JP7626472B2 - Radiation Camera - Google Patents

Description

The present invention relates to a radiation camera that targets gamma rays, X-rays, annihilation radiation, etc.

Conventionally, there are known cancer cells that are likely to take up a specific compound, or tissues in which compounds of a specific size are likely to remain. In order to identify the location of such cancer cells or tissues, a compound containing a radioactive nuclide is administered to a patient, and the location is identified using a gamma camera. For example, a method is known in which a compound preparation containing ^99m Tc is administered to a patient, and lymph nodes in which the compound has accumulated are identified and dissected. Non-Patent Document 1 discloses a portable gamma camera that can determine the presence or absence of cancer metastasis to sentinel lymph nodes during surgery in order to carry out this method.

Non-Patent Document 2 discloses a handheld imaging device with a built-in projector. This imaging device has a camera that detects near-infrared fluorescence of indocyanine green from the surgical site, and is configured so that light is projected from the projector onto the site where the near-infrared fluorescence is detected.

K. Yokoyama, N. Tono, K. Tsugawa, K. Miwa, "Isotope detection method for sentinel lymph nodes," Japan-German Medical Journal, Vol. 46, No. 2, pp. 212-217, 2001. Chenmeng Li, Peng Liu, Pengfei Shao, Jing Pei, Yingrui Li, Timothy M. Pawlik, Edward W. Martin, Ronald X. Xu, “Handheld projective imaging device for near-infrared fluorescence imaging and intraoperative guidance of sentinel lymph node resection”, Journal of Biomedical Optics, Vol. 24(8), 080503, 2019.

However, in the gamma camera disclosed in Non-Patent Document 1, an image of the intensity distribution of detected radiation is displayed on a separate display, making it difficult to grasp the positional relationship between the displayed image and the surgical site. On the other hand, the imaging device disclosed in Non-Patent Document 2 aims to project light onto the site where near-infrared fluorescence is detected. However, in this imaging device, the optical axis of the camera that detects near-infrared fluorescence does not coincide with the optical axis of the projector. Therefore, a distance sensor and a calibration calculation program are required to calibrate the projection position according to the position of the imaging device so that light is projected to the correct position. However, in addition to the size of the distance sensor itself, a high-performance processor is required to perform calibration calculations in real time according to the ever-changing distance, and furthermore, a cooling function and a power supply function for the processor are required, which may result in a large device.

One aspect of the present invention aims to provide a radiation camera that can project visible light toward a radiation source without the need to calibrate the projection direction depending on the position of the radiation camera.

In order to solve the above problems, a radiation camera according to one embodiment of the present invention comprises a collimator that collimates incident radiation, a radiation detection unit that detects radiation that has passed through the collimator, and a light emitting unit that emits visible light in a direction opposite to the incident direction of the radiation detected by the radiation detection unit.

According to one aspect of the present invention, a radiation camera can be provided that can project visible light toward a radiation source without the need to calibrate the projection direction depending on the position of the radiation camera.

FIG. 2 is a diagram conceptually illustrating the function of a gamma camera according to an embodiment of the present invention. FIG. 2(a) is a schematic vertical sectional view showing the configuration of a gamma camera according to the first embodiment of the present invention, FIG. 2(b) is a schematic vertical sectional view showing the configuration of a gamma camera according to a modified example thereof, and FIG. 2(c) is a perspective view of a radiation detection element of the modified gamma camera. 1 is a block diagram showing a configuration of a gamma camera according to a first embodiment. 11A and 11B are a schematic vertical sectional view and a partially enlarged view of a tip portion, showing the configuration of a gamma camera according to a second embodiment of the present invention. FIG. 5A is a perspective view showing an example of the shape of a gamma camera according to the second embodiment, and FIG. 5B is a perspective view showing another example of the shape of a gamma camera. FIG. 11 is a schematic vertical sectional view showing the configuration of a gamma camera according to a third embodiment of the present invention. 7A to 7C are schematic diagrams showing the operation of a gamma camera according to the third embodiment of the present invention, and FIG. 7D is a flowchart thereof. FIG. 8A is a schematic vertical sectional view showing the configuration of a gamma camera according to a fourth embodiment of the present invention, and FIG. 8B is a flow chart showing the operation thereof. FIG. 11 is a schematic vertical cross-sectional view showing the configuration of a gamma camera according to a fifth embodiment of the present invention. 10A to 10J are schematic vertical cross-sectional views showing examples of arrangements of radiation detection elements and laser light-emitting elements according to a sixth embodiment of the present invention. FIG. 11A is an example of a control flow of a gamma camera according to the sixth embodiment, and FIG. 11B is a block diagram showing the configuration of the gamma camera. FIG. 12(a) is a schematic vertical sectional view of a gamma camera according to a seventh embodiment of the present invention, and FIG. 12(b) shows its control flow. FIG. 13 is a plan view showing an arrangement of radiation detection elements and laser light emitting elements of a gamma camera according to a seventh embodiment. FIG. 13 is a perspective view showing an arrangement of radiation detection elements and laser light emitting elements of a gamma camera according to a seventh embodiment. FIG. 13 is a diagram showing a preferred range of the deviation angle between the incident axis of gamma rays and the axis of an emitted laser beam in a gamma camera according to embodiment 7. FIG. 16(a) is a perspective view of a shield for a gamma camera according to an eighth embodiment of the present invention, and FIG. 16(b) is a longitudinal sectional view thereof. FIG. 17A is a vertical cross-sectional view showing one example of a shield for a gamma camera according to the ninth embodiment of the present invention, and FIG. 17B is a vertical cross-sectional view showing another example. FIG. 1 is a schematic diagram showing a medical application of a gamma camera according to an embodiment of the present invention.

(Gamma camera function)
First, the function of a gamma camera as an example of a radiation camera in an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram conceptually showing the function of a medical gamma camera in an embodiment of the present invention. The gamma camera shown in FIG. 1 is a medical gamma camera that detects radiation (e.g., gamma rays) from a radiation source of an object (e.g., a human body) and emits visible light in a direction opposite to the incident direction of the detected gamma rays. With this configuration, visible light is irradiated to a position where the radiation source is present in the object. This allows the operator of the gamma camera to easily visually grasp the position where the radiation source is present in the object. In the example shown in FIG. 1, the radiation source (hereinafter also simply referred to as "radiation source") is present inside the object, but the radiation source may be present on the surface of the object. Gamma rays are generally emitted from a radiation source in an unspecified direction, but a gamma camera is configured to determine the incident direction of the gamma rays and emit visible light in a direction opposite to the incident direction. Below, a specific configuration example of a gamma camera for realizing such a function will be described. Note that "towards the direction opposite to the incident direction" refers not only to the opposite direction coinciding with the incident axis, but also to the opposite direction shifted by a certain angle from the incident axis. The accuracy of this exit angle is preferably about the same as the detection accuracy of the incident angle of the radiation, for example. Note that the radiation camera is a radiation camera that targets gamma rays, X-rays, annihilation radiation, etc.

