Image reconstruction method, device, storage medium, generation method, and imaging system

Abstract

The present application relates to an image reconstruction method, device, storage medium, generation method and imaging system. The method comprises: obtaining scan data of an imaging target; determining whether DOI information exists in the scan data, and if the DOI information exists, applying the DOI information to image reconstruction; and if the DOI information does not exist, using a system response matrix to perform image reconstruction. By utilizing the DOI information, an image reconstruction algorithm support is constructed for different requirement scenarios, so that a reconstruction image meeting different requirements is obtained, and the problem of internal shrinkage during image reconstruction is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of image reconstruction, in particular to an image reconstruction method, device, storage medium, generation method and imaging system. BACKGROUND

[0002] In a high-energy photon detection system, such as a PET (positron emission tomography) system, due to the influence of the depth of interaction (DOI), the reconstructed image will be offset towards the center of the field of view (FOV), for the following reasons: a positron and an electron annihilate after being emitted by a source, generating a pair of gamma photons with opposite directions and equal energy, which then enter a detector containing a crystal array. Due to the different probabilities of physical effects such as photoelectric effect and Compton scattering occurring between each gamma photon and the crystal, and the different energy losses, the photon can be deposited at different depths in the crystal. Due to the close arrangement and small size of the crystals in the detector, inter-crystal transmission occurs, i.e. the gamma photon penetrates the crystal where it first enters and is finally deposited in the surrounding crystal. As shown in FIG. 1, the gamma photon should be deposited in crystal 1, but the physical effects occurring in crystal 1 do not completely consume its energy, so it penetrates crystal 1 and is finally deposited at position A in crystal 2. Figure 1

[0003] When two gamma photons are within a certain time range (time window) and energy range (energy window), we consider that the two gamma photons are generated by the annihilation of a single positron. Since the detector only records the final deposition position of the gamma photon, the line A'B' connecting the centers of the surfaces of the above-mentioned crystals where the two gamma photons are currently deposited is considered to be the line of response (LOR), i.e. the positron annihilation position is considered to be at a certain position on the LOR. However, in reality, the positron annihilates on line AB, and if not corrected, a deviation will occur, resulting in parallax effect.

[0004] The present application aims to establish a systematic method and implementation system for solving the parallax effect. SUMMARY

[0005] To solve the above problems, the first object of the present application is to provide an image reconstruction method, comprising the following steps: obtaining scan data of an imaging target; determining whether DOI information exists in the scan data; wherein the DOI information is used to locate the deposition position of the photon in the crystal; if the DOI information exists, applying the DOI information to image reconstruction; if the DOI information does not exist, using a system response matrix to perform image reconstruction.

[0006] ​Preferably, the application of the DOI information to the image reconstruction comprises the following steps: layering the crystal by Gate simulation; obtaining the spatial coordinates of the accurate deposition position of the current pair of photons in the crystal by Gate simulation; obtaining the line connecting the center coordinates of the layering surface of the crystal and the two crystals where the intersection of the line and the crystal array surface is located, and determining the LOR number of the two crystals to obtain the LOR where the current pair of photons is located; and replacing the photon coordinates in the LOR with the spatial coordinates of the accurate deposition position of the current pair of photons in the crystal to reconstruct the image.

[0007] Preferably, the application of the DOI information to the image reconstruction further comprises the following steps: layering the crystal by Gate simulation under different DOI precisions in the same set of simulation data to obtain several sets of DOI-processed data with different precisions, and then reconstructing the image by using the ordered subset expectation maximization algorithm on the several sets of DOI-processed data.

[0008] Preferably, the method further comprises the following steps: judging whether the quality of the image reconstruction result meets the expectation, and if not, reducing the average DOI precision of the several sets and increasing the number of sets to obtain several sets of optimized DOI-processed data, and then reconstructing the image.

[0009] Preferably, the system response matrix is generated by Gate simulation, comprising collecting the response functions of all positions in the entire image field of view by Monte Carlo simulation, and obtaining the system response matrix according to the response functions of all positions.

[0010] A second object of the present application is to provide an image reconstruction device, comprising: an acquisition unit configured to acquire scan data of an imaging target; a judgment unit configured to judge whether DOI information exists in the scan data; wherein the DOI information is used to locate the deposition position of photons in a crystal; and a processing unit configured to apply the DOI information to image reconstruction if the DOI information exists, and to perform image reconstruction by using a system response matrix if the DOI information does not exist.

[0011] A third object of the present application is to provide an image reconstruction device, comprising: a memory having program codes stored thereon; and a processor coupled to the memory, and when the program codes are executed by the processor, the image reconstruction method described in the present application is implemented.

