JP2016038273A - Use time measuring device for scintillators, use time measuring method for scintillators, and neutron capture therapy system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the use time lengths of scintillators of neutron ray detectors.SOLUTION: A use time measuring unit 40 for measuring a use time of a scintillator 13 of a neutron ray detector 12 is equipped with a light source 41 that emits excitation light for exciting the scintillator 13, a photodetector 42 that detects a quantity of light emitted by the scintillator 13 that is caused to emit light by reception of the excitation light, and a measurement controller 43 that acquires the quantity of light detected by the photodetector 42. The measurement controller 43 stores correlation information representing the quantity of light emitted by the scintillator 13 that is caused to emit light by reception of the excitation light and a neutron ray quantity received by the scintillator 13.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a scintillator usage time measuring device, a scintillator usage time measuring method, and a neutron capture therapy system.

  There are neutron detectors that detect neutrons using a scintillator. A scintillator deteriorates by receiving a neutron beam. An apparatus for judging such deterioration of the scintillator is described in Patent Document 1, for example. The apparatus described in Patent Document 1 irradiates light from a light source to a scintillator (scintillator fiber), and determines deterioration of the scintillator based on an image of light that has passed through the scintillator.

Japanese Patent Laid-Open No. 10-160845

  In a neutron beam detector using a scintillator, it is required to grasp the usage time used to detect a neutron beam. In the apparatus described in Patent Document 1, it can be determined whether or not the scintillator is deteriorated. However, with the apparatus described in Patent Document 1, it is impossible to grasp the usage time in which the scintillator is used to detect neutron beams.

  Therefore, an object of the present invention is to provide a scintillator usage time measuring device, a scintillator usage time measuring method, and a neutron capture therapy system that can measure the scintillator usage time of a neutron detector.

  One embodiment of the present invention is a scintillator usage time measuring device that measures the usage time of a scintillator of a neutron beam detector, and a light source that emits excitation light, which is light that excites the scintillator, and by receiving the excitation light A light detector that detects a light emission amount of the scintillator that emits light, and a control unit that acquires the light emission amount detected by the light detector, and the control unit includes a light emission amount of the scintillator that emits light by receiving excitation light Correlation information representing the correlation with the neutron dose received by the scintillator is stored.

  In this scintillator usage time measuring device, the control unit stores correlation information representing the correlation between the light emission amount of the scintillator that emits light when receiving the excitation light and the neutron dose received by the scintillator. Thereby, the neutron dose received by the scintillator can be grasped by using the light emission amount detected by the photodetector and the correlation information stored in the control unit. The neutron dose received by the scintillator and the usage time of the scintillator have a correlation that the neutron dose received by the scintillator increases as the usage time of the scintillator becomes longer. For this reason, the usage time of the scintillator of the neutron beam detector can be obtained from the neutron dose received by the scintillator. That is, the use time of the scintillator of the neutron beam detector can be measured by using the scintillator use time measuring device.

  The scintillator usage time measurement device may further include a monitor, and the control unit may display the correlation information and the light emission amount detected by the photodetector on the monitor. In this case, the neutron dose received by the scintillator can be grasped by confirming the correlation information displayed on the monitor and the detected light emission amount. Based on the neutron dose received by the scintillator, the usage time of the scintillator can be grasped.

  The control unit may calculate the usage time of the scintillator based on the correlation information and the light emission amount detected by the photodetector, and may further display the calculated usage time of the scintillator on the monitor. In this case, the usage time of the scintillator can be easily grasped by checking the monitor.

  Another embodiment of the present invention is a scintillator usage time measurement method for measuring the usage time of a scintillator of a neutron detector, an irradiation step of irradiating the scintillator with excitation light that is light for exciting the scintillator, Detection process for detecting the amount of light emitted by the scintillator that emits light by receiving the excitation light, correlation information indicating the correlation between the light emission amount of the scintillator that emits light by receiving the excitation light and the neutron dose received by the scintillator, and a detection process And a comparison step of comparing the amount of luminescence detected in (1).

