Neutron dose detection device and neutron capture therapy device

Abstract

The present invention provides a neutron dose detection device and a neutron capture therapy device, wherein the neutron dose detection device includes at least two count rate channels and a count rate channel selection unit that selects one count rate channel from the at least two count rate channels, and the count rate channel includes a detector that detects neutrons and outputs a signal, a signal processing unit that processes the signal output from the detector, and a counter that counts the signal output from the signal processing unit to obtain a count rate.

Description

[Technical field]

[0001] The present invention relates to the field of radiation delivery, and in particular to neutron dose detection devices and neutron capture therapy devices. [Background technology]

[0002] With the development of atomic science, radiation therapy, such as cobalt-60, linear accelerator, electron beam, etc., has become one of the main means of cancer treatment. However, traditional photon or electron therapy, due to the limitations of the physical conditions of the radiation itself, will not only kill tumor cells but also damage many normal tissues in the beam path. In addition, tumor cells have different degrees of sensitivity to radiation, and traditional radiation therapy is not very effective against malignant tumors with high radiation resistance (e.g., glioblastoma multiforme, melanoma).

[0003] To reduce radiation damage to normal tissues surrounding tumors, the concept of targeted therapy in chemotherapy has been used in radiotherapy, and currently, radiation sources with high relative biological effectiveness (RBE), such as proton therapy, heavy ion therapy, and neutron capture therapy, are being actively developed for tumor cells with high radiation resistance. Among these, neutron capture therapy combines the above two concepts. For example, in boron neutron capture therapy, boron-containing drugs are specifically concentrated in tumor cells, and combined with highly precise neutron beam control, it provides a better cancer treatment option than conventional radiation.

[0004] In the process of boron neutron capture therapy, the neutron beam radiation used to irradiate the patient is strong, so it is necessary to accurately control the dose irradiated to the patient. When formulating a treatment plan, there is still a problem that the setting of preset irradiation parameters such as the neutron exposure dose is inaccurate, and the detection of the actual exposure dose is inaccurate.

[0005] In addition, during the actual irradiation process, due to operator or doctor error, it may happen that an operator touches the control panel by mistake, inputs an incorrect command, or changes related commands and irradiation parameters, which increases medical risks. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a neutron dose detection device and a neutron capture therapy device that can irradiate a patient with an accurate dose of a neutron beam, the neutron dose detection device including at least two count rate channels and a count rate channel selection unit that selects one count rate channel from the at least two count rate channels, the count rate channel including a detector that detects neutrons and outputs a signal, a signal processing unit that processes the signal output from the detector, and a counter that counts the signal output from the signal processing unit to obtain a count rate.

[0007] Further, the count rate channels include at least a first count rate channel and a second count rate channel, the first count rate channel including a first detector and the second count rate channel including a second detector, the sensitivity of the first detector being different from the sensitivity of the second detector.

[0008] Furthermore, the charged particle beam accelerated by the accelerator undergoes a nuclear reaction with a target to generate neutrons, and the count rate channel selection unit selects a count rate channel based on the power of the accelerator, the neutron beam flux, or the distance between the detector and the neutron source.

[0009] Furthermore, the neutron dose detection device further includes a conversion unit that converts the count rate recorded by the count rate channel selected by the count rate channel selection unit into a neutron flux rate or a neutron dose rate, and an integration unit that integrates the neutron flux rate or the neutron dose rate to obtain a neutron dose.

[0010] Furthermore, the neutron dose detection device further includes a display for displaying the neutron dose.

[0011] Further, the count rate channel includes a first count rate channel and a second count rate channel, the first count rate channel including a first detector that detects neutrons and outputs a signal, a first signal processing unit that processes the signal output from the first detector, and a first counter that counts the signal output from the first signal processing unit, the second count rate channel including a second detector that detects neutrons and outputs a signal, a second signal processing unit that processes the signal output from the second detector, and a second counter that counts the signal output from the second signal processing unit, the first detector has a first sensitivity for detecting neutrons, and the second detector has a second sensitivity for detecting neutrons, the first sensitivity being less than the second sensitivity.

[0012] Furthermore, when the actual power of the accelerator is less than half the maximum power, the count rate channel selection unit selects the count rate recorded by the second counter of the second count rate channel and transmits it to the conversion unit for use in dose calculation; conversely, the count rate channel selection unit selects the count rate recorded by the first counter of the first count rate channel and transmits it to the conversion unit for use in dose calculation.

[0013] Further, the neutron flux that can be generated when the accelerator is at maximum power is defined as the maximum neutron flux, and when the real-time neutron flux is less than half the maximum neutron flux, the count rate channel selection unit selects the count rate recorded by the second counter in the second count rate channel and transmits it to the conversion unit for use in dose calculation, and conversely, the count rate channel selection unit selects the count rate recorded by the first counter in the first count rate channel and transmits it to the conversion unit for use in dose calculation.

[0014] The neutron capture therapy device includes the neutron dose detection device.

[0015] Further, the neutron capture therapy device includes a neutron beam irradiation system, which includes a neutron beam generation module that generates a neutron beam and a beam adjustment module that adjusts the neutron beam, and the beam adjustment module includes a moderator that can decelerate the neutron beam and a reflector that directs stray neutrons to the moderator. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram of a neutron beam irradiation system of a neutron capture therapy apparatus according to the present invention. [Diagram 2] 1 is a schematic diagram of a beam shaper of a neutron capture therapy device according to the present invention. [Diagram 3] 1 is a schematic diagram of a neutron beam irradiation system and a detection system of a neutron capture therapy device according to the present invention. [Figure 4] 1 is a schematic diagram of a neutron dose detection device of a neutron capture therapy device according to a first embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic diagram of a neutron dose detection device of a neutron capture therapy device according to a second embodiment of the present invention. [Figure 6] 1 is a schematic diagram of a monitoring system for a neutron capture therapy device according to the present invention. [Figure 7] 1 is a schematic diagram of a neutron capture therapy device in which an erroneous operation prevention system according to the present invention is combined with a display unit and an input unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In order to make the objectives, technical means and technical effects of the present invention clearer, and to enable those skilled in the art to carry out the present invention based thereon, the present invention will be described in more detail below with reference to the drawings and examples.

[0018] In the following description, the terms "first", "second", etc. may be used to describe various elements herein, but these elements are not limited to these terms, and these terms are merely used to distinguish the objects being described and do not have any ordering or technical meaning.

[0019] Radiotherapy is a common means of treating cancer, and boron neutron capture therapy has been gradually applied in recent years as a means of effectively treating cancer. As shown in Figs. 1 to 7, a neutron capture therapy device for performing boron neutron capture therapy (BNCT) by irradiating a neutron beam with a preset neutron dose to an irradiation target, for example, a patient S, includes a neutron beam irradiation system 1, a detection system, a monitoring system 3, a calibration system, and an erroneous operation prevention system. The neutron beam irradiation system 1 generates a neutron beam suitable for performing neutron irradiation treatment on the patient S, the detection system detects irradiation parameters such as the neutron dose during the neutron beam irradiation treatment process, the monitoring system 3 controls the entire neutron beam irradiation process, the calibration system calibrates the preset neutron dose, and the erroneous operation prevention system prevents related parties from inputting erroneous commands and information to the monitoring system 3.

