JP2012115559A - Radiation tomograph for small animal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation tomograph for small animals, capable of photographing a plurality of subjects at one time.SOLUTION: The tomograph can be provided which can photograph the plurality of subjects at one time. In other words, the tomograph according to the constitution of an example 1 has a holder 5 having polygonal openings 5a arranged in a honeycomb shape. Thus, the number of openings 5a arranged in the holder 5 can be increased as much as possible. Moreover the tomograph with high operating efficiency of experiment can be provided because it is possible to increase the number of the subjects M which can be held in the holder 5. Further, the tomograph can create more clear tomographic images by partitioning walls 5b getting thin.

Description

  The present invention relates to a radiation tomography apparatus for small animals that captures tomographic images of small animals as a research object, and more particularly to a radiation tomography apparatus for small animals that can photograph a plurality of small animals at once.

  One device for imaging small animals as research objects is a radiation tomography apparatus for small animals. This apparatus is capable of generating a tomographic image of a small animal, and an experimenter can know the internal structure of the small animal with reference to this image (see, for example, Patent Document 1).

  A conventional configuration of such a small animal radiation tomography apparatus will be described. As shown in FIG. 11, the conventional apparatus has a gantry 51 provided with an opening. Inside the gantry 51, a radiation source 53 for irradiating radiation and a radiation detector 54 for detecting radiation are provided. It has been. The radiation source 53 and the radiation detector 54 are arranged so as to sandwich the opening of the gantry 51, and can be rotated around the opening while maintaining the relative position of each other. Inside this opening, a small animal as a subject is arranged.

  The operation of a conventional radiation tomography apparatus for small animals will be described. In order to acquire a tomographic image of a subject using a conventional apparatus, the subject is first inserted into the opening of the gantry 51. Then, imaging is performed a plurality of times while rotating the radiation source 53 and the radiation detector 54 around the subject. Each of the obtained fluoroscopic images includes an image of a subject having a different imaging direction. When these fluoroscopic images are assembled, a tomographic image of the subject can be generated.

International Publication No. 2007/141831

However, the conventional configuration has the following problems.
That is, according to the conventional configuration, only a tomographic image of an integrated small animal can be acquired by one imaging, and the work efficiency of the experiment is low.

  In physiological experiments, there are generally some variations in the results obtained due to individual differences and measurement errors in small animals. Therefore, in an experiment using small animals, the same experimental process is performed on a plurality of small animals, and experimental results are obtained in consideration of variation in results. Therefore, the imaging of the radiation tomography apparatus for small animals is usually performed for a plurality of small animals. That is, when one experiment is performed, photographing of small animals is repeated one by one.

  The tomographic image is taken while a small animal inside the gantry 51 is moved in the gantry 51. At that time, the movement of the small animal with respect to the gantry 51 and the acquisition of a plurality of fluoroscopic images are alternately repeated, and a tomographic image of the whole body of the small animal is photographed. Therefore, once shooting starts, the next shooting cannot be started immediately. Thus, with the conventional configuration, the experimental operation cannot be completed quickly.

  Therefore, if there is a tomography apparatus that can photograph a plurality of small animals at once, the efficiency of the experimental operation will be further improved. In addition, according to such an apparatus, the imaging time of each subject can be matched, so that a more stable experimental result can be derived.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a radiation tomography apparatus for small animals capable of imaging a plurality of subjects at a time.

The present invention has the following configuration in order to solve the above-described problems.
That is, the radiation tomography apparatus for small animals according to the present invention is centered on the center point on the line segment connecting the radiation source and the radiation detection means, the radiation detection means for irradiating the radiation, the radiation detection means for detecting the radiation, Rotating means for rotating both of them while maintaining their positional relationship, and installed between the radiation source and the radiation detecting means, and in a direction perpendicular to the virtual circle that is the locus when the radiation source is rotated A plurality of specimen holding holders having a plurality of elongated openings, each of the openings provided in the holder has a polygonal shape, and the plurality of openings are separated by partition walls to form a honeycomb shape It is characterized by being arranged.

  [Operation / Effect] According to the present invention, a radiation tomography apparatus for small animals capable of imaging a plurality of subjects at a time can be provided. That is, the radiation tomography apparatus for small animals according to the present invention includes a holder having polygonal openings arranged in a honeycomb shape. By making the arrangement of the openings of the holder into a honeycomb shape, the partition walls separating the openings can be made as thin as possible. In this way, the number of openings provided in the holder can be increased as much as possible. In addition, since the number of subjects that can be held by the holder can be increased, a radiation tomography apparatus for small animals with high work efficiency of the experiment can be provided. In addition, since the radiation absorbed by the holder is reduced by making the partition wall thinner, the radiation emitted from the radiation source surely passes through the holder and enters the radiation detection means. That is, according to the present invention, a clearer tomographic image can be generated.