  In this scintillator usage time measurement method, the amount of light emitted from the scintillator is detected in the detection step. In the comparison step, the correlation information indicating the correlation between the light emission amount of the scintillator and the neutron dose received by the scintillator is compared with the detected light emission amount. Thus, the neutron dose received by the scintillator can be grasped by comparing the light emission amount detected by the photodetector with the correlation information. The neutron dose received by the scintillator and the usage time of the scintillator have a correlation that the neutron dose received by the scintillator increases as the usage time of the scintillator becomes longer. For this reason, the usage time of the scintillator of the neutron beam detector can be obtained from the neutron dose received by the scintillator. That is, the usage time of the scintillator of the neutron beam detector can be measured by the scintillator usage time measurement method.

  The scintillator usage time measurement method may further include a display step of displaying the correlation information and the light emission amount detected in the detection step on the monitor. In this case, the neutron dose received by the scintillator can be grasped by confirming the correlation information displayed on the monitor and the detected light emission amount. Based on the neutron dose received by the scintillator, the usage time of the scintillator can be grasped.

  In the scintillator usage time measurement method, in the comparison step, the scintillator usage time is calculated based on the comparison result between the correlation information and the light emission amount detected in the detection step, and in the display step, the scintillator calculated in the comparison step. May be further displayed on the monitor. In this case, the usage time of the scintillator can be easily grasped by checking the monitor.

  Still another embodiment of the present invention is a neutron capture therapy system for irradiating an irradiated object with a neutron beam, the neutron beam generating unit for generating a neutron beam, and the neutron beam generated by the neutron beam generating unit to be irradiated. A neutron beam irradiation unit that irradiates the irradiated body, a neutron beam detection unit that detects a neutron beam irradiated from the neutron beam irradiation unit using a scintillator, and a usage time measurement unit that measures the usage time of the scintillator. The usage time measuring unit includes a light source that emits excitation light that is light that excites the scintillator, a light detector that detects the light emission amount of the scintillator that emits light by receiving the excitation light, and light emission detected by the light detector. A control unit that obtains the amount of light, and the control unit displays a correlation between a light emission amount of the scintillator that emits light when receiving the excitation light and a neutron dose received by the scintillator. And stores the correlation information.

  In this neutron capture therapy system, the control unit stores correlation information indicating the correlation between the light emission amount of the scintillator that emits light when receiving the excitation light and the neutron dose received by the scintillator. Thereby, the neutron dose received by the scintillator can be grasped by using the light emission amount detected by the photodetector and the correlation information stored in the control unit. The neutron dose received by the scintillator and the usage time of the scintillator have a correlation that the neutron dose received by the scintillator increases as the usage time of the scintillator becomes longer. For this reason, the usage time of the scintillator of the neutron beam detector can be obtained from the neutron dose received by the scintillator. That is, the use time of the scintillator of the neutron beam detection unit can be measured by using the neutron capture therapy system.

  The usage time measuring unit of the neutron capture therapy system may further include a monitor, and the control unit may cause the monitor to display the correlation information and the amount of luminescence detected by the photodetector. In this case, the neutron dose received by the scintillator can be grasped by confirming the correlation information displayed on the monitor and the detected light emission amount. Based on the neutron dose received by the scintillator, the usage time of the scintillator can be grasped.

  The control unit of the neutron capture therapy system may calculate the usage time of the scintillator based on the correlation information and the light emission amount detected by the photodetector, and may further display the calculated usage time of the scintillator on the monitor. In this case, the usage time of the scintillator can be easily grasped by checking the monitor.

  According to various embodiments of the present invention, the usage time of a scintillator of a neutron beam detector can be measured.

It is the schematic which shows the neutron capture therapy apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the neutron beam detector provided in the collimator. It is a block diagram which shows the operation | movement control part of a neutron capture therapy apparatus. It is a block diagram which shows the structure of a usage time measurement part. It is a graph showing the correlation with the emitted light amount of the scintillator light-emitted by receiving excitation light, and the neutron dose which the scintillator received. It is a flowchart which shows the procedure of the usage time measuring method which measures the usage time of a scintillator. It is a block diagram which shows the structure of the usage time measurement part which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

A neutron capture therapy device (neutron capture therapy system) 1 shown in FIG. 1 is a device that performs cancer treatment using boron neutron capture therapy (BNCT). In the neutron capture therapy apparatus 1, for example, a neutron beam N is irradiated to a tumor of a patient (irradiated body) 50 to which boron ( ¹⁰ B) is administered.

