JP2011043468A - Radiation tomograph, radiation detector provided for the same, and method for manufacturing radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation tomograph capable of accurately imaging a chemical distribution by reliably and orderly arranging scintillators. <P>SOLUTION: A detector unit 6 has three radiation detectors 1a, 1b, 1c. Scintillators of the radiation detectors 1a, 1b, 1c are glued to one another via a binding member 5. A first scintillator 2a and a second scintillator 2b are integrated via the binding member 5 to form a group of scintillators. The positional relation between the first scintillator 2a and the second scintillator 2b is therefore determined regardless of photo-detectors 3a, 3b, 3c. It is therefore possible to provide the detector unit 6 which is easily manufactured and in which the scintillators are orderly arranged. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a scintillator that converts radiation into light, a radiation detector that includes a light detector that detects light, a manufacturing method thereof, and a radiation tomography apparatus that includes the radiation detector.

  A medical institution is equipped with a radiation tomography apparatus for imaging the distribution of a radiopharmaceutical. A specific configuration of such a radiation tomography apparatus will be described. As shown in FIG. 12, the conventional radiation tomography apparatus includes a detector ring 62 in which radiation detectors 51 (see Patent Document 1) for detecting radiation are arranged in an annular shape. The detector ring 62 detects a pair of radiations (an annihilation radiation pair) that are irradiated from the radiopharmaceutical in the subject and have opposite directions.

  The configuration of the detector ring 62 will be described. As shown in FIG. 12, the detector ring 62 has a thickness corresponding to three radiation detectors 51 in the z direction. The detector rings 62 are all composed of the same radiation detector 51.

  An inspection method using a radiation tomography apparatus will be described. A subject to which a radiopharmaceutical is injected is introduced into the detector ring 62. The radiation tomography apparatus images the distribution of the radiopharmaceutical with respect to the portion of the subject introduced inside the detector ring 62. In this way, the space inside the detector ring 62 is an imaging field of view of the radiation tomography apparatus. The distribution of the radiopharmaceutical imaged is displayed on the attached display unit.

  By the way, the detection data output from the detector ring 62 is assembled into an image showing the distribution of the radiopharmaceutical through various data processing. Data processing at this time is performed on the assumption that the detector rings 62 are arranged in an orderly manner along a virtual circle.

US Pat. No. 6,552,348

  However, the conventional configuration has the following problems. That is, according to the conventional configuration, there is a limit to orderly arranging the radiation detectors 51. Data processing for imaging radiopharmaceuticals cannot take into account the misalignment of the radiation detectors 51. Therefore, if the positions of the radiation detectors 51 are misaligned, the generation positions of the radiopharmaceuticals cannot be correctly reflected. Due to the displacement of the position of the radiation detector 51 constituting the detector ring 62, the generation position of the radiopharmaceutical is displaced and displayed on the image. In other words, if the detector ring 62 is distorted, the image is distorted accordingly.

  Therefore, the radiation detectors 51 constituting the detector ring 62 should be arranged as ideally as possible. However, according to the conventional configuration, there is a dimensional error in each of the radiation detectors 51. Therefore, even if the radiation detectors 51 are arranged in an orderly manner, they are not arranged as set. Therefore, in order to arrange the radiation detector 51 on the detector ring 62 in an orderly manner, it is necessary to manufacture the radiation detector 51 with as much accuracy as possible.

  According to the conventional configuration, the radiation detector 51 is connected to the bottom plate of the detector ring 62 via the bleeder unit 66 as shown in FIG. Thus, since the detector ring 62 is formed by fixing the bleeder unit 66, if the bleeder unit 66 is not manufactured with high accuracy together with the radiation detector 51, the radiation detector 51 is connected to the detector ring 62. They are not neatly arranged. There is a limit to the accuracy with which the radiation detector 51 is manufactured.

  Although the radiation detectors 51 need to be arranged in an orderly manner, more specifically, the arrangement of the scintillators 52 included in the radiation detector 51 should be arranged in an orderly manner. If the position of the scintillator 52 is deviated, the detector ring 62 cannot correctly recognize the radiation generation position. This is because the radiation detector 51 determines the generation position of the radiation by determining which position of the scintillator 52 the radiation has entered. If the scintillator 52 positioned at the forefront of the radiation detector 51 is arranged in an orderly manner, according to the conventional configuration, not only all members constituting the detector ring 62 must be manufactured with high accuracy, but also the detector ring. Considerable attention is also required for the assembly of 62.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a radiation tomography apparatus capable of accurately imaging a drug distribution by arranging scintillators in an orderly manner, and to provide it. And a method of manufacturing the radiation detector.

