Radiation detector

Abstract

The present invention provides a radiation detector capable of more accurately making an operator aware of a location inside body tissue where radionuclides have been incorporated. A radiation detector (1) is provided with: a probe (10) which can be inserted inside a body and has a radiation detection element (20) built therein; a notification unit (30) provided to the probe (10); and a control unit (50) which activates the notification unit (30) on the basis of radiation detection results from the radiation detection element (20).

Description

Technical Field

[0001] The present invention relates to a radiation detector.

Background Art

[0002] Conventionally, cancer cells that are likely to take up a specific compound or tissues where a compound of a specific size tends to remain are known. In order to identify the location of such cancer cells or tissues, a compound containing a radionuclide is administered to a patient, and its location is identified using a gamma camera. For example, 99m a method is known in which a compound preparation containing 99mTc is administered to a patient, and the lymph nodes in which the compound has accumulated are identified and dissected. Non-Patent Document 1 discloses a portable gamma camera capable of determining the presence or absence of cancer metastasis to sentinel lymph nodes during surgery in order to carry out this method.

[0003] Non-Patent Document 2 also discloses a method of detecting lymph node metastasis by intravenously administering F-18-labeled FDG (fluorodeoxyglucose), which has a high track record in PET (Positron Emission Tomography) examinations, and examining the uptake of FDG into lymph nodes. This is a method aimed at minimizing the resection range and reducing the invasiveness of surgery.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

[0005] However, in the gamma camera disclosed in Non-Patent Document 1, since the image of the detected radioactivity distribution is displayed on a separate display, it is difficult to grasp the positional relationship between the displayed image and the surgical site. Further, the technique disclosed in Non-Patent Document 2 does not relate to a method of immediately transmitting to the surgeon (operator) the degree of uptake of FDG into the lymph nodes. Conventionally, as an intraoperative radiation detector, techniques such as a gamma probe, a forceps-type PET, a drop-in type detector, and a method of using a combination of an in-vivo insertion detector and an external detector have been developed. However, in all of them, due to the mechanism of displaying the image of the nuclide distribution and the radioactivity value on the display of the radiation equipment, the operator has to move the viewpoint from the surgical field every time measurement is performed. Therefore, there has been a problem that it is difficult to correctly recognize the position of the affected part from the measured radioactivity. For example, in endoscopic surgery and robot-assisted surgery, it is desired that the operator can correctly grasp the position of the affected part in the camera image seen by the operator.

[0006] An aspect of the present invention is to provide a radiation detector that can enable an operator to more correctly recognize the position of a body tissue in which a radionuclide has been incorporated. MEANS FOR SOLVING THE PROBLEMS

[0007] In order to solve the above problems, a radiation detector according to an aspect of the present invention includes a probe that can be inserted into the body and incorporates a radiation detection element, a notification unit provided on the probe, and a control unit that operates the notification unit based on the detection result of radiation by the radiation detection element.

[0008] Further, a radiation detector according to an aspect of the present invention is a radiation detector configured as a surgical grasping forceps that can be inserted into the body, wherein two tip portions of the grasping forceps are each configured as two probes incorporating radiation detection elements, a notification unit provided on the grasping forceps, and a control unit that operates the notification unit based on the detection result of annihilation gamma rays by simultaneous counting of each radiation detection element incorporated in the two probes.

Effects of the Invention

[0009] According to an aspect of the present invention, it is possible to provide a radiation detector that can more accurately enable an operator to recognize the position of a body tissue incorporating a radionuclide.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] 〔Embodiment 1〕 Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram of a medical radiation detector 1 according to Embodiment 1 of the present invention. FIG. 2 is a morphological example of the light-emitting part according to Embodiment 1. This FIG. 2 includes a perspective view of the probe provided with the light-emitting part and a cross-sectional view of the probe cut along its radial direction. FIG. 3 is a functional block diagram of the radiation detector 1 according to Embodiment 1. The radiation detector 1 detects radiation R from a radionuclide accumulated in the affected area, and when the measured value (count number) of the radiation R satisfies a predetermined condition, it notifies the operator (surgeon) of it.

[0012] (Configuration of Radiation Detector 1) As shown in FIG. 1, the radiation detector 1 includes a probe 10 that can be inserted into the body and an operation unit 80. The probe 10 incorporates a radiation detection element 20 and includes a light-emitting part (notification part) 30. That the light-emitting part 30 operates means that the light-emitting part 30 emits light. The light-emitting part 30 is an example of the notification part. A control unit 50, an input / output interface (I / O) 62, a setting unit 64, and a counting unit 66 are arranged in the operation unit 80. In addition, an input unit 70 is provided in the operation unit 80.

[0013] The radiation detection element 20 is disposed at the tip of the probe 10. The operator can bring the tip of the probe 10 closer to the affected area to check the degree of radiation R detected. The type of the radiation detection element 20 is not particularly limited, but it is preferably a small detection element such as a semiconductor detection element or a scintillation detection element. As the semiconductor detection element, a CdTe (CZT) semiconductor detection element, a Si semiconductor detection element, a Ge semiconductor detection element, or the like can be used. As the scintillation detection element, a CsI (Tl) scintillator, a NaI (Tl) scintillator, or the like can be used. The radiation detection element 20 converts the energy of the radiation R into an electrical signal and outputs it. A known configuration can be used for the configuration that converts the radiation energy into an electrical signal.

[0014] As a method for specifying the incident direction of the radiation R detected by the radiation detection element 20, a collimator method, a Compton camera method, a coincidence counting method, or the like can be selected. In the collimator method, a collimator for regulating the incident direction of the radiation R incident on the radiation detection element 20 is provided. Then, the incident direction of the radiation R incident on the collimator can be determined from the position of the radiation detection element 20 that has detected the radiation R. In the case of the Compton camera method, a radiation detection element 20 for a Compton camera including a scattering part and an absorption part is used. Then, the incident direction of the gamma ray can be determined from the scattered position in the scattering part and the absorbed position in the absorption part. In the case of the coincidence counting method, two radiation detection elements 20 are arranged at positions facing each other. Then, it is counted only when counted simultaneously by the two radiation detection elements 20, and it can be determined that there is a radiation source between the two radiation detection elements 20. The coincidence counting method targets positron-emitting nuclides.

[0015] The light emitting unit 30 is disposed at the tip of the probe 10. The light emitting unit 30 is disposed in the vicinity of the radiation detection element 20. The light emitting unit 30 has a role of notifying an operator when the radiation detection element 20 detects radiation R that satisfies a predetermined condition. The operator brings the tip of the probe 10 close to the affected part to check whether the radiation R is detected. Therefore, the light emitting unit 30 is disposed at the tip of the probe 10 so that the operator can recognize the light emission of the light emitting unit 30 without moving the line of sight during the operation of the probe 10.

[0016] The light emitting unit 30 is provided on the outer surface of the probe 10. More specifically, as shown in Fig. 2(a), the light emitting unit 30 is continuously provided so as to go around the outer peripheral surface of the probe 10. However, the shape of the light emitting unit 30 is not limited to this shape. In the example shown in Fig. 2(a), the light emitting unit 30 goes around at the same height as the outer peripheral surface of the probe 10. However, as shown in Fig. 2(b), the light emitting unit 30 may be configured to at least partially protrude from the outer surface of the probe 10. Also, as shown in Fig. 2(c), the light emitting unit 30 may be provided at a plurality of locations on the outer surface of the probe 10. In any configuration, even if the orientation of the probe 10 changes, the operator can surely recognize the light emission of the light emitting unit 30.