  Moreover, in the above-described radiation tomography apparatus for small animals, it is more desirable that each of the openings provided in the holder has a hexagonal shape.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If the shape of the opening is hexagonal, the mechanical strength of the holder becomes stronger.

  Moreover, in the above-mentioned small animal radiation tomography apparatus, it is more desirable if an integral subject is inserted into each of the openings provided in the holder.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If an integral subject is inserted into each of the openings, it is possible to perform imaging while the subject is individually isolated. Therefore, when the subject is folded, the boundary between the subjects is unclear and difficult to diagnose Can be prevented from being acquired.

  In the above-described radiation tomography apparatus for small animals, it is more desirable if the holder is made of acrylic resin.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If the holder is made of an acrylic resin that easily transmits radiation, a radiation tomography apparatus for small animals capable of acquiring a clearer tomographic image can be provided.

  Further, in the above-described radiation tomography apparatus for small animals, the holder is provided with a plurality of cuts extending in the direction perpendicular to the virtual circle in the partition wall, and when the holder is disassembled from the cuts, the two ridges whose openings face each other It is more desirable if it is divided into concave portions.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If the holder can be disassembled so that the opening of the holder is divided into two bowl-shaped recesses facing each other, the subject can be easily inserted into the opening of the holder.

  In addition, it is more desirable that the above-described radiation tomography apparatus for small animals includes a top plate on which the holder is placed and a top plate moving means for moving the top plate in a direction orthogonal to the virtual circle.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If the holder is provided with a slidable top plate, a radiation tomography apparatus for small animals that can easily introduce the subject into the field of view can be provided.

  In addition, it is more preferable that the above-described radiation tomography apparatus for small animals includes a positron emission tomography apparatus provided so as to be adjacent to the radiation source and the radiation detection means from the orthogonal direction of the virtual circle.

  [Operation / Effect] The above-described configuration shows a more specific aspect of the present invention. If a positron emission tomography apparatus is provided, both a functional image and a structural image of the subject can be acquired, and more information that can be acquired by imaging can be acquired.

  ADVANTAGE OF THE INVENTION According to this invention, the radiation tomography apparatus for small animals which can image | photograph a several subject at once can be provided. That is, the radiation tomography apparatus for small animals according to the present invention includes a holder having polygonal openings arranged in a honeycomb shape. In this way, the number of openings provided in the holder can be increased as much as possible. In addition, since the number of subjects that can be held by the holder can be increased, a radiation tomography apparatus for small animals with high work efficiency of the experiment can be provided. Moreover, a clearer tomographic image can be generated by making the partition wall thinner.

1 is a functional block diagram illustrating a configuration of an X-ray tomography apparatus according to Embodiment 1. FIG. It is a schematic diagram explaining the rotational movement of the X-ray tube and FPD which concern on Example 1. FIG. It is a top view explaining the holder which concerns on Example 1. FIG. It is a perspective view explaining the holder which concerns on Example 1. FIG. It is a schematic diagram explaining the holder which concerns on Example 1. FIG. It is a schematic diagram explaining the holder which concerns on Example 1. FIG. It is a schematic diagram explaining the holder which concerns on Example 1. FIG. 3 is a flowchart for explaining the operation of the X-ray tomography apparatus according to Embodiment 1; FIG. 3 is a cross-sectional view illustrating the operation of the X-ray tomography apparatus according to Embodiment 1. 6 is a functional block diagram illustrating a configuration of an X-ray tomography apparatus according to Embodiment 2. FIG. It is a schematic diagram explaining the structure of the radiography apparatus of a conventional structure.

  Hereinafter, examples of the present invention will be described. X-rays in the examples correspond to the radiation of the present invention. FPD is an abbreviation for flat panel detector. Moreover, the X-ray tomography apparatus of the present invention is for photographing small animals such as a mouse.

