RU2811294C1 - Neutron capture therapy device - Google Patents

Abstract

FIELD: medical technology.

SUBSTANCE: invention is related to irradiation with radioactive rays, and, in particular, to a neutron dose detection device and a neutron capture therapy device. A neutron capture therapy device is configured to irradiate a body to be irradiated with a neutron beam with a predetermined dose of neutrons, wherein the neutron beam enters the body to be irradiated and undergoes a nuclear reaction with boron in the body to be irradiated. The neutron capture therapy device contains a correction system configured to correct a preset neutron dose. The correction factors used by the correction system include the bore self-shielding effect correction factor K_s, calculated using formula (3-6): K _s = ϕ _B / ϕ ₀ (3-6), where ϕ_B is the flux of thermal neutrons in the body to be irradiated when the boron concentration distribution is equal to B, and ϕ_B0 is the flux of thermal neutrons in the body to be irradiated when the distribution of boron concentration is equal to B₀.

EFFECT: invention is aimed at solving problems associated with inaccurate setting of preset radiation parameters, such as neutron radiation dose, with inaccurate determination of the actual radiation dose, with erroneous introduction or change of corresponding commands or parameters.

9 cl, 7 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0001] The invention relates to the field of irradiation with radioactive rays, and, in particular, to a neutron dose detection device and a neutron capture therapy device.

BACKGROUND OF THE ART

[0002] With the development of nuclear technology, radiation therapy such as Cobalt-60, linear accelerator, electron beam or the like has become one of the main means of treating cancer. However, traditional photon or electron therapy is limited by the physical conditions of the radioactive beams themselves, and thus will also harm a large amount of normal tissue in the beam's path as it kills tumor cells. However, due to the varying sensitivity of tumor cells to radioactive rays, traditional radiation therapy often has a weak therapeutic effect on radioresistant malignant tumors (for example, glioblastoma multiforme and melanoma) with radioresistance.

[0003] To reduce radiation damage to normal tissues around tumors, the concept of targeted therapy in chemotherapy is applied to radiation therapy. Regarding tumor cells with high radioresistance, radiation sources with high relative biological effectiveness (RBE), such as proton therapy, heavy particle therapy, neutron capture therapy, etc., are also being actively developed at present. Here, neutron capture therapy combines the two above-mentioned concepts, such as boron neutron capture therapy. Due to the specific aggregation of boron-containing drugs in tumor cells and the interaction with precise control of the neutron beam, it provides cancer treatment options better than traditional radioactive rays.

[0004] During boron capture therapy, the radiation dose applied to the patient must be precisely controlled by the stronger radioactive beams of the neutron beam delivering radiation therapy to the patient. However, when formulating a treatment plan, there are still problems of inaccurately setting preset radiation parameters, such as neutron radiation dose, and inaccurately determining the actual radiation dose.

[0005] In addition, during the actual irradiation, sometimes an event occurs where a command is entered by mistake, or the corresponding irradiation commands and parameters are changed, due to the operator or doctor accidentally touching the control panel by mistake, so that the medical risk increases.

DISCLOSURE OF THE INVENTION

[0006] To solve the above problems, the invention provides a neutron capture therapy device capable of applying a precise dose of neutron irradiation to a body to be irradiated, and comprising a neutron beam irradiation system configured to generate a neutron beam, a detection system configured to detect irradiation parameters during therapy irradiation with a neutron beam, and a correction system configured to correct a preset neutron dose.

[0007] In addition, the correction system can adjust the preset neutron dose in accordance with the real-time boron concentration and neutron flux in the body to be irradiated.

[0008] In addition, the neutron capture therapy device may further comprise a detection system that includes a neutron dose detection device configured to detect the dose of the neutron beam in real time, and a boron concentration detection device configured to detect the boron concentration in the subject to irradiation body

[0009] In addition, the correction factors used by the correction system may include a bore self-shielding effect correction factor K _s calculated using Formula (3-6):

[0010]

[0011] where ϕ _B is the thermal neutron flux in the body to be irradiated when the boron concentration distribution is B, and ϕ _B0 is the thermal neutron flux in the body to be irradiated when the boron concentration distribution is B ₀ .

[0012] In addition, the correction coefficients may further include a positioning correction coefficient K _p calculated using Formula (3-2):

[0013]

[0014] where D is the real-time neutron dose measured by the neutron dose detection device, and D ₀ is the uncorrected preset neutron dose.

[0015] In addition, the uncorrected preset neutron dose D ₀ can be calculated using formula (3-7) as follows:

[0016]

[0017] where D _B is the dose at a boron concentration of 1 ppm, B _con is the actual measured boron concentration, D _f is the fast neutron dose, D _th is the thermal neutron dose, RBE _n is the neutron RBE, D _r is the gamma radiation dose, and RBE _r is the RBE of gamma radiation.

[0018] In addition, the correction factors may further include a neutron beam intensity correction factor K _i calculated using Formula (3-3):

[0019]

[0020] where I is the real-time neutron dose rate measured by the neutron dose detection device, and I ₀ is the theoretical beam intensity.

[0021] In addition, the correction factors may further include a boron concentration correction factor K _b calculated using Formula (3-5):

[0022]

[0023] where B is the real-time boron concentration detected by the boron concentration detection device, and B ₀ is the set value of boron concentration in the therapy plan.

[0024] In addition, the correction factors may include a neutron correction factor K ₁ and a boron correction factor K ₂ calculated using Formula (3-1) and Formula (3-4), respectively:

[0025]

[0026]

[0027] where K _p is the positioning correction factor, K _i is the neutron beam intensity correction factor, K _b is the boron concentration correction factor, K _s is the boron self-shielding effect correction factor.

[0028] In addition, the adjusted preset neutron dose D _total can be calculated using formula (3-8) as follows:

[0029]

[0030] where D _B is the dose at a boron concentration of 1 ppm, has the unit of measurement Gr, B _con is the actual measured boron concentration, has the unit ppm, D _f is the dose of fast neutrons, has the unit Gr, D _th is the dose of thermal neutrons , has a unit of measurement Gy, RBE _n - RBE of a neutron, D _r - dose of gamma radiation, has a unit of measurement Gy, and RBE _r - RBE of gamma radiation.

[0031] In addition, the first boron concentration value in the body to be irradiated is obtained by the boron concentration detection device, and the first boron self-shielding effect correction value is obtained by the correction system; a second boron concentration value in the body to be irradiated is obtained by a boron concentration detection device, and a second boron self-shielding effect correction value is obtained by a correction system, wherein the first boron concentration value is greater than the second boron concentration value, and the first boron self-shielding effect correction value is less than the second self-shielding effect correction factor boron

[0032] The neutron capture therapy device according to the invention is equipped with a correction system configured to correct a predetermined neutron dose, so that the accuracy of the dose of the neutron beam irradiated to the body to be irradiated is ensured from the source.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic diagram of the neutron beam irradiation system of a neutron capture therapy device according to the invention.

[0034] FIG. 2 is a schematic diagram of a beam forming housing of a neutron capture therapy device according to the present invention.

[0035] FIG. 3 is a schematic diagram of a neutron beam irradiation system and detection system of a neutron capture therapy device according to the invention.

[0036] FIG. 4 is a schematic diagram of a neutron dose detection device in a first embodiment of a neutron capture therapy device according to the invention.

[0037] FIG. 5 is a schematic diagram of a neutron dose detection device in a second embodiment of a neutron capture therapy device according to the invention.

[0038] FIG. 6 is a schematic diagram of a monitoring system for a neutron capture therapy device according to the invention.

[0039] FIG. 7 is a schematic diagram of a malfunction prevention system in combination with a display part and an input part of a neutron capture therapy device according to the invention.

IMPLEMENTATION OF THE INVENTION

[0040] To make the purpose, technical solutions and technical results of the invention clearer and to enable those skilled in the art to implement them accordingly, the invention will be further described in detail below with reference to the accompanying drawings and embodiments of the invention.

[0041] In the following description, the terms “first”, “second” and the like. may be used to describe various elements, however, these elements are not limited to these terms, and these terms are used only to distinguish the objects described without any order or technical meaning.

