Method, device, equipment and medium for predicting radiation dose rate of radionuclides

Abstract

The present invention discloses a method, device, equipment and medium for predicting the radiation dose rate of a radionuclide, which specifically includes: obtaining the concentration data and physical parameter data of the radionuclide at N first position points in a three-dimensional space, wherein the concentration data is non-equidistantly distributed data; determining the three-dimensional convolution of the photon flux rate at a second position point according to the concentration data and the physical parameter data, in combination with a preset relationship; reconstructing the three-dimensional convolution of the second position point to obtain the three-dimensional convolution in Fourier form; calculating the three-dimensional convolution of the Fourier form of the second position point using a non-uniform fast Fourier transform algorithm to determine the corresponding target photon flux rate; determining the radiation dose rate in the three-dimensional space according to the physical parameter data and the target photon flux rate. According to an embodiment of the present invention, the efficiency and accuracy of the prediction of the three-dimensional radiation dose rate can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radiation detection, and in particular relates to a method, device, equipment and medium for predicting the radiation dose rate of a radioactive nuclide. Background Art

[0002] With the rapid development of the nuclear energy industry and the widespread application of nuclear technology, research on emergency response and disposal of nuclear accidents is particularly important. Among them, the estimation of the three-dimensional radiation dose rate field, that is, the three-dimensional radiation dose rate, is the basis for formulating emergency plans, evaluating accident consequences and improving emergency response efficiency. However, in radionuclide emission events, it is relatively difficult to estimate and predict the three-dimensional radiation dose rate due to the complexity of radionuclide distribution and terrain. Generally, existing estimation methods include: three-dimensional integral algorithm or three-dimensional convolution algorithm to estimate the three-dimensional radiation dose rate. However, the methods of the prior art still have the following disadvantages:

[0003] On the one hand, when faced with complex terrain and complex building and street environments, the three-dimensional radiation dose rate of the predicted location area is determined using a three-dimensional integration algorithm. It is necessary to calculate the contribution of the radioactive nuclides at all location points in the three-dimensional space of the area, that is, to integrate the relevant values ​​of each point in the entire three-dimensional space. Although the prediction results estimated in this way are more accurate, the amount of calculation is large and the calculation time is long.

[0004] On the other hand, the three-dimensional convolution algorithm has a faster calculation speed, but this method is only suitable for processing data in a relatively simple and flat spatial terrain, that is, processing equidistant data. However, the data obtained by simulating the environment of complex terrain and building streets is often non-equidistant data. If the fast Fourier transform algorithm is used to calculate the three-dimensional convolution algorithm, the non-equidistant data needs to be converted into equidistant grid data, which will lose a certain amount of data accuracy. Therefore, although the three-dimensional convolution algorithm has a faster calculation speed, the calculation accuracy is not high.

[0005] Therefore, how to accurately and quickly estimate and predict the three-dimensional radiation dose rate in a three-dimensional space with complex radionuclide distribution and terrain environment is an urgent problem that technicians need to solve. Summary of the invention

[0006] The embodiments of the present invention provide a method, device, equipment and storage medium for predicting the radiation dose rate of a radionuclide, which can improve the accuracy and efficiency of predicting the distribution of the radiation dose rate in three-dimensional space.

[0007] In a first aspect, an embodiment of the present invention provides a method for predicting a radiation dose rate of a radionuclide, the method comprising:

[0008] Acquire concentration data and physical parameter data of radioactive nuclides at N first position points in a three-dimensional space, wherein N is a natural number greater than 1, and the concentration data is non-equidistantly distributed data;

[0009] According to the concentration data and the physical parameter data, in combination with a preset relationship, determine a three-dimensional convolution of a photon flux rate at a second position point, wherein the photon flux rate is the sum of photon flux rates of rays passing through the second position point, and the second position point is an arbitrary position point in the three-dimensional space;

[0010] Reconstructing the three-dimensional convolution of the photon flux rate at the second position point to obtain a three-dimensional convolution in Fourier form;

[0011] Calculating the three-dimensional convolution of the Fourier form of the second position point using a non-uniform fast Fourier transform algorithm to determine a corresponding target photon flux rate;

[0012] The radiation dose rate in the three-dimensional space is determined according to the physical parameter data and the target photon flux rate.

[0013] Optionally, the three-dimensional convolution of the photon flux rate at the second position point includes a first convolution function and a second convolution function;

[0014] When the distance between the second position point and the first position point of the radionuclide is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of the first smoothing function and a correction term;

[0015] When the distance between the second position point and the first position point of the radioactive nuclide is greater than the preset distance threshold, the second convolution function of the second position point is represented as a first smooth function.

[0016] Optionally, using a non-uniform fast Fourier transform algorithm, calculating the three-dimensional convolution of the Fourier form of the second position point to determine the corresponding target photon flux rate includes:

[0017] According to the first convolution function and the second convolution function in Fourier form, the target photon flux rate corresponding to the second position point is calculated by the following formula using a non-uniform fast Fourier transform algorithm:

[0018]

[0019] in, Represents a correction item, represents the distance between the second position point and the first position point, a represents the preset distance threshold, C represents the first convolution function, represents the first smooth function, represents the non-uniform fast Fourier transform, represents the fast Fourier transform, Represents non-uniform inverse fast Fourier transform.

[0020] Optionally, when the distance between the second position point and the first position point of the radionuclide is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of the first smooth function and a correction term;

[0021] When the distance between the second position point and the first position point of the radionuclide is greater than the preset distance threshold, the second convolution function of the second position point is represented as a first smooth function;

[0022] Wherein, the expression of the first smooth function is:

[0023]

[0024] Among them, d is the distance between the second position point and the first position point, p is the smoothness, k j To calculate the coefficient, is the second convolution function.

