PET data simulation method and device, computer equipment and storage medium

Abstract

The invention relates to a PET data simulation method and device, computer equipment and a storage medium. The method comprises the following steps: acquiring an input function of radionuclide and a parameter diagram corresponding to a pharmacokinetic model, and determining radiation information corresponding to each voxel in a simulation time period according to the input function and the parameter diagram corresponding to the pharmacokinetic model, so as to determine the radiation information corresponding to each voxel in a preset time period according to the radiation information and attenuation information corresponding to each voxel in the preset time period. And simulating each photon corresponding to the radionuclide in the to-be-simulated object to obtain PET raw data in the preset time period. Wherein the input function is used for representing the change condition of the concentration of the radionuclide in the plasma along with time, and the parameter diagram is used for representing the condition of metabolizing the radionuclide by each voxel. By adopting the method, the simulation accuracy can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medicine, and in particular to a PET data simulation method and device, computer equipment and a storage medium. BACKGROUND

[0002] Positron Emission Computed Tomography (PET) is a three-dimensional imaging non-destructive testing technology that utilizes the injection of a compound labeled with a positron-emitting radioisotope into the interior of a living body to measure the spatial distribution and time characteristics of the compound in the body. PET has the characteristics of high sensitivity, good accuracy and accurate positioning. Monte Carlo Simulation (MCS) is a basic tool for positron emission tomography research and industrial applications. MCS can be used to obtain PET data close to reality, while only needing to be simulated in a computer, without the need to operate a scanner and a radioactive source.

[0003] Currently, in the process of simulation using MCS, static simulation is performed using radioactive information and attenuation information. Existing static MCS tools cannot support dynamic simulation and can only simulate stable tracer distribution. After the injection of radioactive substances into the human body, the distribution of the radioactive substances changes due to a series of physiological processes. How to provide a PET simulation method under the condition of time-varying tracer activity is a key research content for persons skilled in the art. SUMMARY

[0004] Therefore, it is necessary to provide a PET data simulation method, device, computer equipment and storage medium capable of improving the accuracy of simulation in view of the above technical problems.

[0005] In a first aspect, the present application provides a PET data simulation method, comprising:

[0006] obtaining an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model; the input function is used to represent the concentration of the radionuclide in the blood plasma over time, and the parameter map is used to represent the metabolism of the radionuclide in each voxel;

[0007] determining radioactive information corresponding to each voxel in a preset time period according to the input function and the parameter map corresponding to the pharmacokinetic model;

[0008] simulating each photon corresponding to the radionuclide in the to-be-simulated object according to the radioactive information and attenuation information corresponding to each voxel in the preset time period, to obtain PET raw data in the preset time period.

[0009] In one of the embodiments, the radiation information corresponding to each voxel in the preset time period is determined according to the input function and the parameter map corresponding to the pharmacokinetic model, including:

[0010] For each voxel, the dynamic parameter of the voxel is determined according to the parameter map;

[0011] The activity value in the preset time period is determined according to the dynamic parameter and the input function from the start time to the end time of the preset time period;

[0012] The radiation information corresponding to each voxel in the preset time period is determined according to the activity value in the preset time period.

[0013] In one of the embodiments, the radiation information corresponding to each voxel in the preset time period is determined according to the activity value in the preset time period, including:

[0014] For each voxel, the average activity value in the preset time period is determined according to the activity value in the preset time period;

[0015] The radiation information corresponding to each voxel in the preset time period is determined according to the physical property of the radionuclide and the average activity value in the preset time period.

[0016] In one of the embodiments, the average activity value in the preset time period is determined according to the activity value in the preset time period, including:

[0017] The average activity value is obtained by integrating the activity value in the preset time period.

[0018] In one of the embodiments, the PET raw data in the preset time period is obtained by simulating each photon corresponding to the radionuclide in the to-be-simulated object according to the radiation information and the attenuation information corresponding to each voxel in the preset time period, including:

[0019] The relative motion information of the to-be-simulated object between the reference coordinate system and the motion coordinate system in each simulation time period is obtained; the reference coordinate system is static relative to the to-be-simulated object, and the motion coordinate system is static relative to the scanner; the simulation time period corresponds to the preset time period;

[0020] For each simulation time period, the motion process of each photon corresponding to the radionuclide in the to-be-simulated object is simulated according to the relative motion information, the radiation information and the attenuation information, and the PET raw data is obtained.

[0021] In one of the embodiments, the PET raw data is obtained by simulating the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the radiation information and the attenuation information, including:

[0022] According to the relative motion information, the emission information and the attenuation information, a target photon state of each photon on a path of the photon in the motion coordinate system is updated;

[0023] The PET raw data is determined according to the target photon states.

[0024] In a second aspect, the present application further provides a PET data simulation device, comprising:

[0025] An acquisition module is configured to acquire an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model, wherein the input function is used to represent a change of a concentration of the radionuclide in blood plasma over time, and the parameter map is used to represent a metabolism of the radionuclide in each voxel;

[0026] A first determination module is configured to determine, according to the input function and the parameter map corresponding to the pharmacokinetic model, emission information corresponding to each voxel in a preset time period;

[0027] A simulation module is configured to simulate each photon corresponding to the radionuclide in a to-be-simulated object according to the emission information and attenuation information corresponding to each voxel in the preset time period, and obtain PET raw data in the preset time period.

[0028] In a third aspect, the present application further provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements steps of any of the above methods when executing the computer program.

[0029] In a fourth aspect, the present application further provides a computer readable storage medium, which stores a computer program, and the computer program implements steps of any of the above methods when executed by a processor.

[0030] In a fifth aspect, the present application further provides a computer program product, comprising a computer program, and the computer program implements steps of any of the above methods when executed by a processor.

