A monte carlo particle transport calculation method and system suitable for neutron therapy

Abstract

The application relates to the technical field of radiotherapy, and particularly provides a Monte Carlo particle transport calculation method and system suitable for neutron therapy. The method comprises the following steps: acquiring a dose calculation input file; and acquiring irradiation dose by selecting one of a particle tracking algorithm and a particle weight attenuation algorithm based on preset conditions through a Monte Carlo program according to the input file.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radiotherapy, and particularly provides a Monte Carlo particle transport calculation method and system suitable for neutron therapy. BACKGROUND

[0002] Neutron capture therapy (NCT) is a modern treatment that selectively positions charged particles with high linear energy transfer (LET) at the cellular level to the tumor area. The principle of BNCT is that boron can be selectively enriched in the tumor area. Since boron has an extraordinary thermal neutron absorption cross section, the boron capture thermal neutron reaction mainly occurs in the tumor area, and the energy after the reaction is deposited within about 10 μm. Therefore, after being irradiated by thermal neutrons, the tumor area absorbs a much higher dose than normal tissues, which can achieve the purpose of killing cancer cells and protecting normal cells. Therefore, theoretically, if an ideal boron-containing drug can be found, and the boron concentration in the tumor area is more than 3 times higher than that in normal tissues after being injected into the human body, the treatment effect will be very good.

[0003] In boron neutron capture therapy (BNCT), in order to solve the problem that the dose calculation speed of the Monte Carlo dose calculation engine of the neutron therapy planning system is too slow under large-scale voxel geometry, and it is difficult to meet the clinical use requirements, the conventional method is to replace the Monte Carlo program with a deterministic program or combine the Monte Carlo program with a deterministic program. The problem is solved by replacing the Monte Carlo program partially or completely with a deterministic program that is faster, but this method still has the problems of difficulty in ensuring accuracy and poor program usability because the deterministic program always introduces assumptions and approximations, and the user needs to set algorithm parameters; the conventional method also has a fast ray tracing technique, which cancels the step of sampling and transporting the length again after penetrating the same material voxel by taking advantage of the characteristics that the voxel grid size is the same, and the materials of adjacent voxels are the same. By judging the positional relationship between the voxel grid corner point and the straight line where the current particle track is located, the next geometry entered by the particle is quickly determined, but this method needs to be used under the condition that the voxel grid size is the same, and it is still based on the traditional particle tracking algorithm, so the acceleration effect on dose calculation is limited.

[0004] Correspondingly, there is a need in the art for a new Monte Carlo particle transport calculation method and system suitable for neutron therapy to solve the above problems. SUMMARY

[0005] In order to overcome the above-mentioned defects, the present application is proposed to provide a Monte Carlo particle transport calculation method and system suitable for neutron therapy to solve or at least partially solve the problem of slow dose calculation speed of the Monte Carlo dose calculation engine of the neutron therapy planning system in the prior art under large-scale voxel geometry.

[0006] In a first aspect, the present invention provides a Monte Carlo particle transport calculation method suitable for neutron therapy, comprising the following steps:

[0007] Obtain the dose calculation input file;

[0008] Based on the input file, the irradiation dose is obtained by selecting one of the particle tracking algorithm and the particle weight attenuation algorithm according to preset conditions using the Monte Carlo program.

[0009] In one specific embodiment, the method further includes:

[0010] Acquire computed tomography (CT) images of the patient;

[0011] Based on the grayscale information of the computed tomography image and the radiation source information set by the user, a dose calculation input file is generated. The input file contains the three-dimensional spatial coordinates of the voxel model, the elemental composition of each voxel, the source intensity, energy spectrum, direction, and three-dimensional spatial coordinates of the radiation source.

[0012] In one specific embodiment, the step of obtaining the irradiation dose by selecting one of a particle tracking algorithm and a particle weight attenuation algorithm based on preset conditions using a Monte Carlo program according to the input file includes:

[0013] Based on the computed tomography images, voxel information is obtained and a voxel model is constructed, wherein the voxel model is a three-dimensional model composed of one or more voxel cubes.

[0014] The Monte Carlo method was used to simulate the transport process of particles in a voxel model;

[0015] Get Proportional value, where ∑ t,i Let ∑ be the reaction cross section where the particle reacts with the i-th voxel cube in the voxel model. t,max The maximum reaction cross section where the particle reacts with all voxel cubes in the voxel model;

[0016] Determine the The relationship between the ratio value and the preset reference threshold is determined, and a corresponding algorithm is used to calculate the deposition energy of the voxel cube that each particle traverses based on the relationship.