[0025] Optionally, determining the three-dimensional convolution of the photon flux rate at the second position point according to the concentration data and the physical parameter data in combination with a preset relationship includes:

[0026] Determine a three-dimensional integral of the photon flux rate at the second position point according to the concentration data and the physical parameter data;

[0027] In combination with a preset relationship, the three-dimensional integral of the photon flux rate of the second position point is converted into a three-dimensional convolution, wherein the number of the second position point is at least one.

[0028] Optionally, the preset distance threshold is a near-field radius of the gamma radiation field.

[0029] Optionally, the concentration data of the radionuclides at the N locations are obtained by simulating an atmospheric diffusion model.

[0030] In a second aspect, an embodiment of the present invention provides a device for predicting a radiation dose rate of a radionuclide, the device comprising:

[0031] An acquisition module, used to acquire concentration data and physical parameter data of radionuclides at N positions in a three-dimensional space, wherein N is a natural number greater than 1, and the concentration data is non-equidistantly distributed data;

[0032] A first determination module is used to determine a three-dimensional convolution of a photon flux rate at a second position point according to the concentration data and the physical parameter data in combination with a preset relationship, wherein the photon flux rate is the sum of the photon flux rates of rays passing through the second position point, and the second position point is an arbitrary position point in the three-dimensional space;

[0033] A reconstruction module, used for reconstructing the three-dimensional convolution of the photon flux rate at the second position point to obtain a three-dimensional convolution in Fourier form;

[0034] A calculation module, configured to calculate the three-dimensional convolution of the Fourier form of the second position point by using a non-uniform fast Fourier transform algorithm to determine a corresponding target photon flux rate;

[0035] The second determination module is used to determine the radiation dose rate in the three-dimensional space according to the physical parameter data and the target photon flux rate.

[0036] In a third aspect, an embodiment of the present invention provides a device for predicting a radiation dose rate of a radionuclide, the device comprising: a processor and a memory storing computer program instructions;

[0037] When the processor executes the computer program instructions, the method for predicting the radiation dose rate of the radionuclide as described in the first aspect and optionally in the first aspect is implemented.

[0038] In a fourth aspect, an embodiment of the present invention provides a computer storage medium having computer program instructions stored thereon, which, when executed by a processor, implements a method for predicting the radiation dose rate of a radioactive nuclide as described in the first aspect and optionally in the first aspect.

[0039] The method, device, equipment and computer storage medium for predicting the radiation dose rate of radionuclides of the embodiments of the present invention can accelerate the processing speed of the convolution operation in the radiation dose rate calculation model through the non-uniform fast Fourier transform (NFFT) algorithm, and realize the rapid solution of the radiation dose rate of radionuclides. At the same time, in three-dimensional space, the concentration data of radionuclides is non-equidistant distribution data, and the non-uniform fast Fourier transform algorithm can realize the processing of non-equidistant distribution data resources, without the need to pre-equidistantly process the non-equidistant distribution data, thereby reducing the loss of data accuracy and ensuring the accuracy of the data to a certain extent. Therefore, through the technical solution of the present invention, the distribution of the radiation dose rate in three-dimensional space can be predicted more accurately and quickly, that is, the efficiency and accuracy of predicting the radiation dose rate in three-dimensional space are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for use in the embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 It is a schematic flow chart of a method for predicting the radiation dose rate of a radionuclide provided by an embodiment of the present invention;

[0042] Figure 2 is a schematic flow chart of a method for predicting the radiation dose rate of a radionuclide provided by another embodiment of the present invention;

[0043] Figure 3 is a schematic structural diagram of a device for predicting the radiation dose rate of a radionuclide provided by another embodiment of the present invention;

[0044] Figure 4 The figure is a structural diagram of an exemplary hardware architecture of an electronic device for predicting the radiation dose rate of a radionuclide according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The features and exemplary embodiments of various aspects of the present invention will be described in detail below. In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present invention by illustrating examples of the present invention.

[0046] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0047] In the event of a radionuclide emission, timely understanding of the radiation dose rate distribution of radionuclides in the three-dimensional space where the incident occurred is very important for the reasonable assessment of radiation exposure and corresponding health risks. For example, in the handling of nuclear accidents, sometimes it is necessary to inject water into the accident reactor in the air by aircraft. At this time, it is necessary to estimate the radiation dose rate in the three-dimensional space of the accident area. Based on the results of accurate estimation, the radiation exposure and corresponding health risks of the area can be effectively assessed, and it can be determined whether emergency measures such as aerial treatment can be carried out.

[0048] However, for three-dimensional spaces with complex distribution of radionuclides, such as spaces with complex geographical terrain and spaces with complex buildings and streets, it is very difficult to estimate and predict the radiation dose rate of radionuclides in such three-dimensional spaces. Existing estimation and prediction methods have problems such as slow calculation speed and possible loss of data accuracy during the calculation process.

[0049] In order to solve the problems of the prior art, the embodiments of the present invention provide a method, device, equipment and computer storage medium for predicting the radiation dose rate of radionuclides. By implementing a fast convolution operation based on the non-uniform fast Fourier transform NFFT algorithm, in the radiation dose rate calculation model of three-dimensional space, the convolution operation speed is improved while the accuracy and versatility of the calculation model are not lost, and thus, a more accurate prediction result of the radiation dose rate of radionuclides can be obtained.

[0050] The following describes the method, device, equipment and medium for predicting the radiation dose rate of radionuclides provided according to the embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that these embodiments are not intended to limit the scope of the present invention.

[0051] First, the method for predicting the radiation dose rate of radionuclides provided in an embodiment of the present invention is introduced.

[0052] like Figure 1 As shown, Figure 1 1 is a flow chart of a method for predicting the radiation dose rate of a radionuclide provided by an embodiment of the present invention. In the embodiment of the present invention, the method for predicting the radiation dose rate of a radionuclide includes:

[0053] S101: Acquire concentration data and physical parameter data of radioactive nuclides at N first position points in a three-dimensional space.