  The neutron capture therapy apparatus 1 includes a cyclotron 2. The cyclotron 2 is an accelerator that generates charged particle beams R by accelerating charged particles such as negative ions. In the present embodiment, the charged particle beam R is a proton beam generated by stripping charges from negative ions. The proton beam is generated by stripping electrons in the cyclotron 2 using a foil stripper or the like in the cyclotron 2 and is emitted from the cyclotron 2. The cyclotron 2 has a capability of generating a charged particle beam R having a beam radius of 40 mm and 60 kW (= 30 MeV × 2 mA), for example. The accelerator is not limited to a cyclotron, and may be a synchrotron, a synchrocyclotron, a linac, or the like.

  The neutron capture therapy apparatus 1 further includes a beam duct 3, a plurality of quadrupole electromagnets 4, a current detection unit 5, a scanning electromagnet 6, and a target (neutron beam generation unit) 7. The charged particle beam R emitted from the cyclotron 2 passes through the beam duct 3 and travels toward the target 7 disposed at the end of the beam duct 3. A plurality of quadrupole electromagnets 4, a current detector 5, and a scanning electromagnet 6 are provided along the beam duct 3. The plurality of quadrupole electromagnets 4 perform beam axis adjustment and beam diameter adjustment of the charged particle beam R using, for example, an electromagnet.

  The current detection unit 5 detects the current value of the charged particle beam R irradiated to the target 7 (that is, charge, irradiation dose rate) in real time during irradiation of the charged particle beam R. The current detection unit 5 uses a non-destructive DCCT (DC Current Transformer) capable of measuring current without affecting the charged particle beam R. The current detection unit 5 outputs the detection result to the operation control unit 20 described later. “Dose rate” means a dose per unit time.

  Specifically, the current detection unit 5 detects the current value of the charged particle beam R irradiated to the target 7 with high accuracy, so that the influence of the quadrupole electromagnet 4 is eliminated on the downstream side (charged particle). It is provided immediately before the scanning electromagnet 6 on the downstream side of the line R). That is, since the scanning electromagnet 6 always scans the target 7 so that the charged particle beam R is not irradiated at the same place, a large current detection is required to dispose the current detection unit 5 downstream of the scanning electromagnet 6. Part 5 is required. In contrast, by providing the current detection unit 5 on the upstream side of the scanning electromagnet 6, the current detection unit 5 can be reduced in size.

  The scanning electromagnet 6 scans the charged particle beam R and controls irradiation of the charged particle beam R to the target 7. The scanning electromagnet 6 controls the irradiation position of the charged particle beam R with respect to the target 7.

  The neutron capture therapy apparatus 1 further includes a neutron beam irradiation unit M and a gamma ray detection unit 11. The neutron capture therapy apparatus 1 generates a neutron beam N by irradiating the target 7 with a charged particle beam R. The neutron beam irradiation unit M irradiates the patient 50 with the neutron beam generated by the target 7. The neutron beam irradiation unit M includes a shield 8, a moderator 9, and a collimator 10.

  Further, the neutron capture therapy apparatus 1 further includes an operation control unit 20. The operation control unit 20 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and is an electronic control unit that comprehensively controls the neutron capture therapy apparatus 1.

  The target 7 receives a charged particle beam R and generates a neutron beam N. The target 7 here is made of, for example, beryllium (Be), lithium (Li), tantalum (Ta), or tungsten (W), and has a disk shape with a diameter of, for example, 160 mm. In addition, the target 7 is not limited to plate shape, For example, a liquid may be sufficient.

  The moderator 9 decelerates the energy of the neutron beam N generated by the target 7. The moderator 9 includes a first moderator 9A that mainly decelerates fast neutrons contained in the neutron beam N, and a second moderator 9B that mainly decelerates epithermal neutrons contained in the neutron beam N. It has a laminated structure.

  The shield 8 shields the generated neutron beam N and the gamma rays generated by the generation of the neutron beam N from being emitted to the outside. The shield 8 is provided so as to surround the moderator 9. The upper part and the lower part of the shield 8 extend to the upstream side of the charged particle beam R from the moderator 9, and a gamma ray detection unit 11 is provided in these extended parts.

  The collimator 10 shapes the irradiation field of the neutron beam N and has an opening 10a through which the neutron beam N passes. The collimator 10 is a block-shaped member having an opening 10a at the center, for example.