  First, an X-ray tomography apparatus according to Embodiment 1 will be described. As shown in FIG. 1, the X-ray tomography apparatus 1 includes a top plate 2 on which a subject M is placed and a gantry 10 having a through hole penetrating in the direction in which the top plate 2 extends. The top plate 2 is inserted through the through hole of the gantry 10 and moves so as to be able to advance and retreat in a direction in which the top plate 2 extends (a direction orthogonal to a virtual circle VC described later) with respect to a support base 2a that supports the top plate 2. be able to. The top plate 2 is moved by a top plate moving mechanism 15. The top plate movement control unit 16 controls the top plate movement mechanism 15. The top plate moving mechanism 15 corresponds to the top plate moving means of the present invention.

  Inside the gantry 10, an X-ray tube 3 for irradiating X-rays and an FPD 4 for detecting X-rays are provided. The X-rays irradiated from the X-ray tube 3 pass through the through hole of the gantry and reach the FPD 4. The X-ray tube 3 corresponds to the radiation source of the present invention, and the FPD 4 corresponds to the radiation detection means of the present invention.

  The X-ray tube control unit 6 is provided for the purpose of controlling the X-ray tube 3 with a predetermined tube current, tube voltage, and pulse width. The FPD 4 detects X-rays emitted from the X-ray tube 3 and transmitted through the subject M, and generates a detection signal. This detection signal is sent to the image generation unit 11, where a perspective image P0 in which a projection image of the subject M is reflected is generated. The tomographic image generation unit 12 generates a tomographic image P1 when the subject M is cut along an arbitrary tomographic plane based on the fluoroscopic image P0 generated by the image generation unit 11.

  The rotation of the X-ray tube 3 and the FPD 4 will be described. The X-ray tube 3 and the FPD 4 are integrally rotated around the central axis extending in the direction in which the top plate 2 extends by the rotation mechanism 7. More specifically, the X-ray tube 3 and the FPD 4 are rotationally moved while maintaining their relative positional relationship as shown in FIG. At this time, the X-ray tube 3 rotates while drawing the locus of the virtual circle VC centered on the center point on the line segment connecting the X-ray tube 3 and the FPD 4 by the rotation mechanism 7. A direction orthogonal to the virtual circle VC (paper surface penetration direction in FIG. 2: Z direction) coincides with the extending direction of the top plate 2. The rotation mechanism 7 corresponds to the rotation means of the present invention. The rotation control unit 8 controls the rotation mechanism 7.

  A holder 5 for holding the subject M is placed on the top 2. The structure of the holder 5 will be described. As shown in FIG. 3, the holder 5 has an opening 5 a in the shape of a regular hexagon (a regular hexagonal column if captured as a solid) extending in the Z direction. The subject M is inserted into each of the openings 5a. According to FIG. 3, the holder 5 is formed by stacking hexagonal prism-shaped rectangular tubes without any gaps while bringing the surfaces into contact with each other, and three openings 5 a are formed on the top plate 2 on the first stage near the top plate 2. The shape is such that two openings 5a are formed in the second stage on the far side. However, actually, the partition wall 5b that divides each opening 5a is a single layer, and the holder 5 cannot be disassembled into a hexagonal prismatic square tube. Thus, the plurality of openings 5a are arranged in a honeycomb shape by being separated by the partition walls 5b.

  The holder 5 is configured to be disassembled so that the subject M can be easily inserted into the opening 5a. That is, as shown in FIG. 4, the partition wall 5b of the holder 5 is provided with a plurality of cuts extending in the Z direction, and the holder 5 can be disassembled into three members: an upper member 5d, an intermediate member 5e, and a lower member 5f. It is. That is, when the upper member 5d is slid with respect to the middle member 5e in the Z direction, the upper member 5d is separated from the middle member 5e, and when the middle member 5e is slid with respect to the lower member 5f in the Z direction, the middle member The member 5e is separated from the lower member 5f. Thus, when the holder 5 is disassembled, the opening 5a is divided into two bowl-shaped recesses facing each other.

  Rails L1 and L2 that mesh with each other are provided at the joint between the upper member 5d and the middle member 5e, and the rails L1 and L2 allow the upper member 5d to move relative to the middle member 5e only in the Z direction. Limited. In addition, rails L3 and L4 that mesh with each other are provided at the joint between the middle member 5e and the lower member 5f, and the rail L3 and L4 can move the middle member 5e relative to the lower member 5f only in the Z direction. It is limited to. In this way, the holder 5 has a structure that is not easily disassembled even when an impact is applied. Nevertheless, when the experimenter slides the members 5d, 5e, and 5f, the holder 5 is easily disassembled. The rails L1, L2, L3, and L4 extend in the Z direction, and at both ends adjacent to the inner wall that forms the through hole of the gantry 10 when the members 5d, 5e, and 5f are inserted into the gantry 10. Is provided. That is, a rail is provided on the cut exposed outside the holder 5, and no rail is provided on the inner cut.