[0031] The PET data simulation method, device, computer device and storage medium have the following advantages. The input function is used to represent the change of the concentration of the radionuclide in the blood plasma over time, and the parameter map is used to represent the metabolism of the radionuclide in each voxel. Therefore, the input function of the radionuclide and the parameter map corresponding to the pharmacokinetic model are obtained, and the corresponding radiation information of each voxel in a preset time period is determined according to the input function and the parameter map corresponding to the pharmacokinetic model. The physiological dynamic condition of the radionuclide in the voxel can be considered in the radiation information, and more accurate radiation information can be obtained. In the related art, the radiation information cannot reflect the dynamic change process of the voxel, and therefore the simulation of the dynamic change of the radionuclide cannot be realized. According to the radiation information and the attenuation information of each voxel in the preset time period, the embodiment can simulate each photon corresponding to the radionuclide in the to-be-simulated object, and therefore more accurate PET raw data in the preset time period can be obtained, and the dynamic change in distribution of the radionuclide in the to-be-simulated object due to a series of physiological processes (such as the change of the tracer activity over time) can be simulated, thereby improving the accuracy of the simulation. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 The internal structure diagram of the computer device in the embodiments of the present application;

[0034] Figure 2 The flowchart of the PET data simulation method in the embodiments of the present application;

[0035] Figure 3 The flowchart of determining the radiation information in the embodiments of the present application;

[0036] Figure 4 The flowchart of determining the radiation information in the embodiments of the present application;

[0037] Figure 5 The flowchart of determining the target photon state in the embodiments of the present application;

[0038] Figure 6 The flowchart of determining the PET raw data in the embodiments of the present application;

[0039] Figure 7 The algorithm flowchart of the PET data simulation method in the embodiments of the present application;

[0040] Figure 8 This is a process diagram of a PET data simulation method in an embodiment of the present application;

[0041] Figure 9 This is a structural block diagram of the PET data simulation device in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0043] Figure 1 This is an internal structure diagram of a computer device in an embodiment of the present application. In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 1 As shown. The computer device includes a processor, a memory, an input / output interface (I / O) and a communication interface. The processor, memory and I / O interface are connected via a system bus, and the communication interface is connected to the system bus via the I / O interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store relevant data. The I / O interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a PET data simulation method is implemented.

[0044] Those skilled in the art will understand that Figure 1 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0045] The embodiment takes the method applied to the server as an example for illustration. It can be understood that the method can also be applied to the terminal, and can also be applied to a system including the terminal and the server, and is realized through the interaction of the terminal and the server. The terminal can be, but is not limited to, various personal computers, notebook computers, smart phones, tablet computers. The server can be realized by an independent server or a server cluster composed of multiple servers.

[0046] Figure 2 For the flowchart of the PET data simulation method in the embodiment of the present application, in an exemplary embodiment, as shown in Figure 2 , a PET data simulation method is provided. Taking the method applied to the computer device in Figure 1 as an example for illustration, the following S201 to S203 are included.

[0047] S201, obtaining an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model; the input function is used to represent the concentration of the radionuclide in the plasma changing with time, and the parameter map is used to represent the metabolism of the radionuclide in each voxel.

[0048] In the embodiment, the computer device can obtain the parameter map corresponding to the pharmacokinetic model and the input function of the radionuclide. The input function of the radionuclide can be in the form of mathematical expression or in the form of mapping table, as long as it can be used to represent the concentration of the radionuclide in the plasma changing with time. For example, according to the input function, the concentration of the radionuclide in the plasma at time 1 can be determined, the concentration of the radionuclide in the plasma at time 2 can be determined, and so on.

[0049] The parameter map corresponding to the pharmacokinetic model is used to represent the metabolism of the radionuclide in each voxel. The voxel refers to each voxel of the object to be simulated. The object to be simulated can include, but is not limited to, a human, an animal or other objects. In the case of a human, the object to be simulated can include at least one part such as the chest, the head or the heart. Each voxel in the parameter map corresponds to a dynamic parameter, which is used to indicate the metabolism of the radionuclide in the voxel, for example, the rate of metabolism of the radionuclide from the plasma in the voxel. The parameter map can be one or more.

[0050] Optionally, different pharmacokinetic models can correspond to different parameter maps. The parameter map can include a K1 parameter map, a k2 parameter map, a k3 parameter map, a K iThe parameter map can include a K1 parameter map and a k2 parameter map, taking a one-compartment model with reversible tissue metabolism (1TC model) in a pharmacokinetic model as an example. In some embodiments, the pharmacokinetic model can also include, but is not limited to, a compartment model and a linear model, etc.

[0051] Optionally, the computer device can acquire the input function and the parameter map corresponding to the pharmacokinetic model in response to the input operation of the user. In some embodiments, the computer device can also determine the corresponding input function and parameter map according to the object to be simulated and the pharmacokinetic model.

[0052] S202, determining the emission information corresponding to each voxel in the preset time period according to the input function and the parameter map corresponding to the pharmacokinetic model.

[0053] Further, after the computer device determines the input function and the parameter map, the computer device can determine the emission information corresponding to each voxel in the preset time period according to the input function and the parameter map corresponding to the pharmacokinetic model.

[0054] The emission information (E-map) can also be referred to as a radioactive activity distribution phantom, and can be used to simulate the photons corresponding to the radionuclide. The emission information includes the radioactivity corresponding to each voxel in the object to be simulated. The preset time period can be 0-1 seconds, 1-2 seconds, 2-3 seconds, etc.

[0055] For example, taking an object to be simulated including a voxel A and a voxel B as an example, if the preset time period includes 0-1 seconds, the computer device can determine the radioactivity of the voxel A and the radioactivity of the voxel B in 0-1 seconds. If the preset time period includes 1-2 seconds, the computer device can determine the radioactivity of the voxel A and the radioactivity of the voxel B in 1-2 seconds, and so on.

[0056] Optionally, the computer device can determine the change of the activity value of the radionuclide in each voxel with time according to the input function and the parameter map corresponding to the pharmacokinetic model, and then determine the emission information corresponding to each voxel according to the change of the activity value of the radionuclide in each voxel with time.

[0057] S203, simulating each photon corresponding to the radionuclide in the object to be simulated according to the emission information corresponding to each voxel in the preset time period and the attenuation information, to obtain the PET raw data in the preset time period.

[0058] The attenuation information (μ-map) can also be referred to as an attenuation coefficient model, and is used for attenuation correction. The attenuation information includes average attenuation coefficients of substances in each voxel in the to-be-simulated object. Alternatively, the computer device can obtain the attenuation information corresponding to each voxel in the preset time period in response to an input operation of a user, or determine the corresponding attenuation information according to the to-be-simulated object.