[Embodiment 1]
(Configuration and Operation of Gamma Camera 1)
Next, a gamma camera 1 according to a first embodiment of the present invention (an example of a "radiation camera" in the claims) will be described with reference to the drawings. FIG. 2 is a schematic vertical cross-sectional view showing the configuration of the gamma camera 1 according to the first embodiment and a gamma camera 1A according to a modified example thereof. As shown in FIG. 2(a), the gamma camera 1 includes a housing 9 and a shielding body 8 provided at one end of the housing 9. In the following description, the vertical direction of the drawing is the vertical direction of the gamma camera 1 for convenience. The shielding body 8 has an upper part 8A that is conical and a lower part 8B that is cylindrical. The shape of the shielding body 8 may be rectangular. For example, the upper part 8A may be pyramidal and the lower part 8B may be prismatic. The shielding body 8 is formed to a predetermined thickness using a material with a high density such as lead or tungsten in order to shield gamma rays. The predetermined thickness is a thickness that can shield gamma rays of a predetermined energy. The gamma camera 1 according to this embodiment is intended to detect gamma rays of about 140 keV emitted from, for example, ^99m Tc. Therefore, the shield 8 is designed to have a thickness that can block 140 keV gamma rays. The shield 8 has a pinhole 8D (an example of a "collimator" in the claims) which is a minute opening formed at a tip 8C in order to collimate the incident gamma rays. The pinhole 8D is formed in a fine hole shape so as to pass only the gamma rays R incident from above.

The gamma camera 1 includes a radiation detection unit and a light-emitting unit. The radiation detection unit is composed of one radiation detection element 13 provided inside the shielding body 8, and the light-emitting unit is composed of one light-emitting element 14 provided inside the shielding body 8 and corresponding to the radiation detection element 13. In this embodiment, the light-emitting element 14 is arranged on the side closer to the pinhole 8D, and the radiation detection element 13 is arranged on the side farther from the pinhole 8D. The light-emitting element 14 and the radiation detection element 13 are arranged adjacent to each other in this order (i.e., vertically) along the traveling direction of the gamma ray R. The traveling direction of the gamma ray is the direction from the side closer to the pinhole 8D (the light-emitting element 14 side) to the side farther from the pinhole 8D (the radiation detection element 13 side). In addition, "adjacent" includes the case where they are adjacent to each other in contact and the case where they are adjacent to each other in a spaced relationship. In other words, the light-emitting element 14 and the radiation detection element 13 may be arranged adjacent to each other or may be arranged in a spaced relationship. Furthermore, when the light-emitting element 14 and the radiation detection element 13 are arranged in contact with each other, the two may be directly stacked on top of each other, or a spacer such as a support member that is transparent to gamma rays R may be interposed between the light-emitting element 14 and the radiation detection element 13.

The type of the radiation detection element 13 is not particularly limited, but is preferably a small detection element such as a scintillation detection element or a semiconductor detection element. As the scintillation detection element, a CsI (Tl) scintillator, a NaI (Tl) scintillator, etc. can be used. As the semiconductor detection element, a CdTe semiconductor detection element, a CZT semiconductor detection element, a Si semiconductor detection element, a Ge semiconductor detection element, etc. can be used. The radiation detection element 13 converts the energy of radiation into an electrical signal and outputs it, but since a known configuration can be used for converting the energy into an electrical signal, illustrations and explanations thereof are omitted. The type of the light-emitting element 14 is not particularly limited, but for example, a light-emitting diode (LED) that emits visible light (hereinafter also simply referred to as "light") can be used.

As described above, in the gamma camera 1, the light emitting elements 14 are arranged above the radiation detecting elements 13. Therefore, as shown in Fig. 2(a), gamma rays R that enter and pass through the pinhole 8D pass through the light emitting elements 14 and reach the radiation detecting elements 13. However, for example, the energy of gamma rays R emitted from ^99m Tc is about 140 keV, and they can easily pass through the light emitting elements 14, so there is little risk of them affecting the detection efficiency of gamma rays R.

The control unit 16 is disposed inside the housing 9 and outside the shielding body 8. Providing the control unit 16 inside the housing 9 improves portability. In addition, by integrating the radiation detection element 13, the light emitting element 14, and the control unit 16, a more compact configuration can be achieved. As shown in FIG. 3, the control unit 16 receives an electrical signal output by the radiation detection element 13 upon receiving gamma rays, and controls the light emitting element 14 to be excited for a predetermined time and emit (emit) light L upon receipt of the electrical signal. If the light emitting element 14 is made to emit light for a long period of time, when the intensity of the radiation (counting rate or spatial dose rate) is strong, the light L will overlap and continue to be projected continuously, which is not preferable. On the other hand, if the emission time is too short, it will be difficult to see, so a certain amount of emission time is necessary. Therefore, the control unit 16 may be configured to adjust the emission time based on the intensity of the radiation so that appropriate viewing is possible. In addition, the control unit 16 may be configured to adjust the emission intensity (brightness) instead of or in addition to the emission time. The control unit 16 includes a processor such as a Micro Processing Unit (MPU) or a Central Processing Unit (CPU), and a memory that stores various programs and data. Alternatively, the control unit 16 may use a dedicated processor such as an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA) as the processor.

Returning to Figure 2, of the light L emitted from the light-emitting element 14, only the light L directed in the opposite direction to the incident direction of the gamma rays R is emitted to the outside via the pinhole 8D. As a result, the light L is projected onto the position of the object corresponding to the radiation source. The position corresponding to the radiation source is the position of the radiation source if the radiation source is on the surface of the object, and is the position where the line segment connecting the radiation source and the light-emitting element 14 intersects with the surface of the object if the radiation source is inside the object.

As described above, the radiation detection element 13 detects the gamma rays R that have passed through the pinhole 8D, and the light emitting element 14 emits visible light L in the direction opposite to the incident direction of the gamma rays R. The emitted visible light L is irradiated toward the radiation source and projected onto the position of the target corresponding to the radiation source.