  The gamma ray detection unit 11 detects gamma rays generated from the target 7 by irradiation of the charged particle beam R in real time during generation of neutron rays (that is, during irradiation of the neutron beam N to the patient 50). As the gamma ray detection unit 11, a scintillator, an ionization chamber, and other various gamma ray detection devices can be employed. In the present embodiment, the gamma ray detector 11 is provided on the upstream side of the charged particle beam R from the moderator 9 around the target 7.

  The gamma ray detectors 11 are respectively arranged inside the upper and lower portions of the shield 8 extending upstream of the charged particle beam R. The number of gamma ray detection units 11 is not particularly limited, and may be one or three or more. When three or more gamma ray detectors 11 are provided, they can be provided at predetermined intervals so as to surround the outer periphery of the target 7. The gamma ray detection unit 11 outputs a gamma ray detection result to the operation control unit 20. A configuration without the gamma ray detection unit 11 may be used.

  As shown in FIG. 2, the collimator 10 detects the neutron beam N passing through the opening 10a of the collimator 10 in real time during generation of the neutron beam (that is, during irradiation of the neutron beam N to the patient 50). A neutron beam detector (neutron beam detection unit) 12 is provided. At least a part of the neutron beam detector 12 is provided in a through hole 10b (a through hole formed in a direction orthogonal to the opening 10a) formed in the collimator 10. The neutron beam detector 12 includes a scintillator 13, an optical fiber 14, and a photodetector 15.

The scintillator 13 is a phosphor that converts incident radiation (neutron beam N, gamma ray) into light. In the scintillator 13, the internal crystal is in an excited state according to the dose of incident radiation, and generates scintillation light. The scintillator 13 has, for example, a cubic shape with one side of about 0.2 mm. The scintillator 13 is provided in the through hole 10 b of the collimator 10 and is exposed to the opening 10 a of the collimator 10. The scintillator 13 emits light when the neutron beam N or gamma ray in the opening 10 a enters the scintillator 13. The scintillator 13 ^may employ 6 Li glass scintillator, LiCAF ^{scintillator,} a plastic scintillator coated with 6 ^LiF, a 6 LiF / ZnS scintillators like.

  In FIG. 2, the traveling direction of the neutron beam N is shown by a straight line, but actually the neutron beam N travels so as to diffuse. For this reason, the neutron beam N is also irradiated to the scintillator 13 provided in the through hole 10 b, and the neutron beam N can be detected by the scintillator 13.

  Here, it is preferable to detect only the neutron beam N by the scintillator 13. However, gamma rays are generated when the neutron beam N is generated or when the moderator 9 decelerates the neutron beam N, and this gamma ray is also detected by the scintillator 13.

The optical fiber 14 functions as a light guide that transmits light generated by the scintillator 13. The length of the optical fiber 14 is about 10 m as an example. The photodetector 15 detects the light transmitted through the optical fiber 14. As the photodetector 15, various types of photodetectors such as a photomultiplier tube and a photoelectric tube can be employed. The photodetector 15 outputs an electrical signal (detection signal) to the operation control unit 20 when detecting light.

  As shown in FIG. 3, the operation control unit 20 includes a dose calculation unit 21 and an irradiation control unit 22. The operation control unit 20 is electrically connected to the current detection unit 5, the gamma ray detection unit 11, and the photodetector 15 (neutron beam detector 12).

  The dose calculation unit 21 measures the dose of the charged particle beam R irradiated to the target 7 in real time during the irradiation of the charged particle beam R based on the detection result of the current value of the charged particle beam R by the current detection unit 5. (calculate. The dose calculation unit 21 sequentially integrates the measured current value of the charged particle beam R with respect to time, and calculates the dose of the charged particle beam R in real time.

  Further, the dose calculation unit 21 measures (calculates) the gamma ray dose in real time during the irradiation of the neutron beam N based on the detection result of the gamma ray by the gamma ray detection unit 11.

  Further, the dose calculation unit 21 measures (calculates) the dose of the neutron beam N passing through the opening 10 a of the collimator 10 based on the detection result of the neutron beam N by the neutron beam detector 12. The dose calculation unit 21 receives the detection signal from the photodetector 15 and discriminates the signal related to the neutron beam and the signal related to the gamma ray. The dose calculation unit 21 constitutes a discrimination unit together with the photodetector 15.

The dose calculation unit 21 determines whether or not the wave height (light quantity) of the detection signal related to the light received by the photodetector 15 exceeds the determination threshold value _Qth, and outputs the detection signal by the neutron beam N and the detection signal by the gamma ray. Discriminate. Since neutron rays N and gamma rays are incident on the scintillator 13 as radiation, the neutron rays N and gamma rays are discriminated according to the intensity of light.