[0017] The irradiation dose is obtained by summing the deposition energies of all particles in each voxel cube.

[0018] In one specific embodiment, the determination of the The relationship between the ratio value and a preset reference threshold, and the calculation of the deposition energy of the voxel cube traversed by each particle using a corresponding algorithm based on the relationship, including:

[0019] obtaining the preset reference threshold value set according to an empirical value;

[0020] judging whether the ratio value is less than the preset reference threshold value;

[0021] if less, using a particle tracking algorithm to calculate the deposition energy of the voxel cube experienced by each particle; and / or

[0022] if not less, using a particle weight attenuation algorithm to calculate the deposition energy of the voxel cube experienced by each particle.

[0023] In one specific embodiment, the using a particle tracking algorithm to calculate the deposition energy of the voxel cube experienced by each particle comprises:

[0024] S2431, randomly extracting one particle;

[0025] S2432, judging whether the particle is in the voxel model according to the three-dimensional coordinates of the particle;

[0026] S2433, if not, continuing to extract the next particle and returning to step S2431; and / or

[0027] S2434, if yes, judging whether the weight of the particle is greater than a first preset reference weight;

[0028] S2435, if not greater than, continuing to extract the next particle and returning to step S2431; and / or

[0029] S2436, if greater than, obtaining the free path L1 of the particle in the voxel model,

[0030]

[0031] wherein, L is a random number, ∑ t,i is the reaction cross section of the particle and the i-th voxel cube in the voxel model;

[0032] S2437, the particle will intersect with the voxel cube boundary according to the current direction of movement, and the distance L0 between the current position of the particle and the intersection point is obtained;

[0033] S2438, judging whether the free path L1 is greater than L0;

[0034] S2439, if greater than, updating the three-dimensional coordinates of the particle to the three-dimensional coordinates of the intersection point, and returning to step S2432; and / or

[0035] ​S24310, if not greater than, the reaction type and reaction energy of the particle and the voxel cube are determined by sampling method, the deposition energy of the voxel cube is calculated, the three-dimensional coordinates of the particle are updated according to the free path L1, and step S2432 is returned.

[0036] In one specific embodiment, the use of the particle weight attenuation algorithm to calculate the deposition energy of the voxel cube experienced by each particle includes:

[0037] S2441, a particle is randomly extracted;

[0038] S2442, it is judged whether the particle is in the voxel model according to the three-dimensional coordinates of the particle;

[0039] S2443, if not, continue to extract the next particle and return to step S2441; and / or

[0040] S2444, if yes, it is judged whether the weight of the particle is greater than a second preset reference weight;

[0041] S2445, if not greater than, continue to extract the next particle and return to step S2441; and / or

[0042] S2446, if greater than, the free path L2 of the particle in the voxel model is obtained;

[0043]

[0044] Wherein, ξ is a random number, ∑ t,max is the maximum reaction cross section of the particle and all voxel cubes in the voxel model;

[0045] S2447, the reaction type and reaction energy of the particle and the voxel cube at the free path end position are determined by sampling method, and the deposition energy of the voxel cube at the free path end position is calculated;

[0046] S2448, after the particle reacts, the weight of the particle is updated,

[0047]

[0048] Wherein, W new is the weight of the particle after updating, W old is the weight of the particle;

[0049] S2449, the particle position is moved from the original coordinates to the coordinates of the free path end position, and step S2442 is returned.

[0050] In one embodiment, the adding of the deposition energy of all the particles in each voxel cube to obtain the irradiation dose comprises:

[0051] determining whether all the particles are extracted;

[0052] if all the particles are extracted, stopping the extraction and adding the deposition energy of all the particles in each voxel cube to obtain the irradiation dose; and / or

[0053] if not all the particles are extracted, continuing to extract the next particle, determining the relationship between the ratio value and a preset reference threshold value, and calculating the deposition energy of the voxel cube experienced by each particle according to the relationship.

[0054] In a second aspect, the present application provides a Monte Carlo particle transport calculation method suitable for neutron therapy, the system comprising:

[0055] an acquisition module for acquiring a dose calculation input file;

[0056] a dose calculation module for obtaining an irradiation dose by a Monte Carlo program according to the input file.