When this configuration is applied to a medical gamma camera as in this embodiment, the position of the affected area can be visualized on the skin. Specifically, the medical gamma camera 1 can detect gamma rays emitted from, for example, ^99m Tc and emit light in the opposite direction to the incident direction. For example, when a labeled compound containing ^99m Tc, such as albumin or phytic acid, is administered to a breast cancer patient, the labeled compound accumulates in the affected area of breast cancer. When a doctor uses the gamma camera 1 to diagnose, light is emitted from the gamma camera 1 in the direction of the source of the gamma rays emitted from ^99m Tc. In other words, the light from the gamma camera 1 is projected directly onto the patient's skin toward the affected area where the labeled compound has accumulated, and is visualized. Therefore, the doctor can visually grasp the position of the affected area. The gamma camera 1 can also be used during surgery, in which case the position of the affected area can be visualized on the surface of the organ.

If the affected area is inside the human body, light is projected onto the position where the line connecting the pinhole 8D of the gamma camera 1 and the affected area intersects with the skin. By changing the position of the gamma camera 1 to diagnose the location of the affected area, the location of the affected area can be ascertained even if it is inside the body.

In conventional technology, the incident axis of the detected radiation does not coincide with the projection axis of the projected light, requiring complex calibration calculations depending on the position where the light is projected. However, with gamma camera 1, it is possible to project visible light toward the radiation source without calibrating the projection direction depending on the position of gamma camera 1.

(Modification)
In the above-described first embodiment, the light-emitting element 14 is disposed on the radiation detection element 13. However, as shown in FIG. 2(b), the light-emitting element 14 and the radiation detection element 13 may be disposed in reverse. In the example shown in FIG. 2(b), the radiation detection element 13 is disposed inside the shielding body 8, and the light-emitting element 14 is disposed inside the housing 9 below the shielding body 8. As shown in FIG. 2(c), a cylindrical opening 13A is provided in the center of the radiation detection element 13, and the light-emitting element 14 emits light through the opening 13A. The light-emitting element 14 may also be provided inside the shielding body 8. Even with such a configuration, the same effect as in the first embodiment can be obtained.

In the above-mentioned embodiment 1, the control unit 16 is provided inside the housing 9. However, the control unit 16 may also be provided inside the shielding body 8. The light-emitting element 14 may be a laser light-emitting element. Note that, although a "gamma camera" is exemplified in this embodiment, the radiation detected does not necessarily have to be gamma rays, as mentioned above. For example, it may be configured to detect beta rays or electromagnetic waves of various energy levels and emit light in the opposite direction. In this case, the radiation detection element 13 is modified to one configured appropriately for detecting radiation.

[Embodiment 2]
(Configuration of Gamma Camera 2)
Next, a gamma camera 2 according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a schematic vertical cross-sectional view showing the configuration of the medical gamma camera 2 according to the second embodiment. As shown in FIG. 4, the gamma camera 2 includes a radiation detection unit 12 and a control unit 16 inside a shield 10. The shield 10 also serves as a housing for the gamma camera 2, and an upper portion 10A is conical and a lower portion 10B is cylindrical. The shield 10 has a pinhole 11 (an example of a "collimator" in the claims) which is a minute opening for collimating gamma rays at a tip portion 10C, similar to the shield 8 of the first embodiment. The pinhole 11 of the gamma camera 2 is formed so as to collimate gamma rays from a wide angle. The material and thickness of the shield 10 are as described in the first embodiment.

The radiation detection unit 12 includes a plurality of radiation detection elements 13 (an example of a "radiation detection unit" in the claims). The plurality of radiation detection elements 13 are regularly arranged on a circular plane in accordance with the cross-sectional shape of the lower portion 10B of the shield 10. As in the first embodiment, the radiation detection elements 13 are preferably scintillation detection elements or semiconductor detection elements, etc.

As shown in the enlarged view in FIG. 4, a light-emitting section including a light-emitting element 14 and a reflecting section 15 is disposed at the tip 10C of the shield 10. The light-emitting element 14 is disposed at one location at the opening end 10D of the pinhole 11. The reflecting section 15 is disposed at a position facing the light-emitting element 14 at the opening end 10D. The light-emitting element 14 is, for example, a light-emitting diode that emits light L toward the reflecting section 15. When the radiation detection element 13 detects gamma rays, the light-emitting element 14 is controlled by the control section 16 to emit light L toward the reflecting section 15 for a predetermined period of time. The reflecting section 15 is composed of a planar reflecting plate 15A and a driving section 15B that drives it. The driving section 15B is, for example, a piezoelectric actuator that can rotate the reflecting plate 15A in two orthogonal axial directions to arbitrarily change the orientation of the reflecting plate 15A. The driving section 15B is driven and controlled by the control section 16. In this embodiment, the orientation of the reflector 15A that reflects the light L emitted from the light emitting element 14 corresponds to the positions of each of the multiple radiation detection elements 13.

(Operation of Gamma Camera 2)
When gamma rays are detected by the radiation detection element 13, the incident direction of the detected gamma rays is determined from the position of the detected radiation detection element 13 and the position of the pinhole 11. In other words, the line connecting the detected radiation detection element 13 and the pinhole 11 is the incident direction of the gamma rays. When the control unit 16 receives a signal from the radiation detection element 13, it drives the driving unit 15B according to the radiation detection element 13 that detected the gamma rays. Specifically, the control unit 16 drives the driving unit 15B to change the orientation of the reflector 15A so that the light L is reflected in the opposite direction to the incident direction of the gamma rays. Thereafter, the light emitting element 14 is caused to emit light for a predetermined time. If the light emitting element 14 is caused to emit light for a long time, the light L continues to be emitted even after the gamma camera 2 is moved, which is not preferable. On the other hand, if the emission time is too short, it becomes difficult to visually observe, so a certain amount of emission time is necessary. In addition, when the intensity of the radiation (counting rate or spatial dose rate) is large, the emission times may overlap, and it may be difficult to distinguish the strength of the radiation source according to the position. Therefore, the light emission time may be adjusted by the user so that the light emission can be properly viewed. Also, instead of or in addition to the light emission time, the light emission intensity (brightness) may be adjusted by the user.

With the above configuration, the gamma camera 2 can achieve the same effect as in embodiment 1. In other words, with the above configuration, it is possible to project visible light toward the radiation source without calibrating the projection direction depending on the position of the gamma camera. Furthermore, by providing multiple radiation detection elements 13, when the radiation detection elements 13 detect radiation that has passed through the pinhole 11, the incident direction of the radiation can be easily determined from the positions of the pinhole 11 and the radiation detection elements 13. Visible light can be emitted from the light emitting element 14 in the opposite direction to the incident direction of the radiation.