[0017] The light emitting unit 30 is composed of, for example, a light guide material that guides light, and guides the light from the built-in light emitting element 32 and emits it to the outside. The light emitting element 32 is, for example, a light emitting diode (LED, Light Emitting Diode). The number of light emitting elements 32 may be one or a plurality.

[0018] The input unit 70 is provided on the outer surface of the operation unit 80. The input unit 70 is, for example, a touch panel type liquid crystal display capable of inputting a threshold value of the number of detections of the radiation R that causes the light emitting unit 30 to emit light. The cable 82 is a power cable that supplies power to the radiation detector 1. Also, the cable 82 may also serve as an information communication cable between the radiation detector 1 and the outside. Note that the cable 82 may be omitted by incorporating a power source in the radiation detector 1.

[0019] (Control of Radiation Detector 1) FIG. 3 is a functional block diagram related to the control of the radiation detector 1 according to Embodiment 1. The control unit 50 controls the entire radiation detector 1. The control unit 50 includes a processor 52 and a memory 54. The memory 54 is composed of, for example, a volatile RAM (Random Access Memory) and a non-volatile ROM (Read Only Memory), and stores various control programs and data. Further, the memory 54 may store, as set values, the threshold value of the radiation measurement value for causing the light emitting unit 30 to emit light, the light emission time, and the like. The processor 52 is, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor 52 reads out various control programs from the ROM, expands them in the RAM, and functions as a setting unit 64 and a counting unit 66 by executing the programs. Alternatively, the processor 52 may be a dedicated processor such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The radiation detection element 20, the light emitting element 32, the control unit 50, the I / O 62, the setting unit 64, the counting unit 66, and the input unit 70 are electrically coupled by a bus 56.

[0020] The input / output interface (I / O) 62 transmits and receives signals and information to and from the outside. The setting unit 64 acquires the threshold value input by the operator and sets it for the control unit 50. The threshold value is a threshold value corresponding to the detection result of radiation for determining whether or not to cause the light emitting unit 30 to emit light. Specifically, the setting unit 64 acquires, for example, information regarding the threshold value input by the operator from the input unit 70 via the I / O 62. The setting unit 64 stores the acquired information regarding the threshold value in the memory 54 or a setting register, thereby setting the threshold value input by the operator for the control unit 50. The counting unit 66 acquires the electrical signal output by the radiation detection element 20, counts the number of times of radiation detection, and outputs it to the control unit 50.

[0021] Based on the radiation detection results by the radiation detection element 20, the control unit 50 causes the light emitting unit 30 to emit light. For example, each time the counting unit 66 counts radiation once, the control unit 50 causes the light emitting unit 30 to emit light. Alternatively, when the number of radiation detections acquired from the counting unit 66 is greater than a set threshold value, the control unit 50 may perform control to cause the light emitting element 32 to emit light for a predetermined time. If the light emitting time is too long, individual detections of radiation cannot be distinguished. If the light emitting time is too short, there is a possibility that the light emission cannot be recognized. Therefore, it is preferable to set an appropriate light emitting time in advance. Also, depending on the measurement conditions, the light emitting time may be configured to be set by the operator from the input unit 70.

[0022] A control method for causing the light emitting unit 30 to emit light will be described with reference to FIG. 4. As an example, as shown in the first flowchart example of FIG. 4(a) and FIG. 4(b), each time the counting unit 66 counts radiation once (step S100), the control unit 50 causes the light emitting element 32 to emit light once for a predetermined time (step S101). This is an example of emitting light regardless of the radiation counting rate. In this case, the operator determines whether they are close to the affected area (radiation source) where the radionuclide has accumulated by looking at the frequency of light emission. If the frequency of light emission is high, it can be determined that they are close to the affected area. The operator can change the position of the probe 10 and check the frequency of light emission, and determine that the affected area is at the position where the light emission frequency is high.

[0023] Further, the control unit 50 may control the light emitting unit 30 to emit light when the radiation count rate is equal to or higher than a predetermined value. The count rate is represented by cps (count per second), which is, for example, the number of radiation detections per second. As shown in the second flowchart example of FIG. 4(c) and FIG. 4(d), the counting unit 66 calculates the count rate by integrating the number of radiation detections over a predetermined time (for example, several seconds to several tens of seconds) and dividing by the predetermined time (step S110). Next, the control unit 50 determines whether the count rate calculated by the counting unit 66 is equal to or higher than a predetermined count rate (threshold value) (step S111). When the count rate is equal to or higher than the predetermined threshold value (step S111: YES), the control unit 50 causes the light emitting unit 30 to emit light for a predetermined time (step S112). When the count rate is not equal to or higher than the predetermined threshold value (step S111: NO), the control unit 50 returns to step S111 without causing the light emitting unit 30 to emit light, and determines whether the count rate within a slightly shifted predetermined time is equal to or higher than the predetermined count rate. If there is light emission, the operator can determine that the affected area is close.

[0024] As another example, the control unit 50 may control the light emitting unit 30 to change the light emission mode according to the radiation count or count rate. As shown in the third flowchart example of FIG. 4(e) and FIG. 4(f), the counting unit 66 counts the number of detected radiation over a predetermined time (for example, several seconds to several tens of seconds) (step S120) and calculates the count rate (step S121). Next, the control unit 50 causes the light emitting unit 30 to emit light in a predetermined mode according to the count rate (step S122). For example, when it is less than the first threshold value, the control unit 50 does not cause the light emitting element 32 to emit light. When it is equal to or higher than the first threshold value and less than the second threshold value, the control unit 50 causes the light emitting element 32 to emit blue light. When it is equal to or higher than the second threshold value, the control unit 50 causes the light emitting element 32 to emit red light. If there is red light emission, the operator can determine that the affected area is close or the accumulation amount of the radionuclide in the affected area is large. Further, the control unit 50 may control to change the light emission intensity (luminance) of the light emitting unit 30 according to the count rate. The operator can determine that the closer the affected area is or the larger the accumulation amount of the radionuclide in the affected area is, the stronger (brighter) the light emission is. Further, the control unit 50 may control to change the light emission pattern or the light emission time of the light emitting unit 30 according to the count rate.

[0025] It is preferable that the operator appropriately sets the above threshold value according to the type of radionuclide, the dose of the radionuclide, the accumulation amount of the radionuclide (the size of the affected area), the elapsed time from administration to measurement, and the like.

[0026] (Example of use of the radiation detector 1) As shown in FIG. 5, the radiation detector 1 can be inserted into the patient's body from a trocar and used in endoscopic surgery or robot-assisted surgery. While viewing the image of the optical camera 200, the operator brings the radiation detection element 20 of the probe 10 closer to examine whether a drug containing a radionuclide has accumulated in the tissue (for example, a lymph node) S, and performs radiation measurement. Whether a predetermined radiation is detected can be confirmed by the light emission, blinking, color tone, etc. of the light emitting portion 30 in the field of view of the optical camera 200. Therefore, the operator can know the radiation measurement result in real time through the optical camera 200.

[0027] As described above, the radiation detector 1 according to Embodiment 1 measures the radiation from the radionuclide taken into the body tissue (affected area) with the radiation detection element 20 of the probe 10, and appropriately causes the light emitting portion 30 at the tip of the probe 10 to emit light. The operator can easily recognize the light emission of the light emitting portion 30 at the tip of the probe 10 without changing the line of sight from the probe 10. That is, the operator does not need to look at another display screen that displays, for example, the radioactivity value, which is different from the display screen that displays the image near the tip of the probe 10 (around the affected area), and can more accurately recognize the position of the body tissue.