[0012] A fourth objective of this invention is to provide an image reconstruction method comprising the following steps: acquiring scanning data of an imaging target; determining whether DOI information exists in the scanning data; wherein the DOI information at least includes the deposition location of local photons in a crystal, which is used to configure and generate a DOI-accurate reconstruction model during simulation; if DOI information exists, activating a DOI-accurate reconstruction model in an image reconstruction model library; wherein the image reconstruction model library at least includes a DOI-accurate reconstruction model and a Monte Carlo simulation reconstruction model; waiting for and responding to the type of reconstruction model called in the image reconstruction model library; constructing a reconstruction model of the aforementioned type using a simulation system, and then performing image reconstruction using the reconstruction model.

[0013] Preferably, the steps for generating the DOI-accurate reconstruction model include: layering the crystal using Gate simulation; obtaining the spatial coordinates of the accurate deposition position of the current pair of photons in the crystal using Gate simulation; using the spatial coordinates to obtain the line connecting the center coordinates of the crystal layer surface and the two crystals where the line intersects with the crystal array surface, and determining the LOR number of the two crystals, i.e., obtaining the LOR where the current pair of photons is located; replacing the photon coordinates in the LOR with the spatial coordinates of the accurate deposition position of the current pair of photons in the detector to reconstruct the image.

[0014] Preferably, the step of generating the DOI precision reconstruction model further includes: using Gate simulation to layer the crystal with different DOI precisions under the same set of simulation data to obtain several sets of DOI-processed data with different precisions, and then using the ordered subset maximum expectation algorithm to reconstruct the image from the several sets of DOI-processed data.

[0015] Preferably, the generation step of the DOI accuracy reconstruction model further includes: determining whether the quality of the image reconstruction result meets expectations; if it does not meet expectations, increasing the average DOI accuracy of several groups and increasing the number of groups to obtain optimized data of several groups of DOI processed data, and then using the ordered subset maximum expectation algorithm to reconstruct the image.

[0016] Preferably, the steps for generating the Monte Carlo simulation reconstruction model include: performing Monte Carlo simulation reconstruction using Gate, acquiring the response functions of all locations within the entire image field of view, and obtaining the system response matrix based on the response functions of all locations.

[0017] A fifth object of the present application is to provide an image reconstruction device, comprising: an acquisition unit configured to acquire scan data of an imaging target; a judgment unit configured to judge whether there is DOI information in the scan data; wherein the DOI information at least contains the deposition position of the positioning photon in the crystal, which is used to configure a DOI precision reconstruction model in the simulation process; a processing unit configured to activate a DOI precision reconstruction model in an image reconstruction model library if there is DOI information; wait for and respond to the type of the called reconstruction model in the image reconstruction model library; construct the type of the reconstruction model by using a simulation system, and then perform image reconstruction by using the reconstruction model; wherein the image reconstruction model library is at least configured with a DOI precision reconstruction model and a Monte Carlo simulation reconstruction model.

[0018] A sixth object of the present application is to provide an image reconstruction device, comprising: a memory having program codes stored thereon; a processor coupled to the memory, and when the program codes are executed by the processor, the image reconstruction method described in the present application is implemented.

[0019] A seventh object of the present application is to provide an image generation method, comprising the image reconstruction method.

[0020] An eighth object of the present application is to provide a computer readable storage medium having program instructions stored thereon, wherein the program instructions are executed to implement the image generation method described in the present application.

[0021] A ninth object of the present application is to provide an imaging system, comprising: an image reconstruction device; a detector connected to the image reconstruction device.

[0022] Preferably, the detector comprises a PET detector, a PET-CT detector, a CT detector, a PET-MR detector or an MR detector.

[0023] Compared with the prior art, the present application has the beneficial effects that: the present application provides an image reconstruction method, which utilizes DOI information to construct image reconstruction algorithms for different demand scenarios, so as to obtain reconstruction images that meet different demands and solve the problem of internal shrinkage during image reconstruction.

[0024] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application and to implement the content of the description, the following will be described in detail with the preferred embodiments of the present application and in conjunction with the accompanying drawings. The specific embodiments of the present application are described in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0026] Figure 1 Schematic diagram of the principle of parallax effect for PET image as an example;

[0027] Figure 2 Schematic diagram of the flow of the image reconstruction method in embodiment 1;

[0028] Figure 3 Schematic diagram of the flow of the DOI precision reconstruction of the image reconstruction method according to the application Figure 1 ;

[0029] Figures 4a-4d Projection image after processing of different DOI depths according to the application using x-y plane point array data;

[0030] Figure 5 Schematic diagram of the flow of the DOI precision reconstruction of the image reconstruction method according to the application Figure 2 ;

[0031] Figures 6a-6d Image obtained after DOI reconstruction according to the application using a circular ring for different DOI depths simulation reconstruction;

[0032] Figures 7a-7c Image obtained after DOI and Monte Carlo simulation reconstruction according to the application using a circular ring;

[0033] Figure 8a , 8b Image obtained after DOI reconstruction according to the application using a circular ring and a polygon;

[0034] Figures 9a-9b Image obtained after low-count DOI and Monte Carlo simulation reconstruction according to the application using a circular ring;