[0020] Boron neutron capture therapy is a method to 10 B) Taking advantage of the property that the contained drug has a large capture cross section for thermal neutrons, 10 B(n,α) 7 Li neutron capture and fission reactions 4 He and 7 The two heavy charged particles, Li and Li+, have an average energy of approximately 2.33 MeV and are characterized by a high linear energy transfer (LET) and a short range. 4 The linear energy deposition and range of the He particles are 150 keV / μm and 8 μm, respectively. 7The linear energy deposition and range of the Li heavy charged particles are 175 keV / μm and 5 μm, respectively, and the total range of the two types of heavy charged particles corresponds to the size of about one cell, so radiation damage to the living body can be limited to the cellular level. The boron-containing drug selectively collects in tumor cells, and after the neutron beam enters the body of patient S, it reacts with the boron in the body of patient S to produce 4 He and 7 It generates two types of heavy charged particles, Li, 4 He and 7 The two heavy charged particles of Li kill tumor cells locally without causing significant damage to normal tissue.

[0021] As shown in FIG. 1, the neutron beam irradiation system 1 includes a neutron beam generating module 11 and a beam adjusting module 12 that adjusts the neutron beam generated by the neutron beam generating module 11.

[0022] The neutron beam generating module 11 includes an accelerator 111 that generates a neutron beam to be irradiated to the patient S and accelerates the charged particle beam, a target 112 that reacts with the charged particle beam to generate a neutron beam, and a charged particle beam transport unit 113 that is located between the accelerator 111 and the target 112 and transports the charged particle beam. The charged particle beam transport unit 113 transports the charged particle beam to the target 112, one end of which is connected to the accelerator 111 and the other end of which is connected to the target 112. In addition, the charged particle beam transport unit 113 is provided with beam control devices such as a beam adjustment unit (not shown) and a charged particle scanning unit (not shown). The beam adjustment unit controls the traveling direction and beam diameter of the charged particle beam. The charged particle beam scanning unit scans the charged particle beam and controls the irradiation position of the charged particle beam with respect to the target 112.

[0023] The accelerator 111 may be a cyclotron, a synchrotron, a synchrocyclotron, a linear accelerator, etc. Typical targets 112 are lithium (Li) targets and beryllium (Be) targets, and the charged particle beam is accelerated to an energy that can overcome the nuclear Coulomb repulsion of the target 112 and is then coupled to the target 112. 7 Li(p,n) 7 The Be nuclear reaction is carried out to generate a neutron beam, and the nuclear reaction that has been generally studied is as follows: 7 Li(p,n) 7 Be and 9 Be(p,n) 9 Typically, the target 112 includes a target layer and an anti-oxidation layer located on one side of the target layer to prevent the target layer from being oxidized, and the anti-oxidation layer is made of Al or stainless steel.

[0024] In an embodiment of the present invention, the neutron source is provided by accelerating charged particles in an accelerator 111 and causing a nuclear reaction with the target 112, while in other embodiments, the neutron source may be provided by a nuclear reactor, a DT neutron generator, a DD neutron generator, etc. However, whether the neutron source is provided by accelerating charged particles and causing a nuclear reaction with the target 112 as in the present invention, or by a nuclear reactor, a DT neutron generator, a DD neutron generator, etc., a mixed radiation field is generated, that is, the generated beam includes a fast neutron beam, an epithermal neutron beam, a thermal neutron beam, and a gamma ray. In the process of boron neutron capture therapy, the higher the content of other radiations (collectively referred to as radiation contamination) except for epithermal neutrons, the higher the proportion of non-selective dose deposition in normal tissues, so the radiation causing these unnecessary dose depositions should be reduced as much as possible.

[0025] The International Atomic Energy Agency (IAEA) has put forward five proposals on the quality elements of air beams for neutron sources used in clinical boron neutron capture therapy, which can be used to compare the advantages and disadvantages of different neutron sources, and can also be used as a reference when selecting the neutron generation pathway and designing the beam shaper 121. The five proposals are as follows:

[0026] Epithermal neutron flux>1×10 9 n / cm 2 s Fast neutron contamination<2×10 -13 Gy-cm 2 / n Photon contamination<2×10 -13 Gy-cm 2 / n Thermal to epithermal neutron flux ratio<0.05 Epithermal neutron current to flux ratio>0.7 Note: The epithermal neutron energy range is from 0.5 eV to 40 keV, the thermal neutron energy range is less than 0.5 eV, and the fast neutron energy range is greater than 40 keV.

[0027] 2 and 3, the beam adjustment module 12 adjusts the mixed radiation generated by the neutron beam generation module 11 so as to minimize contamination of the radiation finally irradiated to the patient S and to focus epithermal neutrons for treating the patient S on a portion of the patient S that needs to be irradiated. The beam adjustment module 12 includes a beam shaper 121 that slows down and shields the neutron beam, and a collimator 122 that focuses the epithermal neutrons on a portion of the patient S that needs to be irradiated. Specifically, the beam shaper 121 includes a moderator 1211 that can moderate the neutron beam generated by the target 112 to an epithermal neutron energy region, a reflector 1212 that guides stray neutrons to the moderator 1211 to improve the beam intensity of the epithermal neutrons, a thermal neutron absorber 1213 that absorbs thermal neutrons to avoid excessive dose deposition in shallow normal tissue during treatment, and a radiation shielding portion 1214 that blocks leaked neutrons and photons to reduce dose deposition in normal tissue in non-irradiated areas. In other embodiments, the thermal neutron absorber is not included, and thermal neutrons may be absorbed by a material contained in the moderator or reflector, or the moderator and the thermal neutron absorber may be installed integrally. In other embodiments, the radiation shielding portion is not included, and may be made of the same material as the reflector, or the reflector and the radiation shielding portion may be installed integrally.

[0028] The moderator 1211 may be formed by laminating a plurality of different materials, and the material of the moderator 1211 is selected according to factors such as the energy of the charged particle beam. For example, when the energy of the proton beam from the accelerator 111 is 30 MeV and a beryllium target is used, the material of the moderator 1211 is lead, iron, aluminum, or calcium fluoride, and when the energy of the proton beam from the accelerator 111 is 11 MeV and a beryllium target is used, the material of the moderator 1211 is heavy water (D2O) or lead fluoride. In a preferred embodiment, the moderator 1211 is made of a mixture of MgF2 and LiF with a weight percentage of MgF2 of 4.6%, the reflector 1212 is made of Pb, and the thermal neutron absorber 1213 is made of Pb. 6The radiation shielding portion 1214 includes a photon shielding portion and a neutron shielding portion, the photon shielding portion is made of lead (Pb), and the neutron shielding portion is made of polyethylene (PE). The shape of the moderator 1211 may be a bicone shape as shown in FIG. 2 or a cylindrical shape as shown in FIG. 3. The reflector 1212 is disposed around the moderator 1211, and its shape adaptively changes according to the shape of the moderator 1211.

[0029] Next, as shown in FIG. 3, the detection system includes a neutron dose detection device 21 that detects the neutron dose of the neutron beam in real time, a temperature detection device 22 that detects the temperature of the target 112, a displacement detection device 23 that detects whether the patient S is displaced during the treatment process, and a boron concentration detection device (not shown) that detects the boron concentration in the body of the patient S.

[0030] 4, the neutron dose detection device 21 includes a detector 211 that receives neutrons and outputs a signal, a signal processing unit 212 that processes the signal output from the detector 211, a counter 213 that counts the signals output from the signal processing unit 212 to obtain a count rate, a conversion unit 214 that converts the count rate recorded in the counter 213 into a neutron flux rate or a neutron dose rate, an integration unit 215 that integrates the neutron flux rate or the neutron dose rate to obtain a neutron dose, and a display 218 that displays the neutron dose. The detector 211, the signal processing unit 212, and the counter 213 constitute a count rate channel 20.