[0059] Further, the computer device can simulate each photon corresponding to a radionuclide in the to-be-simulated object by using Monte Carlo simulation according to the radiation information and the attenuation information corresponding to each voxel in the preset time period, to obtain PET raw data in the preset time period. For example, Monte Carlo simulation is performed based on the radiation information and the attenuation information in 0-1 seconds, to obtain PET raw data in 0-1 seconds.

[0060] In the PET data simulation method, since the input function is used to represent the concentration of the radionuclide in the plasma over time, and the parameter map is used to represent the metabolism of the radionuclide in each voxel, the input function of the radionuclide and the parameter map corresponding to the pharmacokinetic model are obtained, and the radiation information corresponding to each voxel in the preset time period is determined according to the input function and the parameter map corresponding to the pharmacokinetic model. The physiological dynamic conditions of the radionuclide in the voxel can be considered in the radiation information, and more accurate radiation information can be obtained. In related technologies, the radiation information cannot reflect the dynamic change process of the voxel, and therefore cannot simulate the dynamic change of the radionuclide. In this embodiment, each photon corresponding to the radionuclide in the to-be-simulated object can be simulated according to the radiation information and the attenuation information corresponding to each voxel in the preset time period, and therefore more accurate PET raw data in the preset time period can be obtained, and the dynamic change in distribution of the radionuclide in the to-be-simulated object due to a series of physiological processes (such as the change in tracer activity over time) can be simulated, thereby improving the accuracy of the simulation.

[0061] Figure 3 A flowchart for determining radiation information in an embodiment of the present application is shown in FIG. 2. In an exemplary embodiment, as shown in FIG. 2, S202 includes S301-S303. Figure 3

[0062] S301, for each voxel, determining a dynamic parameter of the voxel according to the parameter map.

[0063] In this embodiment, for each voxel, the computer device determines a dynamic parameter of the voxel according to the parameter map. Taking a parameter map and a parameter map as examples, for voxel A, the computer device determines a dynamic parameter A1 of voxel A in the parameter map and a dynamic parameter A2 of voxel A in the parameter map. ​​​​the dynamic parameter A2 corresponding to the voxel A in the parametric map; for the voxel B, the computer device determines the dynamic parameter B1 corresponding to the voxel B in the parametric map, and the dynamic parameter B2 corresponding to the voxel B in the parametric map, and so on.

[0064] S302, determining the activity value in the preset time period according to the dynamic parameter and the input function from the start time to the end time of the preset time period.

[0065] In the embodiment, the start time is the start time of the whole simulation, for example, the 0th second. The end time of the preset time period can also be understood as the last time of the preset time period. For example, if the preset time period is 0-1 second, the end time is the 1st second, and if the preset time period is 1-2 seconds, the end time is the 2nd second.

[0066] The input function from the start time to the end time of the preset time period can represent the concentration of the radionuclide in the plasma between the start time and the end time of the preset time period. Further, the computer device can determine the activity value in the preset time period according to the dynamic parameter and the input function from the start time to the end time of the preset time period.

[0067] It can be understood that different pharmacokinetic models have different methods for calculating the activity value. Taking a single-compartment model with reversible tissue metabolism as an example, for each voxel, the computer device can determine the activity value in the preset time period according to the following formula (1).

[0068] (1)

[0069] In formula (1), for each voxel, is the activity value at time t, represents the activity value in the preset time period, is the input function at time t, and represents the input function from the start time to the end time of the preset time period. represents the dynamic parameter of the voxel in the parametric map, represents the dynamic parameter of the voxel in the parametric map. represents the dynamic parameter of the voxel in the parametric map. represents the dynamic parameter of the voxel in the parametric map.

[0070] Taking formula (1) as an example, for the voxel A, assuming that the start time is the 0th second, if the activity value in 0-1 second needs to be calculated, then represents the activity value in 0-1 second, is the input function in 0-1 second, and if the activity value in 1-2 second needs to be calculated, then represents the activity value in 1-2 second, is the input function in 0-2 second, and so on.

[0071] S303, determine the radiation information corresponding to the voxel in the preset time period according to the activity value in the preset time period.

[0072] In this embodiment, optionally, the computer device can process the activity value in the preset time period according to the decay property of the nuclide and the Poisson statistical characteristics, to determine the radiation information corresponding to the voxel in the preset time period.

[0073] In the above embodiment, since the dynamic parameter of the voxel is determined according to the parameter map for each voxel, and the activity value in the preset time period is determined according to the dynamic parameter and the input function from the start time to the end time of the preset time period, the radiation information corresponding to the voxel in the preset time period can be determined more accurately according to the activity value in the preset time period.

[0074] Figure 4 For another flowchart for determining the radiation information in the embodiments of the present application, in an exemplary embodiment, as shown in Figure 4 S303 includes S401 to S402.

[0075] S401, for each voxel, determine the average activity value in the preset time period according to the activity value in the preset time period.

[0076] For example, assuming that the preset time period is 0-1 second, the computer device will determine the average activity value of voxel A in 0-1 second according to the activity value of voxel A in 0-1 second.

[0077] Optionally, for each voxel, the computer device can multiply the activity value in the preset time period by the corresponding empirical coefficient to determine the average activity value of the voxel in the preset time period.

[0078] S402, determine the radiation information corresponding to the voxel in the preset time period according to the physical property of the radioactive nuclide and the average activity value in the preset time period.

[0079] In this embodiment, the physical property of the radioactive nuclide can include but is not limited to the decay property of the nuclide and the Poisson statistical characteristics. Further, the computer device can sample the average activity value of the voxel in the preset time period according to the decay property of the nuclide and the Poisson statistical characteristics, to determine the radiation information corresponding to the voxel in the preset time period.

[0080] In the above embodiment, since the average activity value in the preset time period is determined according to the activity value in the preset time period for each voxel, the radiation information corresponding to the voxel in the preset time period can be determined more accurately according to the physical property of the radioactive nuclide and the average activity value in the preset time period.

[0081] In an example embodiment, the S401 can be implemented by the following way.

[0082] The average activity value is obtained by integrating the activity values in the preset time period.

[0083] Optionally, the computer device can determine the average activity value of the voxel in the preset time period according to the following formula (2).