(Modification)
In the second embodiment, as shown in FIG. 5(a), the shield 10 has a cylindrical lower part and a conical upper part. However, the shape of the shield 10 is not limited. For example, as shown in FIG. 5(b), the shape of the shield 10 may be rectangular. That is, the lower part of the shield 10 may be prismatic and the upper part may be pyramidal. In the above example, the light emitting element 14 and the reflector 15 are disposed at the tip 10C of the shield 10, but the positions are not limited. As described above, the incident direction of the gamma ray is determined by the position of the radiation detection element 13 that detects the gamma ray, so the light emitting element may be configured to emit light in that direction, and the position of the light emitting element is not limited. In addition, the light emitting element 14 and the reflector 15 may be disposed at different positions, and the light may be guided to be emitted from the tip 10C of the shield 10.

In the second embodiment, the shield 10 also serves as the housing of the gamma camera 2. However, the housing may be configured separately from the shield 10. In that case, the control unit 16 may be disposed inside the housing.

[Embodiment 3]
(Configuration of Gamma Camera 3)
Next, a medical gamma camera 3 according to a third embodiment will be described with reference to the drawings. For ease of description, in the following embodiments, members having the same functions as those described in the previous embodiments will be given the same reference numerals, and their description will not be repeated. Fig. 6 is a schematic vertical cross-sectional view showing the configuration of the gamma camera 3. As shown in Fig. 6, the gamma camera 3 includes a cylindrical shield 20 similar to the shield 10 described in the first embodiment. The shield 20 has a pinhole 11 (an example of a "collimator" in the claims) at its tip. The shield 20 includes a plurality of radiation detection elements 13, a plurality of light-emitting elements 30, and a control unit 16 therein.

The radiation detection elements 13 and the light-emitting elements 30 are arranged adjacent to each other in the direction along the direction of travel of the gamma rays. In this embodiment, the radiation detection elements 13 and the light-emitting elements 30 are arranged adjacent to each other in the vertical direction of the drawing. In this embodiment, the number of radiation detection elements 13 and the light-emitting elements 30 is the same, and one light-emitting element 30 is arranged on one radiation detection element 13. The radiation detection elements 13 and the light-emitting elements 30 arranged adjacent to each other in the vertical direction correspond to each other. The light-emitting elements 30 are arranged to emit light in the upward direction. Since the emitted light is collimated by the pinhole 11, the light-emitting elements 30 do not need to emit directional light. It is preferable that the light-emitting surface of the light-emitting element 30 and the detection surface of the radiation detection element 13 are geometrically similar in shape and size, and more preferably, are equal. This makes it possible to more closely match the distribution of the projected light with the distribution of the radiation source.

(Operation of Gamma Camera 3)
The operation of the gamma camera 3 will be described with reference to Fig. 7. As shown in the flow chart of Fig. 7(d), in this embodiment, when gamma rays are detected by the radiation detection element 13 (step S71), the control unit 16 causes the corresponding light-emitting element 30 to emit light (step S72). As a result, when the radiation detection element 13 detects gamma rays from, for example, a radiation source (affected area) 50 present inside the body, light is projected onto the skin 51 at a position corresponding to the radiation source 50.

More specifically, as shown in FIG. 7(a), the gamma rays that pass through the pinhole 11 and enter are detected by the radiation detection element 13. When the control unit 16 receives a gamma ray detection signal from the radiation detection element 13, as shown in FIG. 7(b), it causes the light emitting element 30 corresponding to the radiation detection element 13 that detected the gamma ray to emit visible light for a predetermined time. The reason for emitting visible light for a predetermined time and the fact that the predetermined emission time may be adjustable are the same as in the first and second embodiments. As shown in FIG. 7(c), the light emitted upward from the light emitting element 30 is collimated by the pinhole 11, and only the light facing in the opposite direction to the incident direction of the gamma rays is emitted to the outside and projected onto the skin 51 at a position corresponding to the radiation source 50 such as a lymph node. This operation is repeated for each radiation detection element 13 and its corresponding light emitting element 30.

By stacking the radiation detection element 13 and the light emitting element 30 adjacent to each other in the direction along the direction of travel of the gamma rays, it is possible to emit light to the outside in the opposite direction to the direction of incidence of the gamma rays entering through the pinhole 11 simply by making the light emitting element 30 emit light. Then, the light from the gamma camera 3 is projected directly onto the patient's skin 51 toward the radiation source (affected area) 50 where the labeled compound that emits gamma rays has accumulated, and is visualized. This allows the doctor to visually grasp the position of the affected area 50. When used during surgery, the surface of an organ may be used instead of the skin 51.

In the gamma camera 3, the light emitting element 30 is arranged adjacent to and above the radiation detecting element 13. Therefore, the incident gamma rays pass through the light emitting element 30 and reach the radiation detecting element 13. However, as described above, for example, the energy of gamma rays emitted from ^99m Tc is about 140 keV, and they can easily pass through the light emitting element 30, so there is little risk of them affecting the detection efficiency of gamma rays.

In the gamma camera 3 according to the third embodiment, the number of light-emitting elements 30 is greater than that in the gamma camera 2 according to the second embodiment, but the reflector 15A that reflects the light L emitted from the light-emitting elements 14 does not need to be driven by the driving unit 15B. The simple configuration of arranging the corresponding radiation detection elements 13 and light-emitting elements 30 adjacent to each other along the radiation propagation direction makes it easy to emit light in the opposite direction to the incident radiation. In other words, it is possible to emit light in the opposite direction to the incident radiation simply by emitting light from the light-emitting elements 30 corresponding to each radiation detection element 13. The modified examples shown in the first and second embodiments can also be appropriately applied to the third embodiment.

[Embodiment 4]
Next, the configuration and operation of a gamma camera 4 according to the fourth embodiment will be described with reference to Fig. 8. As shown in Fig. 8(a), the gamma camera 4 has a shielding body 20 similar to that of the third embodiment. The gamma camera 4 has radiation detection elements 13 and laser light-emitting elements 32 (an example of the "light-emitting section" in the claims) inside the shielding body 20. The radiation detection elements 13 and the laser light-emitting elements 32 are arranged adjacent to each other along the traveling direction of the gamma rays. The radiation detection elements 13 and the laser light-emitting elements 32 are arranged in the same number and in a corresponding manner. The laser light-emitting elements 32 are arranged so as to emit visible laser light in the direction of the pinhole 11.

8(b), when the control unit 16 receives a gamma ray detection signal from a radiation detection element 13 (step S81), it causes the laser light-emitting element 32 corresponding to the radiation detection element 13 that detected the gamma ray to emit visible light for a predetermined period of time (step S82). This flowchart is repeated between the corresponding radiation detection element 13 and laser light-emitting element 32.