[0054] Here, the first position points are position points where the radioactive nuclides are distributed in three-dimensional space, and the number of the first position points may be N, where N is a natural number greater than 1. The concentration data of the radioactive nuclides may be data of non-equidistant distribution.

[0055] The physical parameter data of the radionuclide can be obtained by looking up a table or the like according to the type of the radionuclide. The physical parameter data may include, but are not limited to, any one or more of the following parameter data: air density, proportionality factor between effective dose and air absorption dose, conversion factor, linear energy absorption coefficient, gamma ray energy, branching ratio of the nuclide at a specific energy, distance, etc.

[0056] In addition, the concentration data of the radionuclide is the concentration data obtained by simulating the atmospheric diffusion model. The atmospheric diffusion model may include but is not limited to any one or more of the following models: Gaussian linear model, Lagrangian particle model and Gaussian puff model. It is understood that the concentration data of the radionuclide can be obtained according to the actual situation using the existing technology, and will not be described in detail here.

[0057] The concentration data and related physical parameter data of the first position point can be used to calculate the radiation dose rate of the second position point, that is, the radiation dose rate of the position point to be measured.

[0058] S102: Determine the three-dimensional convolution of the photon flux rate at the second position point according to the concentration data and the physical parameter data in combination with a preset relationship.

[0059] Here, the second position point is any position point in the three-dimensional space, the second position point is a position point to be measured, and the second position point is at least one. The second position point can be any position, can be the same position as the first position point, or can be a different position from the first position point. The second position point and the number of the second position points are selected according to the needs.

[0060] Specifically, the photon flux rate may be the sum of the photon flux rates of rays passing through the second position point, and the rays may specifically be gamma rays in three-dimensional space. The photon flux rate takes into account the contribution of radioactive nuclides at different positions in the air.

[0061] In the calculation model of radiation dose rate, the calculation amount of photon flux rate is relatively large, and usually, it can occupy nearly all the calculation amount of the calculation model of radiation dose rate. Therefore, in order to improve the calculation efficiency of radiation dose rate, it is necessary to improve the calculation efficiency of photon flux rate.

[0062] Specifically, the three-dimensional integral of the photon flux rate at the second position point is determined based on the acquired concentration data and physical parameter data of the N first position points.

[0063] In combination with the preset relationship, the three-dimensional integral of the photon flux rate at the second position point is converted into a three-dimensional convolution, wherein the number of the second position points may be one or more. Here, the preset relationship may be a functional relationship of the relevant physical parameter data, and in combination with the preset relationship, the three-dimensional integral of the photon flux rate may be converted into a three-dimensional convolution.

[0064] Specifically, in the embodiment of the present invention, the three-dimensional convolution of the photon flux rate at the second position point includes a first convolution function and a second convolution function.

[0065] Here, the second position point is the position point to be measured, and correspondingly, the first position point of the radionuclide is the source position of the radionuclide. The distance between the position point to be measured and the source position of the radionuclide may have a singular point in the near field, that is, the distance between the two position points is 0, so the second convolution function needs to be processed to ensure the convergence of the second convolution function.

[0066] Specifically, when calculating the second convolution function, the distance between the two position points is compared with a preset distance threshold:

[0067] When the distance between the second position point and the first position point is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of the first smoothing function and the correction term;

[0068] When the distance between the second position point and the first position point is greater than the preset distance threshold, the second convolution function of the second position point is represented as a first smooth function.

[0069] Specifically, the preset distance threshold may be the near field radius of the gamma radiation field. It is understandable that the preset distance threshold may be adjusted according to different situations.

[0070] Optionally, the first convolution function may be concentration data of three-dimensional convolution, that is, concentration distribution data, and the second convolution function may be a convolution kernel function of three-dimensional convolution.

[0071] Specifically, here, the first smooth function is a smooth function, and specifically, a smooth function refers to a function that is continuously differentiable with infinite order within its definition domain. By processing the singular points, the second convolution function can be optimized to ensure the convergence of the second convolution function and improve the accuracy of data processing.

[0072] S103: reconstructing the three-dimensional convolution of the photon flux rate at the second position point to obtain a three-dimensional convolution in Fourier form.

[0073] Specifically, the three-dimensional convolution in Fourier form is obtained by converting the three-dimensional convolution function into the Fourier domain according to the convolution theorem.

[0074] Here, the convolution theorem states that the Fourier transform of a function convolution is the product of the Fourier transforms of the functions. Specifically, it is divided into the time domain convolution theorem and the frequency domain convolution theorem. The time domain convolution theorem means that the convolution in the time domain corresponds to the product in the frequency domain; the frequency domain convolution theorem means that the convolution in the frequency domain corresponds to the product in the time domain, and the two have a dual relationship.

[0075] Here, the computational complexity of the three-dimensional convolution operation may be very high, and may consume a large amount of processing resources. In order to reduce this burden on computing resources, the three-dimensional convolution of the second position point may be reconstructed to obtain a three-dimensional convolution in Fourier form, that is, the first convolution function and the second convolution function of the three-dimensional convolution are converted into the Fourier domain.

[0076] S104: Calculate the three-dimensional convolution of the Fourier form of the second position point using a non-uniform fast Fourier transform algorithm to determine a corresponding target photon flux rate.

[0077] Here, after the first convolution function and the second convolution function of the three-dimensional convolution are converted into the Fourier domain in S103, the corresponding target photon flux rate of the second position point is calculated by the following formula using a non-uniform fast Fourier transform algorithm, etc.:

[0078]

[0079] in, represents a correction item;

[0080] represents the distance vector between the second position point and the first position point; a represents a preset distance threshold;

[0081] C represents the first convolution function; represents the first smooth function;

[0082] NFFT stands for Non-Uniform Fast Fourier Transform, FFT stands for Fast Fourier Transform, and NFFT-1 stands for Inverse Non-Uniform Fast Fourier Transform.

