Neutron capture therapy equipment and method for using irradiation parameter selection device

Abstract

A method for using a neutron capture therapy device and an irradiation parameter selection device, wherein the neutron capture therapy device comprises: a neutron beam generating component, an irradiation chamber for irradiating a neutron beam to an irradiated body, a management chamber for implementing irradiation control, a platform for placing a patient, and a control system for controlling and managing the treatment process, wherein the control system comprises an irradiation parameter selection device for selecting an optimal irradiation point and irradiation angle, wherein the irradiation parameter selection device comprises a sampling unit and a calculation unit, wherein the sampling unit selects multiple groups of irradiation points and irradiation angles, and the calculation unit calculates an evaluation value corresponding to each group of irradiation points and irradiation angles and outputs a report.

Description

Technical Field

[0001] The present invention relates to a method for using a radiation therapy device and a parameter selection device, and in particular to a method for using a neutron capture therapy device and an irradiation parameter selection device. Background Art

[0002] With the development of atomic science, radiation therapy such as cobalt-60, linear accelerator, and electron beam has become one of the main means of cancer treatment. However, traditional photon or electron therapy is limited by the physical conditions of radiation itself. While killing tumor cells, it will also cause damage to a large number of normal tissues along the beam path. In addition, due to the different sensitivity of tumor cells to radiation, traditional radiotherapy is often not effective in treating malignant tumors that are more resistant to radiation (such as glioblastoma multiforme and melanoma).

[0003] In order to reduce radiation damage to normal tissues around tumors, the concept of targeted therapy in chemotherapy has been applied to radiotherapy; and for tumor cells with high radiation resistance, radiation sources with high relative biological effectiveness (RBE) are also being actively developed, such as proton therapy, heavy particle therapy, neutron capture therapy, etc. Among them, neutron capture therapy is a combination of the above two concepts, such as Boron Neutron Capture Therapy (BNCT), which provides a better cancer treatment option than traditional radiation by specifically aggregating boron-containing drugs in tumor cells and combining precise beam control.

[0004] Boron neutron capture therapy is the use of boron ( 10 B) The drug has a high capture cross section for thermal neutrons, and is produced by 10B(n,α)7Li neutron capture and nuclear fission reaction 4 He and 7 Li has two heavily charged particles, and the total range of the two particles is approximately equivalent to the size of a cell. Therefore, the radiation damage caused to the organism can be limited to the cellular level. When boron-containing drugs selectively accumulate in tumor cells and are combined with appropriate neutron radiation sources, the purpose of locally killing tumor cells can be achieved without causing too much damage to normal tissues.

[0005] In the existing neutron capture therapy planning system, the irradiation geometry angles are all manually judged and defined based on experience. Since the human body structure is quite complex and the sensitivity of various tissues or organs to radiation is also very different, it is very likely that the better irradiation angles will be ignored if it is based solely on manual judgment, which will greatly reduce the treatment effect.

[0006] Therefore, it is necessary to propose a method for using a neutron capture therapy device and an irradiation parameter selection device that can be used to determine the quality of irradiation points and irradiation angles. Summary of the invention

[0007] In order to overcome the defects of the prior art, the inventor provides a method for using a neutron capture therapy device and an irradiation parameter selection device that can be used to judge the quality of irradiation points and irradiation angles.

[0008] The present application provides a neutron capture therapy device, which is characterized in that it includes: a neutron beam generating component, an irradiation chamber for irradiating a neutron beam to an irradiated body, a management room for implementing irradiation control, a placing table for placing a patient, and a control system for controlling and managing the treatment process, wherein the control system includes an irradiation parameter selection device for selecting the best irradiation point and irradiation angle, the irradiation parameter selection device includes a sampling unit and a calculation unit, the sampling unit selects multiple groups of irradiation points and irradiation angles, and the calculation unit calculates the evaluation value corresponding to each group of irradiation points and irradiation angles and outputs a report.

[0009] Furthermore, the calculation unit calculates the depth of the neutron beam entering the patient and the type of the organ passed by, and then determines whether the tumor falls within the maximum treatable depth range corresponding to the group of irradiation points and irradiation angles based on the track information of the neutron beam passing through the human body. If so, the evaluation value corresponding to the group of irradiation points and irradiation angles is calculated based on the track information and the data such as the organ boron concentration, organ radiation sensitivity factor and neutron beam characteristic information set by the user; if not, the worst evaluation value is given.