[0028] (Modification example) In the above-described Embodiment 1, the light-emitting unit 30 was used to notify the operator of the detection of radiation. However, the notification means is not limited to the light-emitting unit 30. For example, instead of the light-emitting unit 30, a speaker that emits a detection sound may be used. In the case of a speaker, the placement position may not be on the outer surface of the probe 10 and may be built-in. However, it is preferable from the viewpoint of notifying the operator that it is placed at a position close to the tip of the probe 10. The detection sound may be emitted each time radiation is detected. Also, by changing the mode (frequency, pitch, etc.) of the detection sound according to the counting rate, the magnitude of the counting rate may be notified to the operator.

[0029] A scintillation detection element may be used as the radiation detection element 20. As shown in FIGS. 6 and 7, the radiation detector 1A includes a radiation detection element 20 that is a scintillation detection element and a light-receiving unit (amplification unit) 40. The light-receiving unit 40 is coupled to the radiation detection element 20 by an optical fiber 22. The optical fiber 22 guides the scintillation light generated by the radiation detection element 20 to the light-receiving unit 40. The light-receiving unit 40 receives the scintillation light that reaches via the optical fiber 22 from the radiation detection element 20, amplifies it, and outputs it as an electrical signal to the counting unit 66. The light-receiving unit 40 is, for example, a silicon photomultiplier. The light-receiving unit 40 requires a relatively high voltage of about 70 volts, for example. Therefore, it is preferably placed inside the operation unit 80 rather than in the probe 10 inserted into the body for safety reasons.

[0030] Also, in the above-described Embodiment 1 and the modification example, the light-emitting element 32 is provided inside the light-emitting unit 30. However, it is not limited to this, and the light-emitting unit 30 and the light-emitting element 32 may be arranged separately (see FIG. 8 described later). In that case, the light-emitting unit 30 and the light-emitting element 32 can be coupled by an optical fiber. Thereby, the probe 10 can be made smaller.

[0031] In the above-described Embodiment 1, the control unit 50 is incorporated in the operation unit 80 of the radiation detector 1. However, the control unit 50 may be provided in a housing separate from the probe 10 or the operation unit 80 of the radiation detector 1. In this case, as illustrated in FIG. 3, the control unit 50 is provided in the separate housing in a state of being electrically connected to the I / O 62, the setting unit 64, the counting unit 66, the radiation detection element 20, the light emitting element 32, and the input unit 70 via the bus 56.

[0032] 〔Embodiment 2〕 Next, Embodiment 2 will be described with reference to the drawings. Note that members having the same configuration or function as those in Embodiment 1 are denoted by the same reference numerals, and the description thereof will be omitted. FIG. 8 is a schematic configuration diagram of a radiation detector 2 according to Embodiment 2 configured as a surgical grasping forceps. The grasping forceps is a surgical instrument for grasping a tissue in the body by sandwiching it with two sandwiching portions having a scissor shape. The radiation detector 2 incorporates a pair of radiation detection elements in two sandwiching portions (probes), and measures the radioactivity of an object by sandwiching it with the radiation detection elements.

[0033] (Configuration of Radiation Detector 2) As shown in FIG. 8, the radiation detector 2 includes a main body portion 110, an operation unit 105 disposed on one end side of the main body portion 110, and a sandwiching portion 140 disposed on the other end side of the main body portion 110. The main body portion 110 incorporates a first light receiving element (amplifying portion) 120, a second light receiving element (amplifying portion) 121, a light emitting element 132, a coincidence counting circuit 136, and a control unit 50. The first light receiving element 120 and the second light receiving element 121 are, for example, silicon photomultipliers and require a relatively high voltage of about 70 volts. Therefore, it is preferably safe to dispose the first light receiving element 120 and the second light receiving element 121 at positions close to the operation unit 105 as far as possible from the sandwiching portion 140. Note that the radiation detector 2 may include an input unit and a setting unit (not shown). The input unit and the setting unit in the radiation detector 2 have the same functions as the input unit 70 and the setting unit 64 described in Embodiment 1, for example.

[0034] The operation unit 105 is a mechanism part for opening and closing the clamping part 140, and has, for example, a first operation unit 103 for placing fingers other than the thumb and a second operation unit 104 for placing the thumb. The first operation unit 103 and the second operation unit 104 can be opened and closed with one hand.

[0035] The clamping part 140 has a first clamping part 142 and a second clamping part 143. The first clamping part 142 and the second clamping part 143 respectively correspond to the probe 10 in the first embodiment. A first scintillator (radiation detection element) 144 is provided on the first clamping part 142. A second scintillator (radiation detection element) 145 is provided on the second clamping part 143. The first scintillator 144 and the first light receiving element 120 are optically coupled by a first optical fiber 122. The second scintillator 145 and the second light receiving element 121 are optically coupled by a second optical fiber 123.

[0036] The first clamping part 142 and the second clamping part 143 perform an opening and closing operation of swinging in opposite directions around an opening and closing axis 160 arranged on the other end side of the main body part 110. The opening and closing operations of the first operation unit 103 and the second operation unit 104 are transmitted by a transmission mechanism (not shown) in the main body part 110 and converted into the opening and closing operations of the first clamping part 142 and the second clamping part 143.

[0037] A light emitting part 130 is provided near the opening and closing axis 160 of the main body part 110. The light emitting part 130 emits light by receiving light from the light emitting element 132. The light emitting part 130 and the light emitting element 132 are arranged separately, and the space between the light emitting part 130 and the light emitting element 132 is optically coupled by an optical fiber 134. The light emitting part 130 is composed of, for example, a light diffusing member. In this embodiment, it is preferable that the light emitting part 130 is provided as close as possible to the clamping part 140 of the main body part 110, such as near the opening and closing axis 160. Furthermore, it is more preferable that the light emitting part 130 is provided on at least one of the first clamping part 142 and the second clamping part 143 of the clamping part 140.

[0038] (Operation of the radiation detector 2) The operator sandwiches the tissue of the affected part between the first clamping part 142 and the second clamping part 143 of the radiation detector 2 and measures the radiation. The operator administers F-18 labeled FDG (fluorodeoxyglucose) to the patient in advance. F-18 labeled FDG has the property of being easily taken up and accumulated in cancer tissue. F-18 emits two annihilation gamma rays due to the annihilation of the positron generated by positron decay and the electron. Both of the two annihilation gamma rays have the same energy of 511 (KeV) and are generated simultaneously in opposite directions of 180 degrees, so they are detected simultaneously by the first scintillator 144 and the second scintillator 145 facing each other. Radiation that is not detected simultaneously is not due to annihilation gamma rays or, even if it is annihilation gamma rays, is radiation incident from outside the field of view, so it can be excluded as background radiation. Therefore, there is no need to consider shielding, etc., and the radiation detector 2 can have a simple configuration.

[0039] The scintillation light caused by the 511 (KeV) radiation generated by the first scintillator 144 is sent to the first light receiving element 120 by the first optical fiber 122. The first light receiving element 120 converts the scintillation light into an electrical signal and outputs it to the coincidence counting circuit 136. The scintillation light caused by the 511 (KeV) radiation generated by the second scintillator 145 is sent to the second light receiving element 121 by the second optical fiber 123. The second light receiving element 121 converts the scintillation light into an electrical signal and outputs it to the coincidence counting circuit 136. When both the electrical signal from the first scintillator 144 and the electrical signal from the second scintillator 145 are due to 511 (KeV) radiation and are detected simultaneously, the coincidence counting circuit 136 determines that an annihilation gamma ray has been detected and outputs a detection signal to the control unit 50. Here, the term "simultaneously" means that the arrival time difference is less than several nanoseconds or less than several tens of nanoseconds. When the detection signal from the coincidence counting circuit 136 satisfies a predetermined condition, the control unit 50 causes the light emitting unit 130 to emit light.