[0083] It can be understood that C represents the first convolution function, that is, it can be the concentration data of three-dimensional convolution, and the concentration data is non-equidistantly distributed data. The operation of the first convolution function can use non-uniform fast Fourier transform calculation technology.

[0084] The first smooth function is for equally distributed data. The calculation of the first smooth function can use either the fast Fourier transform calculation technology or the non-uniform fast Fourier transform calculation technology. Because the fast Fourier transform calculation technology is more efficient in processing resources than the non-uniform fast Fourier transform calculation technology, the fast Fourier transform calculation technology is preferably used here.

[0085] The non-uniform inverse fast Fourier transform is to convert the Fourier form result obtained by the above calculation back to the original three-dimensional convolution result, that is, to convert from the frequency domain of the Fourier domain back to the time domain of the original three-dimensional convolution. Then, the target photon flux rate can be obtained.

[0086] Specifically, the expression of the first smooth function is:

[0087]

[0088] Where d is the distance between the location point and the radionuclide source, p is the smoothness, kj is the calculation coefficient, is the second convolution function. Here d is The parameters have the same meaning.

[0089] Therefore, by implementing the convolution operation in the spatial domain as a multiplication operation in the Fourier domain, the computational burden can be reduced and the target photon flux rate can be calculated more quickly.

[0090] S105: Determine the radiation dose rate in the three-dimensional space according to the physical parameter data and the target photon flux rate.

[0091] Here, for any second position point r0=(x0, y0, z0), the radiation dose rate of the second position point can be calculated according to the physical parameter data of the position point and the target photon flux rate by the following formula:

[0092]

[0093] Among them, ω is the proportionality factor between the effective dose and the air absorbed dose, representing the radiation risk of organisms;

[0094] K is the conversion factor; μ a is the linear energy absorption coefficient; E γ is the gamma ray energy; ρ is the air density; f n (E γ ) is the branching ratio of nuclide n at a specific energy;

[0095] The energy is E γ The photon flux rate formed by the gamma rays at the calculation point, that is, the second position point, takes into account the contribution of radionuclides at different positions in the air.

[0096] Specifically, for the second position point, the corresponding target photon flux rate can be calculated through the above S101 to S104, and then based on the calculated target photon flux rate and the corresponding physical parameter data, the radiation dose rate corresponding to the second position point can be calculated through formula (3).

[0097] Specifically, the second position point may be a position point distributed in the three-dimensional space. The second position point may be selected according to demand, and the number of selected second position points may be at least one. Thus, based on the radiation dose rate of at least one second position point, the distribution of the radiation dose rate in the three-dimensional space may be predicted.

[0098] In summary, in an embodiment of the present invention, the method for predicting the radiation dose rate of the radionuclide can accelerate the processing speed of the convolution operation in the radiation dose rate calculation model through the non-uniform fast Fourier transform NFFT algorithm, and realize the rapid solution of the radiation dose rate of the radionuclide. At the same time, in three-dimensional space, the concentration data of the radionuclide is non-equidistantly distributed data, and the non-uniform fast Fourier transform algorithm can process the non-equidistantly distributed data resources without the need to pre-equidistantly process the non-equidistantly distributed data, thereby reducing the loss of data accuracy and ensuring the accuracy of the data resources to a certain extent. Therefore, through the method of the present invention, the distribution of the radiation dose rate of the radionuclide in three-dimensional space can be predicted more accurately and quickly, that is, the efficiency and accuracy of predicting the radiation dose rate in three-dimensional space are improved.

[0099] Optionally, in another embodiment of the present invention, since the second position point can be a position point to be measured selected arbitrarily in the three-dimensional space, the second position point can be the first position point. Figure 2 As shown, Figure 2 FIG. 1 is a flow chart of a method for predicting the radiation dose rate of a radionuclide provided by another embodiment of the present invention. The prediction method can be specifically implemented as follows:

[0100] S201: Acquire concentration data and physical parameter data of radioactive nuclides at N position points in three-dimensional space.

[0101] Here, N is a natural number greater than 1. The concentration data of the radionuclide are all non-equidistantly distributed data. The concentration data of the radionuclide can be the concentration distribution data of the radionuclide in the three-dimensional space.

[0102] The physical parameter data of the radionuclide can be obtained by looking up a table or the like according to the type of the radionuclide. The physical parameter data may include, but are not limited to, any one or more of the following parameter data: air density, proportionality factor between effective dose and air absorption dose, conversion factor, linear energy absorption coefficient, gamma ray energy, branching ratio of the nuclide at a specific energy, distance, etc.

[0103] In addition, the concentration data of the radionuclide is the concentration data obtained by simulating the atmospheric diffusion model. The atmospheric diffusion model may include but is not limited to any one or more of the following models: Gaussian linear model, Lagrangian particle model and Gaussian puff model. It is understood that the concentration data of the radionuclide can be obtained according to the actual situation using the existing technology, and will not be described in detail here.

[0104] S202: Determine the three-dimensional convolution of the photon flux rates of the N position points according to the concentration data and the physical parameter data in combination with a preset relationship.

[0105] Specifically, in the embodiment of the present invention, the N position points may be any designated position points to be measured, and the N position points may be the N position points in S201. The radiation dose rate of any position point to be measured may be calculated based on the photon flux rate of the position point and the corresponding physical parameter data. The photon flux rate is the photon flux rate of the rays corresponding to the N position points to be measured.

[0106] In the calculation model of radiation dose rate, the calculation amount of photon flux rate is relatively large, and usually, it can occupy almost all the calculation amount of the calculation model of radiation dose rate. Therefore, in order to improve the calculation efficiency of radiation dose rate, it is necessary to improve the calculation efficiency of photon flux rate.

[0107] Specifically, the three-dimensional integral of the photon flux rate of N locations to be measured is determined based on the concentration data and physical parameter data of the radioactive nuclide.