[0035] Figure 9c Center line image obtained after low-count DOI and Monte Carlo simulation reconstruction according to the application using a circular ring;

[0036] Figure 10 Schematic diagram of the image reconstruction device in embodiment 2;

[0037] Figure 11 Schematic diagram of the image reconstruction device in embodiment 3;

[0038] Figure 12 Schematic diagram of the flow of the image reconstruction method in embodiment 4;

[0039] ​Figure 13 This is a schematic diagram of the image reconstruction device in Example 5;

[0040] Figure 14 This is a schematic diagram of the image reconstruction apparatus in Example 6;

[0041] Figure 15 This is a schematic diagram of the image imaging system in Example 8. Detailed Implementation

[0042] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0043] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0044] The image reconstruction method provided in this application is applicable to various high-energy photon imaging systems, such as PET imaging systems, computed tomography (CT) imaging systems, PET-CT imaging systems, magnetic resonance (MR) imaging systems, PET-MR imaging systems, and applications that reconstruct images after data acquisition from various detectors. This is because these imaging systems all require the use of appropriate crystals to deposit high-energy photons (such as X-rays, gamma rays, neutron rays, etc.), ultimately converting the high-energy photons into electrical signals for output. Each high-energy photon will have corresponding DOI information in its respective crystal. Specifically, in a PET system, the detector can include multiple probes; two probes that detect a matching event can form a probe pair, and each probe pair can form one or more response lines.

[0045] like Figure 1 As shown, parallax effects cause reconstructed objects to shrink towards the center, leading to deviations in the reconstruction results. This invention aims to solve this problem to obtain more accurate reconstructed images. There are two main approaches to solving this problem: 1. Using a DOI detector to acquire DOI information, more accurately locating the photon deposition position in the crystal, and applying the DOI information to the reconstruction to obtain an accurate reconstructed image. 2. Using a more precise System Response Matrix (SRM). Both methods can correct image shrinkage, but both have limitations in their application, which is one of the problems this invention attempts to address.

[0046] Embodiment 1

[0047] With reference to Figure 2 The present application provides an image reconstruction method, comprising the following steps:

[0048] S11, obtaining scanning data of an imaging target;

[0049] S12, judging whether DOI information exists in the scanning data;

[0050] S13, if the DOI information exists, applying the DOI information to image reconstruction;

[0051] S14, if the DOI information does not exist, using a system response matrix to perform image reconstruction.

[0052] In the present embodiment, when a system (such as a PET system) for scanning an imaging target is configured with a DOI detector, relevant DOI information can be obtained in the scanning data, wherein the DOI information is used to locate the deposition position of a photon in a crystal; the detector is layered according to the DOI information to obtain the layer in which the photon is deposited in the detector, and the intersection of the connecting line of the layering center and the surface of the detector can obtain more accurate data, eliminating the positioning error of LOR, and then a geometric projection matrix G is calculated by using a Ray-tracing algorithm and used as a system response matrix, so that a better reconstructed image can be obtained.

[0053] As shown in Figure 3 In a preferred embodiment, applying the DOI information to PET image reconstruction comprises the following steps:

[0054] S131, layering the crystals of a PET detector by using Gate simulation;

[0055] S132, obtaining the spatial coordinates of the accurate deposition position of a current pair of photons in the crystals by using Gate simulation;

[0056] S133, obtaining the connecting line of the center coordinates of the layering surface of the crystals and the two crystals in which the intersection of the connecting line and the crystal array surface is located, and determining the LOR number thereof from the two crystals, so that the LOR in which the current pair of photons is located is obtained;

[0057] S134, replacing the photon coordinates in the LOR with the spatial coordinates of the accurate deposition position of the current pair of photons in the crystals to reconstruct an image.

[0058] In the present embodiment, Gate simulation is realized, wherein the simulation prosthesis adopted is an x-y plane point source array, and a Voxelized simulation is used, and the pixel source size is 2x2x2mm 3, the interval between adjacent points is 6mm; the x, y coordinates are all from the center coordinates of the 4th pixel, and increase by 6mm to the center coordinates of the 130th pixel.

[0059] As shown in Figures 4a-4d , after the DOI processing of the projection data (sinogram data), some regular gaps appear, and as the DOI depth increases (wherein, Figure 4a is the original projection data of the x-y plane point array data, Figure 4b is the projection data of the DOI depth of 2mm, Figure 4c is the projection data of the DOI depth of 4mm, Figure 4d is the projection data of the DOI depth of 10mm), the gaps become more obvious, which is due to the decrease of DOI accuracy, resulting in the decrease of the accuracy of spatial point positioning, and the data is more discrete.

[0060] It should be noted that the DOI depth represents the minimum unit of obtaining the position of the photon, that is, the greater the DOI depth, the lower the DOI accuracy, and there should be no technical misunderstanding and unclear technical solutions.