[0042] Radiation therapy is a common treatment for cancer, with boron neutron capture therapy (BNCT) being an effective treatment for cancer and increasingly used in recent years. As shown in FIG. 1-7, a neutron capture therapy device emitting a neutron beam of a predetermined neutron dose onto a subject to be irradiated, such as a patient S, to perform BNCT includes a neutron beam irradiation system 1, a detection system, a monitoring system 3, a correction system, and a malfunction prevention system. . The neutron beam irradiation system 1 is configured to generate a neutron beam suitable for performing neutron irradiation therapy on patient S. The detection system is configured to detect irradiation parameters such as neutron dose or the like during neutron irradiation therapy. The monitoring system 3 is designed to control the entire process of irradiation with a neutron beam. The correction system is configured to correct the preset neutron dosage. The malfunction prevention system is configured to prevent relevant personnel from entering improper commands and information into the monitoring system 3.

[0043] BNCT produces two highly charged particles ⁴ He and ⁷ Li using the characteristic of boron ( ¹⁰ B) drug having a high capture site for thermal neutron, and through the neutron capture of ¹⁰ B(n,α) ⁷ Li and nuclear fission reaction . The two highly charged particles each have an average energy of about 2.33 MeV, and have characteristics of high linear energy transfer (LET) and short range. The LET and range of the ⁴ He particles are 150 keV/µm and 8 µm respectively, the LET and range of the highly charged particles ⁷ Li are 175 keV/µm and 5 µm respectively, and the total range of the two highly charged particles is approximately equivalent to the size of a cell, so that radiation damage organism may be limited to the cellular level. The boron-containing drug selectively assembles into tumor cells. After the neutron beam enters the body of patient S, it undergoes a nuclear reaction with boron in the body of patient S, which leads to the formation of two highly charged particles ⁴ He and ⁷ Li, and the two highly charged particles ⁴ He and ⁷ Li locally destroy tumor cells cells without causing too much damage to normal tissues.

[0044] As shown in FIG. 1, the neutron beam irradiation system 1 includes a neutron beam generation module 11 and a beam adjustment module 12 configured to adjust the neutron beam generated by the neutron beam generation module 11.

[0045] The neutron beam generating unit 11 generates a neutron beam to irradiate the patient S, and includes an accelerator 111 configured to accelerate the charged particle beam, a target 112 configured to interact with the charged particle beam to generate the neutron beam, and a beam transport portion 113 charged particles, located between the accelerator 111 and the target 112 and configured to transport a beam of charged particles. The charged particle beam transport part 113 transports the charged particle beam to the target 112 and has one end connected to the accelerator 111 and the other end connected to the target 112. Here, the charged particle beam transport part 113 is provided with a beam control device such as a beam adjustment part (not shown), charged particle scanning part (not shown), etc. The beam adjustment part controls the direction of movement and diameter of the beam of charged particles. The charged particle beam scanning portion scans the charged particle beam and controls the irradiation position of the charged particle beam relative to the target 112.

[0046] The accelerator 111 may be a cyclotron, synchrotron, synchrocyclotron, linear accelerator, or the like. A commonly used target 112 includes a lithium (Li) target and a beryllium (Be) target. The beam of charged particles is accelerated to an energy sufficient to overcome the Coulomb repulsion of target 112 nuclei and undergoes a ⁷ Li(p, n) ⁷ Be nuclear reaction with target 112 to generate a beam of neutrons. A commonly discussed nuclear reaction involves ⁷ Li(p, n) ⁷ Be and ⁹ Be(p, n) ⁹ B. Typically, the target 112 includes a target layer and an anti-oxidation layer located on a side of the target layer and configured to prevent oxidation of the target layer , and the anti-oxidation layer is made of aluminum or stainless steel.

[0047] In embodiments of the invention, accelerator 111 accelerates charged particles to allow them to undergo a nuclear reaction with target 112 to provide a source of neutrons. In other embodiments, the neutron source may be provided through the use of a nuclear reactor, a D-T neutron generator, a D-D neutron generator, or the like. However, whether the neutron source is provided by accelerating charged particles to allow them to undergo a nuclear reaction with the target 112 as provided in the invention, or whether the neutron source is provided by a nuclear reactor, a D-T neutron generator, a D-D neutron generator, or the like, a mixed irradiation field is generated, that is, the generated beam includes a high-speed neutron beam, an epithermal neutron beam, a thermal neutron beam and a gamma ray. During BNCT, the higher the content of the remaining irradiation beams (collectively called irradiation beam contamination), excluding the epithermal neutron, the greater the proportion of non-selective dose deposition in normal tissues, so radiation causing unnecessary dose deposition can be minimized.

[0048] The International Atomic Energy Agency (IAEA) has made five recommendations on the air beam quality factor for a neutron source used in clinical BNCT. The five guidelines can compare the advantages and disadvantages of various neutron sources and serve as reference for selecting a neutron generation path and designing the beamforming housing 121. The five recommendations are as follows:

[0049] Epithermal neutron flux >1 × 10 ⁹ n/cm ^{2 s}

[0050] Fast neutron contamination <2 × 10 ^-13 Gy-cm ² /n

[0051] Photon contamination <2 × 10 ^-13 Gy-cm ² /n

[0052] Thermal to epithermal neutron flux ratio <0.05

[0053] Epithermal neutron current to flux ratio >0.7.

[0054] Note: The epithermal neutron has an energy region between 0.5 eV and 40 keV, the thermal neutron has an energy region less than 0.5 eV, and the fast neutron has an energy region greater than 40 keV.

[0055] As shown in combination with FIG. 2 and 3, the beam adjustment module 12 is configured to adjust the mixed irradiation beams generated in the neutron beam generation module 11 to minimize contamination of the irradiation beam ultimately irradiating the patient S, and to focus the epithermal neutron for treating the patient S on the subject to be irradiated. part of the patient S. The beam adjustment module 12 contains a beam-forming housing 121 configured to slow down and shield the neutron beam, and a collimator 122 configured to focus an epithermal neutron on the part of the patient S to be irradiated. In particular, the beam-forming housing 121 contains a moderator 1211 , configured to slow down a beam of neutrons generated from the target 112 into the energy region of an epithermal neutron, a reflector 1212 configured to direct the deflected neutron back to the moderator 1211 to increase the intensity of the epithermal neutron beam, a thermal neutron absorber 1213 configured to absorb a thermal neutron to prevent excessive dose deposition in superficial normal tissues during therapy, and a radiation shield 1214 configured to screen neutron and photon leakage to reduce dose deposition in normal tissues in the non-irradiated area. In other embodiments of the invention, a thermal neutron absorber may not be provided; instead, the thermal neutron is absorbed by substances contained in the moderator or reflector, or the moderator and thermal neutron absorber may be provided as one piece. In other embodiments, the radiation shield may not be provided; instead, the radiation shield may be made of the same material as the reflector, or the reflector and radiation shield may be provided as one piece.

[0056] The retarder 1211 can be formed by laying down several different materials. The material of the moderator 1211 is selected in accordance with factors such as the energy of the charged particle beam and the like. For example, when the proton beam energy from the accelerator 111 is 30 MeV and a Be target is used, the material of the moderator 1211 is lead (Pb), iron, aluminum (Al), or calcium fluoride. When the proton beam energy from the accelerator 111 is 11 MeV and a Be target is used, the material of the moderator 1211 is heavy water (D ₂ O), or lead fluoride, etc. In a preferred embodiment of the invention, moderator 1211 is formed by mixing MgF ₂ and LiF, which is 4.6% MgF ₂ by weight, reflector 1212 is made of Pb, and thermal neutron absorber 1213 is made of ⁶ Li. Radiation shield 1214 includes a photon shield and a neutron shield. Here the photonic screen is made of Pb and the neutron screen is made of polyethylene (PE). The retarder 1211 may be configured in a biconical shape, as disclosed in FIG. 2, or in a cylindrical form as disclosed in FIG. 3. The reflector 1212 is located around the retarder 1211 and has a shape adaptively modified in accordance with the shape of the retarder 1211.