  Based on the calculated charged particle beam R dose, gamma ray dose, and neutron beam N dose, the dose calculation unit 21 comprehensively calculates the dose of the neutron beam N generated by the target 7 during irradiation of the neutron beam N. Calculate in real time. The calculation result by the dose calculation unit 21 such as the dose of the neutron beam N is displayed on the monitor 31, for example.

  The irradiation control unit 22 controls irradiation of the charged particle beam R to the target 7 based on the dose of the neutron beam N calculated by the dose calculation unit 21. The irradiation controller 22 controls the irradiation of the patient with the neutron beam N generated from the target 7 by transmitting a command signal to the cyclotron 2 and the scanning electromagnet 6 to control the irradiation of the charged particle beam R to the target 7. . The irradiation control unit 22 performs irradiation control of the neutron beam N so that the dose of the neutron beam N calculated by the dose calculation unit 21 follows a preset treatment plan.

  The neutron capture therapy apparatus 1 further includes a usage time measuring unit 40 shown in FIG. As shown in FIG. 4, the usage time measuring unit 40 (use time measuring device) measures the usage time of the scintillator 13 removed from the collimator 10. In addition, the usage time of the scintillator 13 is the usage time used in order to detect a neutron beam.

  Specifically, the usage time measurement unit 40 includes a light source 41, a photodetector 42, a measurement control unit (control unit) 43, and a monitor 44. The light source 41 emits excitation light that is light that excites the scintillator 13. Here, the scintillator 13 used for detecting the neutron beam, that is, the scintillator 13 that has received the neutron beam has a property of emitting light (fluorescing) when irradiated with ultraviolet rays or the like (stimulated light emission). . The light source 41 irradiates the scintillator 13 with excitation light for causing the scintillator 13 to emit light in accordance with the type of the scintillator 13. As the light source 41, for example, a light emitting diode or the like can be used.

  The photodetector 42 detects the light emission amount of the scintillator 13 that emits light when receiving the excitation light. As the photodetector 42, various types of photodetectors such as a photomultiplier tube and a phototube can be employed. The photodetector 42 outputs an electrical signal (detection signal) to the measurement control unit 43 when detecting light. As the photodetector 42, the photodetector 15 used for detecting the neutron beam may be used, or a photodetector different from the photodetector 15 may be used. In the present embodiment, the photodetector 42 detects the light emitted from the scintillator 13 via the optical fiber 14. That is, the scintillator 13 and the optical fiber 14 are removed from the collimator 10, and the usage time of the scintillator 13 is measured using the usage time measurement unit 40.

  The measurement control unit 43 is electrically connected to the photodetector 42 and the monitor 44. The measurement control unit 43 is an electronic control unit that includes a CPU, a ROM, a RAM, and the like. The operation control unit 20 may also serve as the function of the measurement control unit 43 without separately providing the measurement control unit 43 and the operation control unit 20 that controls each unit of the neutron capture therapy apparatus 1.

  The measurement control unit 43 acquires the light emission amount of the scintillator 13 detected by the photodetector 42. Here, there is a correlation between the light emission amount of the scintillator 13 that emits light by receiving the excitation light and the neutron dose received by the scintillator 13 for detecting the neutron beam. Specifically, as shown in FIG. 5, as the neutron dose received by the scintillator 13 increases, the light emission amount of the scintillator 13 that emits light by receiving excitation light increases.

  The measurement control unit 43 stores correlation information indicating a correlation between the light emission amount of the scintillator 13 that emits light when receiving the excitation light and the neutron dose received by the scintillator 13 for detecting the neutron beam. The data format of the correlation information stored in the measurement control unit 43 is not limited to the graph format shown in FIG. 5 and may be any data format such as a table format.

  The measurement control unit 43 causes the monitor 44 to display the stored correlation information and the light emission amount detected by the photodetector 42. The correlation information displayed on the monitor 44 may be in any display format such as a graph format shown in FIG. 5 or a table format as long as the correlation between the light emission amount and the neutron dose can be grasped. Thereby, the measurer can grasp the neutron dose received by the scintillator 13 from the correlation information and the light emission amount detected by the photodetector 42.