[0061] It should be understood that the decrease of DOI accuracy means the increase of DOI resolution, and conversely, the decrease of DOI resolution will lead to the decrease of the quality of the reconstructed image, and the higher the DOI resolution, the better. Limiting, the most ideal resolution is 0, that is, knowing the accurate deposition position of each photon.

[0062] As shown in Figure 5 , in another preferred embodiment, applying the DOI information to the PET image reconstruction comprises the steps of:

[0063] S135, using Gate simulation to perform different DOI accuracy layering of the crystals of the PET detector under the same set of simulation data;

[0064] S136, using Gate simulation to obtain a set of spatial coordinates of the accurate deposition positions of a pair of photons under different DOI accuracy conditions under the same set of simulation data;

[0065] S137, using the set of spatial coordinates to obtain two crystals where the intersection point of the connecting line of the center coordinates of the crystal layering surface and the crystal array surface is located, and determining the LOR group where the two crystals are located, that is, obtaining the LOR group where a plurality of sets of DOI processed photons are located under different accuracy;

[0066] S138, using the ordered subset maximum expectation (OSEM) to perform image reconstruction on a plurality of sets of DOI processed data (the set of spatial coordinates and the LOR group where the photons are located).

[0067] like Figures 6a-6d The image shown is an image reconstructed from different DOI depths based on Gate simulation. The simulated object is a concentric ring; the object is placed at the center of the detector, with a ring width of 5mm, outer radii ranging from 20mm to 60mm, a spacing of 5mm between adjacent rings, and a ring height of 150mm. The results in the image show that adding the original deposition location (… Figure 6a Reconstruction can be performed with an equivalent DOI resolution of 0, which can accurately locate the deposition position of each photon. As the DOI accuracy increases ( Figure 6b The resolution of the Chinese DOI is 2. Figure 6c The resolution of the Chinese DOI is 4. Figure 6d The DOI resolution is 10, and the positioning is inaccurate, which reduces the effect of position offset recovery.

[0068] The results obtained from DOIs of different precisions differ (see...). Figures 4a-4c However, selecting an excessively high DOI resolution will lead to a geometric increase in the amount of simulation data. Therefore, if... Figure 5 As shown, the image reconstruction method may also include the following steps:

[0069] S139. Determine whether the quality of the image reconstruction result meets expectations;

[0070] S1391. If the expected result is not achieved, reduce the average DOI accuracy of several groups and increase the number of groups. Perform simulation again to obtain the optimized data after processing several groups of DOIs. Then, use the ordered subset maximum expectation algorithm to reconstruct the image.

[0071] S1392. If the result meets expectations, output the current image reconstruction result.

[0072] In this embodiment, when there is no DOI detector in the PET system, DOI information cannot be generated after scanning the imaging target. In this case, the PET system needs to construct the system response matrix in other ways. Specifically, the actual PET system can be used to collect point source imaging data at different locations within the entire field of view (FOV), and the system response matrix can be obtained by fitting the data. Preferably, the system response matrix can also be generated by Gate simulation, i.e., Monte Carlo simulation reconstruction: this includes collecting the response functions at all locations within the entire field of view using Monte Carlo simulation, and obtaining the system response matrix based on the response functions at all locations.

[0073] It should be understood that, due to the large number of points within the FOV, calculating the system response for each location would be extremely laborious. Therefore, when using the two methods mentioned above, the system symmetry is analyzed, the system response of all voxels in a certain region within the FOV is calculated, and the system response of all locations within the FOV is obtained through symmetric calculation, ultimately yielding the complete system response matrix.

[0074] In another specific embodiment, based on Gate simulation, the simulated prosthesis is a concentric ring; the prosthesis is placed at the center of the detector, the ring width is 5mm, the outer radius of the ring is 20mm to 60mm, the interval between adjacent rings is 5mm, and the ring height is 150mm.

[0075] like Figures 7a-7c As shown in the figure, the results indicate that due to the parallax effect, the reconstruction result obtained without any correction is ( Figure 7a Shrink inwards, and then reconstruct using resolution modeling. Figure 7b ) or add to utilize the original sedimentary location ( Figure 7c The equivalent DOI resolution is 0, which can accurately locate the deposition position of each photon for reconstruction. This can effectively solve the "shrinkage" problem. Both reconstruction using two resolution models and reconstruction using the original deposition position can achieve good results.

[0076] like Figure 8a , 8b As shown, the intersection of the LOR and the detector can be determined using two calculation methods:

[0077] 1. Approximate the detection system as a cylinder and calculate the intersection points ( Figure 8a );

[0078] 2. Approximate the detection system as a polygon and calculate the intersection points ( Figure 8b ).

[0079] The results in the figure show that the location can be well recovered after DOI processing. Since the brain PET system consists of 44 probe plates with a shape close to a cylinder, the detectors are approximately two shapes with little difference.