[0057] In a third aspect, the present application provides a control device comprising a processor and a storage device, the storage device being adapted to store a plurality of program codes, characterized in that the program codes are adapted to be loaded and run by the processor to execute the Monte Carlo particle transport calculation method suitable for neutron therapy of any one of the first aspect.

[0058] In a fourth aspect, the present application provides a computer readable storage medium, wherein a plurality of program codes are stored, characterized in that the program codes are adapted to be loaded and run by a processor to execute the Monte Carlo particle transport calculation method suitable for neutron therapy of any one of the first aspect.

[0059] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0060] By implementing the technical solutions of the present application, the speed of the Monte Carlo dose calculation of the neutron therapy planning system can be greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0061] The disclosure of the present application will become more readily understood by referring to the accompanying drawings. It will be readily understood to those skilled in the art that the drawings are not limited to the scope of the present application and are only intended to illustrate the present application. In addition, similar numbers in the figures represent similar components, wherein:

[0062] Figure 1 ​is a schematic diagram of main steps of a Monte Carlo particle transport calculation method suitable for neutron therapy according to an embodiment of the present application;

[0063] Figure 2 is a schematic diagram of steps of obtaining irradiation dose by selecting one of a particle tracking algorithm and a particle weight attenuation algorithm based on preset conditions by a Monte Carlo program according to an embodiment of the present application;

[0064] Figure 3 is a schematic diagram of a voxel model in a two-dimensional form;

[0065] Figure 4 is a schematic diagram of steps of calculating deposition energy of a voxel cube by a particle according to an embodiment of the present application; is a schematic diagram of steps of calculating deposition energy of a voxel cube by a particle according to an embodiment of the present application;

[0066] Figure 5 is a schematic diagram of steps of calculating deposition energy of a voxel cube by a particle according to an embodiment of the present application;

[0067] Figure 6 is a schematic diagram of steps of calculating deposition energy of a voxel cube by a particle according to an embodiment of the present application. DETAILED DESCRIPTION

[0068] Some embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application.

[0069] In the description of the present application, "module" and "processor" can include hardware, software or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and can also include a software portion such as program code, and can be a combination of software and hardware. The processor can be a central processor, a microprocessor, a graphic processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor can be implemented in software, hardware or a combination of both. The non-transitory computer readable storage medium includes any suitable medium that can store program code, such as a magnetic disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or both A and B. The term "at least one of A or B" or "at least one of A and B" has a similar meaning as "A and / or B" and can include only A, only B or both A and B. The singular form of the term "one", "this" can also include the plural form.

[0070] The orientation terms such as "front", "front side", "front portion", "rear", "rear side" and "rear portion" used herein are based on the front-rear direction of the component mounted to the vehicle. The "vertical", "vertical direction", "vertical cross section" mentioned herein are based on the front-rear direction of the component mounted to the vehicle, while the "horizontal", "horizontal direction", "horizontal cross section" represent the direction perpendicular to the vertical direction.

[0071] The Monte Carlo method is also called random sampling method or statistical experiment method, which is a branch of computational mathematics and can truly simulate the physical process of actual particle transport to solve practical problems. Alternatively, a Monte Carlo program is used to construct a model of a patient based on an electronic computed tomography image of the patient and material composition of different tissues, and determine the response of the model to different particles.

[0072] The Monte Carlo program is a general software package based on the Monte Carlo method for calculating neutron, photon, electron or multi-particle transport problems in three-dimensional complex geometric structures. The Monte Carlo program can use one or more of MCNP, GEANT4, TOPAS, GATE, FLUKA, SuperMC or Phits. The Monte Carlo program is used to simulate the energy deposition and particle transport process under different treatment schemes, and obtain the characteristic prompt gamma ray yield distribution map and three-dimensional dose distribution map in the target region under different tumor shapes, different tumor types, different tumor locations and different boron concentration distributions.