[0040] A control method for causing the light emitting unit 130 to emit light by the control unit 50 will be described. First, there is a control method of causing emission each time annihilation gamma rays are detected. As shown in the example of the fourth flowchart of FIG. 9(a) and FIG. 9(b), the coincidence counting circuit 136 receives the electrical signals (detection signals) of the radiation detected by the first scintillator 144 and the second scintillator 145 via the first light receiving element 120 and the second light receiving element 121, respectively (step S160). Next, the coincidence counting circuit 136 determines whether the detection signals from the first scintillator 144 and the second scintillator 145 are received simultaneously (step S161). In step S161, if the two detection signals are received simultaneously (step S161: YES), it can be determined that annihilation gamma rays have been detected, so the coincidence counting circuit 136 outputs a signal indicating that radiation has been detected to the control unit 50. If the two detection signals are not received simultaneously (step S161: NO), the process by the control unit 50 returns to the stage before step S161. Next, when the control unit 50 receives a signal indicating that radiation has been detected from the coincidence counting circuit 136, the light emitting element 132 is caused to emit light (step S162). The light emitted by the light emitting element 132 causes the light emitting unit 130 to emit light via the optical fiber 134.

[0041] Alternatively, a control method may be used that causes the light emitting element to emit light when the counting rate of the annihilation gamma rays is equal to or greater than a predetermined threshold value. The counting rate is as described in Embodiment 1. As shown in the fifth flowchart example of FIG. 9(c) and FIG. 9(d), the coincidence counting circuit 136 receives detection signals of the radiation detected by the first scintillator 144 and the second scintillator 145 (step S170). Next, the coincidence counting circuit 136 determines whether or not the two detection signals have been received simultaneously (step S171). In step S171, when the two detection signals have been received simultaneously (step S171: YES), the coincidence counting circuit 136 outputs a signal indicating that radiation has been detected to the control unit 50. Next, the control unit 50 determines whether or not the reception frequency (counting rate) of the signal indicating that radiation has been detected from the coincidence counting circuit 136 is equal to or greater than the threshold value (step S172). In step S172, when the counting rate is equal to or greater than the threshold value (step S172: YES), the control unit 50 causes the light emitting element 132 to emit light (step S173). When the two detection signals are not received simultaneously (step S171: NO) or when the counting rate is not equal to or greater than the threshold value (step S172: NO), the processing by the control unit 50 returns to the stage before step S171. The light emitted by the light emitting element 132 causes the light emitting unit 130 to emit light via the optical fiber 134.

[0042] Also, the control unit 50 may control to change the light emission mode according to the count rate of the annihilation gamma rays. As shown in the sixth flowchart example of FIG. 9(e) and FIG. 9(f), the coincidence counting circuit 136 receives the detection signals of the radiation detected by the first scintillator 144 and the second scintillator 145 (step S180). Next, the coincidence counting circuit 136 determines whether or not two detection signals are received simultaneously (step S181). In step S181, when two detection signals are received simultaneously (step S181: YES), the coincidence counting circuit 136 outputs a signal indicating that radiation has been detected to the control unit 50. Next, the control unit 50 determines whether or not the reception frequency (count rate) of the signal indicating that radiation has been detected from the coincidence counting circuit 136 is equal to or higher than a threshold value (step S182). In step S182, when the count rate is equal to or higher than the threshold value (step S182: YES), the control unit 50 causes the light emitting element 132 to emit light in a predetermined color according to the count rate (step S183). When two detection signals are not received simultaneously (step S181: NO) or when the count rate is not equal to or higher than the threshold value (step S182: NO), the process by the control unit 50 returns to the stage before step S181. For example, when it is less than the first threshold value, the control unit 50 does not emit light; when it is equal to or higher than the first threshold value and less than the second threshold value, the control unit 50 causes the light emitting element 132 to emit blue light; and when it is equal to or higher than the second threshold value, the control unit 50 causes the light emitting element 132 to emit red light. Alternatively, the control unit 50 may perform control to change the light emission frequency such as blinking according to the count rate. The method of setting the threshold value is as described in Embodiment 1.

[0043] (Example of use of radiation detector 2) As shown in FIG. 10, the radiation detector 2 can be used in endoscopic surgery and robot-assisted surgery. While looking at the image of the optical camera 200, the operator measures the radioactivity of the object by sandwiching it with two scintillators 144 and 145 of the sandwiching part 140 in order to check whether F-18-labeled FDG has accumulated in the tissue (for example, lymph node) S. Whether annihilation gamma rays are detected can be confirmed by the light emission, blinking, color tone, etc. of the light emitting part 130 in the field of view of the optical camera 200. Therefore, the operator can know the radiation measurement result in real time through the optical camera 200.

[0044] As described above, the operator can determine whether F-18-labeled FDG has accumulated in the tissue sandwiched between the first sandwiching part 142 and the second sandwiching part 143 by checking whether the light emitting part 130 emits light.

[0045] In the radiation detector 2 according to the second embodiment, since only the annihilation gamma rays from the tissue sandwiched by the sandwiching part 140 are detected, it is not affected by other radiations. And the operator can easily recognize the light emission of the light emitting part 130 provided in the vicinity of the sandwiching part 140 or the sandwiching part 140 without changing the line of sight from the sandwiching part 140. That is, the operator can more correctly recognize that the radionuclide has accumulated in the tissue sandwiched by the sandwiching part 140 without having to look at, for example, another display screen.

[0046] 〔Embodiment 3〕 Next, Embodiment 3 will be described with reference to the drawings. Note that members having the same configuration or function as those in the second embodiment are denoted by the same reference numerals and their description will be omitted. FIG. 11 is a schematic configuration diagram of a radiation detector 3 according to Embodiment 3 configured as a surgical grasping forceps. FIG. 12 is a diagram showing the relationship between the opening angle of the sandwiching part 140 and the size of the object.

[0047] (Configuration of Radiation Detector 3) The configuration of the radiation detector 3 is substantially the same as that of the radiation detector 2. Specifically, the radiation detector 3 includes a main body 110, an operation unit 105, and a clamping unit 140. In the vicinity of the opening / closing axis 160 of the main body 110, a light emitting unit 130 is arranged, and a light emitting element 132 (not shown) is arranged inside the light emitting unit 130. Further, the main body 110 incorporates a first light receiving element 120, a second light receiving element 121, a coincidence counting circuit 136, a correction unit 137, an encoder 138, and a control unit 50. Although not shown, the radiation detector 3 may include an input unit and a setting unit.

[0048] Unlike the radiation detector 2, the radiation detector 3 includes a correction unit 137 and an encoder 138. The encoder 138 is an angle encoder that outputs the opening angle θ1 of the operation unit 105, that is, the angle θ1 formed between the first operation unit 103 and the second operation unit 104. The opening angle of the operation unit 105 is interlocked with the opening angle θ2 of the clamping unit 140 (the first clamping unit 142 and the second clamping unit 143). Therefore, by detecting the opening angle θ1 of the operation unit 105 with the encoder 138, the opening angle θ2 of the clamping unit 140 can be obtained. When the opening / closing movement of the operation unit 105 is converted into a linear movement of a shaft inside the main body 110 and transmitted as the opening / closing movement of the clamping unit 140, a linear encoder may be used as the encoder 138. In this case, the opening angle θ2 of the clamping unit 140 can be calculated from the movement amount of the shaft output by the linear encoder. Instead of the opening angle θ2 of the clamping unit 140, the distance between the first clamping unit 142 and the second clamping unit 143 may be calculated.