[0080] like Figures 9a-9c As shown in the results above, at low counts, there is almost no difference between resolution modeling reconstruction and DOI precision reconstruction (original deposition location), and both have a good correction effect on parallax response.

[0081] It should be understood that in this embodiment, by judging the DOI information, the corresponding system response matrix is ​​automatically constructed, simplifying the process of selecting the reconstruction model. At the same time, by comparing the advantages of each reconstruction model, a theoretical basis and implementation guidance are provided for recommending the corresponding reconstruction model according to the actual scenario.

[0082] Example 2

[0083] like Figure 10 As shown, an image reconstruction apparatus 100 is provided, including: an acquisition unit 101, a judgment unit 102, and a processing unit 103; wherein,

[0084] The acquisition unit 101 is configured to acquire scanning data of the imaging target; the judgment unit 102 is configured to determine whether there is DOI information in the scanning data; wherein, the DOI information is used to locate the deposition position of photons in the crystal; the processing unit 103 is configured to apply the DOI information to image reconstruction if DOI information exists; if DOI information does not exist, image reconstruction is performed using the system response matrix.

[0085] For a detailed description of each of the above units, please refer to the corresponding description in the above method embodiments, which will not be repeated here.

[0086] In one embodiment, the image reconstruction apparatus 100 further includes a reconstruction model library, which contains at least a DOI-accurate reconstruction model and a Monte Carlo simulation reconstruction model. A corresponding system response matrix is ​​established using the reconstruction models in the reconstruction model library to reconstruct the scanned data and correct image shrinkage.

[0087] It should be understood that the reconstruction model library can also be configured in other devices that communicate with the image reconstruction apparatus 100, and the reconstruction models in the reconstruction model library can be accessed or called through communication, thus implementing this application in the same way.

[0088] Example 3

[0089] Combination Figure 11 , Figure 15 As shown, the image reconstruction device 200 is manifested in the form of a general-purpose computing device; including but not limited to: a memory 201 and a processor 202; wherein,

[0090] A memory 201 stores program code; a processor 202 is connected to the memory and, when the program code is executed by the processor, implements the image reconstruction method in Embodiment 1.

[0091] The PET image reconstruction apparatus 200 may also include a bus 600 connecting different system components (including memory 201 and processor 202), a display unit 700, etc. The bus 600 may represent one or more of several types of bus structures, including a memory unit bus or memory unit controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the various bus structures.

[0092] Example 4

[0093] As Figure 12 An image reconstruction method, comprising the following steps:

[0094] S21, acquiring scanning data of an imaging target;

[0095] S22, judging whether DOI information exists in the scanning data; wherein the DOI information at least contains a deposition position of a positioning photon in a crystal, and is used to configure a DOI precision reconstruction model in a simulation process;

[0096] S23, if the DOI information exists, activating the DOI precision reconstruction model in an image reconstruction model library; wherein the image reconstruction model library is at least configured with the DOI precision reconstruction model and a Monte Carlo simulation reconstruction model;

[0097] S24, if the DOI information does not exist, shielding the DOI precision reconstruction model in the image reconstruction model library;

[0098] S25, waiting for and responding to a type of reconstruction model called in the image reconstruction model library;

[0099] S26, constructing the type of reconstruction model by using a simulation system, and then performing image reconstruction by using the reconstruction model.

[0100] In the embodiment, when the DOI detector is configured in the scanning system, the related DOI information is obtained in the scanning data, wherein the DOI information is used to locate the deposition position of the positioning photon in the crystal; at this time, the DOI precision reconstruction model is activated, and the user can select the DOI precision reconstruction model or the Monte Carlo simulation reconstruction model; although the DOI precision reconstruction model can quickly obtain the system response matrix, it only considers the geometric relationship and does not consider the physical relationship, and the accuracy is not as good as that of the Monte Carlo simulation reconstruction model; therefore, for the scene with high image reconstruction quality requirement, the Monte Carlo simulation reconstruction model is recommended, and the image reconstruction is not performed after the system response matrix is established by using the DOI precision reconstruction model, and the quality judgment and identification whether it meets the expectation are performed, so that the simulation time is greatly saved, and the simulation application is actual.

[0101] It should be understood that the construction processes of the DOI precision reconstruction model and the Monte Carlo simulation reconstruction model respectively correspond to the image reconstruction methods in which the DOI detector exists or does not exist in the embodiment 1, and will not be repeated here.

[0102] It should also be understood that in the embodiment, the image reconstruction model library is reconstructed by judging the DOI information, the selection type of the reconstruction model is enriched, the advantages of each reconstruction model are fully played, and the theoretical basis and implementation guidance for recommending the corresponding reconstruction model according to the actual scene are provided.