[0073] In boron neutron capture therapy (BNCT), in order to solve the problem that the dose calculation speed of the neutron treatment planning system Monte Carlo dose calculation engine is too slow under large-scale voxel geometry and it is difficult to meet the clinical use requirements, the conventional method is to replace the Monte Carlo program with a deterministic program or combine the Monte Carlo program with the deterministic program, which solves the problem by replacing the Monte Carlo program partially or completely with a deterministic program with faster speed, but this method still has the problems of difficult to guarantee the accuracy and poor program usability because the deterministic program always introduces assumptions and approximations and requires the user to set algorithm parameters; the conventional method also has a fast ray tracing technique, which cancels the step of sampling and transporting the length again after penetrating the surface between voxels with the same material by using the characteristics that the voxel grid size is the same and the materials of adjacent voxels are the same, and quickly determines the next geometry entered by the particle by judging the positional relationship between the voxel grid corner point and the straight line where the current particle track is located, but this method needs to be used under the condition that the voxel grid size is the same, and is still based on the traditional particle tracking algorithm, and the acceleration effect on dose calculation is limited.

[0074] In order to solve the above technical problems, especially to solve the problem that the neutron treatment planning system Monte Carlo dose calculation engine in the prior art is too slow in dose calculation under large-scale voxel geometry, for this purpose, a Monte Carlo particle transport calculation method and system suitable for neutron therapy are provided.

[0075] In the embodiments of the present application, refer to the accompanying Figure 1 , Figure 1 is the main step flowchart of the Monte Carlo particle transport calculation method suitable for neutron therapy in an embodiment of the present application, as shown in the figure, the Monte Carlo particle transport calculation method suitable for neutron therapy in the embodiment includes the following steps S1-S2:

[0076] S1, obtain a dose calculation input file.

[0077] In one specific embodiment, the method further comprises:

[0078] obtaining a patient computed tomography image;

[0079] generating a dose calculation input file according to the gray scale information of the computed tomography image and the user-set irradiation source information, wherein the input file contains the three-dimensional space coordinates of the voxel model, the element composition contained in each voxel, the source strength, energy spectrum, direction and three-dimensional space coordinates of the irradiation source.

[0080] In one example, a model of the treatment site (e.g., the head) is established before treatment of the patient, for example, by CT. For example, 100 cross-sectional image data of the head is obtained by CT, and the 100 data is input into a known algorithm to construct a three-dimensional model of the head.

[0081] S2, according to the input file, selecting one of the particle tracking algorithm and the particle weight decay algorithm based on the preset conditions by the Monte Carlo program to obtain the irradiation dose.

[0082] In one embodiment, referring to the accompanying drawings Figure 2 , the method according to the input file, selecting one of the particle tracking algorithm and the particle weight decay algorithm based on the preset conditions by the Monte Carlo program to obtain the irradiation dose, comprises:

[0083] S21, according to the electron computed tomography image, obtaining voxel information and constructing a voxel model, wherein the voxel model is a three-dimensional model composed of one or more voxel cubes.

[0084] In one example, after obtaining the electron computed tomography image (CT) of the patient's head, the patient's head CT image is three-dimensionally reconstructed by an automatic conversion system (e.g., Monte Carlo dosimetry code for brain (MCDB)) to generate a voxel model.

[0085] Figure 3 The voxel model is shown in two-dimensional form, wherein each grid represents a voxel. Three parts with different gray scales represent three different materials (C, H, O, etc.), for example, the voxels from the first row and the first column to the third row and the third column represent C; the voxels from the third row and the fourth column, the fourth row and the first column, the fourth row and the second column, the fourth row and the third column, the fourth row and the fourth column, the fifth row and the first column, the fifth row and the second column, the fifth row and the third column, and the fifth row and the fourth column represent H; and the voxels from the first row and the fourth column, the second row and the fourth column, and all the fifth columns represent O.

[0086] In addition, a straight line with an arrow represents the transport process of a particle in the voxel model, for example, Figure 3 In the example shown, the particle passes through the voxels from the first row and the first column, the second row and the first column, the second row and the second column, the third row and the second column, the third row and the third column, the third row and the fourth column, the fourth row and the fourth column, and the fourth row and the fifth column.

[0087] S22, simulating the transport process of the particle in the voxel model using the Monte Carlo method.

[0088] In one example, particle transport is a stochastic process, and the motion of particles is a statistical law of the motion of a large number of particles. Solving this problem using the Monte Carlo method requires sampling the type of interaction, the free path of the particles in the medium, the scattering energy, and the scattering direction.