[0031] The detector 211 may be placed within the beam shaper 121, within the collimator 122, or at any position close to the beam shaper 121, as long as it can detect the neutron dose of the neutron beam at the position of the detector 211.

[0032] The detector 211, which can realize the real-time detection of the neutron dose of the neutron beam, has an ionization chamber and a scintillation probe, and those based on the ionization chamber structure include He-30% ionization tube, BF30% ionization tube, fission ionization chamber, and boron ionization chamber. The scintillation probe includes organic or inorganic materials, and when detecting thermal neutrons, the scintillation probe is doped with a large number of elements with high thermal neutron capture cross section, such as Li or B. Some elements in the two detectors undergo capture or fission reaction with the neutrons entering the detector to release heavy charged particles and fission fragments, generating a large number of ion pairs in the ionization chamber or scintillation probe, and these charges are collected to form electric signals, which are subjected to noise reduction, conversion, and separation processing by the signal processing unit 212, and the electric signals are converted into pulse signals, and the magnitude of the voltage pulse is analyzed to resolve the neutron pulse signal and the gamma pulse signal. The separated neutron pulse signals are continuously recorded by the counter 213 to obtain the neutron counting rate (n / s). The conversion unit 214 calculates and converts the counting rate using internal software, programs, etc. to obtain a neutron flux rate (cm -2 s -1 ) is obtained, and the neutron flux rate is further calculated and converted to obtain the neutron dose rate (Gy / s), and finally, the integration unit integrates the neutron dose rate to obtain the real-time neutron dose.

[0033] Below, a fission chamber, a scintillator detector, and a BF3 detector will be briefly described as examples.

[0034] As the neutron beam passes through the fission chamber, it interacts with the gas molecules inside the chamber or with the walls of the chamber to produce electrons and positively charged ions, called ion pairs. A high voltage electric field is applied within the fission chamber, causing the electrons to move toward the central anode wire and the positively charged ions to move toward the surrounding cathode walls, producing a measurable electrical signal.

[0035] Materials such as optical fibers in scintillation probes generate visible light after absorbing energy, and use ionizing radiation to excite electrons in crystals or molecules to an excited state, and the fluorescence emitted when the electrons return to the ground state is collected and detected as a neutron beam. The scintillation probes emit visible light after interacting with the neutron beam, and use photomultiplier tubes to convert the visible light into an electrical signal for output.

[0036] The BF3 detector is disposed in the beam shaper 121 and is irradiated with the neutron beam. The B element in the BF3 detector reacts with the neutrons to produce a nuclear reaction. 10 B(n,α) 7 Li, and the alpha particles and 7 The Li-ion particles are driven by a voltage and collected by a high-voltage electrode to generate an electric signal. The electric signal is transmitted to a signal processing unit 212 via a coaxial cable, and is subjected to signal amplification and filtering shaping to form a pulse signal. The processed pulse signal is transmitted to a counter 213 for pulse counting to obtain a counting rate (n / s), which can measure the intensity of the neutron beam, i.e., the neutron dose, in real time.

[0037] The temperature detection device 22 is a thermocouple, in which two conductors (called thermocouple wires or hot electrodes) with different components are joined at both ends to form a circuit, and when the temperatures at the junction are different, an electromotive force is generated in the circuit, and this phenomenon is called the thermoelectric effect, and this electromotive force is called thermoelectromotive force. A thermocouple uses this principle to measure temperature, and one end that directly measures the temperature of a medium is called a working junction (also called a hot junction), and the other end is called a cold junction (also called a compensation junction), and the cold junction is connected to a display instrument or an auxiliary instrument, and the display instrument displays the thermoelectromotive force generated by the thermocouple. Of course, as is well known to those skilled in the art, the temperature detection device 22 may be any detector 211 that can detect temperature, such as a resistance thermometer.

[0038] The displacement detection device 23 is an infrared signal detector, which operates by detecting infrared radiation emitted from the human body. The infrared detector collects external infrared radiation and further collects it in an infrared sensor, which usually uses a pyroelectric element, which emits an electric charge to the outside when it receives infrared radiation and changes its temperature, and issues an alarm after detection processing. Such a detector 211 is aimed at detecting radiation in the human body. Therefore, the radiation sensitive element must be very sensitive to infrared radiation with a wavelength of about 10 μm. Of course, as is well known to those skilled in the art, the displacement detection device 23 may be any detection device that detects a displacement change of an irradiation target, such as a displacement sensor. A displacement sensor is a device that determines whether an irradiation target moves based on a displacement change of the irradiation target relative to a certain reference. As is further well known to those skilled in the art, the displacement detection device 23 can not only detect a displacement change of an irradiation target, but also indirectly know a displacement change of an irradiation target by detecting a displacement change of a support member and / or a treatment table that fixes the irradiation target.

[0039] In the process of performing neutron beam irradiation therapy on patient S, boron is continuously supplied to patient S as necessary. Detection of boron concentration can be achieved by inductively coupled plasma spectroscopy, high-resolution alpha autoradiography, charged ion spectroscopy, neutron capture camera, nuclear magnetic resonance and magnetic resonance imaging, positron emission tomography, prompt gamma spectrometry, etc., and devices related to the above detection methods are called boron concentration detection devices.

[0040] In the present invention, an example will be described in which the boron concentration in the body of patient S is estimated by detecting gamma rays emitted by patient S. A neutron beam enters the patient's body and reacts with boron, generating gamma rays. The amount of gamma rays is measured to estimate the amount of boron reacting with the neutron beam, thereby estimating the boron concentration in the body of patient S. The boron concentration detection device measures the boron concentration in the body of patient S in real time during the process of performing neutron beam irradiation therapy on patient S with neutron beam irradiation system 1.

[0041] The boron concentration detection device is a boron distribution measurement system (PG (Prompt-γ)-SPECT) that can measure boron concentration by detecting gamma rays (478 keV) generated by the reaction of neutrons with boron and can measure boron concentration distribution by measuring gamma rays of unit energy. The boron concentration detection device has a gamma ray detection unit and a boron concentration calculation unit. The gamma ray detection unit detects information about gamma rays emitted from the body of the patient S, and the boron concentration calculation unit calculates the boron concentration in the body of the patient S based on the information about the gamma rays detected by the gamma ray detection unit. As the gamma ray detection unit, a scintillator and various other gamma ray detection devices may be used. In this embodiment, the gamma ray detection unit is placed near the tumor of the patient S, for example, at a position about 30 cm away from the tumor of the patient S.

[0042] The detector 211 of the neutron dose detection device 21 for detecting the neutron dose of the neutron beam belongs to a pulse detector, and the shortest time interval between two consecutively incident neutrons that the detector 211 can resolve is defined as the pulse resolution time τ(s). Since the detector 211 cannot accurately record other incident neutrons within the τ time after a neutron is incident on the detector 211, the τ time is also called a dead time.

[0043] The neutron detection sensitivity of the detector 211 is the ratio between the total output amount of the detector 211 and the corresponding total input amount, and for the detector 211 of the neutron dose detection device 21 listed in the present invention, the input physical amount is a neutron beam, and the output physical amount is generally an optical signal or an electrical signal. It can be seen that the higher the ratio between the total output amount and the corresponding total input amount, the higher the neutron detection sensitivity of the detector 211, and the higher the neutron detection sensitivity, the shorter the corresponding pulse resolution time τ of the detector 211. In order to reduce statistical errors, a low-flux beam is usually detected by a detector 211 with high neutron detection sensitivity, and a high-flux beam is detected by a detector 211 with low neutron detection sensitivity.