[0084] (2)

[0085] In the formula (2), for each voxel, represents the average activity value of the voxel in the preset time period, and represents the start time and the end time of the preset time period. For example, to determine the average activity value in 0-1 seconds, is the activity value in 0-1 seconds, is the first second, is the zeroth second. For example, to determine the average activity value in 1-2 seconds, is the activity value in 1-2 seconds, is the second second, is the first second, and so on.

[0086] In the above embodiment, since the average activity value can be obtained by integrating the activity value corresponding to the voxel at the preset time based on the preset time period, the efficiency of determining the average activity value is improved.

[0087] In the related art, in the process of simulation using MCS, only static simulation can be performed by using radiation information and attenuation information. That is, the simulation process of the related art only focuses on the physical process, and cannot simulate the autonomous motion of the object to be simulated in the scanning process. In some embodiments, only the radiation information and the attenuation information of the object to be simulated at different motion positions can be generated in advance, and multiple static simulations are performed for different motion states, and then the static simulation results are spliced to approximately realize the simulation of the motion, but the simulation efficiency is very low. In addition to the change of the activity of the tracer over time, there is also motion of the simulated object.

[0088] Figure 5 is a flowchart for determining a target photon state in an embodiment of the present application. In an example embodiment, as shown in Figure 5 S203 includes S501-S502.

[0089] S501, obtain relative motion information of the to-be-simulated object between a reference coordinate system and a motion coordinate system in each simulation time period; the reference coordinate system is static relative to the to-be-simulated object, and the motion coordinate system is static relative to the scanner; the simulation time period corresponds to a preset time period.

[0090] In this embodiment, the simulation time period has a certain time length, for example, each simulation time period can be 0-1 seconds, 1-2 seconds, 2-3 seconds, etc. The simulation time period corresponds to the preset time period. Optionally, the simulation time period can correspond to the preset time period one by one, for example, the simulation time period and the preset time period are both 0-1 seconds. Optionally, the simulation time period and the preset time period can also have an overlap, for example, the preset time period can be 0-2 seconds, and the simulation time period can be 0-1 second.

[0091] The reference coordinate system refers to a coordinate system that is not affected by motion and is relatively static relative to the to-be-simulated object, and the motion coordinate system refers to a coordinate system that is affected by motion and is relatively static relative to the scanner. The scanner is used to simulate a scanner in a medical scanning device.

[0092] It should be noted that the radiation information and the attenuation information corresponding to each of the voxels in the preset time period are in the reference coordinate system.

[0093] The relative motion information represents the motion of the to-be-simulated object between the reference coordinate system and the motion coordinate system in the simulation time period. For example, the relative motion information includes relative motion information 1 of the to-be-simulated object between the reference coordinate system and the motion coordinate system in 0-1 seconds, relative motion information 2 of the to-be-simulated object between the reference coordinate system and the motion coordinate system in 1-2 seconds, relative motion information 3 of the to-be-simulated object between the reference coordinate system and the motion coordinate system in 2-3 seconds, and so on.

[0094] Optionally, the relative motion information can include rigid relative motion information and / or non-rigid relative motion information. The rigid relative motion information includes translation information and / or rotation information, and the non-rigid relative motion information includes a deformation field. For example, the relative motion information can be motion information of six degrees of freedom such as rotation and translation, or can be a coordinate change matrix.

[0095] In this embodiment, the computer device can obtain the relative motion information of the to-be-simulated object in each preset time period. Optionally, the computer device can obtain the relative motion information sent by other devices, can obtain the relative motion information in response to the input operation of the user, or can simulate the generation of the relative motion information.

[0096] In some embodiments, the computer device can also acquire an image of the to-be-detected object through the structured light camera, and perform motion detection according to the image of the to-be-detected object to obtain the relative motion information. In some embodiments, the computer device can also extract the relative motion information from the scanning data of the to-be-detected object in a data-driven manner, and the embodiments are not limited thereto.

[0097] S502, for each simulation time period, simulating the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the emission information and the attenuation information, to obtain PET raw data.

[0098] In this embodiment, a plurality of photon pairs will be generated in each simulation time period. Therefore, for each simulation time period, the computer device simulates the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the emission information and the attenuation information corresponding to the simulation time period, to obtain the PET raw data in the simulation time period.

[0099] For example, assuming that the preset time period and the simulation time period correspond to each other, the computer device can simulate the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the emission information of 0-1 seconds, the attenuation information of 0-1 seconds and the relative motion information of the to-be-simulated object in 0-1 seconds, to obtain the PET raw data in 0-1 seconds.

[0100] For example, assuming that the preset time period and the simulation time period correspond to each other, the computer device can simulate the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the emission information of 0-1 seconds, the attenuation information of 0-1 seconds and the relative motion information of the to-be-simulated object in 0-1 seconds, to obtain the PET raw data in 0-1 seconds.

[0101] Optionally, for each simulation time period, the computer device can input the relative motion information, the emission information and the attenuation information into a simulation model, and the simulation model simulates the motion process of each photon corresponding to the radionuclide in the to-be-simulated object to output the PET raw data.

[0102] Further optionally, the computer device can obtain target simulation raw data according to the PET raw data corresponding to each simulation time period. For example, the computer device can splice the PET raw data corresponding to each simulation time period to obtain complete target simulation raw data.

[0103] In the above embodiment, since the reference coordinate system is static relative to the object to be simulated, and the motion coordinate system is static relative to the scanner, the relative motion information of the object to be simulated between the reference coordinate system and the motion coordinate system in each simulation time period is obtained, and the motion process of each photon corresponding to the radionuclide in the object to be simulated is simulated according to the relative motion information, the radiation information and the attenuation information to obtain the PET raw data in each simulation time period. In the above process, the relative motion between the object to be simulated and the scanner is considered, so that the condition that only one motion state can be simulated at a time is avoided, and multiple static simulations for different motion states are not required, but the motion process of each photon is simulated at one time, thereby improving the accuracy of the simulation.

[0104] Figure 6 FIG. 1 is a schematic diagram of a process for determining PET raw data in an embodiment of the present application. In an exemplary embodiment, as shown in FIG. 1, S502 includes S601-S602. Figure 6

[0105] S601, for each photon, updating a target photon state of the photon on the path of travel in the motion coordinate system according to the relative motion information, the radiation information and the attenuation information.