[0057] As shown in FIG. 3, the detection system includes a neutron dose detection device 21, configured to detect the neutron dose of a neutron beam in real time, a temperature detection device 22, configured to detect the temperature of the target 112, a displacement detection device 23, configured to detect whether the patient creates S displacement during therapy, and a boron concentration detection device (not shown) configured to detect boron concentration in the body of the patient S.

[0058] As shown in combination with FIG. 4, the neutron dose detection device 21 includes a detector 211 configured to receive a neutron and output a signal, a signal processing unit 212 configured to process the signal output from the detector 211, a counter 213 configured to count the signal output from the processing unit 212 signal to obtain the count rate, a conversion unit 214 configured to convert the count rate recorded by the counter 213 into a neutron flux density or neutron dose rate, an integration unit 215 configured to integrate the neutron flux density or neutron dose rate to obtain a neutron dose , and a display 218 configured to display the neutron dose. The detector 211, the signal processing unit 212 and the counter 213 form the count rate channel 20.

[0059] The detector 211 may be located in the beam forming housing 121, may also be located in the collimator 122, or may also be located at any position adjacent to the beam forming housing 121, provided that the position in which the detector 211 is located may be adapted for detecting the neutron dose of a neutron beam.

[0060] The detector 211, capable of detecting the neutron dose of a neutron beam in real time, is equipped with an ionization chamber and a scintillation detector. In this case, the He-3 proportional counter, the BF ₃ proportional counter, the fission chamber and the boron ionization chamber use an ionization chamber structure as a substrate, and the scintillation detector contains an organic material or an inorganic material. When detecting a thermal neutron, the scintillation detector usually adds a high thermal neutron capture section element such as Li, or B, etc. A specific element in two types of detectors captures a neutron entering the detector or undergoes a nuclear fission reaction with a neutron entering the detector to release highly charged particles and nuclear fission fragments that generate a large number of ionization pairs in the ionization chamber or scintillation detector, and these the charges collect and form an electrical signal. The signal processing unit 212 performs noise reduction, conversion and division processing of the electrical signal, and the electrical signal is converted into a pulse signal. A distinction is made between a neutron pulse signal and a γ pulse signal by analyzing the magnitude of the voltage pulse. The separated neutron pulse signal is continuously recorded by counter 213 to obtain the neutron count rate (n/s). The conversion unit 214 calculates and converts the count rate through internal software, programs or the like to obtain the neutron flux density (cm ^{-2 s -1} ) and further calculates and converts the neutron flux density to obtain the neutron dose rate (Gy/s). Finally, the integration part integrates the neutron dose rate to obtain the real-time neutron dose.

[0061] Below is a brief description using the example of a fission chamber, a scintillator detector and a BF ₃ detector.

[0062] When a beam of neutrons passes through the fission chamber, it is separated by gas molecules inside the fission chamber or by the wall of the fission chamber to produce an electron and a positively charged ion, which are called an ion pair, as described above. Due to the high electric field voltage applied in the fission chamber, the electron moves towards the central anode wire and the positively charged ion moves towards the surrounding cathode wall so that a measurable electrical signal is generated.

[0063] Substances, such as optical fiber or the like, in a scintillation detector absorb energy and then generate visible light, which uses ionizing radiation to excite an electron in a crystal or molecule to an excited state. The fluorescence emitted when the electron returns to the ground state is collected and then used to detect the neutron beam. Visible light emitted by a scintillation detector and a neutron beam is converted into an electrical signal using a photomultiplier tube and output.

[0064] The detector BF ₃ is located in the beam forming housing 121 and is configured to receive irradiation of a beam of neutrons, the element B in the detector BF ₃ undergoes a nuclear reaction ^{of 10} B(n, alpha) ⁷ Li with a neutron, wherein the alpha particles generated by the nuclear reaction, and ⁷ Li electrical particles are collected by a high voltage electrode under voltage to generate an electrical signal. The electrical signal is transmitted to signal processing unit 212 through a coaxial cable and is subject to signal amplification, filtering, and conditioning to produce a pulse signal. The processed pulse signal is transmitted to the counter 213 for counting pulses therein to obtain a counting rate (n/s) with which the intensity of the neutron beam, that is, the neutron dose, can be measured in real time.

[0065] The temperature detection device 22 is a thermocouple, with two wires with different components (called thermocouple wires or hot electrodes) connected at both ends to form a loop. When the temperature of the connection point is different, an electromotive force can be generated in the loop. This phenomenon is called the thermoelectric effect, and the electromotive force is called thermoelectric potential. A thermocouple performs temperature measurement using this principle, with one end directly adapted to measure the temperature of the medium being called the working end (also known as the measuring end) and the other end being called the cold end (also known as the compensation end). The cold end is connected to a display instrument or a mixed instrument, wherein the display instrument may indicate the thermoelectric potential generated by the thermocouple. Of course, as is known to those skilled in the art, the temperature detecting device 22 can also be any detector 211 capable of detecting temperature, such as a resistance thermometer or the like.

[0066] The displacement detection device 23 is an infrared signal detector, wherein the infrared detector operates by detecting infrared rays emitted by the human body. An infrared detector detects infrared radiation from outside and then collects the infrared radiation on an infrared sensor. An infrared sensor generally uses a pyroelectric element that releases charges outward when the temperature of the infrared radiation changes, and once the charges are detected and processed, an alarm is generated. The detector 211 is designed to detect radiation from the human body. Therefore, the radiation-sensitive element must be very sensitive to infrared radiation with a wavelength of about 10 µm. Of course, it is well known to those skilled in the art that the displacement detection device 23 may be any detection device suitable for detecting a change in displacement of an object to be irradiated, such as a displacement sensor. The displacement sensor determines whether the object to be irradiated moves in accordance with a change in the displacement of the object to be irradiated relative to a certain reference object. It is also well known to those skilled in the art that the displacement detection device 23 can not only be configured to detect a change in displacement of the object to be irradiated, but also to detect a change in displacement of the support member and/or the treatment table fixing the object to be irradiated, with thereby indirectly determining the change in the displacement of the object to be irradiated.

[0067] During neutron beam irradiation therapy for patient S, boron is continuously supplied to patient S as needed. Boron concentration can be detected using inductively coupled plasma spectroscopy, high-resolution α-autoradiography, charged ion spectroscopy, neutron capture chamber, nuclear magnetic resonance imaging and magnetic resonance imaging, positive electron emission tomography, fast γ-ray spectroscopy and the like, wherein the device involved in the above detection method is called a boron concentration detection device.

[0068] The invention is described in terms of calculating the concentration of boron in the body of patient S by detecting a γ-ray emitted by patient S. A beam of neutrons enters the patient's body and reacts with boron to generate a γ-ray. By measuring the amount of γ-ray, it is possible to calculate the amount of boron reacting with the neutron beam, thereby calculating the concentration of boron in the body of the patient S. The boron concentration detection device is configured to measure the concentration of boron in the body of the patient S in real time when the neutron beam irradiation system 1 performs neutron beam irradiation therapy for patient S.

[0069] A boron concentration detection device detects γ-rays (478 keV) generated by the reaction between a neutron and boron to measure boron concentration, wherein a boron distribution measurement system (PG (Prompt-γ)-SPECT) is used as the boron concentration detection device. , capable of measuring single-energy γ-rays to measure the boron concentration distribution. The boron concentration detecting device includes a γ-ray detection part and a boron concentration calculation part. The γ-ray detection portion detects information related to γ-ray emitted from the body of the patient S, and the boron concentration calculation portion calculates the boron concentration in the body of the patient S according to the information related to the γ-ray detected by the γ-ray detection portion. The γ-ray detection portion may use a scintillator and various other γ-ray detection devices. In carrying out the invention, the γ-ray detection portion is located near the tumor of patient S, for example, at a distance of about 30 cm from the tumor of patient S.