[0108] Combined with the preset relationship, the three-dimensional integral of the photon flux rate of the N positions to be measured is converted into a three-dimensional convolution.

[0109] Here, the preset relationship may be a relationship between a correlation function and a physical parameter, converting the three-dimensional integral of the photon flux rate into a three-dimensional convolution.

[0110] Specifically, in the embodiment of the present invention, the three-dimensional convolution of the photon flux rates of N locations to be measured includes a first convolution function and a second convolution function.

[0111] Here, the distance between the position point to be measured and the source position of the radionuclide may have a singular point in the near field, that is, the distance between the above two positions is 0. Therefore, the second convolution function needs to be regularized to ensure the convergence of the second convolution function.

[0112] Specifically, when the distance between the position point to be measured and the source position of the radionuclide is not greater than a preset distance threshold, the second convolution function of the position point to be measured is expressed as the sum of the first smoothing function and the correction term.

[0113] When the distance between the position point to be measured and the source position of the radionuclide is greater than the preset distance threshold, the second convolution function of the position point to be measured is represented by the first smooth function.

[0114] Optionally, the first convolution function may be concentration data of three-dimensional convolution, i.e., concentration distribution data, and the second convolution function may be a convolution kernel function of three-dimensional convolution. The preset distance threshold may be a near field radius of a gamma radiation field, and it is understandable that the preset distance threshold may be adjusted according to different situations.

[0115] Here, the first smooth function is a smooth function, specifically, a smooth function refers to a function that is continuously differentiable with infinite order in its definition domain. By processing the singular points, the second convolution function can be optimized to ensure the convergence of the second convolution function and improve the accuracy of data processing.

[0116] In different three-dimensional spaces, the source may be radionuclides distributed in the space, and the source position is the position of the concentration data of the radionuclides, which can be obtained by simulating the existing numerical model. It is understandable that the source position can be known according to the actual application scenario, and the means of knowing it can be the existing technical means, which will not be repeated here.

[0117] S203: reconstructing the three-dimensional convolution of the N position points to obtain a three-dimensional convolution in Fourier form.

[0118] Here, the computational complexity of the three-dimensional convolution operation may be very high, and may consume a large amount of processing resources. In order to reduce this burden on computing resources, the three-dimensional convolution of N position points can be reconstructed to obtain the three-dimensional convolution in Fourier form, that is, the first convolution function and the second convolution function of the three-dimensional convolution are converted into the Fourier domain.

[0119] S204: Calculate the three-dimensional convolution of the Fourier form of the N position points using a non-uniform fast Fourier transform algorithm to determine the corresponding target photon flux rate.

[0120] Here, after the first convolution function and the second convolution function of the three-dimensional convolution are converted into the Fourier domain in S203, the target photon flux rates corresponding to the N position points are calculated by the following formula using a non-uniform fast Fourier transform algorithm, etc.:

[0121]

[0122] in, represents a correction item;

[0123] Indicates the distance between the location to be measured and the radionuclide; a indicates the preset distance threshold;

[0124] C represents the first convolution function; represents the first smooth function;

[0125] NFFT stands for Non-Uniform Fast Fourier Transform, FFT Fast Fourier Transform, NFFT -1 Represents non-uniform inverse fast Fourier transform.

[0126] It can be understood that C represents the first convolution function, that is, it can be the concentration data of three-dimensional convolution, and the concentration data is non-equidistantly distributed data. The operation of the first convolution function can use non-uniform fast Fourier transform calculation technology.

[0127] The first smooth function is for equally distributed data. The calculation of the first smooth function can use either the fast Fourier transform calculation technology or the non-uniform fast Fourier transform calculation technology. Because the fast Fourier transform calculation technology is more efficient in processing resources than the non-uniform fast Fourier transform calculation technology, the fast Fourier transform calculation technology is preferably used here.

[0128] The non-uniform inverse fast Fourier transform converts the Fourier form result obtained by the above calculation back to the three-dimensional convolution, that is, converts from the frequency domain of the Fourier domain back to the spatial domain of the three-dimensional convolution. Then, the target photon flux rate can be obtained.

[0129] Specifically, the expression of the first smooth function is:

[0130]

[0131] Where d is the distance between the location point and the radionuclide source, p is the smoothness, kj is the calculation coefficient, is the second convolution function. Here d is The parameters have the same meaning.

[0132] Therefore, by implementing the convolution operation in the spatial domain as a multiplication operation in the Fourier domain, the computational burden can be reduced and the target photon flux rate can be calculated more quickly.

[0133] S205: Determine the radiation dose rate in the three-dimensional space according to the physical parameter data of the N position points and the target photon flux rate.

[0134] Here, for a position point r0=(x0, y0, z0), the radiation dose rate of the position point can be calculated according to the physical parameter data of the position point and the target photon flux rate by the following formula:

[0135]

[0136] Among them, ω is the proportionality factor between the effective dose and the air absorbed dose, representing the radiation risk of organisms;

[0137] K is the conversion factor; μ a is the linear energy absorption coefficient; E γ is the gamma ray energy; ρ is the air density; f n (E γ) is the branching ratio of nuclide n at a specific energy;

[0138] The energy is E γ The photon flux rate of gamma rays formed at the calculation point takes into account the contribution of radionuclides at different positions in the air.

[0139] Specifically, for N positions to be measured, the corresponding target photon flux rate can be calculated through the above S201 to S204, and then according to the target photon flux rate of the N positions to be measured and the corresponding physical parameter data, the radiation dose rate corresponding to the N positions to be measured can be calculated through formula (3). The N positions to be measured are distributed in a three-dimensional space, and thus, according to the radiation dose rate of each position point, the distribution of the radiation dose rate in the three-dimensional space can be predicted.