The present invention has the following configuration in order to solve the above-described problems.
That is, the radiation detector according to the present invention includes a first radiation detection unit configured by optically connecting a first scintillator that converts radiation into light and a first photodetector that detects the light; A second scintillator configured to optically connect a second scintillator that converts radiation into light and a second photodetector that detects the light; and the first scintillator and the second scintillator are It is characterized by being bonded via a coupling member.

  [Operation / Effect] According to the present invention, it is possible to provide a radiation detector capable of more accurately discriminating the generation position of radiation. The radiation detector in the present invention has at least two radiation detection means. This radiation detection means is a general one having a scintillator and a photodetector. Various medical devices can be manufactured by arranging a plurality of radiation detection means. However, unless the radiation detection means are arranged in an orderly manner, the radiation generation position cannot be accurately known.

  According to the present invention, the scintillators included in the radiation detection means are bonded to each other via the coupling member. The first scintillator and the second scintillator are integrated through a coupling member to constitute a scintillator group. Therefore, the positional relationship between the first scintillator and the second scintillator is determined by the positional relationship between each scintillator and the coupling member, and is not determined by the positional relationship between the photodetector and the scintillator. Therefore, the position of the first scintillator and the first photodetector is strict, and the position of the second scintillator and the second photodetector is not strict as in the prior art. The relationship is accurate. Therefore, it is possible to provide a radiation detector that is easy to manufacture and in which scintillators are arranged in an orderly manner.

  The invention according to claim 2 is characterized in that, in the radiation detector according to claim 1, the coupling member does not allow light emitted from the scintillator to pass through the adjacent scintillator.

  [Operation / Effect] According to the above-described configuration, it is possible to provide a radiation detector that can accurately determine the incident position of radiation without interfering with an adjacent scintillator. That is, the radiation detection means are independent from each other, the radiation incident on the first scintillator is detected exclusively by the first photodetector, and the radiation incident on the second scintillator is exclusively detected by the second photodetector. Is done. If light travels between adjacent scintillators, radiation cannot be detected accurately. According to the above-described configuration, since the scintillators are optically separated by the coupling member, the scintillator and the photodetector correspond one-to-one, and a radiation detector that can determine the position of radiation more accurately is provided. it can.

  The invention according to claim 3 is the radiation detector according to claim 1 or 2, wherein the first photodetector and the second photodetector are arranged in a direction different from the scintillator arrangement direction. The scintillator is connected to each of the first scintillator and the second scintillator. When the back surface when the scintillator is viewed from the direction in which the photodetector is connected is the incident surface of the scintillator, the first scintillator is the incident surface of the first scintillator. The first incident surface and the second incident surface which is the incident surface of the second scintillator are on the same plane.

  [Operation / Effect] The above-described configuration represents a specific mode of the radiation detector of the present invention. First, the first photodetector and the second photodetector are connected to each scintillator from a direction different from the scintillator arrangement direction (direction in which the scintillators are bonded to each other). The first incident surface on which the radiation of the first scintillator is incident and the second incident surface on which the radiation of the second scintillator is incident exist on the same plane. That is, the second incident surface is provided at a position as if the first incident surface was expanded. By comprising in this way, the radiation detector with which the position of each scintillator was prepared correctly can be provided.

  According to a fourth aspect of the present invention, in the radiation detector according to any one of the first to third aspects, the first scintillator and the second scintillator are configured such that scintillator crystals are arranged vertically and horizontally to form an incident surface. In addition, the horizontal width of the coupling member is an integral multiple of the horizontal arrangement pitch of the scintillator crystals.

  [Operation / Effect] The above-described configuration represents a specific mode of the radiation detector of the present invention. That is, in each scintillator, scintillator crystals are arranged vertically and horizontally to form an incident surface. Moreover, each scintillator is coupled from the lateral direction. The lateral width of the coupling member is an integral multiple of the lateral arrangement pitch of the scintillator crystals. Consider a virtual grid in which dots are arranged vertically and horizontally on the incident surface of the first scintillator. Each grid point is assumed to be located at the center of each first scintillator crystal. And the point of this grid is located in each of the center of the scintillator crystal | crystallization which comprises this entrance plane in the entrance plane of a 2nd scintillator. Thus, the pitch and phase of the arrangement of scintillator crystals constituting the radiation detector are unified across the scintillators. As a result, the positional relationship between the scintillators becomes more precise.

  The invention according to claim 5 is the radiation detector according to any one of claims 1 to 4, wherein the coupling member is configured such that the base member is sandwiched between the two reflective films from the lateral direction. In addition, the scintillator, the reflective film, and the base member are bonded via an adhesive, and the reflective film reflects light and has flexibility and can be peeled from the scintillator. It is what.