According to the gamma camera 4, by replacing the non-directional light-emitting element 30 in the third embodiment with the directional laser light-emitting element 32, it is possible to project brighter light. Since the laser light-emitting element 32 has high directivity, it is preferable to arrange the laser light emission direction toward the pinhole 11 with high precision. Specifically, it is preferable that the light-emitting surface of each of the laser light-emitting elements 32 is adjusted to face the pinhole 11, and the center of the light-emitting surface is on the line segment connecting the center of the detection surface of each radiation detection element 13 and the pinhole 11.

The gamma camera 4 configured as above can provide the same effect as the gamma camera 3 according to embodiment 3. Furthermore, the gamma camera 4 can project light with greater brightness than the gamma camera 3 according to embodiment 3. The modified examples shown in embodiments 1 and 2 can also be applied to embodiment 4 as appropriate.

[Embodiment 5]
Next, a gamma camera 5 according to a fifth embodiment will be described with reference to Fig. 9. The gamma camera 5 has a shielding body 20 similar to that of the third embodiment. The gamma camera 5 has radiation detection elements 13 and laser light-emitting elements 32 inside the shielding body 20. As shown in Fig. 9, the radiation detection elements 13 and the laser light-emitting elements 32 are arranged adjacent to each other along the traveling direction of the gamma rays. The radiation detection elements 13 and the laser light-emitting elements 32 are arranged in the same number and in a corresponding manner.

More specifically, the corresponding radiation detection element 13 and laser light-emitting element 32 are integrated. More specifically, they are integrated along the direction of travel of the gamma rays so that the detection surface of the radiation detection element 13 and the light-emitting surface of the laser light-emitting element 32 face the same direction. The integrated radiation detection element 13 and laser light-emitting element 32 are then arranged toward the pinhole 11. By manufacturing the integrated radiation detection element 13 and laser light-emitting element 32 in advance, it becomes easy to arrange them toward the direction of the pinhole 11. The operation of the gamma camera 5 is similar to that of the gamma camera 3 described in the third embodiment.

The gamma camera 5 configured as above can provide the same effect as the gamma camera 3 according to embodiment 3. Furthermore, by integrating the radiation detection element 13 and the laser light-emitting element 32, it becomes easy to arrange them adjacent to each other facing the direction of the pinhole 11. Note that in the embodiments from embodiment 5 onwards, the laser light-emitting element 32 is used as the light-emitting element, but a light-emitting element other than a laser light-emitting element may be used. Furthermore, the modified examples shown in embodiments 1 and 2 can also be applied to embodiment 5 as appropriate.

[Embodiment 6]
Next, as a sixth embodiment, the arrangement of the radiation detection elements 13 and the laser light-emitting elements 32 will be described with reference to Fig. 10. In the gamma cameras 4 and 5, as shown in Fig. 10(a) and Fig. 10(i), the same numbers of laser light-emitting elements 32 and the same numbers of radiation detection elements 13 are arranged on a substantially flat surface.

However, as shown in Figs. 10(c), (d), (e), and (f), the pitch of the laser light-emitting elements 32 does not have to match the pitch of the radiation detection elements 13. In other words, the number of radiation detection elements 13 and the number of laser light-emitting elements 32 do not have to match. For example, as shown in Figs. 10(c) and (d), when the number of laser light-emitting elements 32 is greater than the number of radiation detection elements 13, a plurality of laser light-emitting elements 32 corresponding to one radiation detection element 13 are determined in advance. The corresponding plurality of laser light-emitting elements 32 are arranged so as to emit light in the same direction as the line connecting the corresponding radiation detection element 13 and the pinhole 11. When one radiation detection element 13 detects gamma rays, the plurality of laser light-emitting elements 32 corresponding to that radiation detection element 13 are controlled to emit light.

10(e) and (f), when the number of laser light-emitting elements 32 is smaller than the number of radiation detection elements 13, one laser light-emitting element 32 corresponding to the multiple radiation detection elements 13 is determined in advance. The corresponding laser light-emitting element 32 is then positioned so as to emit light in the same direction as a line connecting the pinhole 11 and the vicinity of the center of the detection surface of the corresponding multiple radiation detection elements 13. When gamma rays are detected by any of the multiple radiation detection elements 13, the laser light-emitting element 32 corresponding to that radiation detection element 13 is controlled to emit light.

Also, as shown in Fig. 10(g) and (h), the radiation detection element 13 may not be pixelated. When the radiation detection element 13 is not pixelated, the control shown in the flowchart of Fig. 11(a) is performed. That is, when the control unit 16 receives a gamma ray detection signal from the radiation detection element 13 (step S111), it calculates at which position of the radiation detection element 13 the gamma ray was detected (step S112). Next, the control unit 16 determines the laser light-emitting element 32 that is closest to the line segment connecting the gamma ray detection position and the pinhole 11 (step S113). Then, the control unit 16 causes the determined laser light-emitting element 32 to emit light (step S114). A block diagram of the gamma cameras 4 and 5 that perform such control is shown in Fig. 11(b).

Also, as shown in Figures 10(b), (d), (f), and (h), multiple laser light-emitting elements 32 may be arranged in a curved shape. If the element array in which multiple laser light-emitting elements 32 are arranged is curved so that the light-emitting surface (emission direction) of the light faces the pinhole 11, the light can be efficiently emitted to the outside, and the gamma camera can be easily manufactured and assembled. Alternatively, or in addition to these forms, multiple radiation detection elements 13 may be arranged in a curved shape (not shown). If the element array in which multiple radiation detection elements 13 are arranged is curved so that the gamma-ray detection surface faces the pinhole 11, the gamma-ray detection efficiency increases.

Also, as shown in FIG. 10(j), the integrated laser light-emitting element 32 and radiation detection element 13 may be arranged in a curved manner. By integrating the laser light-emitting element 32 and the radiation detection element 13, it is possible to improve the gamma ray detection efficiency and the accuracy of the light emission direction. In addition, both the light-emitting surface of the laser light-emitting element 32 and the detection surface of the radiation detection element 13 can be arranged facing the direction of the pinhole 11, which increases both the gamma ray detection efficiency and the light emission efficiency to the outside. In addition, it becomes easier to manufacture and assemble the gamma camera.