[0140] In summary, in an embodiment of the present invention, the method for predicting the radiation dose rate of the radionuclide can accelerate the processing speed of the convolution operation in the radiation dose rate calculation model through the non-uniform fast Fourier transform NFFT algorithm, and realize the rapid solution of the radiation dose rate of the radionuclide. At the same time, in three-dimensional space, the concentration data of the radionuclide is non-equidistantly distributed data, and the non-uniform fast Fourier transform algorithm can process the non-equidistantly distributed data resources without the need to pre-equidistantly process the non-equidistantly distributed data, thereby reducing the loss of data accuracy and ensuring the accuracy of the data resources to a certain extent. Therefore, through the method of the present invention, the distribution of the radiation dose rate of the radionuclide in three-dimensional space can be predicted more accurately and quickly, that is, the efficiency and accuracy of predicting the radiation dose rate in three-dimensional space are improved.

[0141] In order to better understand the method of the present invention, the method for predicting the radiation dose rate of the radioactive nuclide is now described in detail in conjunction with an application example.

[0142] Optionally, in some embodiments of the present invention, in actual application scenarios, the radiation dose rate of radionuclides in three-dimensional space can be predicted in the following manner.

[0143] First, regarding the radiation dose rate of radionuclides in three-dimensional space, for a position point r0 = (x0, y0, z0) to be measured, the radiation dose rate of the position point can be calculated by the following formula:

[0144]

[0145] Among them, ω is the proportionality factor between the effective dose and the air absorbed dose, representing the radiation risk of organisms;

[0146] K is the conversion factor; μ ais the linear energy absorption coefficient; E γ is the gamma ray energy; ρ is the air density; f n (E γ ) is the branching ratio of nuclide n at a specific energy;

[0147] The energy is E γ The photon flux rate of gamma rays formed at the calculation point takes into account the contribution of radionuclides at different positions in the air.

[0148] In the three-dimensional dose rate field calculation, the photon flux rate The calculation of the radiation dose rate is the largest because it involves three-dimensional integration at each position. Therefore, to quickly and accurately calculate the radiation dose rate, it is mainly necessary to realize the fast and accurate calculation of the photon flux rate.

[0149] Specifically, for any three-dimensional distribution of radionuclides The photon flux rate caused by the single energy ray at the position r0 = (x0, y0, z0) can be calculated by the following formula:

[0150]

[0151] in, is the accumulation factor of scattered photons, μ is the linear attenuation factor of air, which depends on the photon energy, It is a location point At the source location The distance vector of , which can be specifically the Euclidean distance between two location points.

[0152] For example, for the radionuclide argon-41 ( 41 Ar) parameters are involved in the dose calculation, and the radiation energy E γ =1.294 MeV, branching ratio f n (E γ )=99.2%, air linear attenuation coefficient, μ=7.24×10 -3 per meter (m -1 ), linear energy absorption coefficient μ a =2.05×10 -3 per meter (m -1 ), the proportionality factor between effective dose and air absorbed dose ω=7.35×10 -1 Sievers per Gray (Sv / Gy). The volume of the three-dimensional integration is determined by the mean free path and can be 5 / μ = 6.91×10 2 Meter (m).

[0153] Here, due to The accumulation factor is a function of photon energy, linear attenuation coefficient and distance. The accumulation factor in linear form used here is that for a certain photon energy, the linear attenuation factor of air is a constant. It can be understood that the above functional relationship is a preset relationship. Therefore, formula (4) can be converted into formula (5) based on the above functional relationship:

[0154]

[0155] in,

[0156]

[0157] Formula (5) is the function expression of three-dimensional convolution, where: is the three-dimensional convolution kernel function, that is, the second convolution function. The concentration distribution data is a first convolution function, and the first convolution function is non-equidistantly distributed data.

[0158] Optionally, before reconstructing formula (5) and converting it into Fourier form, it is necessary to The singular point in the near field, to handle the situation.

[0159] By comparing the distance between two points and the near field radius, It can be expressed as:

[0160]

[0161] Substituting formula (7) into formula (5), we can get

[0162]

[0163] Among them, calculation It is a key step to achieve fast computing.

[0164] According to the known convolution theorem and Fourier transform properties, the following transformation can be performed:

[0165]

[0166] in, represents Fourier transform and * represents convolution. The concentration data in is non-equidistant distribution data, so NFFT can be used for fast calculation. The first smooth function in can be quickly calculated using either NFFT or FFT. Fast computing improves resource processing efficiency.

[0167] Based on the fast calculation of NFFT, formula (9) can be converted to:

[0168]

[0169] Substituting formula (10) into formula (8), we can obtain formula (1):

[0170]

[0171] Among them, the expression of the first smooth function is:

[0172]

[0173] Among them, d is the distance between the position to be measured and the position of the radionuclide source, p is the smoothness, k is the j To calculate the coefficient, is the second convolution function. Here d can be expressed as

[0174] Optionally, calculate the coefficient k j It can be calculated by the following formula:

[0175]

[0176] Where (n) represents the nth-order derivative.

[0177] Finally, for N locations to be measured, the corresponding target photon flux rate can be calculated according to formula (1). According to the target photon flux rate and the corresponding physical parameter data, the radiation dose rate corresponding to the N locations to be measured can be calculated by formula (3). Thus, the distribution of the radiation dose rate in the three-dimensional space can be predicted.

[0178] In summary, in the calculation model of radiation dose rate in three-dimensional space, the calculation of radiation dose rate is large mainly because the calculation of photon flux rate is large and consumes more processing resources. Calculating photon flux rate is the key step in calculating radiation dose rate. Therefore, solving the problem of calculation efficiency of photon flux rate can improve the calculation speed of radiation dose rate. At the same time, the concentration distribution data in photon flux rate is non-equidistant distribution data and cannot be directly used for calculation.

[0179] In order to solve the existing problems, the technical solution of the present invention can quickly calculate the three-dimensional convolution of the photon flux rate involving non-equidistant distribution data through the non-uniform fast Fourier transform NFFT algorithm. Through this method, non-equidistant distribution data can be processed to improve the accuracy of data processing; the speed of calculating the three-dimensional convolution of the photon flux rate can be accelerated to improve the efficiency of data processing, thereby improving the efficiency and accuracy of predicting radiation dose rate.