[0010] Furthermore, the calculation unit outputs the data of the irradiation point and the irradiation angle and their corresponding evaluation values ​​in the form of a 3D or 2D image.

[0011] Furthermore, corresponding to a certain irradiation point and irradiation angle and a certain irradiation path, the weight factor (W(i)) of organ i is calculated using Formula 1:

[0012] W(i)=I(i)×S(i)×C(i) (Formula 1)

[0013] where I(i), S(i) and C(i) are the neutron intensity, the radiation sensitivity factor of organ i and the boron concentration of organ i, respectively.

[0014] Furthermore, I(i) is calculated using Formula 2 which is an integral of the depth intensity or dose curve of the human body simulated by the used beam:

[0015]

[0016] Where i(x) is the depth intensity or dose curve function of the therapeutic beam in the approximate human body, and x0-x is the depth range of the organ (i) in the beam track.

[0017] Furthermore, the evaluation factor is calculated using Formula 3:

[0018]

[0019] Among them, Q(x, y, z, Φ, θ) as an evaluation factor is equal to the sum of the weight factors of each organ in the organ trajectory.

[0020] Furthermore, the ratio of the evaluation factor to the tumor evaluation factor (QR(x, y, z, Φ, θ)) is calculated using Formula 4:

[0021]

[0022] Among them, W(tumor) is the weight factor of the tumor.

[0023] The present application also provides a method for using the above-mentioned irradiation parameter selection device, which includes the following steps: the sampling part reads the patient's CT / MRI / PET-CT and other images with clear human anatomy, defines the contours of each organ, tissue and tumor one by one, and sets the material type and density. After completing the definition of the contour, material and density, the irradiation point and irradiation angle of the neutron beam are selected; the calculation part calculates the track of the organ through which the neutron beam passes, that is, calculates the type and thickness of the organ passed by the neutron beam after entering the human body. After obtaining the track information of the neutron beam passing through the human body, it is determined whether the tumor falls within the maximum treatable depth range. If so, based on this track information, combined with the user-set organ boron concentration, organ radiation sensitivity factor and neutron beam characteristics and other information, the evaluation value corresponding to the irradiation point and irradiation angle is calculated; if not, the worst evaluation value is given. After completing the calculation of the evaluation value, the irradiation point, irradiation angle and corresponding evaluation value are recorded.

[0024] Furthermore, the selection of the irradiation point and the irradiation angle can be forward selection or reverse selection. Forward selection is to determine the irradiation point at a position outside the human body and can be sampled in sequence according to a fixed angle or distance interval, or by random sampling. Reverse selection is to determine the irradiation point within the tumor range, and the irradiation point can be the tumor centroid or the deepest point, and the irradiation angle can be sampled randomly or at a predetermined interval angle. The neutron beam angle can be set to the vector direction from the irradiation point to the tumor centroid or the deepest point of the tumor.

[0025] Furthermore, the calculation unit outputs the data of the irradiation point and the irradiation angle and their corresponding evaluation values ​​in the form of a 3D or 2D image. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the boron neutron capture reaction.

[0027] Figure 2 yes 10 B(n,α) 7 Li neutron capture nuclear reaction equation.

[0028] Figure 3 Schematic diagram of a neutron capture therapy device in an embodiment of the present invention.

[0029] Figure 4 Schematic diagram of a control system in an embodiment of the present invention.

[0030] Figure 5 This is a logic block diagram of calculation of evaluation values ​​of neutron beam irradiation parameters in an embodiment of the present invention.