[0103] Embodiment 5

[0104] As shown in Figure 13 An image reconstruction apparatus 300, comprising: an acquisition unit 301, a judgment unit 302, a processing unit 303; wherein,

[0105] The acquisition unit 301 acquires scan data of an imaging target; the judgment unit 302 is configured to judge whether there is DOI information in the scan data; wherein the DOI information at least contains the deposition position of the positioning photon in the crystal, which is used to configure a DOI precision reconstruction model in the simulation process; the processing unit 303 is configured to activate the DOI precision reconstruction model in the image reconstruction model library if there is DOI information; wait for and respond to the type of reconstruction model called in the image reconstruction model library; construct the type of reconstruction model by using the simulation system, and then perform image reconstruction by using the reconstruction model; wherein the image reconstruction model library is at least configured with the DOI precision reconstruction model and the Monte Carlo simulation reconstruction model.

[0106] The detailed description of each unit above can refer to the corresponding description in the method embodiment above, which will not be repeated here.

[0107] In an embodiment, the image reconstruction apparatus 300 further comprises a reconstruction model library, which is at least configured with the DOI precision reconstruction model and the Monte Carlo simulation reconstruction model. The corresponding system response matrix is established by the reconstruction model in the reconstruction model library to reconstruct the data scanned by the PET system and correct the image shrinkage.

[0108] It should be understood that the reconstruction model library can also be configured in other devices in communication with the image reconstruction apparatus 300, and the reconstruction model of the reconstruction model library can be accessed or called by communication, and the present application can also be implemented.

[0109] Embodiment 6

[0110] As shown in Figure 14 , Figure 15 An image reconstruction apparatus 400, in the form of a general-purpose computing device; comprising but not limited to: a memory 401, a processor 402; wherein,

[0111] The memory 401 has program code stored thereon; the processor 402 is coupled with the memory, and when the program code is executed by the processor, the image reconstruction method in embodiment 4 is realized.

[0112] The image reconstruction apparatus 400 can further include a bus 600 connecting different system components, including the memory 401 and the processor 402, a display unit 700, etc. Among them, the bus 600 can be one or more of several types of bus structures, including a storage unit bus or a storage unit controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of the bus structures.

[0113] Embodiment 7

[0114] An image generation method includes the image reconstruction method described in Embodiment 1 or Embodiment 4. With the above, different image reconstruction algorithms are provided for users with different needs to obtain the expected reconstruction image under different needs, solving the problem of image shrinkage.

[0115] Embodiment 8

[0116] As shown in Figure 15 An imaging system includes an image reconstruction apparatus and a detector 500 connected to the image reconstruction apparatus. The image reconstruction apparatus can include the image reconstruction apparatus in Embodiment 2, Embodiment 3, Embodiment 5, or Embodiment 6. The detector can include a PET detector, a PET-CT detector, a CT detector, a PET-MR detector, or an MR detector. Detailed descriptions of these detectors can be referred to the prior art, and will not be repeated here.

[0117] Embodiment 9

[0118] Through the description of the above embodiments, those skilled in the art can easily understand that the example embodiments described herein can be implemented by software, or by software combined with necessary hardware. The technical solutions according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a computer readable storage medium (which can be a CD-ROM, a U disk, a mobile hard disk, etc.) or a network, and includes a plurality of computer program instructions to make a computing device (which can be a personal computer, a server, or a network device, etc.) execute the above-mentioned method according to the embodiments of the present application.

[0119] The number of devices and the scale of processing described herein are used to simplify the description of the present application. Applications, modifications, and variations of the present application are obvious to those skilled in the art.

[0120] While embodiments of the application have been disclosed in connection with the above specification and drawings this description is not intended to limit the scope of the application and it will be appreciated that modifications can be made by those skilled in the art without departing from the scope of the present application as defined by the following claims.

[0121] The device, the electronic device, the non-volatile computer storage medium and the method provided by the embodiments of the present application are corresponding, therefore, the device, the electronic device, the non-volatile computer storage medium also have similar beneficial technical effects with the corresponding method, since the beneficial technical effects of the method have been described in detail above, therefore, the beneficial technical effects of the corresponding device, the electronic device, the non-volatile computer storage medium will not be described here.

[0122] In the 1990s, it was relatively easy to distinguish whether an improvement in a technology was a hardware improvement (e.g., an improvement in the circuit structure of a diode, transistor, switch, etc.) or a software improvement (an improvement in a method flow). However, as technology has evolved, many improvements in method flows today can be considered as direct improvements in hardware circuit structures. Designers almost always obtain the corresponding hardware circuit structures by programming the improved method flows into hardware circuits. Therefore, it cannot be said that an improvement in a method flow cannot be implemented using hardware entity modules. For example, a programmable logic device (PLD) (e.g., a field programmable gate array (FPGA)) is an integrated circuit whose logic function is determined by user programming of the device. A digital system is "integrated" on a PLD by the designer programming the PLD, rather than by ordering a chip manufacturer to design and fabricate a custom integrated circuit chip. Moreover, instead of manually fabricating integrated circuit chips, this programming is now mostly implemented using "logic compiler" software, which is similar to software compilers used in program development, and the original code to be compiled is written in a specific programming language, which is called a hardware description language (HDL), and there are many such languages, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc., and the most commonly used are VHDL (Very-High-Speed Integrated Circuit Hardware Description Language) and Verilog. Those skilled in the art should be aware that, as long as the method flow is logically programmed in the above-mentioned hardware description languages and programmed into an integrated circuit, a hardware circuit implementing the logical method flow can be easily obtained.