  [Operation / Effect] The above-described configuration shows the details of the coupling member of the present invention. That is, the coupling member has a three-layer structure of a base member and a reflective film, and the base member is sandwiched between two reflective films. This reflective film is bonded to the scintillator via an adhesive. Moreover, the reflective film has flexibility and can be peeled off from the scintillator. Thereby, a radiation detector can be decomposed | disassembled per scintillator.

  The invention according to claim 6 has a detector ring in which the radiation detectors are arranged in a ring shape in the radiation tomography apparatus equipped with any one of claims 1 to 5. It is characterized by.

  [Operation / Effect] The above-described configuration is obtained by applying the radiation detector of the present invention to a radiation tomography apparatus. In such a radiation tomography apparatus, a detector ring is configured by arranging radiation detectors in which scintillators are arranged in an orderly manner in an annular shape. Since the arrangement of the scintillators of the detector ring is orderly, a radiation tomography apparatus capable of acquiring a tomographic image showing the drug distribution accurately can be provided.

  According to a seventh aspect of the present invention, there is provided a radiation detector manufacturing method comprising: an adhesive introduction step for introducing a liquid adhesive into a concave portion of an adhesive container; and a temporary assembly in which scintillator crystals are three-dimensionally arranged in the concave portion of the adhesive container. For each of the scintillators, a temporary assembly scintillator introduction step for introducing the scintillator and a coupling member, a curing step for curing the adhesive, a step of taking out a scintillator group in which a plurality of scintillators are connected by the coupling member from the adhesive container, and An assembly step for attaching a photodetector for detecting light, and in the provisional assembly scintillator introduction step, a coupling member is arranged at a position sandwiched between each of the temporary assembly scintillators arranged in series It is.

  [Operation / Effect] The method of manufacturing the radiation detector of the present invention is a method of manufacturing the above-described radiation detector. That is, the coupling members are arranged at positions sandwiched between the temporary assembly scintillators, and in this state, the respective members are bonded with an adhesive. Since each of the temporary assembly scintillators is arranged in the concave portion of the adhesive container, each of the temporary assembly scintillators is located on the bottom surface of the concave portion of the adhesive container. In this way, the scintillator crystal of the temporarily assembled scintillator contacts the bottom surface of the concave portion of the bonding container and is bonded in a state where the positions are aligned. If the contact surface of the adhesive container is an incident surface on which radiation is incident, a radiation detector can be provided in which the incident surfaces of the scintillators are on the same plane.

1 is a functional block diagram illustrating a configuration of a radiation tomography apparatus according to Embodiment 1. FIG. FIG. 3 is a perspective view illustrating a configuration of a detector unit according to Embodiment 1. 3 is a perspective view illustrating a configuration of a coupling member according to Embodiment 1. FIG. It is a schematic diagram which shows a mode that the detector unit which concerns on Example 1 is decomposed | disassembled. It is a schematic diagram which shows a mode that the detector unit which concerns on Example 1 is decomposed | disassembled. It is a perspective view explaining the structure of the detector ring which concerns on Example 1. FIG. It is a perspective view explaining the structure of the detector ring which concerns on Example 1. FIG. 6 is a cross-sectional view illustrating a method for manufacturing the detector unit according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a method for manufacturing the detector unit according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a method for manufacturing the detector unit according to Embodiment 1. FIG. 6 is a cross-sectional view illustrating a method for manufacturing the detector unit according to Embodiment 1. FIG. It is a schematic diagram which shows the structure of the conventional radiation tomography apparatus. It is a schematic diagram which shows the structure of the conventional radiation tomography apparatus.

<Configuration of radiation tomography system>
Embodiments of a radiation tomography apparatus according to the present invention will be described below with reference to the drawings. The gamma rays in Example 1 are an example of the radiation of the present invention. The configuration of the first embodiment is a mammography apparatus for breast examination. FIG. 1 is a functional block diagram illustrating a specific configuration of the radiation tomography apparatus according to the first embodiment. The radiation tomography apparatus 9 according to the first embodiment includes a gantry 11 that introduces the subject's breast from the z direction, and a ring-shaped detector ring that introduces the subject's breast provided inside the gantry 11 from the z direction. 12. The inner hole provided in the detector ring 12 has a cylindrical shape (exactly an octagonal prism) extending in the z direction. Therefore, the detector ring 12 itself extends in the z direction. Note that the area of the inner hole of the detector ring 12 is a field of view in which a tomographic image of the radiation tomography apparatus 9 can be generated.

  The shielding plate 13 is made of tungsten or the like. Since the radiopharmaceutical is also present in parts other than the breast B of the subject, annihilation γ-ray pairs are also generated from there. When an annihilation gamma ray pair generated from a part other than such a region of interest enters the detector ring 12, it interferes with tomographic imaging. Therefore, a ring-shaped shielding plate 13 is provided so as to cover one end of the detector ring 12 on the side close to the subject M in the z direction.