[0180] In addition, through the verification experiment of computational complexity, the efficiency of the non-uniform fast Fourier transform algorithm used in the present invention in processing data is significantly better than the existing three-dimensional integral calculation. For example, with the increase of the number of positions to be measured or the increase of the concentration distribution data, the computational complexity of the three-dimensional integral calculation increases rapidly, while the computational complexity of the non-uniform fast Fourier transform algorithm used in the present invention does not change significantly.

[0181] Based on the method for predicting the radiation dose rate of radionuclides provided in the above embodiments, the present application also provides a specific implementation of a device for predicting the radiation dose rate of radionuclides. Please refer to the following embodiments.

[0182] In one embodiment of the present invention, Figure 3 As shown, Figure 3 A schematic diagram of the structure of a device for predicting the radiation dose rate of a radionuclide provided by another embodiment of the present invention, wherein the device for predicting the radiation dose rate of a radionuclide comprises:

[0183] An acquisition module 301 is used to acquire concentration data and physical parameter data of radionuclides at N positions in a three-dimensional space, wherein N is a natural number greater than 1, and the concentration data is non-equidistantly distributed data;

[0184] A first determination module 302 is used to determine a three-dimensional convolution of a photon flux rate at a second position point according to the concentration data and the physical parameter data in combination with a preset relationship, wherein the photon flux rate is a photon flux rate of a ray corresponding to the second position point, and the second position point is an arbitrary position point in the three-dimensional space;

[0185] A reconstruction module 303, used for reconstructing the three-dimensional convolution of the second position point to obtain a three-dimensional convolution in Fourier form;

[0186] A calculation module 304 is used to calculate the three-dimensional convolution of the Fourier form of the second position point by using a non-uniform fast Fourier transform algorithm to determine the corresponding target photon flux rate;

[0187] The second determination module 305 is used to determine the radiation dose rate in the three-dimensional space according to the physical parameter data and the target photon flux rate.

[0188] In summary, in an embodiment of the present invention, the method for predicting the radiation dose rate of the radionuclide can accelerate the processing speed of the convolution operation in the radiation dose rate calculation model through the non-uniform fast Fourier transform algorithm, and realize the rapid solution of the radiation dose rate of the radionuclide. At the same time, in three-dimensional space, the concentration data of the radionuclide is non-equidistantly distributed data, and the non-uniform fast Fourier transform algorithm can process the non-equidistantly distributed data resources without the need to pre-equidistantly process the non-equidistantly distributed data, thereby reducing the loss of data accuracy and ensuring the accuracy of the data resources to a certain extent. Therefore, through the method of the present invention, the distribution of the radiation dose rate of the radionuclide in three-dimensional space can be predicted more accurately and quickly, that is, the efficiency and accuracy of predicting the radiation dose rate in three-dimensional space are improved.

[0189] Optionally, in some embodiments of the present invention, specifically, the first determination module can also be used to determine the three-dimensional integral of the photon flux rate at the second position point based on the concentration data and physical parameter data of the radioactive nuclide; and in combination with a preset relationship, convert the three-dimensional integral of the photon flux rate at the second position point into a three-dimensional convolution.

[0190] Optionally, in some embodiments of the present invention, the calculation module is specifically used for:

[0191] According to the first convolution function and the second convolution function in Fourier form, a non-uniform fast Fourier transform algorithm is used to calculate the corresponding target photon flux rate of at least one second position point through formula (1) in the above embodiment.

[0192] Optionally, in some embodiments of the present invention, the three-dimensional convolution of the photon flux rate of at least one second position point includes a first convolution function and a second convolution function, and at least one second position point is a position point to be measured. The device for predicting the radiation dose rate of the radionuclide further includes:

[0193] A comparison module is used to represent the second convolution function of the second position point as the sum of the first smooth function and the correction term when the distance between the second position point and the first position point of the radionuclide is not greater than a preset distance threshold; and represent the second convolution function of the second position point as the first smooth function when the distance between the second position point and the first position point of the radionuclide is greater than the preset distance threshold.

[0194] Figure 4 It is a structural diagram of an exemplary hardware architecture of an electronic device according to an embodiment of the present invention.

[0195] like Figure 4As shown, the computing device 400 includes an input device 401, an input interface 402, a central processing unit 403, a memory 404, an output interface 405, and an output device 406. The input interface 402, the central processing unit 403, the memory 404, and the output interface 405 are interconnected via a bus 410, and the input device 401 and the output device 406 are connected to the bus 410 via the input interface 402 and the output interface 405, respectively, and are further connected to other components of the computing device 400.

[0196] Specifically, the input device 401 receives input information from the outside and transmits the input information to the central processing unit 403 through the input interface 402; the central processing unit 403 processes the input information based on the computer executable instructions stored in the memory 404 to generate output information, temporarily or permanently stores the output information in the memory 404, and then transmits the output information to the output device 406 through the output interface 405; the output device 406 outputs the output information to the outside of the computing device 400 for user use.

[0197] That is to say, Figure 4 The computing device shown can also be used to implement a device for predicting the radiation dose rate of a radionuclide. The device for predicting the radiation dose rate of a radionuclide may include: a memory storing computer executable instructions; and a processor. When executing the computer executable instructions, the processor may implement a method for combining Figure 1 and Figure 2 A method for predicting radiation dose rates of radionuclides is described.

[0198] An embodiment of the present invention further provides a computer-readable storage medium having computer program instructions stored thereon; when the computer program instructions are executed by a processor, the method for predicting the radiation dose rate of a radioactive nuclide provided in an embodiment of the present invention is implemented.