[0044] Different embodiments will be described in detail below, and the same components will be given the same numbers in the different embodiments for simplicity, and similar components will be given the same numbers in the different embodiments or will be distinguished by adding `` or ''.

[0045] In embodiment 1 shown in FIG. 4, the neutron dose detection device 21 has only one count rate channel 20, and in order to accurately detect the neutron dose of neutron beams with different fluxes, in embodiment 2 shown in FIG. 5, the neutron dose detection device 21' includes at least two count rate channels 20', and the neutron detection sensitivity of the detectors 211' of each count rate channel 20' is different from each other, and further, the neutron dose detection device 21' further includes a count rate channel selection unit 216 for selecting an appropriate count rate channel 20' based on the current power or neutron beam flux of the accelerator 111. Specifically, in Example 2, the neutron dose detection device 21' includes at least two count rate channels 20', a count rate channel selection unit 216 that selects one appropriate count rate channel 20' from the at least two count rate channels 20', a conversion unit 214 that converts the count rate recorded by the count rate channel 20' selected by the count rate channel selection unit 216 into a neutron flux rate or a neutron dose rate, and an integration unit 215 that integrates the neutron flux rate or the neutron dose rate to obtain a neutron dose.

[0046] The two count rate channels 20' are named as a first count rate channel 201 and a second count rate channel 202, respectively, and the first count rate channel 201 includes a first detector 2011 that receives neutrons and outputs a signal, a first signal processing unit 2012 that processes the signal output from the first detector 2011, and a first counter 2013 that counts the signal output from the first signal processing unit 2012, while the second count rate channel 202 includes a second detector 2021 that receives neutrons and outputs a signal, a second signal processing unit 2022 that processes the signal output from the second detector 2021, and a second counter 2023 that counts the signal output from the second signal processing unit 2022. The count rate channel selection unit 216 selects an appropriate count rate channel 20 based on the current power or neutron beam flux of the accelerator 111, the conversion unit 214 converts the count rate recorded by the count rate channel 20 selected by the count rate channel selection unit 216 into a neutron flux rate or neutron dose rate, and the integration unit 215 integrates the neutron flux rate or neutron dose rate to obtain the neutron dose.

[0047] Typically, the neutron flux that can be generated when the accelerator 111 is at maximum power is defined as the maximum neutron flux, and if the detected real-time neutron flux is less than half the maximum neutron flux, the neutron flux is considered to be small, and if the detected real-time neutron flux is more than half the maximum neutron flux, the neutron flux is considered to be large.

[0048] The neutron detection sensitivity of the first detector 2011 is a first sensitivity, and the neutron detection sensitivity of the second detector 2021 is a second sensitivity, and the first sensitivity is smaller than the second sensitivity. Specifically, the first detector 2011 is wrapped with a large amount of neutron absorbing material such as B4C, Cd, or filled with low pressure operating gas, or designed with small dimensions, so that the neutron detection sensitivity is reduced, and when the neutron flux is large, the count rate loss due to the pulse resolution time can be reduced when detected by the first detector 2011. The second detector 2021 is wrapped with a small amount of neutron absorbing material or is not wrapped with any material, or filled with high pressure operating gas, or designed with large dimensions compared to the first detector 2011, so that the second sensitivity is larger than the first sensitivity, and when the neutron flux is small, the statistical error of the count rate due to the low count rate can be reduced when detected by the second detector 2021.

[0049] Correspondingly, the neutron detection sensitivity of the first count rate channel 201 is smaller than that of the second count rate channel 202. The count rate channel selection unit selects an appropriate count rate channel 20' based on the current power or neutron flux of the accelerator 111, for example, when the maximum beam intensity of the accelerator 111 is 10mA, if the beam intensity of the accelerator 111 is greater than 5mA, it selects the count rate recorded by the first counter 2013 of the first count rate channel 201 having the first sensitivity and transmits it to the conversion unit 214 for dose calculation, and if the beam intensity of the accelerator 111 is less than 5mA, it selects the count rate recorded by the second counter 2023 of the second count rate channel 202 having the second sensitivity and transmits it to the conversion unit 214 for dose calculation. The count rate channel selection unit selects an accurate count rate and transmits it to the conversion unit 214 for dose calculation, thereby obtaining an accurate neutron exposure dose.

[0050] The neutron dose detection device 21 is provided with at least two count rate channels, a first count rate channel 201 and a second count rate channel 202, which have different neutron detection sensitivities. The count rate channel selection unit 216 selects an accurate count rate according to the actual situation to calculate the neutron dose, thereby avoiding the count rate loss error caused by the pulse resolution time and avoiding the statistical error caused by the low count rate, thereby improving the accuracy of real-time neutron dose detection and further improving the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0051] In other embodiments, any number of count rate channels 20, 20' may be provided as desired.

[0052] In the above-mentioned embodiment, the count rate channel 20 is selected based on the power, neutron flux, etc. of the accelerator 111. In other embodiments, the count rate channel 20' may be selected based on the distance between the detector 211 and the neutron source. For example, Away from When the detector 211 is placed in the neutron source position, a second count rate channel 202 having a second sensitivity is selected. Close to When placed in position, a first count rate channel 201 having a detector with a first sensitivity is selected.

[0053] The detectors 211 of the above neutron dose detection device 21 all belong to pulse detectors, and generally, pulse detectors have a problem of time resolution. When an incident neutron reacts with the detector 211 to generate a signal pulse, which lasts for one τ time interval, the detector 211 regards all other signal pulses further generated within this interval as the same signal pulse, and in this case, if the time interval between any two signal pulses is smaller than τ, the second pulse will not be recorded. Therefore, there exists a deviation in the count rate recorded by the counter 213 and needs to be corrected. The conversion unit 214 converts the corrected count rate C k Accurate neutron flux rate, neutron dose rate D in real time in combination with dose conversion coefficients based on t (Gy / s).

[0054] As shown again in Figures 4 and 5, the neutron dose detection device 21 further includes a count rate correction unit 217 that corrects the count rate, and the count rate correction unit 217 includes a count rate correction calculation unit, a count rate correction coefficient calculation unit, and a pulse resolution time calculation unit.

[0055] The counting rate correction calculation unit calculates the corrected counting rate C using the following formula (1-1): k Calculate

number

[0056] The counting rate correction coefficient calculation unit calculates the counting rate correction coefficient K using the following formula (1-2):

number

[0057] For the neutrons that enter the detector 211, if the number of neutrons that react within a unit time is m, and the number of pulses actually recorded by the counter 213 within the unit time is n, then the time during which the counter cannot operate is nτ, and the total number of neutrons that enter the counter during this time but are not recorded is mnτ, i.e., the loss count is mn, which can be deduced to obtain equation (1-3).

number

[0058] Substituting equation (1-3) into equation (1-2) gives equation (1-4).

number

[0059] As can be seen from the above equations, if the pulse resolution time τ is known, the count rate correction coefficient can be calculated by combining the number of pulses recorded by counter 213 and equation (1-4), and the corrected count rate can be calculated by substituting the count rate correction coefficient into equation (1-1).

[0060] Common pulse recomposition time calculation methods include the two-ray source method and the reactor power method, which require calculations using two natural neutron sources or reactors, and are expensive. In an embodiment of the present invention, the pulse recomposition time is calculated by the monitoring system of the neutron capture therapy device, making full use of traditional devices and resources to reduce costs.