[0123] The controller can be implemented in any suitable way, for example, the controller can take the form of a microprocessor or processor and a computer readable medium storing computer readable program code, such as software or firmware, executable by the (micro)processor, logic gates, switches, an application specific integrated circuit (ASIC), a programmable logic controller and an embedded microcontroller, examples of which include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320, the memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also know that, in addition to implementing the controller purely in terms of computer readable program code, it is possible to implement the controller to perform the same functions using logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded microcontrollers, by logically programming the method steps. The controller can therefore be considered a hardware component, and the means for performing the various functions comprised within it can be considered structures within the hardware component. Alternatively, or even additionally, the means for performing the various functions can be considered both software modules which implement the method and structures within the hardware component.

[0124] The systems, apparatuses, modules or units illustrated by the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0125] For the sake of description, the above apparatuses are described in various units by functions respectively. Of course, the functions of each unit can be implemented in the same or multiple software and / or hardware when implementing one or more embodiments of the present specification.

[0126] Those skilled in the art will understand that the embodiments of the present specification can be provided as a method, a system or a computer program product. Therefore, the embodiments of the present specification can take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware aspects. Moreover, the embodiments of the present specification can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0127] The specification is presented with reference to flow diagrams and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the specification. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing element or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein.

[0128] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein.

[0129] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein. Figure 1 The flow diagram and / or block diagram in the flow diagrams and / or block diagrams can represent one or more of any appropriate circuitry configured to perform the specified functions. In this regard, one or more flow diagrams and / or block diagrams in the flow diagrams and / or block diagrams can represent a device or devices configured to perform one or more of the functions described herein.

[0130] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0131] The memory can include non-persistent memory and / or persistent memory, such as flash memory, or other non-volatile memory, in the form of a computer-readable medium. The memory is an example of computer-readable media.

[0132] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0133] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or apparatus that comprises a list of elements does not only include those elements, but also other elements not explicitly listed, or other elements inherent to such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0134] The specification can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The specification can also be practiced in a distributed computing environment, in which tasks are performed by remote processing devices connected by a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media, including storage devices.

[0135] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0136] The above merely provides an example of the present specification, and is not intended to limit one or more embodiments of the present specification. One or more embodiments of the present specification can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of one or more embodiments of the present specification shall be included in the scope of claims of one or more embodiments of the present specification. One or more embodiments of the present specification One or more embodiments of the present specification One or more embodiments of the present specification One or more embodiments of the present specification.

Claims

1. An image reconstruction method, characterized in that, Includes the following steps: Acquire scan data of the imaging target; Determine whether DOI information exists in the scan data; DOI information is used to locate the deposition position of photons in the crystal. If DOI information exists, then the DOI information is applied to image reconstruction; If no DOI information exists, image reconstruction is performed using the system response matrix; The application of the DOI information to image reconstruction includes the following steps: By using Gate simulation to layer the crystal with different DOI precisions under the same set of simulation data, several sets of DOI-processed data with different precisions are obtained. Then, the ordered subset maximum expectation algorithm is used to reconstruct the image from these several sets of DOI-processed data.

2. The image reconstruction method according to claim 1, characterized in that, Applying the DOI information to image reconstruction includes the following steps: Layering of the crystal was performed using Gate simulation; The spatial coordinates of the precise deposition location of a pair of photons in the crystal are obtained using Gate simulation. Using the spatial coordinates, the line connecting the center coordinates of the crystal layered surface is obtained, and the two crystals where the line intersects with the crystal array surface are located are obtained. The LOR number of the two crystals is determined, and the LOR of the current pair of photons is obtained. Replace the photon coordinates in the LOR with the spatial coordinates of the exact deposition location of the current pair of photons in the crystal to reconstruct the image.

3. The image reconstruction method according to claim 1, characterized in that, It also includes the following steps: If the quality of the image reconstruction result does not meet expectations, the average DOI precision of several groups is reduced and the number of groups is increased to obtain several optimized DOI-processed data. Then, the ordered subset maximum expectation algorithm is used for image reconstruction.

4. The image reconstruction method according to claim 1, characterized in that, The system response matrix is ​​generated using Gate simulation, which includes acquiring the response functions at all locations within the entire image field of view using Monte Carlo simulation, and obtaining the system response matrix based on the response functions at all locations.