[0049] Based on the opening angle of the clamping unit 140 or the distance between the first clamping unit 142 and the second clamping unit 143, the correction unit 137 corrects the detection efficiency (detection sensitivity) of the coincidence counting of the annihilation gamma rays by the first scintillator 144 and the second scintillator 145. The arrangement relationship between the two scintillators 144 and 145 changes depending on the opening angle of the clamping unit 140. The correction unit 137 corrects the detection efficiency of the coincidence counting based on the arrangement relationship between the two scintillators 144 and 145, so that the detected radioactivity remains unchanged even when the opening angle of the clamping unit 140 changes.

[0050] As shown in Fig. 12(a), when the opening angle of the operation unit 105 is maximum, the opening angle of the clamping unit 140 becomes maximum. As the opening angle of the operation unit 105 is decreased, the opening angle of the clamping unit 140 is decreased. For example, when detecting the annihilation gamma rays by clamping the lymph node S with the clamping unit 140, if the lymph node S is large, the opening angle of the clamping unit 140 is large as shown in Fig. 12(b), and if the lymph node S is small, the opening angle of the clamping unit 140 is small as shown in Fig. 12(c). Thus, when the lymph node S is just clamped by the clamping unit 140, the size of the lymph node S can be measured based on the detection of the annihilation gamma rays and the opening angle of the clamping unit 140 or the distance between the first clamping part 142 and the second clamping part 143.

[0051] For example, assuming that the lymph node S is spherical, the diameter of the lymph node S can be obtained based on the opening angle of the clamping unit 140 or the distance between the first clamping part 142 and the second clamping part 143, and the volume (ml) can be calculated. On the other hand, the simultaneous count value (cps) by the two scintillators 144 and 145 can be corrected by the correction unit 137 and converted into the radiation energy (Becquerel) of the lymph node S. From these results, the radiation density (Becquerel / ml) of the lymph node S can be calculated. Since the radiation density of the lymph node S is proportional to the accumulation density of the radionuclide, it can be used to estimate the amount of cancer cells in the lymph node S.

[0052] As described above, by using the encoder 138, the opening angle of the clamping unit 140 can be calculated. Then, based on the opening angle of the clamping unit 140, by correcting the detection efficiency of the two scintillators 144 and 145 provided in the clamping unit 140, the more accurate radiation energy of the measurement object can be calculated. Further, based on the opening angle of the clamping unit 140, the size of the measurement object can be obtained. And from the radiation energy and the size of the measurement object, the radiation density of the measurement object can be calculated.

[0053] Next, an example of the method of using the radiation detector 3 will be described. The control unit 50 can control the start and / or end of the operation of the radiation detector based on the change in the opening angle of the clamping portion 140 and the change in the distance between the first clamping portion 142 and the second clamping portion 143. For example, when the opening angle of the clamping portion 140 (i.e., the opening angle of the operation unit 105), which was initially closed, reaches the maximum, it may be configured to start radiation measurement. That is, the control unit 50 may be configured to start measuring radiation when the opening angle of the clamping portion 140 changes from a non-maximum state to the maximum state.

[0054] Also, when a predetermined condition is satisfied, the control unit 50 may be configured to end the radiation measurement. For example, the control unit 50 may be configured to end the measurement when a predetermined time has elapsed since the start of the measurement. Also, after the opening angle of the clamping portion 140 changes according to the size of the lymph node, the measurement may be ended when the opening angle of the clamping portion 140 changes again. This is because it is considered that the measurement operation of the lymph node has ended and been released. Alternatively, the measurement may be ended when the opening angle of the clamping portion 140 reaches the minimum (closed). This is because it is considered that the measurement operation has ended. Note that even if the measurement has ended, the measurement can be restarted by setting the opening angle of the clamping portion 140 to the maximum again.

[0055] As described above, by the radiation detector 3 autonomously starting and autonomously ending the radiation measurement based on a predetermined condition, the operator does not need to perform button operations for starting and ending the measurement, and the surgery can be performed smoothly.

[0056] Next, an example of controlling the start and end of radiation measurement of the radiation detector 3 will be described with reference to FIG. 13. As shown in FIG. 13, first, the control unit 50 measures the opening angle of the clamping unit 140 using the encoder 138 (step S201). Next, the control unit 50 determines whether the opening angle of the clamping unit 140 is the maximum angle (step S202). If the opening angle of the clamping unit 140 is the maximum angle (step S202: YES), the control unit 50 starts radiation measurement (step S203). If the opening angle of the clamping unit 140 is not the maximum angle (step S202: NO), the control flow returns to step S201. Next, in step S204, after starting the radiation measurement, the control unit 50 constantly measures the opening angle of the clamping unit 140. Then, based on the measured opening angle of the clamping unit 140, the control unit 50 corrects the detection efficiencies of the two scintillators 144 and 145 (step S205) and calculates the radioactivity value (step S207). Also, in parallel with steps S205 and S207, the control unit 50 calculates the diameter of the object (step S206). Next, the control unit 50 determines whether the end condition of the radiation measurement is satisfied (step S209). If it is determined in step S209 that the end condition is not satisfied (step S209: NO), the control flow returns to step S204. If it is determined in step S209 that the end condition is satisfied (step S209: YES), the control unit 50 records the measured maximum radioactivity value and the diameter of the object (step S210) and ends the radiation measurement. Thereafter, it may return to step S201 again.

[0057] The end condition in step S209 can be set as appropriate, such as that a predetermined time has elapsed since the start of measurement, that the opening angle of the clamping unit 140 has changed and then changed again, that the opening angle of the clamping unit 140 has become the minimum, etc. In the above-described Embodiments 2 and 3, for example, F-18-labeled FDG was exemplified as the agent containing the radionuclide, but the agent is not limited thereto. Further, in Embodiments 1 to 3, the lymph node was exemplified as the tissue in the body for examining whether the agent containing the radionuclide has accumulated, but the tissue is not limited thereto.

[0058] [Embodiment 4] (Shape of scintillator) Next, a radiation detector configured as a surgical grasping forceps according to Embodiment 4 of the present invention will be described with reference to the drawings. The configuration of the radiation detector according to Embodiment 4 is basically the same as the configuration of the radiation detector 3 according to Embodiment 3, and the different parts are the matters described below. For elements having the same configuration as those described in the previous embodiments, the same reference numerals are given and the description and illustration are omitted.

[0059] The radiation detector according to Embodiment 4 may be inserted into the body through a trocar, for example. A trocar is a medical instrument used for drainage in the chest cavity or the like. By using a trocar, a treatment method with a lower degree of invasiveness can be provided. However, the diameter of the trocar is not very large, for example, about 5 mm to a dozen mm. Therefore, from the viewpoint of radiation detection efficiency, the pair of scintillators 144 and 145 preferably has a shape that fits inside a commercially available trocar and a cross-sectional area in a direction orthogonal to the insertion direction that is as large as possible. Since the cross-section of the trocar is circular, the pair of scintillators 144 and 145 also preferably has a circular cross-section in order to make the cross-sectional area as large as possible. By configuring in this way, the volume of the scintillator that can detect radiation increases, and the radiation detection efficiency can be improved.