[0061] Specifically, first, the accelerator 111 is operated in a low flux state, in which the neutron beam flux is a first neutron beam flux I1, and the count rate recorded by the counter 213 at this time is C1, and since it is in a low flux state, theoretically there is no signal pulse that the detector 211 cannot record due to the influence of the pulse resolution time. Next, the accelerator 111 is operated in a high flux state, in which the neutron beam flux is a second neutron beam flux I2, and the count rate recorded by the counter 213 at this time is C2, and since the count rate is influenced by the pulse resolution time in this case, some signal pulses are not recorded, and the pulse resolution time calculation unit calculates the pulse resolution time τ based on the following formula (1-5).

number

[0062] If the position of the detector 211 does not change, there is no need to calculate the pulse resolution time every time the device is operated; however, after the detector 211 has been operated for a long time, the performance parameters will change, causing a change in the pulse resolution time, so the pulse resolution time needs to be calculated periodically.

[0063] The count rate correction unit 217 can calculate the pulse recomposition time of the detector 211, and can correct the count rate error due to the pulse recomposition time by calculating a count rate correction coefficient based on the pulse recomposition time, thereby further improving the accuracy of real-time neutron dose detection, and thus further improving the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0064] Before performing irradiation treatment, irradiation parameters such as the total neutron dose that needs to be delivered to the patient S, the neutron flux rate or neutron dose rate or current during the irradiation period, the required irradiation time, and the irradiation angle are obtained by simulation, calculation, etc., and for ease of explanation, the above parameters are collectively referred to as preset irradiation parameters. In other embodiments, any of the above parameters, including some or more parameters not mentioned, may be understood to be preset irradiation parameters, and may be respectively referred to as the preset neutron dose (Gy), the preset neutron flux rate (cm -2 s -1 ), preset neutron dose rate (Gys -1 ), preset current (A) and preset irradiation time (s), etc. During the irradiation process, some factors change, so the irradiation parameters need to be periodically adjusted based on the relevant parameters detected by the detection system, and the irradiation parameters detected by the detection system are named real-time irradiation parameters, and the adjusted irradiation parameters are named modified irradiation parameters. The adjusted irradiation parameters may be preset irradiation parameters or modified irradiation parameters.

[0065] As shown in FIG. 6, the monitoring system 3 includes an input unit 31 for inputting preset irradiation parameters, a memory unit 32 for storing the irradiation parameters, a control unit 33 for executing a treatment plan based on the irradiation parameters stored in the memory unit 32, a reading unit 34 for reading real-time irradiation parameters detected by the detection system, a calculation unit 35 for calculating the real-time irradiation parameters and the preset irradiation parameters / corrected irradiation parameters stored in the memory unit 32, a judgment unit 36 ​​for determining whether or not the irradiation parameters need to be corrected based on the calculation results of the calculation unit 35, a correction unit 37 for correcting some of the irradiation parameters in the memory unit 32 when the judgment unit 36 ​​determines that the irradiation parameters need to be corrected, and a display unit 38 for displaying the remaining irradiation time or the remaining irradiation time and other irradiation parameters in real time.

[0066] Before the preset irradiation parameters are modified, the irradiation parameters stored in the memory unit 32 are the preset irradiation parameters, the irradiation parameters modified by the modifying unit 37 are also the preset irradiation parameters, the remaining irradiation time displayed on the display unit 38 is the difference between the preset irradiation time and the real-time irradiation time, and the irradiation parameters displayed on the display unit 38 are the preset irradiation parameters. After the preset irradiation parameters are modified, the irradiation parameters stored in the memory unit 32 are the modified irradiation parameters, the irradiation parameters modified again by the modifying unit 37 are also the modified irradiation parameters, the remaining irradiation time displayed on the display unit 38 is the modified remaining irradiation time, and the irradiation parameters displayed on the display unit 38 are the modified irradiation parameters. Naturally, the preset irradiation parameters and the modified irradiation parameters can be displayed simultaneously.

[0067] In other embodiments, the input unit 31, the storage unit 32, etc. may not be included.

[0068] The monitoring system 3 and the detection system are electrically connected so that relevant information detected by the detection system can be transmitted to the monitoring system 3, and the display 218 of the neutron dose detection device 21 in the detection system and the display unit 38 of the monitoring system 3 may be the same device, and is typically a single display panel.

[0069] The operation process of the monitoring system 3 is specifically described as follows with reference to FIG.

[0070] In S1, the input unit 31 inputs preset irradiation parameters, such as a preset neutron flux rate or a preset neutron dose rate or a preset current, a preset neutron dose and a preset exposure time, a preset boron concentration, etc. In S2, the memory unit 32 stores the irradiation parameters. In S3, the control unit 33 executes the treatment plan based on the irradiation parameters stored in the memory unit 32, In S4, the reading unit 34 reads the real-time irradiation parameters detected by the detection system; In S5, the calculation unit 35 calculates the irradiation parameters stored in the memory unit 32 and the real-time irradiation parameters read by the reading unit 34, In S6, the judgment unit 36 ​​judges whether or not it is necessary to modify the irradiation parameters stored in the memory unit based on the calculation result of the calculation unit 35. In S7, when the judgment unit 36 ​​judges that the irradiation parameters stored in the memory unit 32 need to be corrected, the correction unit 37 corrects the most recent irradiation parameters in the memory unit 32, When the judgment unit 36 ​​judges that it is not necessary to modify the irradiation parameters stored in the memory unit 32, the modification unit 37 does not perform the modification operation, In S8, the display unit 38 displays the remaining irradiation time or the remaining irradiation time and other irradiation parameters based on the irradiation parameters stored in the memory unit 32 in real time.

[0071] In the operation process of the monitoring system 3, the reading unit 34 periodically reads the real-time irradiation parameters, for example, reads the real-time irradiation parameters once every 5 minutes, and transmits them to the calculation unit 35 to perform correlation calculation. If the calculation unit 35 calculates that the difference value between the real-time irradiation parameters and the preset irradiation parameters is greater than the first threshold value or the real-time irradiation parameters are greater than the second threshold value or less than the third threshold value, the judgment unit 36 ​​gives an instruction that the irradiation parameters need to be corrected, and then the correction unit 37 corrects the irradiation parameters stored in the memory unit 32; conversely, the judgment unit 36 ​​gives an instruction that the irradiation parameters do not need to be corrected, in this case, the correction unit 37 does not correct the irradiation parameters stored in the memory unit 32. For example, when the calculation unit 35 calculates the difference value between the neutron dose rate and the preset neutron dose rate, or the difference value between the real-time neutron flux rate and the preset neutron flux rate, or the difference value between the real-time boron concentration and the preset boron concentration, or the difference value between the corrected remaining irradiation time and the remaining irradiation time (the difference value between the preset irradiation time and the time when the irradiation was actually performed or the previous corrected remaining irradiation time) is greater than the first threshold value, or when the calculation unit 35 compares, it obtains that the real-time neutron dose rate or the real-time neutron flux rate or the real-time boron concentration is greater than the second threshold value or less than the third threshold value.

[0072] Before the preset irradiation parameters are modified, the memory unit 32 stores the preset irradiation parameters, and the display unit 38 displays the remaining irradiation time and other preset irradiation parameters in real time. After the preset irradiation parameters are modified, the memory unit 32 stores the most recent set of modified irradiation parameters, and the display unit 38 displays the modified remaining irradiation time and the most recent set of other modified irradiation parameters in real time. In addition to the remaining irradiation time, the display unit 38 further displays which irradiation parameters can be selected according to actual needs, and may display all irradiation parameters or only a part of the irradiation parameters. Usually, the display unit 38 displays information such as the remaining irradiation time, real-time irradiation dose, and boron concentration.