[0070] The detector 211 of the above neutron dose detection device 21, configured to detect the neutron dose of a neutron beam, belongs to a pulse detector, and the shortest time interval between two successively incident neutrons detected by the detector 211 is defined as the pulse resolution time τ(s). . The detector 211 may not accurately record other incident neutrons during the τ time after the neutron hits the detector 211, which is therefore also called dead time.

[0071] The sensitivity of the neutron detector 211 is the ratio of the total output of the detector 211 to the corresponding total input. For the detector 211 of the neutron dose detection device 21 exemplified in the invention, its input quantity is a neutron beam, and its output quantity is generally an optical signal or an electrical signal. The higher the ratio of the total output to the corresponding total input, the higher the sensitivity of the neutron detector 211. The higher the neutron detection sensitivity, the shorter the pulse resolution time τ associated with detector 211. In general, to reduce statistical error, the high neutron detection sensitivity detector 211 detects a low density beam, and the low neutron detection sensitivity detector 211 detects a high density beam.

[0072] Various embodiments of the invention are described in detail below. For simplicity, the same component has the same numeral in different embodiments, while similar components are distinguished by the same numeral plus ‘ ' ’ or ‘ ‘’ ’ for different embodiments.

[0073] In the first embodiment of the invention disclosed in FIG. 4, the neutron dose detection device 21 is equipped with only a count rate channel 20. For accurate detection of neutron doses from neutron beams of various densities, in the second embodiment, disclosed in FIG. 5, the neutron dose detection device 21' contains at least two count rate channels 20'. The detector 211' of each count rate channel 20' has a different neutron detection sensitivity. In addition, the neutron dose detection device 21' further comprises a count rate channel selection unit 216 configured to select a corresponding count rate channel 20' in accordance with the current power of the accelerator 111 or the neutron beam flux. In particular, in the second embodiment, the neutron dose detection device 21' includes at least two count rate channels 20', a count rate channel selection unit 216 configured to select a corresponding count rate channel 20' from the at least two count rate channels 20' count rate, a conversion unit 214 configured to convert the count rate recorded by the count rate channel 20' selected by the count rate channel selection unit 216 into a neutron flux density or neutron dose rate, and an integration unit 215 configured to integrate the neutron flux density or neutron dose rate to obtain a neutron dose.

[0074] The two count rate channels 20' are referred to as the first count rate channel 201 and the second count rate channel 202, respectively. The first count rate channel 201 includes a first detector 2011 configured to receive a neutron and output a signal, a first signal processing unit 2012 configured to process a signal output from the first detector 2011, and a first counter 2013 configured to count a signal output from first block 2012 signal processing. The second count rate channel 202 includes a second detector 2021 configured to receive a neutron and output a signal, a second signal processing unit 2022 configured to process a signal output from the second detector 2021, and a second counter 2023 configured to count a signal output from a second signal processing block 2022. The count rate channel selector 216 selects the corresponding count rate channel 20 in accordance with the current power of the accelerator 111 or the neutron beam flux. The conversion unit 214 converts the count rate recorded by the count rate channel 20 selected by the count rate channel selector 216 into a neutron flux density or neutron dose rate. An integration unit 215 integrates the neutron flux density or neutron dose rate to obtain the neutron dose.

[0075] In general, the neutron flux that can be generated when the accelerator 111 is at maximum power is defined as the maximum neutron flux. When the real-time detected neutron flux is less than half of the maximum neutron flux, it is considered to be a low neutron flux. When the real-time detected neutron flux is greater than or equal to half the maximum neutron flux, it is considered to be a large neutron flux.

[0076] The sensitivity of the first neutron detecting detector 2011 is a first sensitivity, the sensitivity of the second neutron detecting detector 2021 is a second sensitivity, the first sensitivity being less than the second sensitivity. In particular, the first detector 2011 is wrapped with a large amount of neutron-absorbing materials such as B ₄ C, Cd, or filled with a low-pressure working gas, or made in a small size, thereby reducing the sensitivity of neutron detection. When the neutron flux is large, the first detector 2011 is used for detection so that the count rate loss due to the pulse resolution time can be reduced. Compared with the first detector 2011, the second detector 2021 is wrapped with a small amount of neutron-absorbing materials, or no material at all, or filled with a high-pressure working gas, or made in a large size, so that the second sensitivity is greater than the first sensitivity. When the neutron flux is small, the second detector 2021 is used for detection so that the statistical error of the count rate caused by the low count rate can be reduced.

[0077] Accordingly, the sensitivity of the first neutron detecting count rate channel 201 is less than the sensitivity of the second neutron detecting count rate channel 202. The count rate selector selects the appropriate count rate channel 20' in accordance with the current accelerator 111 power or neutron flux. For example, in a case where the maximum beam intensity of the accelerator 111 is 10 mA, when the beam intensity of the accelerator 111 exceeds 5 mA, the count rate recorded by the first counter 2013 of the first count rate channel 201 with a first sensitivity is selected to be transmitted to the conversion unit 214 for calculating the dose. ; wherein, when the beam intensity of the accelerator 111 is less than 5 mA, the count rate recorded by the second counter 2023 of the second count rate channel 202 with the second sensitivity is selected for transmission to the conversion unit 214 for calculating the dose. A more accurate count rate is selected by the count rate selection block for transmission to the conversion block 214 for dose calculation, thereby obtaining an accurate neutron dose.

[0078] The neutron dose detection device 21 is provided with at least two count rate channels with different neutron detection sensitivities, that is, a first count rate channel 201 and a second count rate channel 202, wherein the count rate channel selector 216 selects a more accurate count rate in according to the actual situation to calculate the neutron dose, so that the count rate loss error caused by the pulse resolution time can be reduced. This takes into account the statistical error due to the low counting rate, so that the accuracy of real-time neutron dose detection is improved, thereby increasing the neutron dose accuracy of the neutron beam irradiating patient S.

[0079] In other embodiments, the count rate channels 20 and 20' are provided with the ability to have any number of count rate channels as needed.

[0080] Moreover, in embodiments of the invention, as illustrated above, the count rate channel 20 is selected in accordance with the power of the accelerator 111, neutron flux, or the like. In other embodiments of the invention, the count rate channel 20' may be selected in accordance with the distance between the detector 211 and the neutron source. For example, when detector 211 is located in a position close to the neutron source, a second count rate channel 202 with a second sensitivity is selected; wherein, when the detector 211 is located at a position remote from the neutron source, the first count rate channel 201 with the first sensitivity is selected.

[0081] The detector 211 of the above neutron dose detection device 21 is a pulse detector. In general, a pulse detector has a time resolution problem. The incident neutron reacts with detector 211, generating a signal pulse that may be followed by a time interval τ. All other signal pulses generated during the time interval may be considered by the detector 211 to be the same signal pulse. In this case, provided that the time interval between any two signal pulses is less than τ, the second pulse may not be recorded. Therefore, the count rate recorded by the counter 213 has a deviation and must be corrected. The conversion unit 214 obtains the accurate real-time neutron flux density and neutron dose rate D _t (Gy/s) in accordance with the adjusted count rate C _k in combination with the dose conversion factor.

[0082] As again shown in combination with FIG. 4 and 5, in addition, the neutron dose detection device 21 additionally contains a count rate correction unit 217, configured to correct the count rate. The count rate correction unit 217 includes a count rate correction calculation portion, a count rate correction factor calculation portion, and a pulse resolution time calculation portion.

[0083] The count rate correction calculation portion calculates the corrected count rate C _k using Formula (1-1):

[0084]

[0085] where K is the counting rate correction factor; And

[0086] C _t is the real-time count rate recorded by counter 213.

[0087] The calculation part of the count rate correction factor calculates the count rate correction factor K according to formula (1-2):

[0088]

[0089] where n is the number of pulses recorded by the counter 213 per unit of time, that is, the real-time counting rate (n/s) per unit of time; And

[0090] m is the number of signal pulses actually generated in the detector 211 per unit time, that is, the number of neutrons (n/s) reacting with the detector 211 per unit time.