[0089] For example, in a simulated sample (the particles in the simulated sample must conform to the distribution, properties, etc. of actual particles), the particle beam is a cylinder with a radius of 5 cm containing 1,000,000 particles. A particle 'a' is randomly selected from this sample, and a number is randomly selected from the energy spectrum as the energy of particle 'a'. The direction and angle of particle 'a' are obtained using the same random number method. Next, particle 'b' is selected, and similarly, the energy, direction, and angle of particle 'b' are obtained using the random number method. This process continues until the number of selected particles (e.g., 1000) is sufficient to achieve convergence. The particle selection is then stopped, and the result is obtained by multiplying by a scaling factor of 1,000,000 / 1000.

[0090] S23, Obtain Proportional value, where ∑ t,i Let ∑ be the reaction cross section where the particle reacts with the i-th voxel cube in the voxel model. t,max The maximum reaction cross section is the area at which the particle reacts with all voxel cubes in the voxel model.

[0091] Based on the above Figure 3 For example, the probability that a particle reacts with the material carbon (C) when it passes through the voxel in the second row and first column (absorption, fission, collision, scattering, etc.) is the corresponding reaction cross section. The largest probability among the various reactions between the particle and the material is the maximum macroscopic reaction cross section.

[0092] S24, Determine the above The relationship between the ratio value and the preset reference threshold is determined, and a corresponding algorithm is used to calculate the deposition energy of the voxel cube that each particle traverses based on the relationship.

[0093] In BNCT technology, CT is used to reconstruct human models. The pixels of CT are between 0.5 and 1 mm, while the entire model may have 50 million or even 100 million voxel cubes. If the boundary distance is calculated for each voxel cube, the calculation speed will be very slow and the calculation time will be very long. Therefore, this invention proposes a technical solution that couples the particle tracking algorithm and the particle weight decay algorithm.

[0094] Furthermore, in one specific embodiment, see Appendix Figure 4 The judgment The relationship between the ratio value and a preset reference threshold, and the calculation of the deposition energy of the voxel cube traversed by each particle using a corresponding algorithm based on the relationship, including:

[0095] acquiring the preset reference threshold value set according to an empirical value;

[0096] judging whether the ratio value is less than the preset reference threshold value;

[0097] if less, using a particle tracking algorithm to calculate the deposition energy of the voxel cube experienced by each particle; and / or

[0098] if not less, using a particle weight attenuation algorithm to calculate the deposition energy of the voxel cube experienced by each particle.

[0099] It should be noted that, if less than the preset reference threshold value, it means that the reaction cross section of the i-th voxel cube reacting is quite different from the maximum macroscopic reaction cross section of the voxel cube reacting, and if the particle weight attenuation algorithm is used, the probability that the random number obtained by extraction is not less than the reference threshold value is extremely high, resulting in too many virtual reactions, which are not helpful to the final result, and therefore in the case of less than the preset reference threshold value, the particle tracking algorithm is used to calculate the deposition energy of the voxel cube experienced by each particle, and in the case of not less than the preset reference threshold value, the particle weight attenuation algorithm is used to calculate the deposition energy of the voxel cube experienced by each particle.

[0100] In one specific embodiment, referring to the accompanying drawings, Figure 5 the particle tracking algorithm used to calculate the deposition energy of the voxel cube experienced by each particle includes:

[0101] S2431, randomly extracting a particle;

[0102] S2432, judging whether the particle is in the voxel model according to the three-dimensional coordinates of the particle;

[0103] S2433, if not, continuing to extract the next particle and returning to step S2431; and / or

[0104] S2434, if yes, judging whether the weight of the particle is greater than a first preset reference weight;

[0105] S2435, if not greater than, continuing to extract the next particle and returning to step S2431; and / or

[0106] S2436, if greater than, acquiring the free path L1 of the particle in the voxel model,

[0107]

[0108] ​wherein ξ is a random number, ∑ t,i is a reaction cross section of the particle with the i-th voxel cube in the voxel model;

[0109] S2437, the particle moves according to the current direction and intersects with the voxel cube boundary, and a distance L0 between the particle current position and the intersection point is obtained;

[0110] S2438, it is judged whether the free path L1 is greater than L0;

[0111] S2439, if greater, the three-dimensional coordinates of the particle are updated to the three-dimensional coordinates of the intersection point, and step S2432 is returned; and / or

[0112] S24310, if not greater, a reaction type and a reaction energy of the particle with the voxel cube are determined by a sampling method, a deposition energy of the voxel cube is calculated, the three-dimensional coordinates of the particle are updated according to the free path L1, and step S2432 is returned.