[0073] In the embodiment of the present invention, the calculation unit 35 calculates the real-time neutron dose Dr detected by the neutron dose detection device 21 and the preset neutron dose D input from the input unit 31. total By combining these, the corrected remaining exposure time t r where t0 is the preset irradiation time, t is the real-time irradiation time detected by the detection system, i.e., the time when the irradiation is performed;

number

number

[0074] If P is less than 97%, the corrected remaining exposure time t r Calculate.

number

number

[0075] In this case, the correcting unit 37 only needs to correct the preset irradiation time stored in the memory unit 32 or the corrected remaining irradiation time.

[0076] If P is 97% or more, the correction unit 37 adjusts the neutron dose rate to a first neutron dose rate smaller than the preset neutron dose rate in order to prevent the patient S from absorbing excessive neutrons, and lengthens the irradiation time accordingly, and the first neutron dose rate is 1 / 7 to 1 / 2 of the preset neutron dose rate. Preferably, the neutron dose rate is adjusted to a preset neutron dose rate I d The first neutron dose rate is adjusted to 1 / 5 of I d / 5, and the corrected remaining exposure time t r Calculate.

number

[0077] In this case, the correction unit 37 corrects the remaining exposure time and the preset neutron dose rate in the memory unit 32 to the corrected remaining exposure time t rand the neutron dose rate needs to be corrected to the corrected neutron dose rate, and the control unit 33 executes the treatment plan based on the corrected irradiation parameters. In other embodiments, in order to prevent the patient S from absorbing excessive neutrons under irradiation with a neutron beam with a high neutron dose rate, the neutron dose rate may be adjusted to other multiples, such as 1 / 3, 1 / 4, 1 / 6, or 1 / 7 of the preset neutron dose rate, and the correction unit 37 may adjust the neutron dose rate when P is 90% or more, 95% or more, or other ratios, and the specific ratios may be preset according to the actual situation. Of course, the neutron dose rate may be adjusted to a first multiple smaller than the preset neutron dose rate based on the value of P calculated by the calculation unit 35. Alternatively, instead of judging whether or not it is necessary to adjust the neutron dose rate to the preset neutron dose rate, a threshold value may be manually set and input to and stored in the memory unit 32 via the input unit 31 when the detected real-time neutron dose is equal to or greater than the threshold value, and the correction unit 37 may be activated to adjust the neutron dose rate to a first neutron dose rate smaller than the preset neutron dose rate.

[0078] In the above embodiment, when P is less than 97%, the calculation unit 35 calculates the exposure time required to complete the exposure of the preset neutron dose on the premise that the real-time neutron dose rate is kept unchanged; in other embodiments, the exposure time is kept unchanged, and the purpose of completing the exposure of the preset dose within the preset exposure time can be achieved by changing the neutron dose rate or the boron concentration, and the method of changing the neutron dose rate includes changing the power of the accelerator, the thickness of the target layer of the target 112, etc. The corrected neutron dose rate Ir is calculated using the following formula (2-5):

number

[0079] The neutron dose rate is obtained by calculating the neutron flux rate using a conversion coefficient, and the neutron flux rate is obtained by integrating the neutron count rate. Therefore, correcting the neutron dose rate is equivalent to correcting the neutron flux rate and the neutron count rate.

[0080] In this embodiment, if P is 97% or more, in order to prevent the patient S from absorbing excessive neutrons under the irradiation of the neutron beam with a high neutron dose rate, the neutron dose rate is still adjusted to 1 / 5 of the preset neutron dose rate, and the corrected remaining exposure time t is calculated using formula (2-4). r Calculate.

[0081] When the time during which irradiation is actually performed reaches the preset irradiation time or the amount of neutron radiation actually irradiated reaches the preset neutron radiation dose, the control unit transmits an irradiation stop command to the neutron capture therapy device.

[0082] The monitoring system 3 is equipped with a correction unit 37 that corrects the irradiation parameters for executing the treatment plan stored in the memory unit 32, thereby ensuring that the neutron dose of the neutron beam irradiated to the patient S is basically consistent with the preset neutron dose, further improving the accuracy of the neutron dose of the neutron beam irradiated to the patient S. In addition, when the percentage between the real-time neutron dose and the preset neutron dose is 97% or more, in order to prevent the patient S from absorbing excessive neutrons under irradiation of a neutron beam with a high neutron dose rate, the neutron dose rate is adjusted lower and the irradiation time is extended accordingly, which also serves to improve the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0083] In the above-mentioned embodiment, the preset irradiation parameters are judged to be corrected based on the real-time neutron dose obtained from the neutron dose detection device 21, and the corrected irradiation parameters are calculated based on the real-time irradiation parameters and the preset irradiation parameters. In another embodiment, the preset parameters are judged to be corrected based on the real-time irradiation parameters detected by the temperature detection device 22, the displacement detection device 23, or the boron concentration detection device, and the corrected irradiation parameters are calculated based on the real-time irradiation parameters detected by these detection devices. For example, when the boron concentration detection device detects that the boron concentration in the body of the patient S does not match the preset boron concentration or is not within the preset interval range, the correction unit 37 corrects the remaining irradiation time or corrects the transport rate of boron into the patient's body. Usually, when the irradiation treatment is nearing the end, it is difficult to correct the boron concentration in the body of the patient S in a short time, and in this case, it is usually selected to correct the remaining irradiation time.

[0084] The accuracy of the neutron beam exposure dose is very important during practical treatment, and too much exposure dose will cause potential damage to the patient S, while too little exposure dose will reduce the quality of treatment. The calculation error of the preset neutron dose calculation part and the deviation between the real-time exposure parameters and the preset exposure parameters during the actual irradiation process will both result in inaccuracies in the neutron exposure dose, so in the actual irradiation process, in addition to correcting the exposure parameters in real time, the calculation of the preset exposure parameters is also very important. Therefore, in order to ensure that the neutron exposure dose administered to the patient S is more accurate, the calibration system needs to calibrate the preset neutron dose. When calibrating the preset neutron dose of the neutron beam, it is necessary to consider the influence of factors such as the positioning deviation of the patient S, the deviation of the real-time neutron dose rate, the boron concentration in the patient's body, and the neutron flux.

[0085] The calibration coefficients used by the calibration system include a neutron calibration coefficient K1 and a boron calibration coefficient K2. The neutron calibration coefficient K1 is a positioning calibration coefficient Kp and neutron beam intensity calibration factor K i The boron calibration factor K2 is related to the boron concentration calibration factor K b and boron self-shielding effect calibration factor K s Related to.

[0086] Since deviations between the real-time neutron dose rate and the preset neutron dose rate directly lead to deviations in the neutron dose ultimately delivered to the patient, the positioning calibration factor K p and neutron beam intensity calibration factor K i is introduced to correct the neutron exposure dose.

[0087] The self-shielding effect is that when the boron concentration is different, the neutron beam will have different tracks on the tumor site. Specifically, the higher the boron concentration in the patient S's body, the lower the penetrating ability of the neutron beam, the shorter the track of the neutron beam on the tumor, and the neutron beam will react with boron in a shallower track; conversely, the longer the track of the neutron beam on the tumor, and the neutron beam will react with boron in a deeper track. Specifically, a first boron concentration value in the patient's body is obtained by the boron concentration detection device, and a first track is formed when the neutron beam is irradiated to the tumor site, and a calibration system obtains a first boron calibration factor, and a second boron concentration value in the patient's body is obtained by the boron concentration detection device, and a second track is formed when the neutron beam is irradiated to the tumor site, and a calibration system obtains a second boron calibration factor, and when the first boron concentration value is greater than the second boron concentration value, the first track is smaller than the second track, and the first boron calibration factor is smaller than the second boron calibration factor. Therefore, when calculating the neutron exposure dose, it is necessary to take into account the effect of the self-shielding effect on the actual exposure effect of the neutron beam and the impact on the exposure track, so the boron concentration calibration factor K b and boron self-shielding effect calibration factor K s is introduced to calibrate the neutron exposure dose.