[0031] Figure 6 Schematic diagram of organ tracks during neutron beam irradiation in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0033] Neutron capture therapy has been increasingly used in recent years as an effective means of treating cancer. Among them, boron neutron capture therapy is the most common. Neutrons for boron neutron capture therapy can be supplied by nuclear reactors or accelerators. Boron neutron capture therapy (BNCT) is a method of using boron-containing 10 B) The drug has a high capture cross section for thermal neutrons. 10 B(n,α) 7 Li neutron capture and nuclear fission reaction production 4 He and 7 Li two heavily charged particles. Figure 1 and Figure 2 , which respectively show the schematic diagram of the boron neutron capture reaction and 10 B(n,α) 7 Li neutron capture nuclear reaction equation, the average energy of the two heavily charged particles is about 2.33MeV, with the characteristics of high linear energy transfer (LET) and short range. The linear energy and range of alpha particles are 150keV / μm and 8μm respectively, while 7The Li heavy-charge particles are 175keV / μm and 5μm, and the total range of the two particles is approximately equivalent to the size of a cell, so the radiation damage to the organism can be limited to the cellular level. When boron-containing drugs selectively accumulate in tumor cells, combined with an appropriate neutron source, they can achieve the purpose of accurately killing tumor cells without causing too much damage to normal tissues.

[0034] Regardless of whether the neutron source of BNC therapy comes from a nuclear reactor or a nuclear reaction between charged particles and a target material, a mixed radiation field is generated, that is, the beam contains neutrons and photons ranging from low energy to high energy; for BNC therapy of deep tumors, in addition to epithermal neutrons, the more radiation content there is, the greater the proportion of non-selective dose deposition in normal tissues, so these radiations that cause unnecessary dose deposition should be reduced as much as possible. In order to better understand the dose distribution of neutrons in the human body, in addition to the air beam quality factor, the embodiment of the present invention uses a human head tissue prosthesis to calculate the dose distribution, and uses the prosthesis beam quality factor as a reference for the design of the neutron beam.

[0035] The International Atomic Energy Agency (IAEA) has given five recommendations for air beam quality factors for neutron sources used in clinical boron neutron capture therapy. These five recommendations can be used to compare the advantages and disadvantages of different neutron sources and serve as a reference for selecting neutron production methods and designing beam shapers. The five recommendations are as follows:

[0036] Epithermal neutron flux>1x 10 9 n / cm 2 s

[0037] Fast neutron contamination <2x 10 -13 Gy-cm 2 / n

[0038] Photon contamination<2x 10 -13 Gy-cm 2 / n

[0039] Thermal to epithermal neutron flux ratio <0.05

[0040] Epithermal neutron current to flux ratio>0.7

[0041] Note: The epithermal neutron energy range is between 0.5eV and 40keV, the thermal neutron energy range is less than 0.5eV, and the fast neutron energy range is greater than 40keV.

[0042] 1. Epithermal neutron beam flux:

[0043] The neutron beam flux and the concentration of boron-containing drugs in the tumor jointly determine the clinical treatment time. If the concentration of boron-containing drugs in the tumor is high enough, the requirement for neutron beam flux can be reduced; conversely, if the concentration of boron-containing drugs in the tumor is low, high-flux epithermal neutrons are required to give the tumor a sufficient dose. The IAEA requirement for epithermal neutron beam flux is more than 10 epithermal neutrons per square centimeter per second. 9 For current boron-containing drugs, neutron beams at this flux can roughly control the treatment time to within one hour. In addition to the advantages of patient positioning and comfort, the short treatment time can also more effectively utilize the limited residence time of boron-containing drugs in the tumor.

[0044] 2. Fast neutron contamination:

[0045] Since fast neutrons can cause unnecessary normal tissue doses, they are considered contamination. The dose is positively correlated with the neutron energy, so the content of fast neutrons should be minimized in neutron beam design. Fast neutron contamination is defined as the fast neutron dose associated with a unit epithermal neutron flux. The IAEA recommends that fast neutron contamination be less than 2x 10 -13 Gy-cm 2 / n.

[0046] 3. Photon pollution (gamma ray pollution):

[0047] Gamma rays are highly penetrating radiation and will non-selectively cause dose deposition in all tissues along the neutron beam path. Therefore, reducing the gamma ray content is also a necessary requirement for beam design. Gamma ray contamination is defined as the gamma ray dose associated with a unit epithermal neutron flux. The IAEA recommends that gamma ray contamination be less than 2x 10 -13 Gy-cm 2 / n.

[0048] 4. Ratio of thermal neutron to epithermal neutron flux:

[0049] Since thermal neutrons decay quickly and have poor penetration, most of their energy is deposited in the skin tissue after entering the human body. In addition to epidermal tumors such as melanocytoma, which require thermal neutrons as the neutron source for boron neutron capture therapy, the thermal neutron content should be reduced for deep tumors such as brain tumors. The IAEA recommends that the ratio of thermal neutrons to epithermal neutrons be less than 0.05.