[0091] When the number of neutrons entering the detector 211 to react per unit time is m, and the number of pulses actually recorded by the counter 213 per unit time is n, the time that the counting tube may not operate is nτ, and the total the number of neutrons that enter the counting tube at this time and cannot be recorded is equal to mnτ, that is, the counting loss is m-n, and formula (1-3) is obtained from:

[0092]

[0093] Formula (1-3) is substituted into formula (1-2) to obtain formula (1-4):

[0094]

[0095] From the above formula, it can be determined that when the pulse resolution time τ is known, the count rate correction factor can be calculated by a combination of the number of pulses recorded by the counter 213 and formula (1-4), wherein the count rate correction factor can be substituted into formula (1-1) to calculate the adjusted count rate.

[0096] Traditional methods for calculating pulse resolution time include the dual source method and the reactor power method. These two methods require two natural neutron sources or reactors to calculate and are relatively expensive. Embodiments of the invention provide for computing pulse time resolution based on a neutron capture therapy device monitoring system, allowing full use of existing devices and resources to reduce cost.

[0097] Specifically, first, the accelerator 111 operates in a low flux state, and at this time, the neutron beam flux is the first neutron beam flux I ₁ , and the count rate recorded by the counter 213 is C ₁ . Theoretically, due to the low flow condition, the detector 211 is not affected by the pulse resolution time, and there are signal pulses that may not be recorded. Then, the accelerator 111 is put into a high flux state, at which time the neutron beam flux is the second neutron beam flux I ₂ and the count rate recorded by the counter 213 is C ₂ . In this case, the counting rate is affected by the pulse resolution time, so that some of the signal pulses are not recorded, and the pulse resolution time calculation part calculates the pulse resolution time τ using formula (1-5):

[0098]

[0099] When the position of the detector 211 does not change, it is not necessary to calculate the pulse resolution time each time the device is operated. However, after operating the detector 211 for a long time, the operating parameters of the detector 211 may change, causing the pulse resolution time to change, so it is necessary to periodically calculate the pulse resolution time.

[00100] The count rate correction portion 217 can calculate the pulse resolution time of the detector 211, and can calculate the count rate correction factor according to the pulse resolution time, so that the count rate error caused by the pulse resolution time is corrected, further improving the real-time neutron dose detection accuracy , and further improves the neutron dose accuracy of the neutron beam irradiating patient S.

[00101] Before radiation therapy, the total neutron dose to be delivered to the patient S, the neutron flux density or neutron dose rate or current during irradiation, and the required irradiation time, irradiation angle and other irradiation parameters during irradiation are obtained through simulation, calculation and etc. For convenience of description, the above parameters are collectively called preset irradiation parameters. In other embodiments of the invention, part or more of the unmentioned parameters, including the above parameters, can be understood as preset irradiation parameters called preset neutron dose (Gy), preset neutron flux density (cm ^-2 s ^-1 ), preset neutron dose rate (Gy s ^-1 ), preset current (A), preset irradiation time (s), etc. respectively. During irradiation, due to changes in certain coefficients, the irradiation parameters must be periodically adjusted in accordance with the relevant parameters detected by the detection system. The irradiation parameter detected by the detection system is called the real-time irradiation parameter, and the adjusted irradiation parameter is called the adjusted irradiation parameter. The adjusted irradiation parameter may be a preset irradiation parameter or an adjusted irradiation parameter.

[00102] As shown in FIG. 6, the monitoring system 3 contains an input part 31, configured to enter preset irradiation parameters, a storage part 32, configured to store irradiation parameters, a control part 33, configured to execute a treatment plan in accordance with the irradiation parameters stored in the storage part 32 , a reading portion 34 configured to read real-time irradiation parameters detected by the detection system, a calculation portion 35 configured to calculate real-time irradiation parameters and preset irradiation parameters/corrected irradiation parameters stored in the storage portion 32, determination portion 36 , configured to determine, in accordance with the calculation result of the calculation part 35, whether correction of the irradiation parameters is required, the correction part 37, configured to correct a portion of the irradiation parameters stored in the storage part 32, when the determination part 36 determines what needs to be corrected irradiation parameters, and a display portion 38 configured to display the remaining irradiation time or the remaining irradiation time and other irradiation parameters in real time.

[00103] Before correcting the preset irradiation parameters, the irradiation parameters stored in the storage part 32 are preset irradiation parameters, the irradiation parameters corrected by the correction part 37 are also preset irradiation parameters, the remaining irradiation time displayed by the display part 38 is the difference between the preset irradiation time and real-time irradiation time, and the irradiation time displayed by the display portion 38 is a preset irradiation time. After correcting the preset irradiation parameters, the irradiation parameters stored in the storage portion 32 are the corrected irradiation parameters, the irradiation parameters corrected by the correction portion 37 are also the corrected irradiation parameters, the remaining irradiation time displayed by the display portion 38 is the corrected remaining irradiation time, and The irradiation parameters displayed by the display portion 38 are the corrected irradiation parameters. Of course, preset exposure parameters and adjusted exposure parameters can also be displayed simultaneously.

[00104] In other embodiments of the invention, the input portion 31, storage portion 32, and the like. may not be provided.

[00105] The monitoring system 3 is electrically coupled to the detection system so that relevant information detected by the detection system can be transmitted to the monitoring system 3. The display 218 of the neutron dose detection device 21 in the detection system and the display portion 38 of the monitoring system 3 may be the same device, generally a display screen.

[00106] The operation process of the monitoring system 3 is shown in FIG. 6, specific details are described below.

[00107] In step S1, preset irradiation parameters such as preset neutron flux density or preset neutron dose rate or preset current, preset neutron dose, preset irradiation time, preset boron concentration and other irradiation parameters are input by the input portion 31.

[00108] In step S2, the irradiation parameters are stored in the storage portion 32.

[00109] In step S3, the treatment plan is executed by the control portion 33 in accordance with the irradiation parameters stored in the storage portion 32.

[00110] In step S4, the real-time irradiation parameters detected by the detection system are read by the reading part 34.

[00111] In step S5, the irradiation parameters stored in the storage portion 32 and the real-time irradiation parameters read by the reading portion 34 are calculated by the calculation portion 35.

[00112] In step S6, whether adjustment of the irradiation parameters stored in the storage part is required is determined by the determination part 36 in accordance with the calculation result of the calculation part 35.

[00113] In step S7, the last irradiation parameters in the storage portion 32 are corrected by the correction portion 37 in response to the determination by the determination portion 36 that the irradiation parameters stored in the storage portion 32 are to be corrected; And

[00114] The corrective action is not performed by the correction portion 37, in response to the determination by the determination portion 36 that the irradiation parameters stored in the storage portion 32 do not need to be adjusted.

[00115] In step S8, the remaining irradiation time or remaining irradiation time and other irradiation parameters are displayed by the display portion 38 in real time in accordance with the irradiation parameters stored in the storage portion 32.

[00116] During operation of the monitoring system 3, the reading part 34 periodically reads the real-time irradiation parameters, for example, reads the real-time irradiation parameters every 5 minutes, and transmits the real-time irradiation parameters to the calculation part 35 for corresponding calculation. In response to a difference between the real-time irradiation parameter and the preset irradiation parameter calculated by the calculation portion 35 that is greater than the first threshold value, or in response to the real-time irradiation parameter that is greater than the second threshold value or less than the third threshold value, part 36 of the definition may command that the irradiation parameters should be adjusted. Then, the correction part 37 corrects the irradiation parameters stored in the storage part 32. On the contrary, part 36 of the definition gives the command that the irradiation parameters do not need to be adjusted. At this time, the correction part 37 does not correct the irradiation parameters stored in the storage part 32. For example, in response to a difference between the neutron dose rate and the preset neutron dose rate calculated by the calculation portion 35 that exceeds the preset first threshold value, or in response to a difference between the real-time neutron flux density and the target neutron flux density calculated by the calculation portion 35, exceeding the preset first threshold value, or in response to the difference between the real-time boron concentration and the preset boron concentration calculated by the calculation portion 35 exceeding the preset first threshold value, or in response to the difference between the adjusted remaining irradiation time and the remaining irradiation time (the difference between the preset irradiation time and the actual realized irradiation time or the last adjusted remaining irradiation time) calculated by the calculation portion 35 exceeding the preset first threshold value, or in response to the calculation portion 35 obtaining by comparison that the real-time neutron dose rate or neutron flux density in real-time or real-time boron concentration is greater than a preset second threshold value or less than a preset third threshold value.