[0088] Specifically, the neutron calibration coefficient K1 and the positioning calibration coefficient K2 are calculated using equations (3-1), (3-2), and (3-3), respectively. p and neutron beam intensity calibration factor K i The correlation equation is as follows:

number

number

number

[0089] Here, D is the dose actually used in the treatment, i.e., the real-time neutron dose D measured by the neutron dose detector 21. r and D0 is the preset neutron dose that is not calibrated, I is the actual neutron beam intensity and the real-time neutron dose rate measured by the neutron dose detector 21; I0 is the theoretical beam intensity, i.e. the preset neutron dose rate entered at input 31.

[0090] Using equations (3-4), (3-5) and (3-6), respectively, the boron calibration factor K2 and the boron concentration calibration factor K b and boron self-shielding effect calibration factor K s The correlation equation is as follows:

number

number

number

[0091] where B is the actual boron concentration in the body of patient S, i.e., the real-time boron concentration detected by the boron concentration detection device; B0 is the set value of the boron concentration in the treatment plan, i.e., the preset boron concentration input from the input unit 31; φ B is the thermal neutron flux in the body of patient S when the boron concentration distribution is B, φ B0 is the thermal neutron flux in the body of patient S when the boron concentration distribution is B0.

[0092] Calculate the uncalibrated preset neutron dose D0 using the following equation (3-7).

number

[0093] The calibrated preset neutron dose D in the treatment plan is calculated using the following formula (3-8): total Calculate.

number

[0094] Here, D B is the dose at 1 ppm boron concentration in Gy, B con is the actual measured boron concentration in ppm, D f is the fast neutron dose in Gy, D th is the thermal neutron dose in Gy, RBE n is the relative biological effectiveness of neutrons, D r is the gamma radiation dose in Gy, RBE r is the gamma relative biological effectiveness.

[0095] During an actual treatment, the calibration system calibrates the preset neutron doses in the pre-formulated treatment plan to prevent the delivery of an inaccurate neutron dose to the patient S.

[0096] The calibration system comprehensively takes into consideration the influence of factors such as the positioning deviation of patient S, the deviation of the real-time neutron dose rate, and the real-time boron concentration on the preset neutron dose, and introduces the neutron calibration factor K1 and the boron calibration factor K2 to calibrate the preset neutron dose, thereby fundamentally ensuring the accuracy of the neutron dose of the neutron beam irradiated to patient S.

[0097] During actual treatment, after the input unit 31 completes inputting the preset irradiation parameters, the operator starts the neutron capture therapy device to perform irradiation treatment. After the irradiation is started, the input function of the input unit 31 is locked, and the relevant irradiation parameters cannot be re-input, thus ensuring that the irradiation process is prevented from being touched or operated incorrectly and inputting incorrect parameters and commands, but if the treatment process is slightly different from the ideal state, the irradiation will be stopped or irradiation will continue according to the abnormal state, and the parameters cannot be timely corrected or the commands cannot be timely changed during the irradiation process. However, if the operation interface is easily set to be operated in real time, the irradiation parameters and control commands can still be input by the input unit 31 after the irradiation is started, thus ensuring that the accurate irradiation parameters and commands are input in real time during the irradiation process, but there is a risk that the irradiation process will result in the input of incorrect parameters and commands or repeated input of operation commands due to incorrect operation, which will further affect the irradiation results.

[0098] As shown in FIG. 7, the neutron capture therapy device has an operation interface, which is composed of the input unit 31, the display unit 38, the information error confirmation button 51, the irradiation start button 52, the irradiation pause button 53, the irradiation cancel button 54, and the report generation button 55. The operator activates the information error confirmation button 51 to transmit a signal to the monitoring system 3 indicating that all information is confirmed to be error-free, and the monitoring system 3 has the necessary conditions to start the neutron capture therapy device and irradiate the neutron beam only after receiving the signal indicating that all information is confirmed to be error-free. After receiving the signal indicating that all information is confirmed to be error-free, the monitoring system 3 further activates the irradiation start button 52, and has the sufficient conditions to start the neutron capture therapy device and irradiate the neutron beam. After the neutron capture therapy device is started, the irradiation of the neutron beam can be temporarily stopped by the irradiation pause button 53, and the irradiation of the neutron beam can be canceled by the irradiation cancel button 54. After the irradiation is completed, the report generation button 55 can be activated to automatically generate a report related to the irradiation treatment. It is necessary to temporarily suspend neutron beam irradiation, i.e., keep all irradiation parameters and commands unchanged, and irradiate the neutron beam according to the original irradiation parameters and commands by activating the irradiation start button 52 again, or to cancel neutron beam irradiation, i.e., clear all irradiation parameters and commands, and when irradiating the neutron beam again, re-enter the irradiation parameters and commands and activate the no information error confirmation button 51 and the irradiation start button 52 in sequence.

[0099] The misoperation prevention system is provided with a double confirmation unit and a foolproof unit, which comprehensively considers two factors, operability and safety, to ensure safe and accurate irradiation, and the system does not lack real-time operability. Before the operator activates the double confirmation unit to transmit a signal to the neutron capture therapy device that he / she has confirmed that all information is correct, the neutron capture therapy device cannot be activated to execute the irradiation treatment plan, i.e., the irradiation start button 52 cannot be activated. During the activation period of the foolproof unit, the input unit 31 and the report generation button 55, which can modify and input irradiation parameters and commands, are locked.

[0100] In the embodiment of the present invention, the double confirmation unit is a confirmation button 51 for confirming that there is no information error on the operation interface. Before starting the program to execute the treatment plan, the doctor needs to confirm the relevant information twice. The operator can start the device to execute the treatment plan only after confirming that there is no input error and inputting a command to the monitoring system 3 that the information is confirmed to be free of error by clicking the confirmation button 51 for confirming that there is no information error, thereby reducing the risk of introducing an erroneous input command due to an erroneous operation. For example, before performing irradiation treatment on the patient S, the doctor needs to verify the patient information (e.g., name, sex, age, etc.) and irradiation parameters (e.g., irradiation dose, collimator number), etc., and only after verifying that all information is free of error, can the doctor start the irradiation function by clicking the confirmation button 51 for confirming that there is no information error on the operation interface. Otherwise, even if the doctor clicks the irradiation start button 52, the device will be started and refuse to irradiate the neutron beam, and will give a notice that the information is not confirmed.