  The clock 19 sends time information as a serial number to the detector ring 12. The detection data output from the detector ring 12 is given time information indicating when the γ-ray is detected, and is input to the filter unit 20 described later.

  The filter unit 20 (see FIG. 1) is provided for the purpose of preventing unnecessary data in the detector ring 12 from being sent to the coincidence counting unit 21. Since the coincidence counting unit 21 has to handle a large amount of data, it is likely to be loaded. The filter unit 20 can thin out the detection data so as to reduce the load on the coincidence counting unit 21. For example, all the detection data when the subject M is not inserted into the detector ring 12 is discarded by the filter unit 20 and is not input to the coincidence counting unit 21.

  Detection data output from the detector ring 12 is sent to the coincidence counting unit 21 (see FIG. 1) via the filter unit 20. The two gamma rays simultaneously incident on the detector ring 12 are annihilation gamma ray pairs caused by the radiopharmaceutical in the subject. The coincidence counting unit 21 counts the number of times that an annihilation γ-ray pair is detected for every two combinations of scintillator crystals constituting the detector ring 12, and sends the result to the tomographic image generation unit 22. The positional relationship of the scintillator crystals in coincidence indicates the position and direction in which the annihilation γ-ray pair enters the detector ring 12, and is used for mapping of the radiopharmaceutical. The number of detected annihilation γ-ray pairs and the energy intensity of annihilation radiation memorized for each combination of scintillator crystals indicate the variation in the generation of annihilation γ-ray pairs in the subject, which is also used for mapping radiopharmaceuticals. It is done. The coincidence of the detected data by the coincidence counting unit 21 uses time information given to the detected data by the clock 19.

  The display unit 36 displays the tomographic image generated by the tomographic image generation unit 22, and the console 35 allows the operator to input various operations performed on the radiation tomography apparatus 9. The storage unit 37 includes detection data output from the detector ring 12, coincidence count data generated by the coincidence counting unit 21, tomographic images output from the tomographic image generation unit 22, and the like, and data generated by the operation of each unit and operation of each unit It stores all referenced parameters.

  The radiation tomography apparatus 9 includes a main control unit 41 that controls each unit in an integrated manner, and a display unit 36 that displays a radiation tomographic image. The main control unit 41 is constituted by a CPU, and realizes the respective units 19, 20, 21, and 22 by executing various programs. In addition, each above-mentioned part may be divided | segmented and implement | achieved by the control apparatus which takes charge of them.

  The detector ring 12 will be described. Specifically, detector units 6 (see FIG. 2) in which three radiation detectors are connected in the z direction are arranged in an annular shape to form a detector ring 12 having a central axis along the z direction. Yes. First, the detector unit 6 will be described. The detector unit 6 corresponds to the radiation detector of the present invention.

  The detector unit 6 has a configuration in which three radiation detectors are arranged along the z direction (the lateral direction of the present invention) as shown in FIG. Attention is paid to the first radiation detector 1a among the radiation detectors. The first radiation detector 1a includes a first scintillator 2a that converts γ-rays into light (fluorescence), and a first photodetector 3a that detects the light, and further includes the first scintillator 2a and the first scintillator 2a. A first light guide 4a for transmitting and receiving light provided at a position intervening with the one photodetector 3a is provided. The first scintillator 2a, the first light guide 4a, and the first photodetector 3a are stacked in this order, and are optically coupled to each other. The first radiation detector 1a corresponds to the first radiation detection means of the present invention.

The first scintillator 2a that is a rectangular parallelepiped is configured by three-dimensionally arranging the rectangular scintillator crystals C. The scintillator crystal C is composed of Lu _{2 (1-X)} Y _2X SiO ₅ (hereinafter referred to as LYSO ₎ in which Ce is diffused. The first photodetector 3a can specify the light generation position, which scintillator crystal emits light, and also specifies the light intensity and the time when the light was generated. can do.

  The first scintillator 2a has an incident surface Sa on which γ rays are incident. The incident surface Sa is a back surface when a surface adjacent to the first photodetector 3a of the first scintillator 2a is taken as a table. That is, the incident surface Sa is the back surface when the surface connected to the first light guide 4a in the first scintillator 2a is set as the front.