[00117] Before adjusting the preset irradiation parameters, the storage portion 32 stores the preset irradiation parameters, and the display portion 38 displays the remaining irradiation time and other preset irradiation parameters in real time. After correcting the preset irradiation parameters, the storage portion 32 stores the last set of adjusted irradiation parameters, and the display portion 38 displays the adjusted remaining irradiation time and the latest set of other adjusted irradiation parameters in real time. The display portion 38 also specifically displays which irradiation parameters, in addition to the remaining irradiation time, can be selected according to actual needs. The display portion 38 may display all of the irradiation parameters and may also display a portion of the irradiation parameters. In general, the display portion 38 displays information such as remaining irradiation time, real-time irradiation dose, boron concentration, and the like.

[00118] In the embodiments disclosed in the invention, the calculation portion 35 combines the real-time neutron dose D _r detected by the neutron dose detection device 21 and the preset neutron dose D _total input by the input portion 31 to obtain the adjusted remaining irradiation time t _r by calculation. Here t ₀ is the preset irradiation time, t is the real-time irradiation time detected by the detection system, that is, the realized irradiation time, is the average value of the neutron dose in period t, and P is the percentage of the real-time neutron dose relative to the preset neutron dose. P is calculated using formula (2-1):

[00119]

[00120] When P is less than 97%, the adjusted remaining irradiation time t _r is calculated by Formula (2-2) and Formula (2-3):

[00121]

[00122]

[00123] At this time, the correction portion 37 is required to correct only the preset irradiation time or the corrected remaining irradiation time stored in the storage portion 32.

[00124] When P is greater than or equal to 97%, the correction portion 37 adjusts the neutron dose rate to a first neutron dose rate less than the preset neutron dose rate, and accordingly increases the irradiation time to prevent the patient S from absorbing excess neutrons. The first neutron dose rate is from 1/7 to 1/2 of the preset neutron dose rate. Preferably, the neutron dose rate is adjusted to 1/5 of the preset neutron dose rate I _d , that is, the first neutron dose rate is equal to I _d /5, while the adjusted remaining irradiation time t _r is calculated by formula (2-4):

[00125]

[00126] At this time, the correction part 37 is required to change the remaining irradiation time and the preset neutron dose rate in the storage part 32 to the adjusted remaining irradiation time t _r and the adjusted neutron dose rate, respectively, and the control part 33 carries out the therapy plan in accordance with adjusted irradiation parameters. In other embodiments, the neutron dose rate may be adjusted to other factors such as 1/3, 1/4, 1/6, 1/7, and the like. preset neutron dose rate to prevent the patient S from absorbing excess neutrons when irradiated with a neutron beam with a high neutron dose rate. In addition, the correction part 37 can adjust the neutron dose rate when P is greater than or equal to 90%, or greater than or equal to 95%, or greater than or equal to other ratios, and the specific ratio can be preset according to actual situations. Of course, whether the neutron dose rate needs to be adjusted to a first neutron dose rate less than the preset neutron dose rate can also be determined without the P value calculated by calculation part 35, instead after the condition that the neutron dose rate needs to be adjusted by what - the percentage of the real-time neutron dose to the preset neutron dose based on the preset neutron dose, the threshold value is set manually and input into the storage portion 32 through the storage inlet portion 31. When the real-time detected neutron dose is greater than or equal to the threshold value, the determination part 36 determines that the irradiation parameters need to be adjusted, wherein the correction part 37 is adapted to adjust the neutron dose rate to be a first neutron dose rate less than the preset dose rate neutrons.

[00127] In the above embodiments, when P is less than 97%, the calculation unit 35 calculates the irradiation time required to complete irradiation with a preset neutron dose based on the condition of maintaining a constant neutron dose rate in real time. In other embodiments of the invention, the goal of completing irradiation at a predetermined dose within a predetermined irradiation time is achieved by changing the neutron dose rate or boron concentration while keeping the irradiation time constant. Methods for changing the neutron dose rate include changing the power of the accelerator, changing the thickness of the target layer of the target 112, and the like. The adjusted neutron dose rate _Ir is calculated using formula (2-5):

[00128]

[00129] Since the neutron dose rate is calculated from the neutron flux density through a conversion factor, and the neutron flux density is obtained by integrating the neutron count rate, the adjusted neutron dose rate is equivalent to the corrected neutron flux density and the neutron count rate.

[00130] When implemented, when P is greater than or equal to 97%, to prevent the patient S from absorbing excess neutrons when irradiating a 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 adjusted remaining time t _r of irradiation is calculated using formula (2-4).

[00131] When the actual realized irradiation time reaches the preset irradiation time or when the actual irradiated neutron dose reaches the preset neutron dose, the control part sends a command to the neutron capture therapy device to stop irradiation.

[00132] The monitoring system 3 is provided with a correction portion 37 that corrects the irradiation parameters stored in the storage portion 32 and configured to carry out the therapy plan, so that it is ensured that the neutron dose of the neutron beam irradiating the patient is substantially consistent with the preset neutron dose, and further the accuracy of the neutron dose of the neutron beam irradiating the patient S is increased. In this case, when the percentage of the real-time neutron dose to the preset neutron dose is greater than or equal to 97%, the neutron dose rate is reduced and the irradiation time is correspondingly increased to prevent the patient S from absorbing excess neutrons during irradiation a neutron beam with a high neutron dose rate, which also has the effect of increasing the neutron dose accuracy of the neutron beam irradiating patient S.

[00133] In the above embodiments, it can be determined, according to the real-time neutron dose received by the neutron dose detection device 21, whether adjustment of the preset irradiation parameters is required, and the adjusted irradiation parameters are calculated in accordance with the real-time irradiation parameters and preset irradiation parameters. In other embodiments of the invention, it can be determined, according to the real-time irradiation parameters detected by the temperature detection device 22, the displacement detection device 23, or the boron concentration detection device, whether correction of the preset parameters is required, and the corrected irradiation parameters are calculated in accordance with the irradiation parameters in real time detected by these detection devices. For example, when the boron concentration detecting device detects that the boron concentration in the body of the patient S does not correspond to the preset boron concentration or does not fall within the preset range, the correction part 37 adjusts the remaining irradiation time or adjusts the boron delivery intensity to the patient. In general, it is difficult to adjust the boron concentration in patient S in a short period of time when radiation therapy is nearing the end. At this time, in general, the remaining irradiation time is selected for its correction.

[00134] The accuracy of the neutron beam radiation dose is critical in practical therapy. Excessive doses of radiation can cause potential harm to patient S, and too low doses of radiation can reduce the quality of therapy. Both calculation error in calculating the preset neutron dose and the deviation between the real-time irradiation parameter and the preset irradiation parameter during actual irradiation can cause inaccurate neutron irradiation dosage. Therefore, in addition to irradiation parameters adjusted in real time, the calculation of preset irradiation parameters is also critical during actual irradiation. Thus, a correction system is needed to correct the preset neutron dose to ensure that the neutron dose administered to patient S is more accurate. When adjusting the preset neutron beam dose, the influence of factors such as patient positioning deviation S, real-time neutron dose rate deviation, boron concentration in the patient's body, neutron flux, etc. should be taken into account.

[00135] The correction factors used by the correction system include the neutron correction factor K ₁ and the boron correction factor K ₂ . Here, the neutron correction coefficient K ₁ is related to the positioning correction coefficient K _p and the neutron beam intensity correction coefficient K _i . The boron correction coefficient K ₂ is related to the boron concentration correction coefficient K _b and the boron self-shielding effect correction coefficient K _s .

[00136] A deviation between the real-time neutron dose rate and the preset neutron dose rate can directly result in a deviation in the neutron dose ultimately irradiated to the patient. Therefore, to correct the dose of neutron irradiation, the position correction coefficient K _p and the neutron beam intensity correction coefficient K _i are introduced.