[0060] FIG. 14 is a cross-sectional view of the first scintillator 144 and the second scintillator 145 built in the first clamping portion 142 and the second clamping portion 143 of the radiation detector according to Embodiment 4 in a direction orthogonal to the major axis. As shown in FIG. 14, the cross-sectional shapes of the first scintillator 144 and the second scintillator 145 are each semi-circular, and the two scintillators 144 and 145 facing each other are arranged so that their cross-sections become circular.

[0061] Similarly, the clamping portion 140 of the radiation detector according to Embodiment 4 is configured such that the first clamping portion 142 and the second clamping portion 143 are each semi-circular and become circular when the two are closed.

[0062] In this case, the sizes of the scintillators 144 and 145 and the overall size (diameter) of the radiation detector according to Embodiment 4 are set to sizes that can be inserted into the body through an existing trocar. That is, the radiation detector incorporating the scintillators 144 and 145 is set to a size that can pass through the trocar. With the above configuration, it is possible to provide a radiation detector that enables minimally invasive diagnosis and treatment using an existing trocar.

[0063] 〔Embodiment 5〕 (Preset Count Method) Next, a radiation counting method for the radiation detector according to Embodiment 5 of the present invention will be described with reference to the drawings. The configuration of the radiation detector according to Embodiment 5 configured as a surgical grasping forceps is basically the same as the configuration of the radiation detector 3 according to Embodiment 3, and the different parts will be described below. For elements having the same configuration as those described in the previous embodiments, the same reference numerals will be used and the description and illustration will be omitted.

[0064] When the user (surgeon) measures the radioactivity of the affected area using the radiation detector during the operation, there may be many measurement targets. For example, when measuring cancerous lymph nodes, it is necessary to sandwich a large number of lymph nodes one by one with the sandwiching part 140 and measure them. In such a case, measurement may be performed using the preset count method. By measuring using the preset count method, the measurement time can be shortened when the radioactivity of the affected area is high. The preset count method is effective when measuring a large number of lymph nodes and can suppress an increase in the operation time due to performing radiation measurement during the operation.

[0065] The preset count is performed as follows. FIG. 15 is a flowchart of the measurement method performed by the control unit 50 of the radiation detector according to Embodiment 5. As shown in FIG. 15, after the measurement starts, in step S300, the control unit 50 integrates the count value. The count value is the number of times radiation has been detected. Next, in step S301, the control unit 50 determines whether the integrated value of the count is equal to or greater than a preset value. If it is determined in step S301 that the integrated value is equal to or greater than the preset value (step S301: Y), the process proceeds to step S303. In step S303, the control unit 50 notifies (informs) the user that the count value is equal to or greater than the reference value and ends the measurement. Here, for the control unit 50 to notify the user that the count value is equal to or greater than the reference value means that the control unit 50 causes the light emitting unit 130 to emit light in a predetermined manner.

[0066] On the other hand, if it is determined in step S301 that the integrated value is not equal to or greater than the preset value (step S301: N), the process proceeds to step S302. In step S302, the control unit 50 determines whether a predetermined measurement time has elapsed. If it is determined in step S302 that the predetermined measurement time has not elapsed (step S302: N), the process returns to step S300. On the other hand, if it is determined in step S302 that the predetermined measurement time has elapsed (step S302: Y), the process proceeds to step S304. In step S304, the control unit 50 notifies the user that the value is less than the reference value and ends the measurement.

[0067] The reference value is a reference value set based on an index related to the malignancy of the affected part preset by the user. That is, the control unit 50 notifies the comparison result between the measured value of radiation and the index related to the malignancy of the affected part.

[0068] Specifically, for example, the reference value is a count value indicating the possibility that cancer has metastasized from the affected part. The inventors have discovered that there is a correlation between the radiation energy of the lymph node and the possibility of metastasis, that is, when the radiation energy of the lymph node is equal to or higher than the first value, the possibility of metastasis is high. Specifically, the inventors have discovered that when the radiation energy of one lymph node is 10,000 (Bq) or higher, the possibility of metastasis is high. The user can convert such radiation energy into a count integration value measured for a predetermined time using predetermined scintillators 144 and 145 of the radiation detector and set it as the reference value.

[0069] Alternatively, the reference value may be a count value considered to have a low possibility of cancer metastasis. The inventors have discovered that when the radiation energy of the lymph node is equal to or lower than the second value, the possibility of metastasis is low. Specifically, the inventors have discovered that when the radiation energy of one lymph node is 600 (Bq) or lower, the possibility of metastasis is low. The user can convert such radiation energy into a count integration value in a predetermined time and set it as the reference value.

[0070] For example, depending on the size and shape of the scintillators 144 and 145 and the structure of the clamping part 140, when 185 (MBq) of FDG is administered to a cancer patient and the radioactivity is measured 6 hours after administration, the radiation energy accumulated when measuring the radioactivity is predicted to be 100 counts in 30 seconds for the radiation energy of the lymph node considered to have a low possibility of metastasis (the radiation energy per one is 600 (Bq)). On the other hand, for the radiation energy of the lymph node considered to have a high possibility of metastasis (the radiation energy per one is 10,000 (Bq)), it is predicted to be 100 counts in 1.8 seconds.

[0071] For example, the reference value of the radiation energy is set to 600 (Bq), the set value of the measured value is set to 100 counts, and the predetermined measurement time is set to 30 seconds. If the measured value does not reach the set value even after the 30 - second measurement time has elapsed, the radiation energy of the lymph node is determined to be 600 (Bq) or less, and the possibility of metastasis is low. Also, if the measured value becomes equal to or greater than the set value within 1.8 seconds or less, it can be determined that the lymph node has a high possibility of metastasis.

[0072] By measuring radioactivity in this way, lymph nodes with high radiation energy are notified in a short time and the measurement ends. Therefore, when measuring a large number of lymph nodes, the measurement time can be shortened. Also, by being notified promptly after the measurement ends, or by ensuring that the time until notification after the measurement ends is always constant, the user can recognize the approximate radiation energy from the time from the start of measurement to notification. Note that the measurement time and the reference value of the count integration value can be appropriately set according to the amount of the radionuclide expected to accumulate in the affected area and the detection efficiency of the scintillators 144, 145 of the radiation detector.

[0073] The method by which the control unit 50 notifies the user preferably varies depending on whether it notifies that it is equal to or greater than the reference value or that it is less than the reference value. For example, when it is less than the reference value, the lighting state of the light emission is continued, and when it is equal to or greater than the reference value, by changing the light emission from lighting to flashing, the user can be notified that it has become equal to or greater than the reference value. The flashing time may be constant. If the lighting state remains even after the measurement ends, it means that it is less than the reference value. If it changes to the flashing state quickly, it means that the radiation energy is large. Alternatively, the notification method may be voice, or a combination of voice and light.

[0074] (Modification example) Alternatively, the following measurement method may also be used. FIG. 16 is a flowchart of the measurement method according to a modification of Embodiment 5. The flowchart shown in FIG. 16 is a flowchart for calculating the radiation energy accumulated in the lymph node and notifying the user. As shown in FIG. 16, after the measurement starts, first, in step S310, the control unit 50 accumulates the counts. Next, in step S311, the control unit 50 determines whether the integrated value of the counts is equal to or greater than a preset value.