  The second radiation detector 1b and the third radiation detector 1c have the same configuration as the first radiation detector 1a. That is, the second radiation detector 1b includes a second scintillator 2b, a second light guide 4b, and a second photodetector 3b. And when the surface connected to the 2nd light guide 4b in the 2nd scintillator 2b is made into a table | surface, the back surface is the 2nd entrance plane Sb. Similarly, the third radiation detector 1c includes a third scintillator 3c, a third light guide 4c, and a third photodetector 3c. And when the surface connected to the 3rd light guide 4c in the 3rd scintillator 3c is made into a table | surface, the back surface becomes the 3rd entrance plane Sc. The second radiation detector 1b corresponds to the second radiation detection means of the present invention.

  The first incident surface Sa, the second incident surface Sb, and the third incident surface Sc are formed by two-dimensionally arranging the scintillator crystals C vertically and horizontally (zx direction). In addition, all the incident surfaces Sa, Sb, and Sc are on the same plane.

  The most characteristic configuration of the detector unit 6 in the present invention will be described. That is, each of the scintillators is arranged in the z direction with the coupling member 5 interposed therebetween, and each of the scintillators is bonded and integrated through the coupling member 5. The width in the z direction of the coupling member 5 is an integral multiple (preferably twice) of the arrangement pitch in the z direction of the scintillator crystals C constituting the scintillator. Moreover, the arrangement of the scintillator crystals C is unified across the scintillators. That is, each of the scintillators is arranged to be at the same position in the x direction. In other words, the scintillator crystal C mainly forms the scintillator crystal array A (see FIG. 2) in a row in the z direction (lateral direction) across the scintillators 2a, 2b, and 2c. This scintillator crystal array A is arranged in the x direction (longitudinal direction), and the respective incident surfaces Sa, Sb, Sc are formed.

  Further, the direction in which the scintillator, the light guide, and the photodetector are arranged and the direction in which the scintillators are arranged are orthogonal to each other and different from each other. The z direction in which the first scintillator and the second scintillator are coupled is parallel to the central axis of the detector ring 12 in FIG.

  The configuration of the coupling member 5 will be described. As shown in FIG. 3, the coupling member 5 includes an acrylic base member 5a and two reflective films 5b. The base member 5a is disposed at a position between the two reflection films 5b. The reflective film 5b is a member having excellent flexibility capable of reflecting light, and the thickness in the z direction is about 65 μm. Light generated by a certain scintillator hits the reflection film 5b and is reflected, and does not go to the adjacent scintillator. In this way, each of the scintillators is optically independent. The base member 5a, the reflective film 5b, and the scintillators 2a, 2b, 2c constituting the coupling member 5 are fixed with an adhesive.

  Moreover, the detector unit 6 can be disassembled for each scintillator in some cases. As shown in FIG. 4, when the metal shim 7 is inserted into the coupling surface between the base member 5a and the reflective film 5b, the base member 5a and the reflective film 5b are separated, and the reflective film 5b covering the side surface of the first scintillator 2a is formed. Exposed.

  If the reflective film 5b is exposed, the reflective film 5b has flexibility, so that the reflective film 5b covering the side surface of the first scintillator 2a can be peeled off as shown in FIG. Thus, according to the configuration of the first embodiment, the detector unit 6 can be disassembled for each scintillator (for each radiation detector), and at that time, it is necessary to bring the metal shim 7 into contact with the first scintillator 2a. No. Thereby, the metal shim 7 does not damage the first scintillator 2a.

  A plurality of detector units 6 are arranged in an annular shape to form a detector ring 12. Next, the detector ring 12 will be described. Each detector unit 6 is fixed to a support plate 21 via a bleeder unit 16 as shown in FIG. The three bleeder units 16 are coupled to the back surface when the surfaces coupled to the light guides 4a, 4b, and 4c among the surfaces of the photodetectors 3a, 3b, and 3c are the front. On the back surface of the photodetectors 3a, 3b, 3c, pins for electrical connection with the bleeder unit 16 are erected, and the coupling surface coupled to the photodetectors 3a, 3b, 3c of the bleeder unit 16 is It is a socket of the above-described pin group. Of each surface of the bleeder unit 16, the back surface of the surface coupled to the photodetector is fixed to the main plate 21 a of the L-shaped support plate 21. Thus, if the direction in which the scintillators 2a, 2b, 2c and the photodetectors 3a, 3b, 3c are stacked is the y direction, the detector unit 6, the bleeder unit 16, and the support plate 21 are stacked in this order in the y direction. Has been. The bleeder unit 16 is provided for the purpose of supplying a high voltage to the photodetectors 3a, 3b, 3c. The support plate 21 includes a sub-plate 21b that extends away from the bleeder unit 16 in the y direction.