  Further, the measurement control unit 43 calculates a neutron dose based on the correlation information and the amount of luminescence detected by the photodetector 42. The measurement control unit 43 calculates the usage time of the scintillator 13 from the calculated neutron dose. Here, the neutron dose received by the scintillator 13 and the usage time of the scintillator 13 have a correlation that the neutron dose received by the scintillator 13 increases as the usage time of the scintillator 13 becomes longer. For this reason, the usage time of the scintillator 13 can be obtained from the neutron dose received by the scintillator 13.

  The measurement control unit 43 causes the monitor 44 to further display the calculated usage time of the scintillator 13 together with the correlation information and the detected light emission amount. Note that the measurement control unit 43 may display only the correlation information and the detected light emission amount on the monitor 44, or may display only the usage time of the scintillator 13 on the monitor 44.

  Further, the measurement control unit 43 may determine the replacement time of the scintillator 13 by comparing the calculated use time with a reference use time. Alternatively, the measurement control unit 43 may determine the replacement time of the scintillator 13 by comparing the calculated neutron dose with a reference neutron dose. The measurement control unit 43 may display a determination result such as the replacement time of the scintillator 13 on the monitor 44.

  Next, the procedure of the usage time measuring method for measuring the usage time of the scintillator 13 will be described. As shown in FIG. 6, the measurer removes the scintillator 13 and the optical fiber 14 from the collimator 10, and connects the optical fiber 14 to the photodetector 42 (step S101: preparation step). When measuring the usage time using the photodetector 15, the scintillator 13 and the optical fiber 14 are removed from the collimator 10, and the photodetector 15 is connected to the measurement control unit 43.

  In addition, after removing the scintillator 13 from the collimator 10, it is preferable to shield the scintillator 13 so that light does not enter until the usage time measuring unit 40 measures the usage time of the scintillator 13.

  Next, the scintillator 13 is irradiated with excitation light from the light source 41 (step S102: irradiation step). When the excitation light is excessively applied to the scintillator 13, the light emission amount of the scintillator 13 is attenuated. For this reason, the irradiation time of the excitation light is set to an irradiation time (one second or less as an example) that does not attenuate the light emission amount of the scintillator 13.

  Next, the photodetector 42 detects the light emission amount of the scintillator 13 through the optical fiber 14 (step S103: detection step). The measurement control unit 43 compares the light emission amount detected by the photodetector 42 with the stored correlation information. Then, the measurement control unit 43 calculates the neutron dose received by the scintillator 13 based on the correlation information and the light emission amount. The measurement control unit 43 calculates the usage time of the scintillator 13 from the calculated neutron dose (step S104: comparison step).

  Next, the measurement control unit 43 displays the calculated usage time of the scintillator 13 on the monitor 44 together with the correlation information and the detected light emission amount (step S105: display step).

  The present embodiment is configured as described above, and the measurement control unit 43 stores correlation information representing a correlation between the light emission amount of the scintillator 13 that emits light by receiving excitation light and the neutron dose received by the scintillator 13. doing. Thereby, the neutron dose received by the scintillator 13 can be grasped by using the light emission amount detected by the photodetector 42 and the correlation information stored in the measurement control unit 43.

  The neutron dose received by the scintillator 13 and the usage time of the scintillator 13 have a correlation that the neutron dose received by the scintillator 13 increases as the usage time of the scintillator 13 increases. For this reason, the usage time of the scintillator 13 of the neutron beam detector 12 can be obtained from the neutron dose received by the scintillator 13. That is, by using the usage time measuring unit 40, the usage time of the scintillator 13 of the neutron beam detector 12 can be measured.

  The measurement control unit 43 displays the correlation information and the light emission amount detected by the photodetector 42 on the monitor 44. In this case, the measurer can grasp the neutron dose received by the scintillator 13 by confirming the correlation information displayed on the monitor 44 and the detected light emission amount. Then, the measurer can grasp the usage time of the scintillator 13 based on the neutron dose received by the scintillator 13.

  The measurement control unit 43 calculates the usage time of the scintillator based on the correlation information and the light emission amount detected by the photodetector. The measurement control unit 43 further displays the calculated usage time of the scintillator 13 on the monitor 44. In this case, the measurer can easily grasp the usage time of the scintillator 13 by checking the monitor 44.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, as a modification, the light emitted from the scintillator 13 upon receiving the excitation light is directly detected by the photodetector 42 without passing through the optical fiber 14 as in the usage time measuring unit 40A shown in FIG. Also good. Even in this case, the usage time of the scintillator 13 can be measured as in the usage time measuring unit 40 described in the embodiment.