[0075] In step S311, if it is determined that the integrated value is equal to or greater than the set value (step S311: Y), the process proceeds to step S314. In step S314, the control unit 50 stops the timer. Next, in step S315, the control unit 50 calculates the radiation energy of the lymph node from the count value. The radiation energy of the lymph node is obtained by converting the count value from the shapes of the scintillators 144 and 145, the opening angle of the radiation detector, the size of the affected area, etc. Next, in step S316, the control unit 50 notifies the user of the radiation energy and ends the measurement.

[0076] On the other hand, in step S311, if it is determined that the integrated value is not equal to or greater than the set value (step S311: N), the process proceeds to step S312. In step S312, the control unit 50 determines whether a predetermined measurement time has elapsed. In step S312, if it is determined that the predetermined measurement time has not elapsed (step S312: N), the process returns to step S310. On the other hand, in step S312, if it is determined that the predetermined measurement time has elapsed (step S312: Y), the process proceeds to step S313. In step S313, the control unit 50 notifies the user that it is less than the reference value and ends the measurement.

[0077] By measuring the radioactivity in such a method, lymph nodes with a large radiation energy are notified and the measurement ends in a short time. Therefore, when measuring a large number of lymph nodes, the measurement time can be shortened.

[0078] The method of notifying the user may be the same as the above-described example. Also, the blinking frequency may be changed. For example, when the radiation energy of the lymph node is large, the blinking frequency may be increased, and when the radiation energy is small, the blinking frequency may be decreased.

[0079] Note that as a method of instructing the start of measurement of the radiation energy, many methods are possible. For example, the measurement may be started by the movement of the radiation detector. For example, a sensor capable of detecting the opening degree of the clamping portion 140 of the radiation detector may be attached, and the measurement may be configured to start when the clamping portion 140 is opened from a completely closed state. Alternatively, a contact sensor may be provided at the tip of the clamping portion 140 or the like, and the measurement may be configured to start when the contact sensor senses contact with the lymph node (measurement target). Also, a voice recognition system for detecting the user's voice may be provided, and the measurement may be configured to start when a specific voice of the user (for example, the voice of "start") is recognized.

[0080] Also, for example, by displaying the opening degree of the clamping portion 140 on the clamping portion 140, the user can determine the timing to start the measurement. When displaying the opening degree of the clamping portion 140, it is preferable to arrange a display portion for displaying the opening degree at a position visible to the user during normal operation. This is to eliminate the need for the user to change the orientation of the radiation detector when checking the opening degree.

[0081] As described above, by automatically starting the measurement under specific conditions, the burden on the user is reduced compared to when the user performs a switch operation, and the measurement can be started in a shorter time.

[0082] 〔Summary〕 The radiation detector according to Embodiment 1 of the present invention includes a probe that can be inserted into the body and incorporates a radiation detection element, a notification unit provided on the probe, and a control unit that operates the notification unit based on a detection result of radiation by the radiation detection element.

[0083] According to the above configuration, the position of the internal tissue in which the radionuclide is incorporated can be more accurately recognized by the operator. Specifically, while the operator (surgeon) operates the probe, the position of the radiation source (affected area) where the radionuclide has accumulated can be confirmed with the notification information from the notification unit. Furthermore, since the notification unit is provided in the probe incorporating the radiation detection element, the operator can confirm the position of the affected area without changing the orientation of the face or the direction of the line of sight.

[0084] Note that the present invention can also provide a radiation detection method having, for example, a step of detecting radiation by a radiation detection element provided in a probe inserted into the body, and a step of operating a notification unit further provided in the probe based on the detection result of the radiation.

[0085] In the radiation detector according to Aspect 2 of the present invention, a setting unit for setting a threshold value corresponding to the detection result for determining whether or not to operate the notification unit may be further provided for the control unit.

[0086] According to the above configuration, the radioactivity detected varies depending on the type of radionuclide used, the dose administered, or the amount of the accumulated radionuclide. By changing the threshold value for operating the notification unit according to such a situation, it is possible to cope with various clinical situations.

[0087] In the radiation detector according to Aspect 3 of the present invention, the notification unit may be a light emitting unit provided on the outer surface of the probe.

[0088] According to the above configuration, by using the notification unit as a light emitting unit, the position of the affected area can be visually recognized.

[0089] In the radiation detector according to Aspect 4 of the present invention, the control unit may control the light emitting unit so as to change at least one of the light emission intensity, light emission pattern, light emission color, and light emission time based on the radiation count or count rate obtained as the detection result.

[0090] According to the above configuration, since the operator can visually recognize radioactivity from the light emission mode of the light emitting unit, the position and spread where the radionuclide accumulates, that is, the position and spread of the affected part, can be easily recognized.

[0091] In the radiation detector according to Aspect 5 of the present invention, the light emitting unit and the light emitting element for causing the light emitting unit to emit light may be spaced apart, and the space between the light emitting element and the light emitting unit may be optically coupled by an optical fiber.

[0092] According to the above configuration, by arranging the light emitting element at a position separated from the probe, the probe can be miniaturized.

[0093] In the radiation detector according to Aspect 6 of the present invention, the light emitting unit may be continuously provided so as to go around the outer peripheral surface of the probe, may at least partially protrude from the outer surface of the probe, or may be provided at a plurality of locations on the outer surface of the probe.

[0094] According to the above configuration, since the light from the light emitting unit is emitted over a wide solid angle, or since the light is emitted from the light emitting units at a plurality of locations, the operator can easily recognize the presence or absence of light emission even if the orientation or position of the probe changes.

[0095] In the radiation detector according to Aspect 7 of the present invention, a collimator for regulating the incident direction of the radiation incident on the radiation detection element may be provided.

[0096] According to the above configuration, since the collimator can suppress the radiation from the surrounding environment from entering the radiation detection element, the radiation from the affected part can be efficiently detected, and the position of the affected part can be efficiently detected.

[0097] In the radiation detector according to Aspect 8 of the present invention, the radiation detection element may be a detection element for a Compton camera.

[0098] According to the above configuration, by the Compton camera method, radiation from the affected part can be efficiently detected without using a collimator or a shield, and the position of the affected part can be efficiently detected.

[0099] In the radiation detector according to Embodiment 9 of the present invention, the radiation detection element may be a simultaneous counting type radiation detection element.

[0100] According to the above configuration, when using a radionuclide that emits gamma rays by pair annihilation, by using a simultaneous counting type radiation detection element, the position of the affected part can be efficiently detected.

[0101] In the radiation detector according to Embodiment 10 of the present invention, two of the probes may be provided, and the radiation detection elements may be built in each of the probes.

[0102] According to the above configuration, by providing two probes and providing a radiation detection element in each, the characteristics of the simultaneous counting method of radiation can be utilized.

[0103] The radiation detector according to Embodiment 11 of the present invention may be configured as a surgical grasping forceps, and the two tip portions of the grasping forceps may each function as the probe provided with the radiation detection element.

[0104] According to the above configuration, by configuring it as a surgical grasping forceps, it becomes easy to specify the position of the affected part during the operation.

[0105] The radiation detector according to Embodiment 12 of the present invention is a radiation detector configured as a surgical grasping forceps that can be inserted into the body, and the two tip portions of the grasping forceps are each configured as two probes each having a built-in radiation detection element, and a notification unit provided in the grasping forceps, and a control unit that operates the notification unit based on the detection result of annihilation gamma rays by simultaneous counting of each radiation detection element built in the two probes.