[0106] In the present embodiment, since there are a plurality of photon pairs in each simulation time period, for each simulation time period, the computer device updates the target photon state of each photon on the path of travel in the motion coordinate system according to the relative motion information, the radiation information and the attenuation information.

[0107] Exemplarily, for the simulation time period 0-1 second, it is assumed that 100 photon pairs are generated in 0-1 second, that is, a total of 200 photons, and for each photon of the 200 photons, the computer device updates each target photon state of the photon on the path of travel. The above 200 photons are photon 1-photon 200, the computer device obtains target photon state 1-1, target photon state 1-2 of photon 1 on the path of travel, target photon state 2-1, target photon state 2-2 of photon 2 on the path of travel, and so on.

[0108] The target photon state includes at least one of the direction, the energy and the position of the photon on the path of travel.

[0109] ​Optionally, for each photon, the computer device can periodically update the target photon state of the photon on the path of travel in the moving coordinate system according to the physical effect according to the relative motion information, the emission information and the attenuation information every fixed time. For example, for photon 1, the computer device updates the target photon state of the photon on the path of travel every 1 nanosecond, and target photon state 1-1, target photon state 1-2, and the like can be obtained.

[0110] S602, determine the PET raw data according to each target photon state.

[0111] In the embodiment, continuing the above example, according to each target photon state of the above 200 photons on the path of travel, for example, target photon state 1-1, target photon state 1-2, … of photon 1 on the path of travel, target photon state 2-1, target photon state 2-2, and the like of photon 2 on the path of travel, the PET raw data corresponding to the simulation time period 0~1 second can be determined.

[0112] Further, the computer device can count the deposition energy of the above 200 photons passing through the crystal according to each target photon state, and obtain coincidence events according to the deposition energy of each photon passing through the crystal, and obtain the PET raw data corresponding to 0~1 second according to the coincidence events.

[0113] In the above embodiment, since for each photon, the target photon state of the photon on the path of travel in the moving coordinate system can be updated according to the relative motion information, the emission information and the attenuation information, the PET raw data determined according to each target photon state can reflect the motion process of each photon corresponding to the radionuclide in the object to be simulated, and the accuracy of the simulation is improved.

[0114] In an exemplary embodiment, optionally, the “updating the target photon state of the photon on the path of travel in the moving coordinate system according to the relative motion information, the emission information and the attenuation information” in S301 can include the following steps:

[0115] According to the emission information and the relative motion information in the reference coordinate system, the radionuclide in the object to be simulated is simulated for decay and annihilation, and the initial photon state of the photon in the moving coordinate system is determined; and each target photon state is determined according to the initial photon state and the attenuation information in the reference coordinate system.

[0116] In the embodiment, the radionuclide emits a positron by beta+ decay, the positron combines with a negative electron in the tissue to be simulated to annihilate, i.e., an annihilation event, and two photons with equal energy and opposite directions are generated. Therefore, for each photon in each simulation time period, the computer device performs decay and annihilation simulation on the radionuclide in the tissue to be simulated according to the emission information in the reference coordinate system and the relative motion information, to determine the initial photon state of the photon in the motion coordinate system.

[0117] Optionally, for each photon in each simulation time period, the computer device can perform decay and annihilation simulation on the radionuclide in the tissue to be simulated according to the emission information in the reference coordinate system, to obtain the initial photon state of the photon corresponding to the radionuclide in the reference coordinate system, and convert the initial photon state of the photon in the reference coordinate system to the motion coordinate system according to the relative motion information, to obtain the initial photon state of the photon in the motion coordinate system. The initial photon state of the photon in the motion coordinate system includes at least one of the position, energy and direction of the photon in the motion coordinate system.

[0118] For example, the computer device performs decay and annihilation simulation on the radionuclide in the tissue to be simulated according to the emission information in the reference coordinate system, to obtain the initial photon state of each photon in the reference coordinate system within 0-1 seconds, and converts the initial photon state of each photon in the reference coordinate system within 0-1 seconds to the motion coordinate system using the relative motion information corresponding to 0-1 seconds, to obtain the initial photon state of each photon in the motion coordinate system within 0-1 seconds.

[0119] Further, after the photon is generated, it will be transmitted along the path. Therefore, after determining the initial photon state of the photon, the computer device can periodically update the target photon state of the photon according to the initial photon state and the attenuation information in the reference coordinate system at fixed distances. It can be understood that, since the speed of light is fixed, each fixed distance is also a fixed time.

[0120] For example, after the computer device determines the initial photon state of each photon in the motion coordinate system within the simulation time period 0-1 seconds, it updates the target photon state of each photon within the simulation time period 0-1 seconds every 1 nanosecond.

[0121] Optionally, the computer device can perform Monte Carlo simulation according to the physical modeling of Compton scattering, to determine the target photon state according to the initial photon state and the attenuation information in the reference coordinate system. In some embodiments, the computer device can also perform decay and annihilation simulation on the radionuclide in the tissue to be simulated according to the initial photon state, the attenuation information in the reference coordinate system, and the corresponding relative motion information, to obtain the target photon state.

[0122] In the above embodiments, since the initial photon state of the photon in the moving coordinate system can be determined according to the radioactive information in the reference coordinate system and the relative motion information, and the decay and annihilation simulation of the radionuclide in the to-be-simulated object, the target photon state of the photon on the path can be determined according to the initial photon state and the decay information in the reference coordinate system.

[0123] In an exemplary embodiment, optionally, the above-mentioned "determining the target photon state according to the initial photon state and the decay information in the reference coordinate system" can further include the following steps:

[0124] determining a first position of the photon in the moving coordinate system according to the initial photon state; determining the corresponding target positions of the photon on the path in the reference coordinate system according to the first position and the relative motion information; and determining the target photon state according to the decay information in the reference coordinate system and the target positions.

[0125] In the present embodiment, the computer device can take the position in the initial photon state as the first position of the photon in the moving coordinate system. Optionally, in some embodiments, the energy and / or direction of the photon in the moving coordinate system can also be determined according to the initial photon state.

[0126] Further, after determining the first position, the computer device can determine the corresponding target positions of the photon on the path in the reference coordinate system by using the physical modeling of Compton scattering for Monte Carlo simulation according to the first position and the relative motion information. Optionally, the computer device can periodically determine the corresponding target positions of the photon on the path in the reference coordinate system at fixed distances or fixed times.