[0101] In the embodiment of the present invention, the foolproof unit is the irradiation start button 52, and after starting the treatment plan by activating the irradiation start button 52, the input function of the input unit 31 is locked and any information cannot be re-input. Specifically, before performing irradiation treatment, when the relevant command and irradiation parameters are input by the input unit 31 and the relevant irradiation parameters and commands are input to the monitoring system 3, the operator checks whether the relevant irradiation parameters and commands are incorrect, and after confirming that there are no errors, activates the information no error confirmation button 51, after which the input unit 31 is locked and the relevant irradiation parameters and commands cannot be modified or added by the input unit 31, thus preventing erroneous input, and only when the input unit 31 is unlocked can the relevant irradiation parameters and commands be re-input. In the embodiment of the present application, after clicking the irradiation pause button 53 or the irradiation cancel button 54, the irradiation treatment is stopped and the input unit 31 for inputting relevant information is unlocked, in which case the relevant information can be modified and added by the input unit 31. Naturally, after completing the irradiation treatment, the input unit is automatically unlocked. In this way, not only can erroneous input be prevented, but the operability of the system can be guaranteed. For example, after a medical professional confirms that there are no errors in the information of the patient S, the irradiation parameters, etc., he or she clicks the "No Errors in Information" button 51 on the operation interface, and then clicks the "Start Irradiation" button 52. After that, the system starts irradiation treatment. In this case, the input unit 31 for inputting related information is locked, and no information can be input.

[0102] Before the radiation treatment is completed, the report generation button 55 is also locked. Only after the radiation treatment is completed can the report generation button 55 be automatically unlocked, ie the treatment report generation function be activated.

[0103] The foolproof part is not limited to the irradiation start button 52 in the above example, but also applies to other important buttons and parameter input windows, and the carrier for realizing foolproofing by double confirmation and buttons may be software or hardware, for example, the foolproof part may be a key or a dial switch on a control panel, and some operations cannot be performed before the key or switch is turned on, and only after the key or switch is turned on can the related operations be performed.

[0104] In some embodiments of the present invention, commands and irradiation parameters are input by means of a touch screen, but in other embodiments, they may be input by means of keys (eg, mechanical keys).

[0105] The anti-misoperation system can not only ensure that parameter setting and control command input functions are performed when necessary, but also reduce erroneous input of parameters or repeated input of commands due to erroneous operation or other causes, thereby reducing the operation risks of the device.

[0106] The neutron dose detection device 21 of the neutron capture therapy device of the present invention is provided with at least two count rate channels, a first count rate channel 201 and a second count rate channel 202, which have different neutron detection sensitivities, and a count rate channel selection unit 216. The count rate channel selection unit 216 selects an accurate count rate according to the actual situation to calculate the neutron dose, thereby avoiding the count rate loss error caused by the pulse recomposition time, and avoiding the statistical error caused by a low count rate, thereby improving the accuracy of the real-time neutron dose detection and further improving the accuracy of the neutron dose of the neutron beam irradiated to the patient S. In addition, the neutron dose detection device 21 is further provided with a count rate correction unit 217, which calculates the pulse recomposition time of the detector 211 and calculates a count rate correction coefficient based on the pulse recomposition time to correct the count rate error caused by the pulse recomposition time, thereby further improving the accuracy of the real-time neutron dose detection and thus the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0107] The neutron capture therapy device of the present invention further has a monitoring system 3, which is equipped with a correction unit 37 that periodically corrects the irradiation parameters for executing the treatment plan stored in the memory unit 32, thereby ensuring that the neutron dose of the neutron beam irradiated to the patient S basically coincides with the preset neutron dose, further improving the accuracy of the neutron dose of the neutron beam irradiated to the patient S. In addition, when the percentage between the real-time neutron dose and the preset neutron dose is 97% or more, in order to prevent the patient S from absorbing excessive neutrons under irradiation of a neutron beam with a high neutron dose rate, the neutron dose rate is adjusted lower and the irradiation time is extended accordingly, which also serves to improve the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0108] The neutron capture therapy device of the present invention further has a calibration system, which takes into consideration the influence of factors such as the positioning deviation of the patient S, the deviation of the real-time neutron dose rate, and the real-time boron concentration on the preset neutron dose, and introduces a neutron calibration factor K1 and a boron calibration factor K2 to calibrate the preset neutron dose, thereby fundamentally ensuring the accuracy of the neutron dose of the neutron beam irradiated to the patient S.

[0109] As described above, the neutron capture therapy device according to the present invention can irradiate a patient with a neutron beam with an accurate dose, and can reduce the risk of device operation due to erroneous operation, on the premise that the operability of the device is guaranteed.

[0110] The neutron capture therapy device according to the present invention is not limited to the contents described in the above embodiment and the configuration shown in the drawings. Any obvious changes, substitutions or modifications made to the material, shape and position of the components based on the present invention are within the scope of the claims of the present invention.

Claims

1. at least two count rate channels; and a count rate channel selection unit for selecting one count rate channel from the at least two count rate channels, the count rate channel including a detector for detecting neutrons and outputting a signal, a signal processing unit for processing the signal output from the detector, and a counter for counting the signal output from the signal processing unit to obtain a count rate; the count rate channels include at least a first count rate channel and a second count rate channel, the first count rate channel including a first detector, the second count rate channel including a second detector, and a sensitivity of the first detector to detect neutrons differs from a sensitivity of the second detector to detect neutrons; A neutron dose detection device characterized in that a charged particle beam accelerated by an accelerator undergoes a nuclear reaction with a target to generate neutrons, and the count rate channel selection unit selects a count rate channel based on the power of the accelerator, a neutron beam flux, or a distance between the detector and a neutron source.

2. 2. The neutron dose detection device according to claim 1, further comprising: a conversion unit for converting a count rate recorded by a count rate channel selected by the count rate channel selection unit into a neutron flux rate or a neutron dose rate; and an integration unit for integrating the neutron flux rate or the neutron dose rate to obtain a neutron dose.

3. 3. The neutron dose detection device according to claim 2, further comprising a display for displaying the neutron dose.

4. 3. The neutron dose detection device according to claim 2, wherein the count rate channel includes a first count rate channel and a second count rate channel, the first count rate channel including a first detector that detects neutrons and outputs a signal, a first signal processing unit that processes the signal output from the first detector, and a first counter that counts the signal output from the first signal processing unit, and the second count rate channel includes a second detector that detects neutrons and outputs a signal, a second signal processing unit that processes the signal output from the second detector, and a second counter that counts the signal output from the second signal processing unit, the first detector having a first sensitivity for detecting neutrons, and the second detector having a second sensitivity for detecting neutrons, the first sensitivity being smaller than the second sensitivity.

5. 5. The neutron dose detection device according to claim 4, wherein when the actual power of the accelerator is less than half of the maximum power, the count rate channel selection unit selects the count rate recorded by the second counter of the second count rate channel and transmits it to the conversion unit for use in dose calculation, and when the actual power of the accelerator is equal to or greater than half of the maximum power, the count rate channel selection unit selects the count rate recorded by the first counter of the first count rate channel and transmits it to the conversion unit for use in dose calculation.

6. 5. The neutron dose detection device according to claim 4, wherein a neutron flux that can be generated when the accelerator is at maximum power is defined as a maximum neutron flux, and when the real-time neutron flux is less than half the maximum neutron flux, the count rate channel selection unit selects the count rate recorded by the second counter of the second count rate channel and transmits it to the conversion unit for use in dose calculation, and when the real-time neutron flux is equal to or greater than half the maximum neutron flux, the count rate channel selection unit selects the count rate recorded by the first counter of the first count rate channel and transmits it to the conversion unit for use in dose calculation.

7. A neutron capture therapy device comprising the neutron dose detection device according to any one of claims 1 to 6.

8. 8. The neutron capture therapy device according to claim 7, further comprising a neutron beam irradiation system, the neutron beam irradiation system including a neutron beam generation module that generates a neutron beam, and a beam adjustment module that adjusts the neutron beam, the beam adjustment module including a moderator that can decelerate the neutron beam, and a reflector that guides stray neutrons to the moderator.

Images