[0106] According to the above configuration, there is no need for an operator to view a predetermined display screen or the like that can display, for example, an image of nuclide distribution or a radioactivity value by gripping body tissue with gripping forceps and measuring radiation from radionuclides incorporated into the body tissue, and the operator can correctly recognize whether or not radionuclides are accumulated in the body tissue.

[0107] In addition, the present invention is a radiation detection method using a radiation detector configured as, for example, surgical gripping forceps that can be inserted into the body, and includes a step of detecting annihilation gamma rays in a simultaneous counting method by each radiation detection element provided in each of two probes configured at each tip of the gripping forceps inserted into the body, and a step of operating a notification unit provided in the gripping forceps based on the detection result of the annihilation gamma rays. It is also possible to provide a radiation detection method having.

[0108] In the radiation detector according to Embodiment 13 of the present invention, the control unit may correct the detection sensitivity of simultaneous counting based on the opening angle of the two probes or the distance between the two probes.

[0109] According to the above configuration, the radioactivity of the affected area can be accurately measured.

[0110] In the radiation detector according to Embodiment 14 of the present invention, the control unit may measure the size of the measurement target based on the opening angle of the two probes or the distance between the two probes.

[0111] According to the above configuration, not only the position of the affected area but also the size of the affected area can be detected.

[0112] In the radiation detector according to Embodiment 15 of the present invention, the control unit may calculate the volume of the measurement target based on the opening angle of the two probes or the distance between the two probes, and calculate the radioactivity per volume.

[0113] According to the above configuration, not only the position of the affected part but also the accumulation density of the radionuclide, that is, the degree of dispersion of the affected part can be detected.

[0114] In the radiation detector according to Aspect 16 of the present invention, the control unit may control the start and / or end of the operation of the radiation detector based on a change in the opening angle between the two probes or a change in the distance between the two probes.

[0115] According to the above configuration, since the operator does not need to operate the start and stop of the operation of the radiation detector, the work efficiency of diagnosis or treatment can be improved.

[0116] In the radiation detector according to Aspect 17 of the present invention, the notification unit may be a light-emitting unit and may be disposed on at least one of the two probes or on the main body of the grasping forceps.

[0117] According to the above configuration, while observing the probe of the grasping forceps, it is not necessary to look at a separate display screen, and the operator can correctly recognize whether or not a radionuclide has accumulated in the in-vivo tissue.

[0118] In the radiation detector according to Aspect 18 of the present invention, the radiation detection elements built in each of the two probes may each have a semi-circular cross-sectional shape.

[0119] According to the above configuration, the volume of the radiation detection element can be increased, and the detection efficiency can be improved.

[0120] In the radiation detector according to Aspect 19 of the present invention, the notification unit may notify a comparison result between the detection result of the annihilation gamma rays and an index related to the malignancy of the affected part.

[0121] According to the above configuration, the user can easily recognize the malignancy of the affected part from the notification mode of the notification unit.

[0122] In the radiation detector according to Embodiment 20 of the present invention, the control unit may be provided in a housing separate from the main body of the radiation detector.

[0123] According to the above configuration, even when the processing amount of the control unit is large and it is necessary to increase the size of the control unit, it is possible to eliminate the risk of impairing the operability of the radiation detector that is held and operated by hand.

[0124] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0125] 1, 1A, 2, 3 Radiation detector 10 Probe 20 Radiation detection element 22, 134 Optical fiber 30, 130 Light emitting unit (notification unit) 32, 132 Light emitting element 40 Light receiving unit (amplification unit) 50 Control unit 52 Processor 54 Memory 56 Bus 62 Input / output interface (I / O) 64 Setting unit 66 Counting unit 70 Input unit 80, 105 Operation unit 82 Cable 103 First operation unit 104 Second operation unit 110 Main body unit 120 First light receiving element (amplification unit) 121 Second light receiving element (amplification unit) 122 First optical fiber 123 Second optical fiber 136 Simultaneous counting circuit 137 Correction unit 138 Encoder 140 Clamping part (probe) 142 First clamping part 143 Second clamping part 144 First scintillator (radiation detection element) 145 Second scintillator (radiation detection element) 160 Opening / closing axis 200 Optical camera

Claims

A radiation detector configured as a grasping forceps having two clamping parts that can be inserted into the body and perform opening and closing operations, wherein each of the clamping parts is configured as a probe incorporating a simultaneous counting type radiation detection element, a notification unit provided on the probe, a control unit that operates the notification unit based on a detection result of annihilation gamma rays by simultaneous counting of radiation by the radiation detection element, and the control unit corrects the detection sensitivity of simultaneous counting based on an opening angle of the two probes or a distance between the two probes, a radiation detector. The radiation detector according to claim 1, wherein the control unit corrects the detection sensitivity of simultaneous counting based on an opening angle of the two probes.

3. The radiation detector according to claim 1 or 2, further comprising a setting unit that sets a threshold value corresponding to the detection result for determining whether to operate the notification unit for the control unit.

4. The radiation detector according to any one of claims 1 to 3, wherein the notification unit is a light emitting unit provided on an outer surface of the probe.

5. The radiation detector according to claim 4, wherein the control unit controls the light emitting unit to change at least one of light emission intensity, light emission pattern, light emission color, and light emission time based on the count or count rate of radiation obtained as the detection result.

6. The radiation detector according to claim 4 or 5, wherein the light emitting unit and a light emitting element for causing the light emitting unit to emit light are spaced apart, and an optical fiber optically couples between the light emitting element and the light emitting unit.

7. The radiation detector according to any one of claims 4 to 6, wherein the light emitting unit is continuously provided so as to go around an outer peripheral surface of the probe, at least partially protrudes from an outer surface of the probe, or is provided at a plurality of locations on the outer surface of the probe.

8. The radiation detector according to any one of claims 1 to 7, comprising a collimator that regulates an incident direction of radiation incident on the radiation detection element.

9. A radiation detector configured as a grasping forceps having two clamping parts that can be inserted into the body and perform opening and closing operations, wherein the two clamping parts are configured as two probes each incorporating a radiation detection element, a notification unit provided on the grasping forceps, A control unit that operates the notification unit based on the detection results of annihilation gamma rays by simultaneous counting of each radiation detection element built into the two probes respectively, is provided, wherein the control unit corrects the detection sensitivity of simultaneous counting based on the opening angle between the two probes or the distance between the two probes, a radiation detector.

10. The radiation detector according to claim 9, wherein the control unit corrects the detection sensitivity of simultaneous counting based on the opening angle between the two probes.

11. The radiation detector according to claim 9, wherein the control unit measures the size of the measurement object based on the opening angle between the two probes or the distance between the two probes.

12. The radiation detector according to claim 9, wherein the control unit calculates the volume of the measurement object based on the opening angle between the two probes or the distance between the two probes, and calculates the radioactivity per volume.

13. The radiation detector according to claim 9, wherein the control unit controls the start and / or end of the operation of the radiation detector based on the change in the opening angle between the two probes or the change in the distance between the two probes.

14. The radiation detector according to any one of claims 9 to 13, wherein the notification unit is a light emitting unit and is disposed on at least one of the two probes or the main body of the grasping forceps.

15. The radiation detector according to any one of claims 9 to 14, wherein the radiation detection elements built into the two probes respectively have a semi-circular cross-sectional shape.

16. The radiation detector according to any one of claims 9 to 15, wherein the notification unit notifies the comparison result between the detection result of the annihilation gamma rays and an index related to the malignancy of the affected part.

17. The radiation detector according to any one of claims 1 to 16, wherein the control unit is provided in a housing separate from the main body of the radiation detector.

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