[0127] For example, after the computer device determines the first position A of the photon 1 in the moving coordinate system within 0-1 seconds, the corresponding target positions of the photon 1 on the path in the reference coordinate system are determined every 1 nanosecond by using the physical modeling of Compton scattering for Monte Carlo simulation according to the first position A and the relative motion information within 0-1 seconds.

[0128] In the present embodiment, the decay information in the reference coordinate system can represent the probability of scattering of the photon, and then the computer device can determine the target photon state of the photon on the path by using the decay information in the reference coordinate system and the corresponding target positions of the photon on the path in the reference coordinate system. Optionally, the computer device can perform Monte Carlo simulation according to the decay information in the reference coordinate system and the target positions to determine the target photon state.

[0129] Continuing the above example, the computer device can determine, according to the attenuation information in the reference coordinate system and the target positions, a target photon state 1-1, a target photon state 1-2, and the like of photon 1 on the path of travel within 0-1 seconds.

[0130] In the above embodiment, since the first position of the photon in the reference coordinate system can be determined according to the initial photon state and the target positions corresponding to the path of travel can be determined according to the first position and the relative motion information, the target photon states of the photon on the path of travel can be determined according to the attenuation information in the reference coordinate system and the target positions.

[0131] In an exemplary embodiment, optionally, the above-mentioned "determining the target photon states according to the attenuation information in the reference coordinate system and the target positions" can further include the following steps:

[0132] According to the target positions and the attenuation information in the reference coordinate system, determining attenuation coefficient values corresponding to the path of travel; and determining the target photon states according to the attenuation coefficient values corresponding to the path of travel.

[0133] Since the attenuation information in the motion coordinate system is not directly generated, in the present embodiment, for each photon in each simulation time period, the computer device determines the attenuation coefficient values corresponding to the path of travel according to the target positions and the attenuation information in the reference coordinate system.

[0134] The attenuation coefficient values corresponding to the path of travel can be attenuation coefficient values corresponding to the target positions. The attenuation coefficient value can be an average attenuation coefficient in the attenuation information, and the attenuation coefficient value can indicate the scattering probability of the photon at a certain spatial position.

[0135] Continuing the above example, for photon 1 within 0-1 seconds, the computer device determines the target positions corresponding to photon 1 on the path of travel in the reference coordinate system every 1 nanosecond, and then the computer device can determine the attenuation coefficient values corresponding to each target position according to the target positions corresponding to photon 1 and the attenuation information in the reference coordinate system.

[0136] In the present embodiment, optionally, the computer device can determine the scattering of the photon according to the attenuation coefficient values, and perform Monte Carlo simulation on the photon according to the scattering of the photon and the physical modeling of Compton scattering to determine the target photon states. Continuing the above example, according to the attenuation coefficient values corresponding to the target positions, the target photon state 1-1, the target photon state 1-2, and the like of photon 1 on the path of travel within 0-1 seconds can be determined.

[0137] In the above embodiment, the attenuation coefficient values ​​corresponding to the travel paths are determined based on the attenuation information of each target position and the reference coordinate system, and the states of each target photon are determined based on the attenuation coefficient values ​​corresponding to the travel paths. Therefore, there is no need to generate emission and attenuation information for different motion states. The motion process of each photon corresponding to the radioactive nuclide in the simulation object can be simulated by simply using the emission and attenuation information in the reference coordinate system, thereby improving simulation efficiency.

[0138] In an exemplary embodiment, optionally, the above-mentioned “performing a decay and annihilation simulation of the radioactive nuclides in the object to be simulated based on the radiation information and the relative motion information in the reference coordinate system, and determining the initial photon state of the photons in the moving coordinate system” may include the following steps:

[0139] According to the radiation information in the reference coordinate system, the decay and annihilation simulation of the radioactive nuclides in the simulation object is carried out to determine the annihilation position of the positron corresponding to the radioactive nuclide in the reference coordinate system; according to each annihilation position and relative motion information, the initial position of the positron in the motion coordinate system is determined; and according to the initial position, the initial photon state is determined.

[0140] In this embodiment, the computer device can optionally perform Poisson distribution sampling on the radiation information in the reference coordinate system for each simulation time period to determine the radiation information in the reference coordinate system during that simulation time period. Based on the radiation information in the reference coordinate system during that simulation time period, the computer device can determine the number of positrons that actually underwent β+ decay within each voxel. For each positron, the computer device can simulate its decay and annihilation process based on physical effects (positron range) to determine the annihilation location of the positron in the reference coordinate system during that simulation time period.

[0141] Furthermore, for each simulation time period, the relative motion information corresponding to the simulation time period can be used to convert the annihilation position of the positron in the reference coordinate system during the simulation time period into the motion coordinate system to determine the initial position of the positron in the motion coordinate system during the simulation time period.

[0142] Furthermore, based on the initial position of the positron in the moving coordinate system during the simulation time period, the directions of two 511 keV (kilo-electron-volt) photons emitted at 180° to each other are generated by sampling according to physical effects (such as non-collinearity). The directions of the two 511 keV photons are used as the directions in the initial photon state, and the initial position in the moving coordinate system is used as the position in the initial photon state. The energy in the initial photon state is 511 keV. In this way, the initial photon state of the photon in the moving coordinate system during the simulation time period is determined.

[0143] In the above embodiment, since the decay and annihilation simulation of the radionuclide in the to-be-simulated object can be performed according to the radiation information in the reference coordinate system, the annihilation positions of the positrons corresponding to the radionuclide in the reference coordinate system are determined, and therefore, the initial positions of the positrons in the motion coordinate system can be accurately determined according to the annihilation positions and the relative motion information, and the more accurate initial photon state is determined according to the initial positions.

[0144] In an exemplary embodiment, optionally, the "simulating the motion process of each photon corresponding to the radionuclide in the to-be-simulated object to obtain PET raw data" in S502 can be implemented in the following manner:

[0145] In the case that the photon is within the field of view of the scanner or the energy of the photon is greater than the first energy threshold, the motion process of each photon corresponding to the radionuclide in the to-be-simulated object is simulated to obtain the PET raw data.