[0113] In one specific embodiment, referring to the accompanying drawings Figure 6 The particle weight decay algorithm is used to calculate the deposition energy of the voxel cube experienced by each particle, comprising:

[0114] S2441, a particle is randomly extracted;

[0115] S2442, it is judged whether the particle is in the voxel model according to the three-dimensional coordinates of the particle;

[0116] S2443, if not, the next particle is continuously extracted and step S2441 is returned; and / or

[0117] S2444, if yes, it is judged whether the weight of the particle is greater than a second preset reference weight;

[0118] S2445, if not greater, the next particle is continuously extracted and step S2441 is returned; and / or

[0119] S2446, if greater, a free path L2 of the particle in the voxel model is obtained;

[0120]

[0121] wherein ξ is a random number, ∑ t,max is a maximum reaction cross section of the particle with all voxel cubes in the voxel model;

[0122] S2447, determining the reaction type and reaction energy of the particle with the voxel cube at the free path end position by the sampling method, and calculating the deposition energy of the voxel cube at the free path end position;

[0123] S2448, updating the weight of the particle after the particle is reacted,

[0124]

[0125] wherein W new is the updated weight of the particle, W old is the weight of the particle;

[0126] S2449, moving the particle position from the original coordinates to the coordinates of the free path end position, returning to step S2442.

[0127] It should be noted that in the particle weight decay algorithm, all collision reactions are default true collisions, and the weight of each neutron is updated and calculated. The weight of the neutron decreases each time the neutron reacts, and when the weight is low to a certain extent, the neutron can be ignored. Then continue to extract the next neutron.

[0128] S25, adding the deposition energy of all particles in each voxel cube to obtain the irradiation dose.

[0129] For example, taking the above example of extracting 1000 neutrons in the simulation sample to meet the convergence, the energy of the first to the 1000th neutron is randomly extracted from the energy spectrum in turn, the direction and angle of the neutron a are obtained using the same random number method, and then they are added to obtain the neutron dose.

[0130] In one example, the BNCT real-time total dose can be calculated in combination with the boron concentration distribution information, human tissue anatomy information, and neutron beam information.

[0131] In one specific embodiment, the adding the deposition energy of all particles in each voxel cube to obtain the irradiation dose comprises:

[0132] determining whether all particles have been extracted;

[0133] If extraction is complete, stop extracting and add the deposition energy of all particles in each voxel cube to obtain the irradiation dose; and / or

[0134] If extraction is not complete, continue to extract the next particle, determine the the relationship between the proportion value and the preset reference threshold, and according to the relationship, calculate the deposition energy of the voxel cube experienced by each particle.

[0135] Further, according to the obtained neutron dose, the irradiation direction and irradiation time of the neutron beam treatment process can be determined.

[0136] Based on the above steps S1-S2, the speed of the boron neutron capture therapy Monte Carlo dose calculation is greatly improved by coupling the particle tracking algorithm and the particle weight attenuation algorithm, and the calculation time is saved.

[0137] It should be noted that, although the above embodiment describes each step in a specific order, those skilled in the art can understand that, in order to achieve the effect of the present application, the different steps do not have to be executed in such an order, they can be executed simultaneously (in parallel) or in other order, and these changes are within the protection scope of the present application.

[0138] Those skilled in the art can understand that all or part of the processes in the method of the above embodiment can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer readable storage medium. When the computer program is executed by a processor, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable files or some intermediate forms, etc. The computer readable storage medium can include any entity or device, medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code. It should be noted that the contents included in the computer readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to legislation and patent practice, the computer readable storage medium does not include electrical carrier signals and telecommunication signals.

[0139] Further, the present application also provides a Monte Carlo particle transport calculation system suitable for neutron therapy, the system comprises:

[0140] The acquisition module is configured to acquire a dose calculation input file.

[0141] The dose calculation module is configured to acquire an irradiation dose by a Monte Carlo program according to the input file.

[0142] Further, it should be understood that, as the setting of each module is only for illustrating the functional units of the device of the present application, the corresponding physical device of the module can be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of the software and the hardware. Therefore, the number of each module in the figure is only illustrative.

[0143] Those skilled in the art can understand that each module in the device can be adaptively split or combined. Such splitting or combining of the specific module does not cause the technical solution to deviate from the principles of the present application, and therefore, the technical solution after splitting or combining will fall within the protection scope of the present application.

