation detector comprising at least a plurality of scintillator elements that convert incident radiation into fluorescent light and a photoelectric conversion element that photoelectrically converts the fluorescent light emitted by the scintillator elements, each scintillator element receives radiation IiO incident on the radiation detector. Radiation detector characterized by being integrally combined outside the range〇 (2) The radiation detector according to claim 1, wherein the scintillator element is any one of cadmium tungstate, magnesium tungstate, zinc tungstate, and bismuth germanate.