[0050] 5. Neutron current and flux ratio:

[0051] The ratio of neutron current to flux represents the directionality of the beam. The larger the ratio, the better the forward direction of the beam. A highly forward-directed neutron beam can reduce the dose to surrounding normal tissues caused by neutron divergence, and also increase the treatment depth and positioning flexibility. The IAEA recommends that the ratio of neutron current to flux be greater than 0.7.

[0052] The prosthesis is used to obtain the dose distribution in the tissue, and the prosthesis beam quality factor is derived based on the dose-depth curve of normal tissue and tumor. The following three parameters can be used to compare the therapeutic benefits of different neutron beams.

[0053] 1. Effective treatment depth:

[0054] The depth at which the tumor dose is equal to the maximum dose of normal tissue. After this depth, the dose received by the tumor cells is less than the maximum dose of normal tissue, which means that the advantage of boron neutron capture is lost. This parameter represents the penetration ability of the beam. The greater the effective treatment depth, the deeper the depth of the tumor that can be treated. The unit is cm.

[0055] 2. Effective treatment depth dose rate:

[0056] That is, the tumor dose rate at the effective treatment depth is equal to the maximum dose rate of normal tissue. Because the total dose received by normal tissue is a factor that affects the total dose that can be given to the tumor, the parameter affects the length of treatment time. The larger the effective treatment depth dose rate, the shorter the irradiation time required to give a certain dose to the tumor. The unit is cGy / mA-min.

[0057] 3. Effective therapeutic dose ratio:

[0058] The ratio of the average dose received by the tumor and normal tissue from the brain surface to the effective treatment depth is called the effective treatment dose ratio. The average dose can be calculated by integrating the dose-depth curve. The larger the effective treatment dose ratio, the better the treatment effect of the beam.

[0059] In order to provide a comparative basis for the design of the beam shaper, in addition to the five IAEA-recommended beam quality factors in air and the above three parameters, the present invention also uses the following parameters for evaluating the performance of the beam dose:

[0060] 1. Irradiation time ≤ 30 min (the proton current used by the accelerator is 10 mA)

[0061] 2. 30.0RBE-Gy can treat a depth of ≥7cm

[0062] 3. Maximum tumor dose ≥ 60.0 RBE-Gy

[0063] 4. Maximum dose to normal brain tissue ≤ 12.5 RBE-Gy

[0064] 5. Maximum skin dose ≤ 11.0 RBE-Gy

[0065] Note: RBE (Relative Biological Effectiveness) is the relative biological effect. Since photons and neutrons have different biological effects, the dose items above are multiplied by the relative biological effects of different tissues to obtain the equivalent dose.

[0066] like Figure 3 As shown, the neutron capture therapy device 100 for implementing neutron capture therapy comprises a neutron beam generating component 1, an irradiation chamber 2 for irradiating a neutron beam to an irradiated body, such as a patient, a preparation room 3 for performing pre-irradiation preparations, a communication room 4 connecting the irradiation room 2 and the preparation room 3, a management room 5 for implementing irradiation control, a positioning device for positioning a patient (not shown), a carrying table 6 for carrying a patient and moving within the preparation room 3 and the irradiation room 2, and a control system 7 for controlling and managing the treatment process.

[0067] The neutron beam generating assembly 1 is configured to generate a neutron beam outside the irradiation room 2 and to irradiate the neutron beam to the patient placed in the irradiation room 2. A collimator 20 is provided in the irradiation room 2. The preparation room 3 is a room used to carry out the preparation work required before irradiating the patient with a neutron beam. A simulated collimator 30 is provided in the preparation room 3. The preparation work includes fixing the patient on the stage 6, positioning the patient's tumor and making three-dimensional positioning marks, etc. The management room 5 is a room used to manage and control the overall treatment process implemented by the boron neutron capture therapy device 100. For example, the management personnel can visually confirm the status of the preparation work in the preparation room 3 from the management room 5, and the management personnel can operate the control system 7 to control the start and stop of the neutron beam irradiation, the position adjustment of the stage 6, etc. The stage 6 is used to carry the patient to perform rotation, translation and lifting movements together. The control system 7 is just a general term here. It can be a general control system, that is, the start and stop of neutron beam irradiation, the position adjustment of the mounting table 6, etc. are all controlled by one system, or it can be multiple control systems, that is, the start and stop of neutron beam irradiation, the position adjustment of the mounting table 6, etc. are respectively controlled by one control system.