5. An image reconstruction apparatus, characterized in that, include: An acquisition unit configured to acquire scan data of the imaging target; The judgment unit is configured to determine whether DOI information exists in the scan data; wherein, DOI information is used to locate the deposition position of photons in the crystal; The processing unit is configured to apply the DOI information to image reconstruction if DOI information exists, and to perform image reconstruction using the system response matrix if DOI information does not exist. The application of the DOI information to image reconstruction includes the following steps: By using Gate simulation to layer the crystal with different DOI precisions under the same set of simulation data, several sets of DOI-processed data with different precisions are obtained. Then, the ordered subset maximum expectation algorithm is used to reconstruct the image from these several sets of DOI-processed data.

6. An image reconstruction apparatus, characterized in that, include: A memory that stores program code; A processor, which is connected to the memory, and which, when the program code is executed by the processor, implements the method of any one of claims 1 to 4.

7. An image reconstruction method, characterized in that, Includes the following steps: Acquire scan data of the imaging target; Determine whether DOI information exists in the scan data; whereby DOI information includes at least the deposition location of the local photon in the crystal, which is used to configure and generate a DOI-accurate reconstruction model during the simulation process; If DOI information exists, the DOI-accurate reconstruction model in the image reconstruction model library is activated; wherein the image reconstruction model library is configured with at least the DOI-accurate reconstruction model and the Monte Carlo simulation reconstruction model. Waiting for and responding to the type of reconstruction model invoked in the image reconstruction model library; A reconstruction model of the aforementioned type is constructed using a simulation system, and then image reconstruction is performed using the reconstruction model; The steps for generating the DOI precision reconstruction model include: using Gate simulation to layer the crystal with different DOI precisions under the same set of simulation data to obtain several sets of DOI-processed data with different precisions, and then using the ordered subset maximum expectation algorithm to reconstruct the image from the several sets of DOI-processed data.

8. The image reconstruction method according to claim 7, characterized in that, The steps for generating the DOI-accurate reconstruction model include: Layering of the crystal was performed using Gate simulation; The spatial coordinates of the precise deposition location of a pair of photons in the crystal are obtained using Gate simulation. Using the spatial coordinates, the line connecting the center coordinates of the crystal layered surface is obtained, and the two crystals where the line intersects with the crystal array surface are located are obtained. The LOR number of the two crystals is determined, and the LOR of the current pair of photons is obtained. Replace the photon coordinates in the LOR with the spatial coordinates of the exact deposition location of the current pair of photons in the detector to reconstruct the image.

9. The image reconstruction method according to claim 7, characterized in that, The steps for generating the DOI accuracy reconstruction model further include: determining whether the quality of the image reconstruction result meets expectations; if it does not meet expectations, increasing the average DOI accuracy of several groups and increasing the number of groups to obtain optimized data after processing several DOI groups, and then using the ordered subset maximum expectation algorithm for image reconstruction.

10. The image reconstruction method according to claim 7, characterized in that, The steps for generating the Monte Carlo simulation reconstruction model include: performing Monte Carlo simulation reconstruction using Gate, acquiring the response functions of all locations within the entire image field of view, and obtaining the system response matrix based on the response functions of all locations.

11. An image reconstruction apparatus, characterized in that, include: The acquisition unit acquires scan data of the imaging target; The judgment unit is configured to determine whether DOI information exists in the scan data; wherein, the DOI information includes at least the deposition position of the location photon in the crystal, which is used to configure the generation of the DOI accuracy reconstruction model during the simulation process; The processing unit is configured to activate a DOI-accurate reconstruction model in the image reconstruction model library if DOI information exists; wait for and respond to the type of reconstruction model called in the image reconstruction model library; construct a reconstruction model of the type using a simulation system, and then perform image reconstruction using the reconstruction model; wherein the image reconstruction model library is configured with at least a DOI-accurate reconstruction model and a Monte Carlo simulation reconstruction model; wherein the generation steps of the DOI-accurate reconstruction model include: using Gate simulation to perform different DOI-accuracy layering on the crystal under the same set of simulation data to obtain several sets of DOI-processed data with different accuracies, and then using the ordered subset maximum expectation algorithm to perform image reconstruction on the several sets of DOI-processed data.

12. An image reconstruction apparatus, characterized in that, include: A memory that stores program code; A processor, which is connected to the memory, and which, when the program code is executed by the processor, implements the method of any one of claims 7 to 10.

13. An image generation method, characterized in that, Including the image reconstruction method as described in any one of claims 1-4 or 7-10.

14. A computer-readable storage medium, characterized in that, It stores program instructions, which, when executed, implement the image generation method of claim 13.

15. An imaging system, characterized in that, include: The image reconstruction apparatus as described in any one of claims 5-6 or 11-12; The detector is connected to the image reconstruction device.

16. The imaging system according to claim 15, characterized in that, The detector includes a PET detector, a PET-CT detector, a CT detector, a PET-MR detector, or an MR detector.

Images