[00137] The self-shielding effect means that with different boron concentrations, the trajectory of the neutron beam irradiating part of the tumor also differs. In particular, the higher the concentration of boron in the body of patient S, the lower the penetrating power of the neutron beam, the shorter the path of the neutron beam irradiated to the tumor, and thus the neutron beam can react with boron in a less deep path. On the contrary, the longer the path of the neutron beam irradiating the tumor, the deeper the path in which the neutron beam can react with boron. Specifically, a first boron concentration value in a patient's body is obtained by a boron concentration detection device, a first neutron beam path irradiating a tumor portion is provided, and a first boron correction factor is obtained by a correction system. A second boron concentration value in the patient's body is obtained using a boron concentration detection device, a second neutron beam path is provided to irradiate a portion of the tumor, and a second boron correction factor is obtained using a correction system. In this case, the first boron concentration value is greater than the second boron concentration value, the first path is less than the second path, and the first boron correction factor is less than the second boron correction factor. Therefore, when calculating the neutron irradiation dose, the influence of the self-shielding effect on the actual irradiation effect of the neutron beam and its irradiation path should be taken into account; to correct the neutron irradiation dose, the boron concentration correction coefficient K _b and the boron self-shielding effect correction coefficient K _s are introduced.

[00138] Specifically, the neutron correction coefficient K ₁ , the positioning correction coefficient K _p and the neutron beam intensity correction coefficient K _i are calculated according to Formula (3-1), Formula (3-2) and Formula (3-3), respectively, the corresponding formulas look as follows.

[00139]

[00140]

[00141]

[00142] where D is the actual therapy dose, that is, the real-time neutron dose D _r measured by the neutron dose detection device 21;

[00143] D ₀ - unadjusted preset neutron dose;

[00144] I is the actual intensity of the neutron beam, that is, the real-time neutron dose rate measured by the neutron dose detection device 21; And

[00145] I ₀ is the theoretical beam intensity, that is, the preset neutron dose rate introduced by the input part 31.

[00146] The boron correction coefficient K ₂ , the boron concentration correction coefficient K _b , and the boron self-protective effect correction coefficient K _s are calculated using formula (3-4), formula (3-5) and formula (3-6), respectively, and the corresponding the formulas look like this.

[00147]

[00148]

[00149]

[00150] where B is the actual boron concentration in the body of patient S, that is, the real-time boron concentration detected by the boron concentration detection device;

[00151] B ₀ is the set value of boron concentration in the therapy plan, that is, the preset boron concentration introduced by the inlet portion 31;

[00152] ϕ _B is the thermal neutron flux in the body of patient S when the boron concentration distribution is B; And

[00153] ϕ _B0 is the flux of thermal neutrons in the body of patient S, when the distribution of boron concentration is equal to B ₀ .

[00154] The uncorrected preset D ₀ neutron dose is calculated using formula (3-7) as follows.

[00155]

[00156] The adjusted preset neutron dose D _total in the therapy plan is calculated using formula (3-8) as follows.

[00157]

[00158] where D _B is the dose at a boron concentration of 1 ppm, has a unit of measurement Gy;

[00159] B _con is the actual measured boron concentration, has a unit of measurement ppm;

[00160] D _f - dose of fast neutrons, has a unit of measurement Gy;

[00161] D _th - dose of thermal neutrons, has a unit of measurement Gy;

[00162] RBE _n is the relative biological effectiveness (RBE) of the neutron;

[00163] D _r - dose of gamma radiation, has a unit of measurement Gy; And

[00164] RBE _r - RBE of gamma radiation.

[00165] During actual therapy, the correction system adjusts the preset neutron dose in the preset therapy plan to prevent an inaccurate neutron dose from being applied to patient S.

[00166] The correction system comprehensively takes into account the influence of factors such as patient positioning deviation S, real-time neutron dose rate deviation, real-time boron concentration, and the like. to the preset neutron dose, and introduces a neutron correction factor K ₁ and a boron correction factor K ₂ to correct the preset neutron dose, so that the accuracy of the neutron dose emitted to the patient S from the source is ensured.

[00167] During the actual therapy, after the input portion 31 completes inputting the preset irradiation parameters, the operator starts the neutron capture therapy device to conduct radiation therapy. After irradiation starts, the input function of the input portion 31 is locked and the corresponding irradiation parameters cannot be entered again, thus it can be ensured that the situation where incorrect parameters and commands are entered due to accidental touch or operating error in irradiation can be prevented. However, when the therapy process is somewhat inconsistent with the ideal state, irradiation may be stopped or continued according to the abnormal state, and parameters may not be adjusted in time or commands may not be changed in time during irradiation. However, when the operating interface is simply set to real-time operation, irradiation parameters and control commands can still be inputted by the input portion 31 after irradiation starts, thus it can be ensured that the correct irradiation parameters and commands can be input in real time during irradiation. However, there is still a risk that the irradiation result is affected by entering incorrect parameters and commands or re-entering operation commands due to an erroneous operation during irradiation.

[00168] As shown in FIG. 7, the neutron capture therapy device is equipped with a control interface. The control interface consists of the above input part 31, a display part 38, a button 51 to confirm the accuracy of the information, a button 52 to start irradiation, a button 53 to pause irradiation, a button 54 to cancel irradiation, and a button 55 to generate a report. The operator activates the error-free information confirmation button 51 to transmit a signal to the monitoring system 3 that all information has been confirmed as error-free. After the monitoring system 3 receives a signal that all information has been confirmed as error-free, a necessary condition is met to start the neutron capture therapy device for irradiation with a neutron beam. After the monitoring system 3 receives a signal that all information has been confirmed as error-free, the irradiation start button 52 is activated and a sufficient condition is satisfied to start the neutron capture therapy device for irradiation with a neutron beam. After starting the neutron capture therapy device, irradiation with a neutron beam can be paused by the irradiation pause button 53, while irradiation with the neutron beam can be canceled by the irradiation cancel button 54. After completion of the irradiation, the report generation button 55 may be activated to automatically generate a report related to radiation therapy. When neutron beam irradiation is suspended, this means that all irradiation parameters and commands remain unchanged. When the irradiation start button 52 is activated again, neutron beam irradiation is performed with the original irradiation parameters and commands. When neutron beam exposure is canceled, this means that all exposure parameters and commands are cleared. When neutron beam irradiation is performed again, the irradiation parameters and commands must be entered again, and the information accuracy confirmation button 51 and the irradiation start button 52 are sequentially activated.

[00169] The malfunction prevention system comprehensively considers the two factors of performance and safety, and is provided with a secondary confirmation part and a protection part to ensure safe and accurate irradiation while the system is not deprived of real-time performance. Before the operator activates the secondary confirmation portion to signal to the neutron capture therapy device that all information has been confirmed as error-free, the neutron capture therapy device cannot be started to execute the radiation therapy plan, that is, the irradiation start button 52 cannot be activated. During the launch of the protective part, the input part 31, which can change and enter parameters and irradiation commands, and the report generation button 55 are blocked.

[00170] In embodiments of the invention, the secondary confirmation part is a confirmation button 51 on the control interface. Before the physician runs the program to execute the therapy plan, the relevant information must be confirmed twice. After the operator confirms that the input is error-free and presses the error-free information confirmation button 51 to input commands into the monitoring system 3 that the information is confirmed as error-free, the device can be started to execute the therapy plan, thereby reducing the risk of erroneously entering incorrect control commands from -for an erroneous operation. For example, before performing radiation therapy on patient S, the doctor must check the patient's information (such as name, gender, age, etc.), radiation parameters (such as radiation dose, collimator number, etc.), or the like. . After checking that all information is correct, the irradiation start function can only be activated by pressing the information accuracy confirmation button 51 on the control interface. Otherwise, even if the doctor presses the irradiation start button 52, the device refuses to start irradiation with a neutron beam and gives a prompt that the information is not confirmed.