[0068] Ginseng Figure 4As shown, before performing boron neutron capture therapy, the management personnel need to clarify at what angle the neutron beam irradiates the patient to kill tumor cells to the maximum extent and reduce the damage of radiation to surrounding normal tissues as much as possible, and adjust the platform 6 carrying the patient to the corresponding position after determining the optimal irradiation point and irradiation angle. Specifically, the control system 7 includes an irradiation parameter selection device 71 for selecting the optimal irradiation point and irradiation angle, a conversion unit 72 for converting the optimal irradiation parameters into coordinate parameters of the platform 6, an adjustment unit 73 for adjusting the platform 6 to a predetermined position, and a start-stop unit 74 for controlling the start and stop of neutron beam irradiation.

[0069] Continue to participate Figure 4 As shown, each group of irradiation parameters includes the irradiation point and irradiation angle of the neutron beam, and the irradiation parameter selection device 71 includes a sampling unit 711, a calculation unit 712 and a selection unit 713. First, the sampling unit 711 selects multiple groups of irradiation points and irradiation angles. Next, the calculation unit 712 calculates the evaluation value corresponding to each group of irradiation points and irradiation angles. Then, the selection unit 713 selects a group of optimal feasible irradiation parameters from all sampled irradiation points and irradiation angles according to the evaluation value calculated by the calculation unit 712. Specifically, the selection unit 713 eliminates irradiation parameters that are not feasible in the actual treatment process and selects a group of optimal feasible irradiation parameters. The sampling unit 711 may select the irradiation point and irradiation angle randomly or regularly. The calculation of the evaluation value is to calculate the organ track through which the neutron beam passes, that is, the calculation unit 712 calculates the depth of the neutron beam after entering the human body and the type of organ passed through, and then determines whether the tumor falls within the maximum treatable depth range corresponding to the group of irradiation parameters based on the track information of the neutron beam passing through the human body. If so, the evaluation value corresponding to the group of irradiation points and irradiation angles is calculated based on this track information and in combination with the boron concentration of the organ, the radiation sensitivity factor of the organ, and the neutron beam characteristic information set by the user; if not, the irradiation point and irradiation angle are given a worst evaluation value, and the irradiation point and irradiation angle of the neutron beam are sampled and calculated again. After the evaluation values ​​corresponding to several groups of irradiation points and irradiation angles are calculated, the advantages and disadvantages of each group of irradiation points and irradiation angles can be intuitively ranked according to the evaluation values. Since the position of the collimator 20 is fixed and the irradiation room 2 is also provided with a positioning device and other equipment, some patient positions cannot be achieved and some movement positions of the treatment bed are interfered with. In addition, some parts of the patient, such as the eyes and other organs, cannot be irradiated. Therefore, some irradiation points and irradiation angles cannot be irradiated. In the actual treatment process, the selection unit 713 needs to eliminate these irradiation points and irradiation angles that cannot be implemented.