  Thus, the reason why the holder 5 can be disassembled is to allow the subject M to be easily inserted into the opening 5a. FIG. 5 shows one of the openings 5 a of the holder 5 extracted. The opening 5a is formed by the upper stage member 5d and the middle stage member 5e. When the upper member 5d is slid in the Z direction with respect to the middle member 5e, the opening 5a is divided into two bowl-shaped recesses facing each other, as shown in FIG. The subject M can be easily placed in the recess.

  When the upper member 5d is slid with respect to the middle member 5e in the opposite direction with the subject M placed, an opening 5a is formed again as shown in FIG. 7, and the opening 5a is formed in the opening 5a. The sample M is inscribed. Thus, since the holder 5 can be disassembled, the subject M can be easily stored in the holder 5.

  The holder 5 is made of an acrylic resin that easily transmits X-rays.

  The display unit 25 is provided for the purpose of displaying a tomographic image P1 acquired by X-ray imaging. The console 26 is provided for the purpose of inputting an instruction such as an X-ray irradiation start by an experimenter. The main control unit 27 is provided for the purpose of comprehensively controlling each control unit. The main control unit 27 is constituted by a CPU, and realizes the control units 6, 8, 16 and the units 11, 12 by executing various programs. Further, each of the above-described units may be divided and executed by an arithmetic device that takes charge of them. The storage unit 28 stores all parameters relating to control of the X-ray tomography apparatus 1 such as parameters used for imaging and intermediate images generated in accordance with image processing.

<Operation of X-ray tomography apparatus>
Next, the operation of the X-ray tomography apparatus 1 will be described. In order to acquire a tomographic image P1 of a small animal using the X-ray tomography apparatus 1 according to the first embodiment, as shown in FIG. 8, first, the subject M is stored in the holder 5 (subject storing step S1). , Photographing of the fluoroscopic image P0 is started (shooting start step S2). Then, a tomographic image P1 is generated (tomographic image generation step S3). Hereinafter, these steps will be described in order.

<Subject storage step S1>
Prior to imaging, the subject M is anesthetized so that the subject M does not move during imaging. The anesthetized subject M is stored in the opening 5a of the holder 5 in the manner described with reference to FIGS. At this time, an integrated subject M is accommodated per one opening 5 a of the holder 5. Since the holder 5 is provided with the five openings 5a, the holder 5 can accommodate five specimens M. A holder 5 storing a plurality of subjects M is placed on the top 2.

<Shooting start step S2>
When the experimenter instructs the X-ray tomography apparatus 1 to start tomography through the console 26, the top 2 slides and the subject M is introduced into the through hole of the gantry 10 (see FIG. 1). ). The X-ray tube control unit 6 irradiates X-rays intermittently according to the irradiation time, tube current, and tube voltage stored in the storage unit 28. Meanwhile, the rotation mechanism 7 rotates the X-ray tube 3 and the FPD 4. The FPD 4 detects X-rays that have passed through the subject M among X-rays irradiated by the X-ray tube 3, and sends detection data at this time to the image generation unit 11.

  The image generation unit 11 converts the detection data transmitted from the FPD 4 into an image, and generates a fluoroscopic image P0 in which the X-ray intensity is mapped. Since the FPD 4 sends detection data to the image generation unit 11 every time the X-ray tube 3 emits X-rays, the image generation unit 11 generates a plurality of fluoroscopic images P0. Since a plurality of fluoroscopic images P0 are acquired while the X-ray tube 3 and the FPD 4 are rotated, each of the fluoroscopic images P0 is reflected while changing the direction in which the fluoroscopic image of the subject M is seen through. It will be. When the X-ray tube 3 and the FPD 4 make one rotation from the start of imaging, the X-ray tube 3 ends the X-ray irradiation.

  The movement of the top 2 after the start of shooting will be described. The X-ray tomography apparatus 1 can image only a part of the subject M by one imaging. This is because the width in the Z direction in the field of view of the X-ray tomography apparatus 1 is smaller than the width of the subject M in the Z direction. Therefore, according to the configuration of the first embodiment, a tomographic image of the entire image of the subject M is acquired by performing imaging a plurality of times when the above-described X-ray tube 3 and FPD 4 complete one rotation. . That is, as shown on the left side of FIG. 9, first, the tail of the subject M is imaged, and then the top 2 is slid to change the relative position of the subject M and the gantry 10. As shown by the center of 9, the abdomen of the subject M is imaged. Thereafter, the top 2 is slid again, and the head of the subject M is imaged as shown on the right side of FIG. In this way, the fluoroscopic image P0 is acquired for the entire subject.