[0144] Further, the present application also provides a control device, comprising a processor and a memory, the memory can be configured to store the program of the Monte Carlo particle transport calculation method suitable for neutron therapy for executing the above-mentioned method embodiments, and the processor can be configured to execute the program in the memory, which includes but is not limited to executing the program of the Monte Carlo particle transport calculation method suitable for neutron therapy as shown above. In order to facilitate the description, only the part related to the embodiments of the present application is shown, and the specific technical details not disclosed are referred to the method part of the embodiments of the present application. Figure 1 Further, the present application also provides a control device, comprising a processor and a memory, the memory can be configured to store the program of the Monte Carlo particle transport calculation method suitable for neutron therapy for executing the above-mentioned method embodiments, and the processor can be configured to execute the program in the memory, which includes but is not limited to executing the program of the Monte Carlo particle transport calculation method suitable for neutron therapy as shown above. In order to facilitate the description, only the part related to the embodiments of the present application is shown, and the specific technical details not disclosed are referred to the method part of the embodiments of the present application.

[0145] Further, the present application also provides a computer readable storage medium, which stores a plurality of program codes, characterized in that the program codes are suitable for being loaded and run by the processor to execute the above-mentioned method as shown. Figure 1 Further, the present application also provides a control device, comprising a processor and a memory, the memory can be configured to store the program of the Monte Carlo particle transport calculation method suitable for neutron therapy for executing the above-mentioned method embodiments, and the processor can be configured to execute the program in the memory, which includes but is not limited to executing the program of the Monte Carlo particle transport calculation method suitable for neutron therapy as shown above. In order to facilitate the description, only the part related to the embodiments of the present application is shown, and the specific technical details not disclosed are referred to the method part of the embodiments of the present application.

[0146] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solution after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A Monte Carlo particle transport calculation method suitable for neutron therapy, characterized in that, The method includes: Obtain the dose calculation input file; Based on the input file, the irradiation dose is obtained by selecting one of the particle tracking algorithm and the particle weight attenuation algorithm according to preset conditions using the Monte Carlo program. The step of obtaining the irradiation dose by selecting one of the particle tracking algorithm and the particle weight attenuation algorithm based on preset conditions using the Monte Carlo program according to the input file includes: The Monte Carlo method was used to simulate the transport process of particles in a voxel model; Get Proportional value, where ∑ t,i This represents the reaction cross section where the particle reacts with the i-th voxel cube in the voxel model, which is constructed based on voxel information from a patient's computed tomography (CT) image, and is a three-dimensional model composed of one or more voxel cubes; ∑ t,max The maximum reaction cross section where the particle reacts with all voxel cubes in the voxel model; Determine the The relationship between the ratio value and the preset reference threshold; If the above If the ratio is less than the preset reference threshold, a particle tracking algorithm is used to calculate the deposition energy of each particle across the voxel cube. The particle tracking algorithm calculates the deposition energy based on the relationship between the free path and the voxel cube boundary when the particle is within the voxel model and its weight satisfies a first preset condition; and / or If it is not less than, the particle weight decay algorithm is used to calculate the deposition energy of the voxel cube that each particle traverses; the particle weight decay algorithm is to calculate the deposition energy based on the end position of the free path when it is determined that the particle is within the voxel model and meets the second preset condition. The irradiation dose is obtained based on the deposition energy.

2. The method according to claim 1, characterized in that, The method further includes: Acquire the patient's computed tomography (CT) scan images; Based on the grayscale information of the computed tomography image and the radiation source information set by the user, a dose calculation input file is generated. The input file contains the three-dimensional spatial coordinates of the voxel model, the elemental composition of each voxel, the source intensity, energy spectrum, direction, and three-dimensional spatial coordinates of the radiation source.

3. The method according to claim 2, characterized in that, The method further includes: Based on the computed tomography (CT) images, the voxel information is obtained and the voxel model is constructed; The process of obtaining the irradiation dose based on the deposition energy includes: The irradiation dose is obtained by summing the deposition energies of all particles in each voxel cube.

4. The method according to claim 1, characterized in that, The method further includes: Obtain the preset reference threshold set based on empirical values.