[0070] Combination Figure 5 , Figure 6As shown, the following is a detailed description of the method for using the irradiation parameter selection device 71. The method includes the following steps: the sampling unit 711 reads the patient's CT / MRI / PET-CT and other images with clear human anatomy, defines the contours of each organ, tissue and tumor one by one, and sets the material type and density. After the definition of the contour, material and density is completed, the irradiation point and irradiation angle of the neutron beam are selected. The selection of the irradiation point and the irradiation angle can be forward selection or reverse selection. Forward selection is to determine the irradiation point at a position outside the human body and can be sampled in sequence according to a fixed angle or distance interval, or sampling can be performed by random sampling; the neutron beam angle can be set to the vector direction from the irradiation point to the tumor mass center or the deepest part of the tumor; reverse selection is to determine the irradiation point within the tumor range, and the irradiation point can be the tumor mass center or the deepest part, and the irradiation point can be selected by the reverse selection. The beam angle can be sampled randomly or at a predetermined interval angle. After determining the irradiation point and irradiation angle of the neutron beam, the calculation unit 712 calculates the path of the organ through which the neutron beam passes, that is, calculates the type and thickness of the organ through which the neutron beam passes after entering the human body. After obtaining the path information of the neutron beam passing through the human body, it is determined whether the tumor falls within the maximum treatable depth range. If so, based on this path information, combined with the boron concentration of the organ, the radiation sensitivity factor of the organ, and the neutron beam characteristics set by the user, the evaluation value corresponding to the irradiation point and irradiation angle is calculated and returned to sample the irradiation point and irradiation angle of the beam. If not, the worst evaluation value is given, and the irradiation point and irradiation angle of the neutron beam are sampled again. After completing the calculation of the evaluation value, the irradiation point, irradiation angle and the corresponding evaluation value are recorded. After repeating the above sampling and calculation for a certain number of times, a report is output; the optimal selection unit 713 selects a set of optimal and implementable irradiation parameters from all sampled irradiation parameters. The calculation unit 712 can output the data of the irradiation point and irradiation angle and their corresponding evaluation values ​​in the form of 3D or 2D images. In this case, the doctor or physiotherapist can more intuitively judge the pros and cons of the irradiation point and irradiation angle.

[0071] Preferably, after the optimization unit 713 ranks each group of irradiation points and irradiation angles by their quality, it verifies in order from the best to the worst whether each group of irradiation points and irradiation angles is feasible, until a group of optimal irradiation points and irradiation angles that can be implemented is found. Of course, the optimization unit 713 can also find out all the irradiation points and irradiation angles that are not feasible after calculating the evaluation value, and then eliminate these irradiation points and irradiation angles that are not feasible, and finally select the optimal group of irradiation points and irradiation angles from the remaining irradiation points and irradiation angles to implement neutron capture therapy; the optimization unit 713 can also exclude the irradiation points and irradiation angles that are not feasible before calculating the evaluation value, and then after the calculation is completed, the optimal group of irradiation points and irradiation angles can be selected for neutron capture therapy.

[0072] The optimization process can be performed completely automatically by relevant equipment, or it can be partially performed manually, or it can be performed completely manually, that is, no optimization unit 713 is set. For example, unfeasible irradiation points and irradiation angles can be listed by experienced doctors, or they can be determined by simulation of relevant equipment. The same is true for the ranking of evaluation values ​​and the selection of the optimal irradiation points and irradiation angles after excluding unfeasible irradiation points and irradiation angles.

[0073] After obtaining the optimal irradiation point and irradiation angle that can be implemented, the conversion unit 72 converts the parameters of the irradiation point and irradiation angle into coordinate parameters that the platform 6 needs to move to during the irradiation process in combination with the patient's CT / MRI / PET-CT information, positioning information, and structural information of the platform 6, and then the adjustment unit 73 adjusts the platform 6 to a predetermined position according to the coordinate information obtained from the conversion unit 72. After the platform 6 is adjusted to the predetermined position, the positioning device further confirms whether the irradiation point and irradiation angle of the neutron beam relative to the patient's tumor correspond to the pre-selected optimal irradiation point and irradiation angle that can be implemented. If not, the patient's positioning or the position of the platform 6 is manually adjusted to ensure that the neutron beam irradiates the patient's tumor at the optimal irradiation point and irradiation angle, or the adjustment unit 73 is driven to adjust the position of the platform 6 to ensure that the neutron beam irradiates the patient's tumor at the optimal irradiation point and irradiation angle.

[0074] In order to prevent the radiation in the irradiation room 2 from being scattered outside the irradiation room 2, a first shielding door 21 is provided between the irradiation room 2 and the communication room 4, and a second shielding door 31 is provided between the communication room 4 and the preparation room 3. In other embodiments, a shielding wall with a maze can be used to replace the first shielding door 21 and the second shielding door 31, and the shape of the maze includes but is not limited to a "Z" shape, a "bow" shape, and a "H" shape.