[0146] If the photon is outside the field of view of the scanner or the energy of the photon is not greater than the first energy threshold, it indicates that the photon will not affect the subsequent raw data, and therefore, the simulation of the photon is not required. Therefore, in the embodiment, the computer device continues to simulate the motion process of each photon corresponding to the radionuclide in the to-be-simulated object in the case that the photon is within the field of view of the scanner or the energy of the photon is greater than the first energy threshold, until the photon is outside the field of view of the scanner or the energy of the photon is not greater than the first energy threshold, and the computer device can stop the simulation and obtain the PET raw data. The first energy threshold can be set according to requirements.

[0147] In the above embodiment, the motion process of each photon corresponding to the radionuclide in the to-be-simulated object is simulated in the case that the photon is within the field of view of the scanner or the energy of the photon is greater than the first energy threshold to obtain the PET raw data. Therefore, the reliability of the simulation is improved.

[0148] In an exemplary embodiment, optionally, S602 can include the following steps:

[0149] In the case that the energy of the photon received by the detector is greater than the second energy threshold, the deposition energy of each photon passing through the crystal is determined according to the target photon state, the coincidence event is obtained according to the deposition energy of each photon passing through the crystal, and the PET raw data is determined according to the coincidence event.

[0150] In the embodiment, in the process of simulating the photons, if the photon energy received by the detector is greater than the second energy threshold, it indicates that most of the photons have entered the scanner from the object to be simulated, and therefore, the computer device can determine the deposition energy of each photon passing through the crystal according to the state of each target photon. The second energy threshold can also be set according to requirements.

[0151] Optionally, the computer device can record the energy deposited by each photon in each crystal in each scanner based on the state of each target photon by using a photon metabolism physical model, a Compton scattering physical model, a coherent scattering physical model, and the like, to obtain the deposition energy of each photon passing through the crystal. It can be understood that the crystal passed by the photon can be one crystal or multiple crystals.

[0152] Further, the corresponding coincidence event can be determined according to the deposition energy of each photon passing through the crystal. The simulation raw data in the preset format, such as listmode data format, can be determined by processing the obtained coincidence event. Optionally, the computer device can store the simulation raw data, for example, record the simulation raw data into a disk.

[0153] In the above embodiment, the deposition energy of each photon passing through the crystal is determined according to the state of each target photon in the case that the photon energy received by the detector is greater than the second energy threshold, and the coincidence event is obtained according to the deposition energy of each photon passing through the crystal, so that the PET raw data can be efficiently and accurately determined according to the coincidence event.

[0154] In order to more clearly introduce the PET data simulation method in the present application, the following Figure 7 and Figure 8 are described. Figure 7 The flow chart of the algorithm of the PET data simulation method in the embodiment is shown in the following figure.

[0155] Figure 8 The process diagram of the PET data simulation method in the embodiment is shown in the following figure. Figure 8 As shown in the figure, the computer device can execute the PET data simulation method according to the following flow.

[0156] S801, obtain the input function of the radionuclide and the parameter graph corresponding to the pharmacokinetic model.

[0157] S802, determining, for each voxel, a dynamic parameter of the voxel according to the parameter map.

[0158] S803, determining, for each voxel, an activity value in the preset time period according to the dynamic parameter and the input function from the start time to the end time of the preset time period.

[0159] S804, integrating, for each voxel, the activity value in the preset time period to obtain an average activity value.

[0160] S805, determining, according to the physical property of the radionuclide and the average activity value in the preset time period, radiation information corresponding to the voxel in the preset time period.

[0161] S806, obtaining relative motion information of the object to be simulated between the reference coordinate system and the motion coordinate system in each simulation time period.

[0162] S807, for each simulation time period, updating, for each photon, a target photon state of the photon on the path of travel in the motion coordinate system according to the relative motion information, the radiation information and the attenuation information.

[0163] S808, determining PET raw data according to each target photon state.

[0164] It should be understood that although each step in the flowchart involved in each of the above embodiments is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each of the above embodiments can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least part of other steps or steps or stages in other steps.

[0165] Based on the same inventive concept, the embodiments of the present application also provide a PET data simulation device for implementing the above-mentioned PET data simulation method. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme described in the above method, so the specific limitations in one or more PET data simulation device embodiments provided below can refer to the limitations of the PET data simulation method in the above text, which will not be repeated here.

[0166] Figure 9 The structure block diagram of the PET data simulation device in the embodiments of the present application is as follows in an exemplary embodiment, Figure 9As shown, a PET data simulation device 900 is provided, comprising an acquisition module 901, a first determination module 902 and a simulation module 903, wherein:

[0167] The acquisition module 901 is configured to acquire an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model; the input function is used to represent a change of a concentration of the radionuclide in blood plasma over time, and the parameter map is used to represent a metabolism of the radionuclide in each voxel.

[0168] The first determination module 902 is configured to determine, according to the input function and the parameter map corresponding to the pharmacokinetic model, radiation information corresponding to each voxel in a preset time period.

[0169] The simulation module 903 is configured to simulate, according to the radiation information corresponding to each voxel in the preset time period and attenuation information, each photon corresponding to the radionuclide in a to-be-simulated object, to obtain PET raw data in the preset time period.

[0170] In the PET data simulation device, since the input function is used to represent a change of a concentration of the radionuclide in blood plasma over time, and the parameter map is used to represent a metabolism of the radionuclide in each voxel, the input function of the radionuclide and the parameter map corresponding to the pharmacokinetic model are acquired, and then the radiation information corresponding to each voxel in a preset time period is determined according to the input function and the parameter map corresponding to the pharmacokinetic model, so that the physiological dynamic condition of the radionuclide in the voxel can be considered in the radiation information, and more accurate radiation information can be obtained. In related technologies, the radiation information cannot reflect the dynamic change process of the voxel, and thus the simulation of the dynamic change of the radionuclide cannot be realized. However, the embodiment can simulate, according to the radiation information corresponding to each voxel in the preset time period and the attenuation information, each photon corresponding to the radionuclide in the to-be-simulated object, so that more accurate PET raw data in the preset time period can be obtained, and the dynamic change in distribution of the radionuclide in the to-be-simulated object due to a series of physiological processes (such as a change of tracer activity over time) can be simulated, thereby improving the accuracy of the simulation.