As described above, there are various types of configurations in which the radiation detection element 13 and the light-emitting element 32 corresponding to the radiation detection element 13 are arranged adjacent to each other along the direction of radiation travel. The radiation detection element 13 and the light-emitting element 32 corresponding to the radiation detection element 13 may be arranged at a distance from each other, or may be arranged in contact with each other. By arranging the radiation detection element 13 and the light-emitting element 32 corresponding to the radiation detection element 13 at a distance from each other, the degree of freedom in the arrangement of the two is improved. Therefore, the degree of freedom in the structural design of the gamma camera is increased.

In addition, the radiation detection element 13 and the light-emitting element 32 do not have to correspond one-to-one. It is preferable that at least the light-emitting surface of the laser light-emitting element 32 is arranged to face the direction of the pinhole 11. This is because the laser light emitted by the laser light-emitting element 32 has high directivity. In addition, the detection surface of the radiation detection element 13 does not necessarily have to face the direction of the pinhole 11, but it is preferable to arrange it so that it faces the direction of the pinhole 11 as much as possible. This can increase the detection efficiency of the radiation detection element 13.

[Embodiment 7]
Next, a gamma camera 6 according to a seventh embodiment will be described with reference to the drawings. Fig. 12 is a schematic vertical cross-sectional view of the gamma camera 6 and a control flow thereof. Fig. 13 is a plan view showing the arrangement of the radiation detection elements 13 and the laser light-emitting elements 32. Fig. 14 is a perspective view showing the arrangement of the radiation detection elements 13 and the laser light-emitting elements 32.

As shown in Figure 12(a), in the gamma camera 6, the radiation detection elements 13 are arranged closer to the pinhole 11 than the laser light-emitting elements 32. The laser light-emitting elements 32 are arranged farther from the pinhole 11 than the radiation detection elements 13. The corresponding radiation detection elements 13 and laser light-emitting elements 32 are arranged adjacent to each other in a direction intersecting the direction of travel of the gamma rays. The radiation detection elements 13 and laser light-emitting elements 32 are also arranged at a distance from each other. The flowchart shown in Figure 12(b) will be described later.

The arrangement of the radiation detection elements 13 and the laser light-emitting elements 32 will be described in more detail. As shown in FIG. 13, the radiation detection elements 13 and the laser light-emitting elements 32 are arranged in two orthogonal directions, shifted by a distance L1 and a distance L2, respectively. The shift direction is a direction intersecting the traveling direction of the gamma rays, and in this embodiment, it is a direction perpendicular to the traveling direction of the gamma rays. The distances L1 and L2 are both equal to or more than half the width of the radiation detection elements 13 along each direction. By arranging them in this manner, the laser light can be emitted from the laser light-emitting elements 32 while avoiding the radiation detection elements 13. In addition, the radiation detection elements 13 can be arranged as densely as possible, improving the accuracy of the detection position. The amount of shift may be larger, but the detection efficiency or the detection position accuracy may decrease accordingly.

To easily form the above array, it is preferable to use a spherical support 40 centered on the pinhole 11, as shown in Figures 12(a) and 14. The support 40 is a curved plate, and supports the radiation detection element 13 on the side closer to the pinhole 11. The support 40 also supports the laser light-emitting element 32 on the side farther from the pinhole 11 than the radiation detection element 13. The support 40 is provided with a plurality of through holes 41 for passing the laser light L in advance. The through holes 41 are provided facing the light-emitting surfaces of the plurality of laser light-emitting elements 32, respectively, and facing the gaps between the plurality of radiation detection elements 13.

In other words, the support 40 supports the laser light emitting element 32 so that it can irradiate the laser light L toward the pinhole 11 through the gap between the radiation detection elements 13. By using the support 40, it is possible to arrange the laser light L from the laser light emitting element 32 so that it passes through the hole of the pinhole 11 without performing complicated optical axis adjustment work. Note that in Figure 14, the radiation detection element 13 and the laser light emitting element 32 are depicted as being arranged at a distance from the support 40, but in reality they are in contact as shown in Figure 12(a).

The gamma camera 6 is one of the effective modes when the laser light-emitting element 32 becomes large in the direction of incidence of the gamma rays. In this way, by arranging the radiation detection element 13 and the corresponding laser light-emitting element 32 adjacent to each other in the intersecting direction, the degree of freedom in arranging the radiation detection element 13 and the laser light-emitting element 32 is improved. Therefore, the degree of freedom in the structural design of the gamma camera is increased.

In the gamma camera 6, the radiation detection element 13 and the laser light-emitting element 32 are arranged adjacent to each other in a direction intersecting the direction of travel of the gamma rays, so that the axis of incidence of the gamma rays and the optical axis of the laser are slightly misaligned. Therefore, after detecting the gamma rays, it is preferable to perform control to select an appropriate corresponding laser light-emitting element 32 in the vicinity of the radiation detection element 13. Specifically, as shown in the flowchart in FIG. 12(b), when the control unit 16 receives a gamma ray detection signal from the radiation detection element 13 (step S121), it selects a laser light-emitting element 32 located close to the radiation detection element 13 (step S122). Then, the control unit 16 causes the selected laser light-emitting element 32 to emit light (step S123).

Methods for selecting the laser light-emitting elements 32 in the above-mentioned flowchart include (1) selecting all laser light-emitting elements 32 adjacent to the radiation detection element 13, (2) selecting only a specific laser light-emitting element 32 adjacent to the radiation detection element 13 (e.g., the right side), or (3) randomly selecting only one element from among the laser light-emitting elements 32 adjacent to the radiation detection element 13.

In this embodiment, as described above, the axis of incidence of the gamma rays and the optical axis of the laser light emitted in response to the gamma rays are slightly misaligned in principle. Therefore, the projection position of the laser light is also slightly misaligned. However, the size (width in the direction intersecting the direction of travel of the gamma rays) of the radiation detection element 13 (or the laser light emitting element 32) that causes the misalignment is small, and the projection distance is small, so the magnitude of the misalignment is small. Therefore, even if the position of the projected light is misaligned, there is no practical problem. Note that it is preferable that the angle of misalignment between the axis of incidence of the gamma rays and the axis of the emitted laser light is within an angle equivalent to the angle error when detecting the angle of incidence of the gamma rays. Specifically, as shown in FIG. 15, when the angle between the adjacent radiation detection elements 13 and the pinhole 11 is θ1, it is more preferable that the angle of misalignment θ2 between the axis of incidence of the gamma rays R and the axis of the emitted laser light L is half or less of θ1.