5. The method according to claim 4, characterized in that, The calculation of the deposition energy of the voxel cube traversed by each particle using a particle tracking algorithm includes: S2431. Randomly select a particle; S2432. Determine whether the particle is within the voxel model based on its three-dimensional coordinates; S2433. If not, continue to extract the next particle and return to step S2431; and / or S2434. If so, determine whether the weight of the particle is greater than the first preset reference weight; S2435. If not greater than, continue to extract the next particle and return to step S2431; and / or S2436. If it is greater than 1, obtain the path of freedom L1 of the particle in the voxel model. Where ξ is a random number, ∑ t,i The reaction section in which the particle reacts with the i-th voxel cube in the voxel model; S2437. The particle moves in the current direction and intersects with the boundary of the voxel cube it is in. Obtain the distance L0 between the particle's current position and the intersection point. S2438. Determine whether the free path L1 is greater than L0; S2439. If the value is greater than the specified value, update the three-dimensional coordinates of the particle to the three-dimensional coordinates of the intersection point, and return to step S2432; and / or S24310. If not greater than, determine the reaction type and reaction energy of the particle reacting with the voxel cube by sampling, calculate the deposition energy of the voxel cube, update the three-dimensional coordinates of the particle according to the free path L1, and return to step S2432.

6. The method according to claim 4, characterized in that, The calculation of the deposition energy of the voxel cube traversed by each particle using the particle weight decay algorithm includes: S2441. Randomly select a particle; S2442. Determine whether the particle is within the voxel model based on its three-dimensional coordinates; S2443. If not, continue to extract the next particle and return to step S2441; and / or S2444. If yes, determine whether the weight of the particle is greater than the second preset reference weight; S2445. If not greater than, continue to extract the next particle and return to step S2441; and / or S2446. If it is greater than 2, obtain the path of freedom L2 of the particle in the voxel model. Where ξ is a random number, ∑ t,max The maximum reaction cross section where the particle reacts with all voxel cubes in the voxel model; S2447. Determine the reaction type and reaction energy of the particle reacting with the voxel cube at the end of the free path using a sampling method, and calculate the deposition energy of the voxel cube at the end of the free path. S2448. After the particle reacts, the weight of the particle is updated. Among them, W new For the updated weights of the particles, W old The weight of the particle; S2449. Move the particle position from its original coordinates to the coordinates of the end point of the free path, and return to step S2442.

7. The method according to claim 3, characterized in that, The step of summing the deposition energies of all particles in each voxel cube to obtain the irradiation dose includes: Determine whether all particles have been extracted; If extraction is complete, extraction is stopped and the deposition energies of all particles in each voxel cube are summed to obtain the irradiation dose; and / or If the extraction is not complete, continue extracting the next particle and determine the result. The relationship between the ratio value and the preset reference threshold is determined, and a corresponding algorithm is used to calculate the deposition energy of the voxel cube that each particle traverses based on the relationship.

8. A Monte Carlo particle transport calculation system suitable for neutron therapy, characterized in that, The system includes: The acquisition module is used to acquire the dose calculation input file; The dose calculation module is used to obtain the irradiation dose according to the input file through a Monte Carlo program; The dose calculation module is also used to simulate the transport process of particles in a voxel model using the Monte Carlo method; to obtain... Proportional value, where ∑ t,i This represents the reaction cross section where the particle reacts with the i-th voxel cube in the voxel model. The voxel model is constructed based on voxel information from a patient's computed tomography (CT) image. The voxel model is a three-dimensional model composed of one or more voxel cubes. ∑ t,max The maximum reaction cross section in which the particle reacts with all voxel cubes in the voxel model; and, determining the... The relationship between the ratio value and the preset reference threshold; if the If the ratio is less than the preset reference threshold, a particle tracking algorithm is used to calculate the deposition energy of the voxel cube traversed by each particle. The particle tracking algorithm calculates the deposition energy based on the relationship between the free path L1 and the boundary of the voxel cube when the particle is within the voxel model and the weight satisfies the first preset condition. And / or, if it is not less than the threshold, a particle weight decay algorithm is used to calculate the deposition energy of the voxel cube traversed by each particle. The particle weight decay algorithm calculates the deposition energy based on the endpoint position of the free path L2 when the particle is within the voxel model and satisfies the second preset condition. The irradiation dose is then obtained based on the deposition energy.

9. A control device, comprising a processor and a storage device, said storage device being adapted to store a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by the processor to perform the Monte Carlo particle transport calculation method for neutron therapy as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the Monte Carlo particle transport calculation method for neutron therapy as described in any one of claims 1 to 7.

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