<Tomographic image generation step S3>
The fluoroscopic image P0 is sent to the tomographic image generation unit 12. The tomographic image generation unit 12 reconstructs a series of fluoroscopic images P0 having information related to the three-dimensional structure of the subject M by being photographed while changing the direction, and uses the Z direction as the body axis. A tomographic image P1 in which M is cut into circles is generated. A plurality of the tomographic images P1 are generated while changing the position to be cut in the Z direction. The tomographic image P1 generated in this way is displayed on the display unit 25, and the imaging ends.

  As described above, according to the configuration of the first embodiment, it is possible to provide the X-ray tomography apparatus 1 capable of imaging a plurality of subjects M at a time. That is, the X-ray tomography apparatus 1 according to the configuration of the first embodiment includes a holder 5 having polygonal openings 5a arranged in a honeycomb shape. By arranging the openings 5a of the holder 5 in a honeycomb shape, the partition walls 5b separating the openings 5a can be made as thin as possible. By doing in this way, the number of the openings 5a provided in the holder 5 can be increased as much as possible. In addition, since the number of subjects M that can be held by the holder 5 can be increased, the X-ray tomography apparatus 1 with high work efficiency of the experiment can be provided. Further, since the partition wall 5b is thinned, X-rays absorbed by the holder 5 are reduced, so that the X-rays irradiated from the X-ray tube 3 surely pass through the holder 5 and enter the FPD 4. That is, according to the configuration of the first embodiment, a clearer tomographic image P1 can be generated.

  Moreover, if the shape of the opening 5a is a hexagon, the mechanical strength of the holder 5 becomes stronger. Further, if the integral subject M is inserted into each of the openings 5a, it is possible to perform imaging in a state where the subject M is individually isolated. Therefore, when the subject M is folded, the boundary between the subjects is separated. It is possible to prevent an image that is unknown and difficult to diagnose from being acquired.

  If the holder 5 is made of an acrylic resin that easily transmits X-rays, the X-ray tomography apparatus 1 that can acquire a clearer tomographic image can be provided. Furthermore, if the holder 5 can be disassembled so that the opening 5a of the holder 5 is divided into two bowl-shaped recesses facing each other, the subject M can be easily inserted into the opening 5a of the holder 5. .

  Next, the tomography apparatus 20 according to the second embodiment will be described. As shown in FIG. 10, the tomography apparatus 20 according to the second embodiment includes a positron emission tomography apparatus (PET apparatus) in addition to the apparatus configuration according to the first embodiment. Therefore, in the tomography apparatus 20 according to the second embodiment, description of the same parts as those of the apparatus configuration according to the first embodiment will be omitted.

  In addition to the gantry 10, the tomography apparatus 20 has a gantry 10a related to the PET apparatus 1a. This gantry 10a also has a through hole extending in the Z direction, and the top plate 2 is inserted therethrough. Therefore, the PET apparatus 1a is provided adjacent to the X-ray tube 3 / FPD 4 from the Z direction.

  Inside the gantry 10a, a ring-shaped detector ring 32 is provided following the shape of the gantry 10a. The detector ring 32 is configured by arranging detectors capable of detecting γ rays in a ring shape.

  The coincidence unit 33 is provided for the purpose of performing coincidence processing on the detection data output from the detector ring 32. The coincidence counting unit 33 specifies the detection frequency and the detection position of the annihilation γ-ray pairs incident simultaneously on different portions of the detector ring 32. The coincidence unit 33 outputs the coincidence result to the PET image generation unit 34. The PET image generation unit 34 calculates the generation position of the annihilation γ-ray pair based on the detection frequency and the detection position of the annihilation γ-ray pair specified by the coincidence unit 33, and the generation intensity of the annihilation γ-ray pair is mapped. A PET image P2 is generated. The PET image P2 is a tomographic image showing the distribution of occurrence of annihilation γ-ray pairs.

  The tomography apparatus 20 can acquire both the tomographic image P1 by X-rays and the PET image P2 by annihilation γ-ray pairs in one inspection. In order to generate both images P1 and P2 using the tomography apparatus 20, first, a positron emitting radiopharmaceutical is injected into the subject M. The radiopharmaceutical has a property of concentrating on a specific part such as a lesion of the subject M. Radiopharmaceuticals emit positrons, which generate annihilation gamma ray pairs that fly 180 degrees in the opposite direction. Therefore, an annihilation gamma ray pair is emitted from the subject M. Since the distribution of the radiopharmaceutical is different within the subject, the frequency of occurrence of annihilation γ-ray pairs differs depending on the portion of the subject M.