[00171] In embodiments of the invention, the protective part is the irradiation start button 52. After the irradiation start button 52 starts the therapy plan, the input function of the input portion 31 is blocked and no information can be entered. In particular, before radiation therapy, the corresponding irradiation commands and parameters are input by means of the input portion 31. After entering the corresponding irradiation parameters and commands into the monitoring system 3, the operator checks the correctness of the corresponding irradiation parameters and commands. After confirming that the corresponding irradiation parameters and commands are correct, the operator activates the error-free information confirmation button 51, after which the input part 31 can be locked, and the corresponding irradiation parameters and commands cannot be changed or added through the input part 31 to prevent incorrect input . The corresponding irradiation parameters and commands can only be entered again after the input portion 31 is unlocked. In embodiments of the invention, after pressing the irradiation pause button 53 or the irradiation cancel button 54, the radiation therapy is stopped. At the same time, the input portion 31 configured to input the corresponding information is unlocked, after which the corresponding information can be changed or added by the input portion 31. Of course, the entrance part can be automatically unlocked after completion of radiation therapy. This prevents incorrect input while maintaining system functionality. For example, after checking that the patient information S, irradiation parameters and other information are correct, the medical personnel presses the information accuracy confirmation button 51 on the control interface, and then presses the irradiation start button 52. The system then begins radiation therapy. At this time, the input portion 31 configured to input relevant information is blocked, and information input cannot be performed.

[00172] Until the completion of radiation therapy, the report generation button 55 is also locked, and the report generation button 55 can be automatically unlocked only after the completion of radiation therapy, that is, the therapy report generation function can be turned on.

[00173] The protective part is not limited to application to the irradiation start button 52 as in the above embodiment, but is also applicable to other important buttons and parameter input windows. In addition, the means for implementing the secondary confirmation and protection of the button may be software or hardware, for example, the security part may also be a key or switch on the control panel. Before turning on the key or switch, some operations may not be performed, and the corresponding operations can only be performed when the key or switch is turned on.

[00174] In embodiments of the invention, commands and radiation parameters are entered via a touch screen. In other embodiments, a key (eg, a mechanical key) may be used for entry.

[00175] The incorrect operation prevention system can not only provide functions for setting parameters and inputting control commands if necessary, but also reduce the incorrect input of parameters or repeated input of commands due to operation error or other reasons, which reduces the risk in the operation of the device.

[00176] In the neutron capture therapy device according to the invention, the neutron dose detection device 21 is provided with at least two count rate channels with different neutron detection sensitivities, that is, a first count rate channel 201 and a second count rate channel 202, and a count rate channel selection unit 216, which selects a more accurate count rate according to the actual situation to calculate the neutron dose, so that the count rate loss error caused by the pulse resolution time can be avoided. In this case, the statistical error due to the low count rate is taken into account, so that the accuracy of real-time neutron dose detection is increased, thereby increasing the neutron dose accuracy of the neutron beam irradiating patient S. In addition, the neutron dose detection device 21 is also equipped with a count rate correction unit 217 , which can calculate the pulse resolution time of the detector 211 and can calculate the count rate correction factor according to the pulse resolution time, so that the count rate error caused by the pulse resolution time is corrected, the real-time neutron dose detection accuracy is further improved, and the beam dose accuracy is further improved neutrons irradiating patient S.

[00177] The neutron capture therapy device according to the invention is also provided with a monitoring system 3. The monitoring system 3 is provided with a correction portion 37, which periodically corrects the irradiation parameters stored in the storage portion 32 and configured to carry out the therapy plan, so that the neutron dose of the neutron beam irradiating the patient S is ensured to be substantially consistent with the preset neutron dose, and the accuracy the neutron dose of the neutron beam irradiating patient S is further increased. In addition, when the percentage of the real-time neutron dose to the preset neutron dose is greater than or equal to 97%, the neutron dose rate is reduced and the irradiation time is correspondingly increased to prevent the patient S from absorbing excess neutrons when irradiated with a neutron beam with a high neutron dose rate, which also has the effect of increasing the accuracy of the neutron dose of the neutron beam irradiating patient S.

[00178] The neutron capture therapy device according to the invention is also provided with a correction system. The correction system comprehensively takes into account the influence of factors such as patient positioning deviation S, real-time neutron dose rate deviation, real-time boron concentration or the like on the preset neutron dose, and introduces the neutron correction coefficient K ₁ and the boron correction coefficient K ₂ to correct a predetermined neutron dose such that the source provides an accurate neutron dose to the neutron beam irradiating patient S.

[00179] Finally, the neutron capture therapy device of the invention can apply a precise dose of neutron beam radiation to a patient and reduce the risk caused by erroneous operation of the device while ensuring the operability of the device.

[00180] The neutron capture therapy device according to the invention is not limited to the solution described above in terms of embodiments and the structures shown in the drawings. Obvious changes, substitutions or modifications of materials, shapes and positions of components therein based on the invention are included within the scope of legal protection of the invention.

Claims (21)

1. A neutron capture therapy device configured to irradiate a body to be irradiated with a neutron beam with a predetermined dose of neutrons, wherein the neutron beam enters the body to be irradiated and undergoes a nuclear reaction with boron in the body to be irradiated, and the neutron capture therapy device contains a correction system configured to correction of the preset neutron dose; wherein the correction coefficients used by the correction system contain the correction coefficient K _s for the boron self-shielding effect, calculated using formula (3-6): where ϕ _B is the thermal neutron flux in the body to be irradiated when the boron concentration distribution is equal to B, and ϕ _B0 is the thermal neutron flux in the body to be irradiated when the boron concentration distribution is equal to B ₀ . 2. The neutron capture therapy device according to claim 1, wherein the correction system adjusts the preset neutron dose in accordance with the real-time boron concentration and the neutron flux in the body to be irradiated. 3. The neutron capture therapy device according to claim 1, further comprising a detection system, which contains a neutron dose detection device configured to detect the neutron beam dose in real time, and a boron concentration detection device configured to detect the boron concentration in the body to be irradiated. 4. The neutron capture therapy device according to claim 1, in which the correction coefficients additionally contain a positioning correction coefficient K _p , calculated using formula (3-2): where D is the real-time neutron dose measured by the neutron dose detection device, and D ₀ is the uncorrected preset neutron dose. 5. The neutron capture therapy device according to claim 4, in which the correction coefficients additionally contain a neutron beam intensity correction coefficient K _i , calculated using formula (3-3): where I is the real-time neutron dose rate measured by the neutron dose detection device, and I ₀ is the theoretical beam intensity. 6. The neutron capture therapy device according to claim 5, in which the correction coefficients additionally contain a boron concentration correction coefficient K _b , calculated using formula (3-5): where B is the real-time boron concentration detected by the boron concentration detection device, and B ₀ is the set value of boron concentration in the therapy plan. 7. The neutron capture therapy device according to claim 6, in which the correction coefficients comprise a neutron correction coefficient K ₁ and a boron correction coefficient K ₂ calculated using formula (3-1) and formula (3-4), respectively: 8. The neutron capture therapy device according to claim 7, wherein the adjusted preset neutron dose D _total is calculated using formula (3-8) as follows: where D _B is the dose at a boron concentration of 1 ppm, has the unit of measurement Gr, B _con is the actual measured concentration of boron, has the unit of ppm, D _f is the dose of fast neutrons, has the unit of Gr, D _th is the dose of thermal neutrons, has the unit measurements of Gy, RBE _n is the relative biological effectiveness (RBE) of a neutron, D _r is the dose of gamma radiation, has a unit of measurement of Gy, and RBE _r is the RBE of gamma radiation. 9. The neutron capture therapy device according to claim 1, wherein the first value of boron concentration in the body to be irradiated is obtained using a boron concentration detection device, and the first correction factor for the boron self-shielding effect is obtained using a correction system; a second boron concentration value in the body to be irradiated is obtained using a boron concentration detection device, and a second boron self-shielding effect correction coefficient is obtained using a correction system, wherein the first boron concentration value is greater than the second boron concentration value, and the first boron self-shielding effect correction coefficient is smaller, than the second correction factor for the boron self-shielding effect.

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