  Then, as shown in FIG. 7, eight members in which the detector unit 6 and the support plate 21 are integrated are prepared, and these are arranged in an annular shape to constitute the detector ring 12. Each sub-plate 21b of the support plate 21 contacts the disk 14 from the z direction. The sub plate 21b is provided with a hole 21c, and the disc 14 is provided with a hole 14a corresponding to the hole 21c. Bolts are inserted into the holes 21c and 14a, and the support plate 21 and the disc 14 are fixed by fastening the bolts. A shield plate 13 is provided on the back surface of the detector ring 12 when the disk 14 side is the front.

<Operation of radiation tomography system>
Next, the operation of the radiation tomography apparatus according to Embodiment 1 will be described. First, a radiopharmaceutical is injected into the subject M. When a predetermined time has elapsed from this point, the subject's breast B is inserted into the detector ring 12. When the surgeon instructs the detection of the annihilation gamma ray pair through the console 35, the detector ring 12 starts sending detection data to the filter unit 20. The detection data transmitted at this time is a data set in which the incident position, energy, and incident time of the radiation detector ring 12 are linked.

  The coincidence unit 21 performs coincidence on the detected data and sends the result to the tomographic image generation unit 22. The tomographic image generation unit 22 generates a tomographic image such that the breast B of the subject is cut into circles, and this is displayed on the display unit 36. This completes the operation of the radiation tomography apparatus according to the first embodiment.

  As described above, according to the present invention, it is possible to provide the detector unit 6 that can more accurately determine the generation position of γ rays. The detector unit 6 in the present invention has three radiation detectors 1a, 1b, and 1c. The radiation detectors 1a, 1b, and 1c are general ones having a scintillator and a photodetector. Various medical devices are manufactured by arranging a plurality of radiation detectors 1a, 1b, and 1c. However, unless the radiation detectors 1a, 1b, and 1c are arranged in an orderly manner, the generation position of γ rays cannot be accurately known.

  According to the present invention, the scintillators 2 a, 2 b, 2 c of the radiation detectors 1 a, 1 b, 1 c are bonded to each other via the coupling member 5. The 1st scintillator 2a, the 2nd scintillator 2b, and the 3rd scintillator 2c are integrated via the coupling member 5, and a scintillator group is comprised. Therefore, the positional relationship among the first scintillator 2a, the second scintillator 2b, and the third scintillator 2c is determined regardless of the photodetector. Therefore, as in the prior art, the positional relationship between the first scintillator 2a and the first photodetector 3a is strict, and the positional relationship between the second scintillator 2b and the second photodetector 3b is also strict, Even if the positional relationship between the third scintillator 2c and the third photodetector 3c is not accurate, the positional relationship between the scintillators is accurate. Therefore, it is possible to provide the detector unit 6 that is easy to manufacture and in which the scintillators are arranged in an orderly manner.

  According to the above configuration, it is possible to provide the detector unit 6 that can accurately determine the incident position of the γ-ray without interfering with the adjacent scintillator. That is, the radiation detectors 1a, 1b, and 1c are independent from each other, and the γ rays incident on the first scintillator 2a are exclusively detected by the first photodetector 3a and are incident on the second scintillator 2b. Is detected exclusively by the second photodetector 3b. Similarly, γ rays incident on the third scintillator 2c are exclusively detected by the third photodetector 3c. If light travels between adjacent scintillators, γ rays cannot be detected accurately. According to the above-described configuration, since the scintillators are optically separated by the coupling member 5, the scintillator and the photodetector correspond one-to-one, and the detector unit can more accurately determine the position of the γ-ray. 6 can be provided.

  The detector unit 6 of the present invention is specifically as follows. First, the first photodetector 3a, the second photodetector 3b, and the third photodetector 3c are connected to the scintillators 2a, 2b, and 2c from the y direction different from the z direction. And the 1st entrance plane Sa which injects the gamma ray of the 1st scintillator 2a, 2nd entrance plane Sb in which the gamma ray of the 2nd scintillator 2b injects, and the 3rd entrance plane in which the gamma ray of the 3rd scintillator 2c enters Sc is on the same plane. That is, the second incident surface Sb and the third incident surface Sc are provided at positions as if the first incident surface Sa was expanded. With this configuration, it is possible to provide the detector unit 6 in which the positions of the scintillators 2a, 2b, 2c are accurately aligned.

  Further, each scintillator 2a, 2b, 2c is composed of scintillator crystals C arranged vertically and horizontally to form each incident surface Sa, Sb, Sc. Moreover, each scintillator 2a, 2b, 2c is coupled from the z direction (lateral direction). The width in the z direction of the coupling member 5 is an integral multiple of the arrangement pitch of the scintillator crystals C in the z direction. Consider a virtual grid in which dots are arranged on the zx plane to which the incident surface Sa of the first scintillator 2a belongs. Each point of the grid is assumed to be located at the center of each of the first scintillator crystals C. The grid point is located at each of the centers of the scintillator crystals C constituting the incident surface in the second incident surface Sb of the second scintillator 2b, and is incident on the third incident surface Sc of the third scintillator 2c. It is located at each of the centers of scintillator crystals C constituting the surface. As described above, the pitch and phase of the arrangement of the scintillator crystals C constituting the detector unit 6 are unified over the scintillators 2a, 2b, and 2c. As a result, the positional relationship between the scintillators becomes more precise.