[Embodiment 8]
Next, the shield 22 of the gamma camera according to the eighth embodiment will be described with reference to the drawings. FIG. 16(a) is a perspective view of the shield 22 according to the eighth embodiment, and FIG. 16(b) is a longitudinal sectional view thereof. The collimator shown in the first to seventh embodiments is a pinhole collimator. In contrast, the shield 22 according to the eighth embodiment has a parallel hole collimator as shown in FIGS. 16(a) and 16(b). In this case, the holes 22A provided in plurality serve as collimators. Thus, in the embodiment of the present invention, not only the pinhole collimator but also a general parallel hole collimator can be applied. In the case of the parallel hole collimator, the larger the opening area of the hole 22A, the higher the radiation detection sensitivity. On the other hand, since the imaging/projection field size and the detector size match, it is preferable to apply it to a handheld device used outside the body. Even when such a collimator is used, it is easily possible to emit light in the opposite direction to the incident direction of the incident radiation.

[Embodiment 9]
Next, the shields 23 and 24 of the gamma camera according to the ninth embodiment will be described with reference to the drawings. The shield 23 according to the ninth embodiment has a collimator of a converging hole type as shown in FIG. 17(a). In this case, the holes 23A provided in plurality serve as the collimator. In this embodiment, the imaging and projection field size is smaller than the size of the detector portion, but a spatial resolution finer than the interval between the radiation detection elements 13 can be obtained due to the magnification effect. Also, as shown in FIG. 17(b), a shield 24 having a collimator of a diverging hole type may be used. In this case, the holes 24A provided in plurality serve as the collimator. In this embodiment, the imaging and projection field size can be larger than the size of the detector portion, but the spatial resolution is deteriorated compared to the interval between the radiation detection elements 13. It is preferable to use these collimators 23A and 24A appropriately depending on the place of use and the purpose of use. Even when such a collimator is used, it is easily possible to emit light in the opposite direction to the incident direction of the incident radiation.

(Application example)
The gamma camera of each of the above embodiments can be applied to medical treatment. Fig. 18 is a schematic diagram showing an example of application of the gamma camera according to each of the above embodiments to laparoscopic surgery or robotic surgery. As shown in Fig. 18, in addition to an optical camera and forceps that are inserted into a port in a normal laparoscopic surgery or robotic surgery, the gamma camera of each of the above embodiments is inserted near the affected area. Since the gamma camera independently projects the distribution of the radiopharmaceutical on the surface of the affected area, the surgeon can visually confirm the distribution state of the radiopharmaceutical projected on the surface of the affected area through the image of the normal optical camera.

(Modification)
In the above embodiments, a medical gamma camera has been described as an example. However, the embodiments of the present invention do not necessarily have to be for medical use. For example, the present invention may be configured as a radiation camera for confirming the location of a contamination source in a nuclear power plant, a facility using radioactive materials, a nuclear fuel processing facility, a reprocessing facility, etc. Alternatively, the present invention may be configured as a radiation camera for security purposes for monitoring the presence or absence of radioactive materials or nuclear materials in luggage at an airport, a border, etc.

By configuring it in this way, it is possible to visualize, for example, areas to be decontaminated. In this case, the light-emitting element may be configured so that the emission time or intensity of the emitted light can be changed depending on the intensity of the detected radiation (energy intensity, counting rate, or spatial dose rate). Since the distance to the radiation source is long, it is preferable to use a highly directional laser light-emitting element as the light-emitting element. Furthermore, when the radiation energy intensity of the radiation source to be detected covers a wide range, it is preferable to set the thickness of the shielding body to a thickness that can block radiation of the maximum energy.

〔summary〕
A radiation camera according to aspect 1 of the present invention includes a collimator that collimates incident radiation, a radiation detection unit that detects the radiation that has passed through the collimator, and a light emitting unit that emits visible light in a direction opposite to the incident direction of the radiation detected by the radiation detection unit.

According to the above configuration, when the radiation detection unit detects radiation that has passed through the collimator, the incident direction of the radiation is determined from the positions of the collimator and the radiation detection unit. By emitting visible light from the light emitting element in the opposite direction to the incident direction of the radiation, it is possible to project visible light toward the radiation source without the need to calibrate the projection direction based on the position of the radiation camera. This makes it possible to visualize, for example, the position of an affected area on the skin.

In the radiation camera according to aspect 2 of the present invention, the radiation detection unit is composed of one or more radiation detection elements, the light emitting unit is composed of one or more light emitting elements, and the radiation detection elements may be associated with the light emitting elements that emit visible light in a direction opposite to the incident direction of the radiation detected by the radiation detection elements.

According to the above configuration, by matching one or more radiation detection elements with one or more light-emitting elements, visible light can be easily emitted from the light-emitting unit in the opposite direction to the incident direction of the radiation.

In a radiation camera according to aspect 3 of the present invention, the radiation detection element and the light-emitting element corresponding to the radiation detection element may be arranged adjacent to each other along the direction in which the radiation travels.

According to the above configuration, by arranging the radiation detection element and the corresponding light emitting element adjacent to each other along the direction of radiation propagation, the direction of the emitted light can be easily aligned with the incident direction of the incident radiation.

In the radiation camera according to aspect 4 of the present invention, the radiation detection element and the light-emitting element corresponding to the radiation detection element may be integrated together.

According to the above configuration, by integrating the radiation detection element with the corresponding light-emitting element, the radiation detection element and the corresponding light-emitting element can be easily arranged adjacent to each other.

In a radiation camera according to aspect 5 of the present invention, the radiation detection element and the light-emitting element corresponding to the radiation detection element may be arranged adjacent to each other in a direction intersecting the direction of travel of the radiation.

According to the above configuration, by arranging the radiation detection element and the corresponding light emitting element adjacent to each other in a direction intersecting the direction of radiation propagation, the direction of the emitted light can be easily aligned with the incident direction of the incident radiation.

In a radiation camera according to aspect 6 of the present invention, the radiation detection element and the light-emitting element corresponding to the radiation detection element may be arranged at a distance from each other.

According to the above configuration, the radiation detection elements and the corresponding light-emitting elements are arranged at a distance from each other, which increases the degree of freedom in arranging the radiation detection elements and the corresponding light-emitting elements. This increases the degree of freedom in the structural design of the radiation camera.

In a radiation camera according to aspect 7 of the present invention, a support portion is provided that supports the radiation detection elements on a side closer to the collimator and supports the light-emitting elements on a side farther from the collimator than the radiation detection elements, and the support portion may have a plurality of through holes that face the light-emitting surfaces of the plurality of light-emitting elements and face the gaps between the plurality of radiation detection elements.

With the above configuration, the light from the light-emitting element can be arranged to pass through the pinhole without the need for complicated optical axis adjustment work.

In the radiation camera according to aspect 8 of the present invention, the plurality of radiation detection elements and the plurality of light-emitting elements may each be arranged in a planar or curved shape.