  In the embodiment described above, the usage time of the scintillator 13 of the neutron beam detector 12 provided in the neutron capture therapy apparatus 1 is measured using the usage time measurement unit 40, but the neutron capture therapy apparatus 1 is provided. You may measure the usage time etc. of scintillators other than the neutron beam detector 12. FIG. For example, a neutron detector scintillator used as a monitor for monitoring the operating state of a nuclear reactor, a neutron detector scintillator used in measuring accelerated neutrons used in physical experiments, or non- The usage time measurement unit 40 may be used to measure the usage time of a scintillator or the like of a neutron beam detector used in a neutron irradiation apparatus for destructive inspection.

  DESCRIPTION OF SYMBOLS 1 ... Neutron capture therapy apparatus (neutron capture therapy system), 7 ... Target (neutron beam generation part), 12 ... Neutron beam detector (neutron beam detection part), 13 ... Scintillator, 15, 42 ... Photo detector, 40, 40A ... Usage time measurement unit (usage time measurement device), 41 ... light source, 43 ... measurement control unit (control unit), 44 ... monitor, M ... neutron beam irradiation unit.

Claims (9)

A scintillator usage time measuring device for measuring a scintillator usage time of a neutron detector,
A light source that emits excitation light that is light that excites the scintillator;
A photodetector for detecting a light emission amount of the scintillator that emits light by receiving the excitation light;
A controller that acquires the amount of light emission detected by the photodetector; and
The scintillator usage time measuring device, wherein the control unit stores correlation information indicating a correlation between a light emission amount of the scintillator that emits light by receiving the excitation light and a neutron dose received by the scintillator. A monitor,
The scintillator usage time measuring apparatus according to claim 1, wherein the control unit displays the correlation information and the light emission amount detected by the photodetector on the monitor.   The control unit calculates a usage time of the scintillator based on the correlation information and the light emission amount detected by the photodetector, and further displays the calculated usage time of the scintillator on the monitor. Item 3. A scintillator usage time measuring device according to Item 2. A scintillator usage time measuring method for measuring a scintillator usage time of a neutron beam detector,
An irradiation step of irradiating the scintillator with excitation light that is light for exciting the scintillator;
A detection step of detecting a light emission amount of the scintillator that emits light by receiving the excitation light;
A comparison step for comparing correlation information indicating a correlation between a light emission amount of the scintillator that emits light by receiving the excitation light and a neutron dose received by the scintillator, and the light emission amount detected in the detection step; Method for measuring the usage time of scintillators including   The scintillator usage time measurement method according to claim 4, further comprising a display step of displaying the correlation information and the light emission amount detected in the detection step on a monitor. In the comparison step, the usage time of the scintillator is calculated based on a comparison result between the correlation information and the light emission amount detected in the detection step.
The scintillator usage time measuring method according to claim 5, wherein in the display step, the usage time of the scintillator calculated in the comparison step is further displayed on the monitor. A neutron capture therapy system that irradiates an irradiated object with a neutron beam,
A neutron beam generator for generating the neutron beam;
A neutron beam irradiation unit that irradiates the irradiated object with the neutron beam generated by the neutron beam generation unit;
A neutron beam detection unit that detects the neutron beam irradiated from the neutron beam irradiation unit using a scintillator;
A usage time measuring unit for measuring the usage time of the scintillator,
The usage time measuring unit is:
A light source that emits excitation light that is light that excites the scintillator;
A photodetector for detecting a light emission amount of the scintillator that emits light by receiving the excitation light;
A controller that acquires the amount of light emission detected by the photodetector; and
The said control part is a neutron capture therapy system which has memorize | stored the correlation information showing the correlation with the emitted light amount of the said scintillator emitted by receiving the said excitation light, and the neutron dose which the said scintillator received. The usage time measuring unit further includes a monitor,
The neutron capture therapy system according to claim 7, wherein the control unit displays the correlation information and the light emission amount detected by the photodetector on the monitor.   The control unit calculates a usage time of the scintillator based on the correlation information and the light emission amount detected by the photodetector, and further displays the calculated usage time of the scintillator on the monitor. Item 9. The neutron capture therapy system according to Item 8.

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