  The above-described coupling member 5 has a three-layer structure of a base member 5a and a reflective film 5b, and the base member 5a is sandwiched between two reflective films 5b. This reflection film 5b is bonded to the scintillator via the adhesive 44. The reflective film 5b has flexibility and can be peeled off from the scintillator. Thereby, the detector unit 6 can be disassembled in units of scintillators.

  The detector unit 6 of the present invention is adapted for a radiation tomography apparatus. In the radiation tomography apparatus, a detector ring is formed by arranging detector units 6 in which scintillators are arranged in an orderly manner in an annular shape. Since the arrangement of the scintillators of the detector ring is orderly, a radiation tomography apparatus capable of acquiring a tomographic image showing the drug distribution accurately can be provided.

<Manufacturing method of detector unit>
Next, a method for manufacturing the detector unit 6 will be described. In order to manufacture the detector unit 6, first, scintillator crystals C are three-dimensionally arranged to manufacture a temporarily assembled scintillator. The scintillator crystals C at this time are not bonded to each other. As shown in FIG. 8, the temporarily assembled scintillator includes a temporary assembled scintillator K in which scintillator crystals C are three-dimensionally arranged along the x, y, and z directions. The film in FIG. 8 covers the bottom surface, side surface (yz surface), and top surface of the scintillator. Although not shown, another film 42 is prepared and covers the bottom surface, side surface (zx surface), and top surface of the scintillator. Accordingly, the side surface (zx plane) where the scintillator crystal C appears to be exposed in FIG. 8 is actually covered with another film 42 (not shown). That is, all six surfaces of the temporary assembly scintillator K that is a rectangular parallelepiped are covered with the film 42. The tongues at both ends of the film 42 are attached with an adhesive tape. The temporary assembly scintillator K is restrained by the two films 42 and maintains its shape without collapsing.

  The three temporarily assembled scintillators are introduced into the adhesive container 43 (see FIG. 9). The adhesive container 43 is provided with a recess 43a for fitting the temporary assembly scintillator K, and the recess 43a is uncured. The liquid adhesive 44 is introduced in advance (adhesive introduction step). As the adhesive, a silicon-based or epoxy-based optical adhesive is desirable.

  A bottom plate 43b is fitted into the bottom of the recess 43a. The bottom plate 43b is rotatably connected to a screw 43c that penetrates the bottom of the adhesive container 43 and extends vertically downward (z direction), and when the screw 43c is pushed in the direction of the recess 43a, The bottom plate 43b is pushed up in the direction of coming out of the recess 43a.

  Three temporary assembly scintillators K are introduced into the recess 43a (temporary assembly scintillator introduction step). At this time, the coupling member 5 is introduced at a position between the adjacent temporary assembly scintillators K. In this way, as shown in FIG. 10, the temporary assembly scintillator K and the coupling member 5 are alternately arranged in series. At this time, the temporary assembly scintillator and the coupling member 5 sink to the adhesive before curing.

  When the adhesive tape affixed to the tongue portion of the film 42 is peeled off and tension is applied to one of the tongue portions, the film 42 is extracted from the recess 43a. At this time, the temporary assembly scintillator K and the coupling member 5 (precisely, the reflection film b) are brought into contact with each other. At this time, the shim 45 is introduced into the gap between the temporary assembly scintillator K and the inner wall of the recess 43a, and the temporary assembly scintillator K and the connecting member 5 are pressed against the recess 43a on the opposite inner wall side. Then, the scintillator crystal C and the coupling member 5 are arranged without gaps in the series direction (x direction) of the temporary assembly scintillator K (see FIG. 11). At this time, the adhesive container 43 is placed in a reduced pressure state to expel the air accumulated in the gaps between the members. As a result, the adhesive infiltrates all over the gaps between the scintillator crystal C and the coupling member 5.

  In this state, the adhesive container 43 is introduced into the oven and the thermosetting adhesive is cured (curing step). When the adhesive container 43 is taken out from the oven, the adhesive is cured, and a scintillator group in which the scintillators are connected by the connecting member 5 is generated. When the bottom plate 43b is pushed up at this point, the scintillator group comes out of the recess 43a of the bonding container 43 (takeout step).