[0075] The following is a detailed description of a specific embodiment of the calculation unit 712 calculating the evaluation value. Of course, it is not limited to this embodiment, and other methods and public expressions can also be used to calculate the evaluation value. The evaluation value is calculated based on the neutron beam characteristics, the radiation sensitivity factor of the organ and the boron concentration of the organ. The weight factor (W(i)) of the organ i corresponding to a certain irradiation point, irradiation angle and a certain irradiation track is calculated as shown in Formula 1, where I(i), S(i) and C(i) are the neutron intensity, the radiation sensitivity factor of the organ i and the boron concentration of the organ i, respectively.

[0076] W(i)=I(i)×S(i)×C(i) (Formula 1)

[0077] Among them, I(i) is obtained by integrating the depth intensity or dose curve of the neutron beam used in the simulated human body, as shown in Formula 2, where i(x) is the depth intensity or dose curve function of the therapeutic neutron beam in the approximate human body, and x0-x is the depth range of organ i in the neutron beam track.

[0078]

[0079] By using the above algorithm, after the weight factors of each organ in the organ track are calculated in sequence and summed up, the evaluation value corresponding to the neutron beam can be obtained, as shown in Formula 3. In this calculation, the weight factor of the tumor should not be included in the calculation.

[0080]

[0081] According to the above evaluation values, the degree of harm to normal tissue during treatment can be judged more intuitively. In addition to using the evaluation value to evaluate the irradiation position and angle, the evaluation ratio factor can also be used for evaluation, which is defined as the ratio of the evaluation value to the tumor weight factor, as shown in Formula 4. This can more fully demonstrate the expected treatment effect of the irradiation position and angle.

[0082]

[0083] The above embodiments involve these steps - "reading images with clear human anatomy such as CT / MRI / PET-CT of the patient, defining the contours of each organ, tissue and tumor one by one, and setting the material type and density." Please refer to the patent application submitted by the applicant to the State Intellectual Property Office on November 17, 2015, with application number 201510790248.7 and invention name "Method for establishing a geometric model based on medical imaging data", which is fully introduced here.

[0084] It is well known to those skilled in the art that some simple transformations of the above formulas 1 to 4 are still within the scope of protection claimed by the present invention, such as I(i), S(i) and C(i) are transformed from multiplication to addition; I(i), S(i) and C(i) are multiplied by the nth power respectively, where n can be an integer multiple of 1 or other multiples depending on the situation; i(x) can be the average or middle number between x0-x multiplied by (x0-x), or any calculation method that can achieve a result consistent with the intensity integral calculation.

[0085] Although the above describes an illustrative specific embodiment of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiment. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious and are all within the scope of protection required by the present invention.

Claims

1. A neutron capture therapy device, characterized in that include: A neutron beam generating assembly, an irradiation room for irradiating a neutron beam to an irradiated body, a management room for implementing irradiation control, a platform for placing a patient, and a control system for controlling and managing the treatment process, wherein the control system comprises an irradiation parameter selection device for selecting an optimal irradiation point and irradiation angle, wherein the irradiation parameter selection device comprises a sampling unit and a calculation unit, wherein the sampling unit selects a plurality of groups of irradiation points and irradiation angles, and the calculation unit calculates an evaluation value corresponding to each group of irradiation points and irradiation angles and outputs a report; The irradiation point and irradiation angle are selected by forward selection or reverse selection. The forward selection is to determine the irradiation point at a position outside the human body and to sample in sequence according to a fixed angle or distance interval, or to sample by random sampling. The reverse selection is to determine the irradiation point within the tumor range. The irradiation point is the tumor centroid or the deepest part, and the irradiation angle is sampled by random sampling or by a predetermined interval angle. The neutron beam angle is set to the vector direction from the irradiation point to the tumor centroid or the deepest part of the tumor. The irradiation parameter selection device further includes a selection unit, which is used to automatically exclude in advance the irradiation points and irradiation angles that cannot be implemented before calculating the evaluation value; the infeasible irradiation points and irradiation angles include irradiation points and irradiation angles corresponding to positions where the patient cannot be positioned or the treatment bed cannot move to, and irradiation points and irradiation angles corresponding to parts of the human body that cannot be irradiated within the range that the neutron beam can irradiate; The control system also includes a conversion unit, which combines the patient's CT / MRI / PET-CT information, positioning information, and structural information of the mounting table to convert the parameters of the irradiation point and irradiation angle into coordinate parameters that the mounting table needs to move into place during the irradiation process.