  After a sufficient time has passed since the injection of the radiopharmaceutical, the subject M is anesthetized and stored in the holder 5. That is, the integral of the anesthetized subject M is accommodated in each of the openings 5a of the holder 5 in the manner described with reference to FIGS. Then, the holder 5 in a state in which a plurality of subjects M are stored is placed on the top 2. When the experimenter instructs the tomography apparatus 20 to start PET image capturing through the console 26, the top 2 slides and the subject M is introduced into the through hole of the gantry 10a (see FIG. 10). . From this point in time, the detector ring 32 starts detecting the annihilation γ-ray pair, and the PET image generation unit 34 generates the PET image P2. In the PET image P2, the frequency of occurrence of annihilation γ-ray pairs that varies depending on the portion of the subject M is mapped. Since the distribution of the occurrence frequency of the annihilation gamma ray pair is the distribution of the radiopharmaceutical as it is, the experimenter can know the distribution of the radiopharmaceutical in the subject by diagnosing the PET image P2. When photographing, if the visual field range in the Z direction of the PET apparatus 1a cannot cover the whole body of the subject M, the PET image P2 is photographed while sliding the top 2 in the Z direction. May be.

  The subsequent operation is the same as that after step S2 described above. The tomographic image P1, the PET image P2 and the composite image obtained by superimposing these are displayed on the display unit 25, and the photographing is finished.

  As described above, according to the configuration of the second embodiment, both the tomographic images of the plurality of subjects M and the PET image P2 can be acquired by one imaging, so that the tomography apparatus 20 with excellent experimental work efficiency is provided. it can.

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

  (1) According to the configuration of the first embodiment, the holder 5 has the hexagonal columnar opening 5a. However, the shape of the opening 5a may be a triangular columnar shape or a quadrangular columnar shape.

  (2) According to the configuration of Example 1, the subject M is a mouse, but other small animals may be the subject M.

  (3) According to the configuration of the first embodiment, the holder 5 has the five openings 5a. However, the number of the openings 5a may be changed according to the size of the small animal to be photographed.

VC Virtual circle 2 Top plate 3 X-ray tube (radiation source)
4 FPD (radiation detection means)
5 Holder 5a Opening 5b Partition 7 Rotating mechanism (rotating means)
15 Top plate moving mechanism (top plate moving means)

Claims (7)

A radiation source that emits radiation;
Radiation detection means for detecting radiation;
Rotating means for rotating the radiation source and the radiation detecting means around a center point on a line segment that maintains the mutual positional relationship between them,
A holder for holding a plurality of subjects, which is installed between the radiation source and the radiation detection means and has a plurality of openings extending in a direction perpendicular to a virtual circle that is a locus when the radiation source is rotated. And
Each of the openings provided in the holder has a polygonal shape, and the plurality of openings are arranged in a honeycomb shape by being separated by a partition wall. The radiation tomography apparatus for small animals according to claim 1,
Each of the openings provided in the holder has a hexagonal shape, and is a radiation tomography apparatus for small animals. In the radiation tomography apparatus for small animals according to claim 1 or 2,
A radiation tomography apparatus for small animals, wherein an integral subject is inserted into each of the openings provided in the holder. The radiation tomography apparatus for small animals according to any one of claims 1 to 3,
A radiation tomography apparatus for small animals, wherein the holder is made of acrylic resin. The radiation tomography apparatus for small animals according to any one of claims 1 to 4,
The holder is provided with a plurality of cuts extending in a direction perpendicular to the virtual circle in the partition wall, and when the holder is disassembled from the cuts, the opening is divided into two bowl-shaped recesses facing each other. Characteristic radiation tomography device for small animals. In the radiation tomography apparatus for small animals according to any one of claims 1 to 5,
A top plate on which the holder is placed;
A radiation tomography apparatus for small animals, comprising: a top plate moving means for moving the top plate in a direction orthogonal to the virtual circle. The radiation tomography apparatus for small animals according to any one of claims 1 to 6,
A radiation tomography apparatus for small animals, comprising: a positron emission tomography apparatus provided adjacent to the radiation source and the radiation detection means from a direction orthogonal to the virtual circle.

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