  The bottom and side surfaces of the scintillator are in contact with the adhesive container 43, and there is no room for burrs of the hardened adhesive or the like to adhere to the scintillator, and the scintillator can be used for the detector unit 6 without any processing. The upper surface of the scintillator is a portion that has become the liquid surface of the adhesive 44, and a thin skin of the useless adhesive 44 is attached thereto. If this thin skin is removed, the scintillator group is completed.

  A light guide and a photodetector are attached to each of the scintillators constituting the scintillator group to complete a detector unit (assembly step).

  As described above, the method for manufacturing the detector unit 6 according to the present invention shows a method for manufacturing the detector unit 6 described above. That is, the coupling member 5 is disposed at a position sandwiched between the temporary assembly scintillators K, and in this state, the members are bonded by the adhesive 44. Since each of the temporary assembly scintillators K is arranged in the recess 43a of the bonding container 43, each of the temporary assembly scintillators K is located on the bottom surface of the recess 43a of the bonding container 43. In this way, the scintillator crystal C of the temporarily assembled scintillator K abuts on the bottom surface of the recess 43a of the bonding container 43 and is bonded in a state where the positions are aligned. If the contact surface of the adhesive container 43 is an incident surface on which γ rays are incident, the detector unit 6 in which the incident surfaces of the scintillators 2a, 2b, and 2c are on the same plane can be provided.

  The present invention is not limited to the above-described configuration, and can be modified as follows.

(1) The scintillator crystal referred to in each of the above embodiments is composed of LYSO. However, in the present invention, the scintillator crystal is composed of other materials such as GSO (Gd ₂ SiO ₅ ) instead. Also good. According to this modification, it is possible to provide a method of manufacturing a radiation detector that can provide a cheaper radiation detector.

  (2) In each of the embodiments described above, the photodetector is composed of a photomultiplier tube, but the present invention is not limited to this. Instead of the photomultiplier tube, a photodiode, an avalanche photodiode, a semiconductor detector, or the like may be used.

C scintillator crystal K temporary assembly scintillator Sa first incident surface Sb second incident surface 1a first radiation detector (first radiation detection means)
1b Second radiation detector (second radiation detection means)
2a 1st scintillator 2b 2nd scintillator 3a 1st photodetector 3b 2nd photodetector 5 Coupling member 5a Base member 5b Reflective film 6 Detector unit (radiation detector)
43 Adhesive container 43a Recess 44 Adhesive

Claims (7)

A first radiation detector configured to optically connect a first scintillator that converts radiation into light and a first photodetector that detects the light;
A second scintillator that converts radiation into light, and a second radiation detector configured to be optically connected to a second photodetector that detects the light,
The radiation detector, wherein the first scintillator and the second scintillator are bonded via a coupling member. The radiation detector according to claim 1.
The coupling member prevents a light emitted from a scintillator from passing through an adjacent scintillator. The radiation detector according to claim 1 or 2,
The first photodetector and the second photodetector are connected to each of the first scintillator and the second scintillator from a direction different from the arrangement direction of the scintillators,
When the back surface when the scintillator is viewed from the direction in which the photodetector is connected is the entrance surface of the scintillator,
The radiation detector according to claim 1, wherein the first incident surface that is the incident surface of the first scintillator and the second incident surface that is the incident surface of the second scintillator are on the same plane. The radiation detector according to any one of claims 1 to 3,
The first scintillator and the second scintillator have scintillator crystals arranged vertically and horizontally to form an incident surface and coupled from the lateral direction,
The radiation detector according to claim 1, wherein a width of the coupling member in a lateral direction is an integral multiple of a lateral arrangement pitch of the scintillator crystals. The radiation detector according to any one of claims 1 to 4,
The coupling member has a configuration in which the base member is sandwiched between two reflective films from the lateral direction,
The scintillator, the reflective film, and the base member are bonded via an adhesive,
The reflection film reflects light, has flexibility, and can be peeled off from the scintillator. In the radiation tomography apparatus carrying the radiation detector in any one of Claims 1 thru | or 5,
A radiation tomography apparatus comprising: a detector ring configured by arranging the radiation detectors in an annular shape. An adhesive introduction step for introducing a liquid adhesive into the recess of the adhesive container;
A temporary assembly scintillator introduction step for introducing a temporary assembly scintillator in which scintillator crystals are three-dimensionally arranged in the concave portion of the adhesive container, and a coupling member;
A curing step for curing the adhesive;
A step of taking out a scintillator group in which a plurality of scintillators are connected by the coupling member from the adhesive container;
An assembly step of attaching a photodetector for detecting light to each of the scintillators;
In the temporary assembly scintillator introduction step, the coupling member is disposed at a position sandwiched between the temporary assembly scintillators arranged in series.

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