2. The neutron capture therapy device according to claim 1, characterized in that: The calculation unit calculates the depth of the neutron beam entering the patient and the type of organ passed by, and then determines whether the tumor falls within the maximum treatable depth range corresponding to the group of irradiation points and irradiation angles based on the track information of the neutron beam passing through the human body. If so, the evaluation value corresponding to the group of irradiation points and irradiation angles is calculated based on the track information and the boron concentration of the organ, the radiation sensitivity factor of the organ and the neutron beam characteristic information set by the user; if not, the worst evaluation value is given.

3. The neutron capture therapy device according to any one of claims 1 to 2, characterized in that: The calculation unit outputs data of the irradiation point and the irradiation angle and their corresponding evaluation values ​​in the form of a 3D or 2D image.

4. The neutron capture therapy device according to claim 2, characterized in that: The weight factor (W(i)) of organ i corresponding to a certain irradiation point, irradiation angle and irradiation path is calculated using formula 1: W(i)=I(i)×S(i)×C(i) (Formula 1) where I(i), S(i) and C(i) are the neutron intensity, the radiation sensitivity factor of organ i and the boron concentration of organ i, respectively.

5. The neutron capture therapy device according to claim 4, characterized in that: I(i) is calculated using Formula 2 which is an integral of the depth intensity or dose curve of the human body simulated by the beam used: Where i(x) is the depth intensity or dose curve function of the therapeutic beam in the approximate human body, and x0-x is the depth range of the organ (i) in the beam track.

6. The neutron capture therapy device according to claim 5, characterized in that: The evaluation factor is calculated using Formula 3: Among them, Q(x, y, z, Φ, θ) as an evaluation factor is equal to the sum of the weight factors of each organ in the organ trajectory.

7. The neutron capture therapy device according to claim 6, characterized in that: The ratio of the evaluation factor to the tumor evaluation factor (QR(x, y, z, Φ, θ)) is calculated using Formula 4: Among them, W(tumor) is the weight factor of the tumor.

8. A method for using the irradiation parameter selection device according to claim 1, characterized in that: The following steps are involved: The sampling unit reads the patient's CT image, MRI image or PET-CT image, defines the contours of each organ, tissue and tumor one by one, and sets the material type and density. After the definition of the contour, material and density is completed, the irradiation point and irradiation angle of the neutron beam are selected; Before calculating the evaluation value, the optimization unit automatically excludes in advance the irradiation points and irradiation angles that are not feasible; the infeasible irradiation points and irradiation angles include the irradiation points and irradiation angles corresponding to the positions where the patient cannot be positioned or the treatment bed cannot move, and the irradiation points and irradiation angles corresponding to the parts of the human body that cannot be irradiated within the range that the neutron beam can irradiate; The calculation unit calculates the track of the organ through which the neutron beam passes, that is, calculates the type and thickness of the organ through which the neutron beam passes after entering the human body. After obtaining the track information of the neutron beam passing through the human body, it determines whether the tumor falls within the maximum treatable depth range. If so, it uses this track information as a basis to combine the boron concentration of the organ, the radiation sensitivity factor of the organ and the neutron beam characteristic information set by the user to calculate the evaluation value corresponding to the irradiation point and the irradiation angle; if not, it gives the worst evaluation value. After completing the calculation of the evaluation value, the irradiation point, the irradiation angle and the corresponding evaluation value are recorded; The irradiation point and irradiation angle are selected by forward selection or reverse selection. The forward selection is to determine the irradiation point at a position outside the human body and can be sampled in sequence according to a fixed angle or distance interval, or by random sampling. The reverse selection is to determine the irradiation point within the tumor range, and the irradiation point is the tumor centroid or the deepest point, and the irradiation angle is sampled by random sampling or by predetermined interval angle sampling. The neutron beam angle is set to the vector direction from the irradiation point to the tumor centroid or the deepest point of the tumor.

9. The method for using the irradiation parameter selection device according to claim 8, characterized in that: The calculation unit outputs data of the irradiation point and the irradiation angle and their corresponding evaluation values ​​in the form of a 3D or 2D image.

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