According to the above configuration, the radiation detection elements or the light-emitting elements are arranged in a planar shape, which makes manufacturing easier. In addition, the radiation detection elements are arranged in a curved shape (i.e., facing the incident portion), which increases the radiation detection efficiency. In addition, the light-emitting elements are arranged in a curved shape, which makes it possible to efficiently emit the emitted light to the outside.

In the radiation camera of aspect 9 of the present invention, the collimator may be at least one of a pinhole collimator, a parallel hole collimator, a converging multi-hole collimator, and a diverging multi-hole collimator.

With the above configuration, regardless of which one is used, it is easily possible to align the direction of the emitted light with the incident direction of the incoming radiation.

The radiation camera according to aspect 10 of the present invention may further include a control unit that controls the light emitting unit to emit visible light in a direction opposite to the incident direction of the radiation detected by the radiation detection unit.

According to the above configuration, the control unit is provided inside the radiation camera, which improves portability. In addition, the radiation detection unit, light emission unit, and control unit are integrated into one unit, resulting in a compact configuration.

In a radiation camera according to aspect 11 of the present invention, the control unit may adjust the emission time or emission intensity of the light-emitting unit based on the intensity of the radiation detected by the radiation detection unit.

According to the above configuration, if the amount of radioactive nuclide accumulation correlates with the malignancy of cancer, information on radiation intensity is thought to be useful for distinguishing cancer. By adjusting the emission time or emission intensity based on the radiation intensity and displaying the radiation intensity, more detailed information can be obtained. In addition, when measuring an environment in which multiple radiations of different intensities are detected, light can be projected onto the position of the radiation source, making it possible to directly recognize the amount of radiation emitted from which position.

Furthermore, a method of operating a radiation camera according to one aspect of the present invention includes the steps of detecting collimated radiation and emitting visible light in a direction opposite to the incident direction of the detected radiation. More specifically, for example, a method of operating a medical radiation camera includes the steps of collimating and detecting gamma rays emitted from a radiopharmaceutical that has accumulated at a specific site in a living body, and emitting visible light in a direction opposite to the incident direction of the detected gamma rays.

The present invention is not limited to the above-described embodiments, but various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

1, 1A, 2, 3, 4, 5, 6 Gamma camera (radiation camera)
8, 10, 20, 22, 23, 24 Shielding body 8A, 10A Upper part 8B, 10B Lower part 8C, 10C Tip part 8D, 11 Pinhole (collimator)
9 Housing 10D Open end 12 Radiation detection unit 13 Radiation detection element (radiation detection unit)
14, 30 Light emitting element (light emitting portion)
15 Reflection section 15A Reflection plate 15B Driving section 16 Control section 22A, 23A, 24A Hole section (collimator)
32 Laser light emitting element (light emitting section)
40 Support part 41 Penetration hole 50 Radiation source 51 Skin

Claims (12)

a collimator for collimating the incident radiation;
a radiation detection unit that detects radiation that has passed through the collimator;
a light emitting unit that emits visible light in a direction opposite to an incident direction of the radiation detected by the radiation detection unit ,
the radiation detection unit is composed of a plurality of radiation detection elements, the light emitting unit is composed of a plurality of light emitting elements, each of the plurality of radiation detection elements is associated with each of the plurality of light emitting elements, and each of the plurality of light emitting elements emits visible light in a direction opposite to an incident direction of radiation detected by the associated radiation detection element,
Radiation camera. 2. The radiation camera according to claim 1 , wherein the radiation detection elements and the light emitting elements corresponding to the radiation detection elements are arranged adjacent to each other along a traveling direction of the radiation. 3. The radiation camera according to claim 2 , wherein the radiation detection element and the light emitting element corresponding to the radiation detection element are integrated together. 2. The radiation camera according to claim 1 , wherein the radiation detection elements and the light emitting elements corresponding to the radiation detection elements are arranged adjacent to each other in a direction intersecting a traveling direction of the radiation. The radiation camera according to claim 4 , wherein the radiation detection elements and the light emitting elements corresponding to the radiation detection elements are arranged at a distance from each other. 6. The radiation camera according to claim 5, further comprising a support section that supports the radiation detection elements on a side closer to the collimator and supports the light emitting elements on a side farther from the collimator than the radiation detection elements, the support section facing each of the light emitting surfaces of the plurality of light emitting elements and having a plurality of through holes provided facing gaps between the plurality of radiation detection elements. 7. The radiation camera according to claim 2 , wherein the plurality of radiation detection elements and the plurality of light emitting elements are each arranged in a planar or curved shape. 8. The radiation camera according to claim 1 , wherein the collimator is at least one of a pinhole collimator, a parallel hole collimator, a converging multi-hole collimator, and a diverging multi-hole collimator. 9. The radiation camera according to claim 1, further comprising a control unit that controls the light emitting unit to emit visible light in a direction opposite to an incident direction of the radiation detected by the radiation detection unit. The radiation camera according to claim 9 , wherein the control unit adjusts a light emission time or a light emission intensity of the light emitting unit based on the intensity of the radiation detected by the radiation detection unit. a collimator for collimating the incident radiation;
a radiation detection unit that detects radiation that has passed through the collimator;
a light emitting unit that emits visible light in a direction opposite to an incident direction of the radiation detected by the radiation detection unit,
the radiation detection unit is composed of one or a plurality of radiation detection elements, the light emitting unit is composed of one or a plurality of light emitting elements, each of the one or a plurality of radiation detection elements is associated with each of the one or a plurality of light emitting elements, and each of the one or a plurality of light emitting elements emits visible light in a direction opposite to a direction of incidence of radiation detected by the associated one or a plurality of radiation detection elements,
the radiation detection elements and the light emitting elements corresponding to the radiation detection elements are arranged adjacent to each other along a traveling direction of the radiation;
Radiation camera. a collimator for collimating the incident radiation;
a radiation detection unit that detects radiation that has passed through the collimator;
a light emitting unit that emits visible light in a direction opposite to an incident direction of the radiation detected by the radiation detection unit,
the radiation detection unit is composed of one or a plurality of radiation detection elements, the light emitting unit is composed of one or a plurality of light emitting elements, each of the one or a plurality of radiation detection elements is associated with each of the one or a plurality of light emitting elements, and each of the one or a plurality of light emitting elements emits visible light in a direction opposite to a direction of incidence of radiation detected by the associated one or a plurality of radiation detection elements,
the radiation detection elements and the light emitting elements corresponding to the radiation detection elements are arranged adjacent to each other in a direction intersecting with a traveling direction of the radiation,
Radiation camera.

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