[0171] Optionally, the first determination module 902 comprises:

[0172] The first determination unit is configured to determine, for each voxel, a dynamic parameter of the voxel according to the parameter map.

[0173] The second determination unit is configured to determine, according to the dynamic parameter and the input function from the start time to the end time of the preset time period, an activity value in the preset time period.

[0174] The third determination unit is configured to determine, according to the activity value in the preset time period, the radiation information corresponding to the voxel in the preset time period.

[0175] Optionally, the third determining unit comprises:

[0176] The first determining sub-unit is configured to determine, for each voxel, an average activity value in the preset time period according to the activity values in the preset time period.

[0177] The second determining sub-unit is configured to determine the radiation information corresponding to the voxel in the preset time period according to the physical property of the radionuclide and the average activity value in the preset time period.

[0178] Optionally, the first determining sub-unit is further configured to integrate the activity values in the preset time period to obtain the average activity value.

[0179] Optionally, the simulation module 903 comprises:

[0180] The acquisition unit is configured to acquire relative motion information of the to-be-simulated object between a reference coordinate system and a motion coordinate system in each simulation time period; the reference coordinate system is static relative to the to-be-simulated object, and the motion coordinate system is static relative to the scanner; the simulation time period corresponds to the preset time period.

[0181] The simulation unit is configured to simulate, for each simulation time period, a motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the radiation information, and the attenuation information, to obtain the PET raw data.

[0182] Optionally, the simulation unit comprises:

[0183] The updating sub-unit is configured to update, for each photon, a target photon state of the photon on the path of travel in the motion coordinate system according to the relative motion information, the radiation information, and the attenuation information.

[0184] The fourth determining sub-unit is configured to determine the PET raw data according to the target photon states.

[0185] Each module in the PET data simulation apparatus described above can be realized wholly or partially by software, hardware, and combinations thereof. Each module described above can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in a computer device in software form, so as to be called and executed by a processor to perform operations corresponding to each module.

[0186] In one embodiment, a computer device is provided, comprising a memory and a processor, the memory storing a computer program, and the processor implementing the steps in each method embodiment described above when executing the computer program.

[0187] In one embodiment, a computer readable storage medium is provided, storing a computer program, and the computer program is executed by a processor to implement the steps in each method embodiment described above.

[0188] In one embodiment, a computer program product is provided, comprising a computer program which, when executed by a processor, implements the steps of any of the above method embodiments.

[0189] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing related hardware through a computer program. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned method embodiments. Any reference to memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical storage, high-density embedded non-volatile memory, resistive memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The database involved in the embodiments provided in the present application can include at least one of a relational database and a non-relational database. The non-relational database can include a distributed database based on a block chain, etc., without being limited thereto. The processor involved in the embodiments provided in the present application can be a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., without being limited thereto.

[0190] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0191] The above-described embodiments are merely illustrative of several embodiments of the present application, and the description is relatively specific and detailed, but should not be understood as a limitation on the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method of PET data simulation, characterized by, The method comprises: acquiring an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model; the input function is used to represent the concentration of the radionuclide in the plasma over time, and the parameter map is used to represent the metabolism of the radionuclide in each voxel; determining the radiation information corresponding to each voxel in a preset time period according to the input function and the parameter map corresponding to the pharmacokinetic model; simulating each photon corresponding to the radionuclide in the to-be-simulated object according to the radiation information and the attenuation information of each voxel in the preset time period, to obtain PET raw data in the preset time period.

2. The method of claim 1, wherein, The determination of the radiation information corresponding to each voxel in the preset time period according to the input function and the parameter map corresponding to the pharmacokinetic model comprises: for each voxel, determining the dynamic parameter of the voxel according to the parameter map; determining the activity value in the preset time period according to the dynamic parameter and the input function from the start time to the end time of the preset time period; determining the radiation information corresponding to the voxel in the preset time period according to the activity value in the preset time period.

3. The method of claim 2, wherein, The determination of the radiation information corresponding to the voxel in the preset time period according to the activity value in the preset time period comprises: for each voxel, determining the average activity value in the preset time period according to the activity value in the preset time period; determining the radiation information corresponding to the voxel in the preset time period according to the physical properties of the radionuclide and the average activity value in the preset time period.

4. The method of claim 3, wherein, The determination of the average activity value in the preset time period according to the activity value in the preset time period comprises: integrating the activity value in the preset time period to obtain the average activity value.

5. The method according to any one of claims 1 to 4, characterized in that, The simulation of each photon corresponding to the radionuclide in the to-be-simulated object according to the radiation information and the attenuation information of each voxel in the preset time period to obtain the PET raw data in the preset time period comprises: acquiring the relative motion information of the to-be-simulated object between a reference coordinate system and a motion coordinate system in each simulation time period; the reference coordinate system is stationary relative to the to-be-simulated object, and the motion coordinate system is stationary relative to the scanner; the simulation time period corresponds to the preset time period; for each simulation time period, simulating the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the radiation information and the attenuation information, to obtain the PET raw data.

6. The method of claim 5, wherein, The simulation of the motion process of each photon corresponding to the radionuclide in the to-be-simulated object according to the relative motion information, the radiation information and the attenuation information to obtain the PET raw data comprises: for each photon, updating the target photon state of the photon on the path of travel in the motion coordinate system according to the relative motion information, the radiation information and the attenuation information; determining the PET raw data according to each target photon state.

7. A PET data simulation apparatus characterized by comprising: The device comprises: An acquisition module is configured to acquire an input function of a radionuclide and a parameter map corresponding to a pharmacokinetic model; the input function is used to represent a change of a concentration of the radionuclide in blood plasma over time, and the parameter map is used to represent a metabolism of the radionuclide by each voxel; A first determination module is configured to determine, according to the input function and the parameter map corresponding to the pharmacokinetic model, radioactive information corresponding to each voxel in a preset time period; A simulation module is configured to simulate, according to the radioactive information and attenuation information corresponding to each voxel in the preset time period, each photon corresponding to the radionuclide in a to-be-simulated object, and obtain PET raw data in the preset time period.

8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that, The processor executes the computer program to implement the steps of the method in any one of claims 1 to 6.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 6.

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