[0199] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figure. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiment, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention. The functional blocks shown in the structural block diagram described above can be implemented as hardware, software, firmware or a combination thereof. When implemented in hardware, it can be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, plug-in, function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or communication link via a data signal carried in a carrier. "Machine-readable medium" can include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROMs, flash memories, erasable ROMs (EROMs), floppy disks, CD-ROMs, optical disks, hard disks, optical fiber media, radio frequency (RF) links, and the like. The code segments may be downloaded via a computer network such as the Internet, an intranet, or the like.

[0200] The present invention may be implemented in other specific forms without departing from its spirit and essential features. For example, the algorithms described in a specific embodiment may be modified, and the device architecture does not depart from the basic spirit of the present invention. Therefore, the current embodiments are considered to be illustrative and not restrictive in all aspects, the scope of the present invention is defined by the appended claims rather than the above description, and all changes that fall within the meaning and equivalent scope of the claims are thus included in the scope of the present invention.

Claims

1. A method for predicting the radiation dose rate of a radionuclide, characterized in that: include: Acquire concentration data and physical parameter data of radioactive nuclides at N first position points in a three-dimensional space, wherein N is a natural number greater than 1, and the concentration data is non-equidistantly distributed data; According to the concentration data and the physical parameter data, in combination with a preset relationship, determine a three-dimensional convolution of a photon flux rate at a second position point, wherein the photon flux rate is the sum of photon flux rates of rays passing through the second position point, and the second position point is an arbitrary position point in the three-dimensional space; Reconstructing the three-dimensional convolution of the photon flux rate at the second position point to obtain a three-dimensional convolution in Fourier form, the three-dimensional convolution of the photon flux rate at the second position point includes a first convolution function and a second convolution function, when the distance between the second position point and the first position point is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of a first smooth function and a correction term; when the distance between the second position point and the first position point is greater than the preset distance threshold, the second convolution function of the second position point is expressed as the first smooth function; Using a non-uniform fast Fourier transform algorithm, calculating the three-dimensional convolution of the Fourier form of the second position point to determine the corresponding target photon flux rate, the three-dimensional convolution of the Fourier form is obtained based on the conversion of the first convolution function and the second convolution function; The radiation dose rate in the three-dimensional space is determined according to the physical parameter data and the target photon flux rate.

2. The method according to claim 1, characterized in that Calculating the three-dimensional convolution of the Fourier form of the second position point using a non-uniform fast Fourier transform algorithm to determine the corresponding target photon flux rate includes: According to the first convolution function and the second convolution function in Fourier form, the target photon flux rate corresponding to the second position point is calculated by the following formula using a non-uniform fast Fourier transform algorithm: in, Represents a correction term, represents the distance between the second position point and the first position point, a represents the preset distance threshold, C represents the first convolution function, represents the first smooth function, NFF T represents non-uniform fast Fourier transform, FFT represents fast Fourier transform, NF FT -1 Represents inverse non-uniform fast Fourier transform.

3. The method according to claim 1 or 2, characterized in that: When the distance between the second position point and the first position point is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of the first smoothing function and the correction term; When the distance between the second position point and the first position point is greater than the preset distance threshold, the second convolution function of the second position point is represented as a first smooth function; Wherein, the expression of the first smooth function is: Among them, d is the distance between the second position point and the first position point, p is the smoothness, k j To calculate the coefficient, is the second convolution function.

4. The method according to claim 1 or 2, characterized in that: Determining the three-dimensional convolution of the photon flux rate at the second position point according to the concentration data and the physical parameter data in combination with a preset relationship includes: Determine a three-dimensional integral of the photon flux rate at the second position point according to the concentration data and the physical parameter data; In combination with a preset relationship, the three-dimensional integral of the photon flux rate of the second position point is converted into a three-dimensional convolution, wherein the number of the second position point is at least one.

5. The method according to claim 1, characterized in that The preset distance threshold is the near-field radius of the gamma radiation field.

6. The method according to claim 1, characterized in that The concentration data of the radioactive nuclides at the N first position points are obtained by simulating an atmospheric diffusion model.

7. A device for predicting radiation dose rate of radionuclides, characterized in that: The device comprises: An acquisition module, used to acquire concentration data and physical parameter data of radionuclides at N first position points in a three-dimensional space, wherein N is a natural number greater than 1, and the concentration data is non-equidistantly distributed data; A first determination module is used to determine a three-dimensional convolution of a photon flux rate at a second position point according to the concentration data and the physical parameter data in combination with a preset relationship, wherein the photon flux rate is the sum of the photon flux rates of rays passing through the second position point, and the second position point is an arbitrary position point in the three-dimensional space; A reconstruction module, used for reconstructing the three-dimensional convolution of the photon flux rate of the second position point to obtain a three-dimensional convolution in Fourier form, wherein the three-dimensional convolution of the photon flux rate of the second position point includes a first convolution function and a second convolution function, and when the distance between the second position point and the first position point is not greater than a preset distance threshold, the second convolution function of the second position point is expressed as the sum of a first smooth function and a correction term; when the distance between the second position point and the first position point is greater than the preset distance threshold, the second convolution function of the second position point is expressed as the first smooth function; A calculation module, configured to calculate the three-dimensional convolution of the Fourier form of the second position point by using a non-uniform fast Fourier transform algorithm to determine a corresponding target photon flux rate, wherein the three-dimensional convolution of the Fourier form is obtained by converting the first convolution function and the second convolution function; The second determination module is used to determine the radiation dose rate in the three-dimensional space according to the physical parameter data and the target photon flux rate.

8. A device for predicting radiation dose rate of radionuclides, characterized in that: The device comprises: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, the method for predicting the radiation dose rate of a radionuclide according to any one of claims 1 to 6 is implemented.

9. A computer storage medium, characterized in that: The computer storage medium stores computer program instructions, which, when executed by a processor, implement the method for predicting the radiation dose rate of a radioactive nuclide as claimed in any one of claims 1 to 6.

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