Correction method and device, computer equipment and readable storage medium

Abstract

The invention relates to a correction method and device, computer equipment and a readable storage medium. The method comprises the steps of obtaining to-be-corrected data of the medical scanning equipment under target environment parameters, correcting the to-be-corrected data according to the target environment parameters and a target uniformity correction relation to obtain target correction data, and determining a target reconstructed image according to the target correction data. Wherein the to-be-corrected data comprises a response relationship between an image domain unit corresponding to the to-be-detected object and a detection unit in the medical scanning equipment, or the to-be-corrected data comprises an actual projection image detected by the medical scanning equipment; the target uniformity correction relation comprises a corresponding relation between the environment parameters and the radioactive source projection drawing. By adopting the method, the quality of the reconstructed image can be improved.

Description

Technical Field

[0001] This application relates to the field of medical technology, and in particular, to a calibration method, device, computer device, and readable storage medium. Background Art

[0002] A collimator is a key component in a medical scanning device and plays a decisive role in the sensitivity and imaging resolution of the medical scanning device.

[0003] However, currently, the collimator is usually processed in blocks and then the blocks of each collimator are spliced together to form an integral collimator. The collimator obtained in this way will have seams, and the seams will affect the quality of the finally obtained reconstructed image.

[0004] Therefore, how to propose a calibration method that can improve the quality of the reconstructed image is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a calibration method, device, computer device, and readable storage medium that can improve the quality of the obtained reconstructed image.

[0006] In a first aspect, this application provides a calibration method, including:

[0007] Obtain calibration data of a medical scanning device under target environmental parameters; the calibration data includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the calibration data includes the actual projection image detected by the medical scanning device;

[0008] Calibrate the calibration data according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibration data; the target uniformity calibration relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map;

[0009] Determine a target reconstructed image according to the target calibration data.

[0010] In one embodiment, the radiation source projection map includes the ratio between the theoretical distribution and the actual distribution of the radionuclide corresponding to different detection units; calibrating the calibration data according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibration data includes:

[0011] Determine a target radiation source projection map according to the target environmental parameters and the target uniformity calibration relationship;

[0012] Multiply the calibration data corresponding to the same detection unit by the target radiation source projection map to obtain target calibration data.

[0013] In one embodiment, determining a target reconstructed image according to target calibration data includes:

[0014] If the data to be calibrated includes an actual projection image, reconstruct the target calibration data to obtain a target reconstructed image;

[0015] If the data to be calibrated includes a response relationship, reconstruct the actual projection image detected by the medical scanning device according to the target calibration data to obtain a target reconstructed image.

[0016] In one embodiment, the method further includes:

[0017] Obtain radiation source projection maps corresponding to different environmental parameters;

[0018] Determine a target uniformity calibration relationship according to each environmental parameter and the radiation source projection map corresponding to each environmental parameter.

[0019] In one embodiment, determining a target uniformity calibration relationship according to each environmental parameter and the radiation source projection map corresponding to each environmental parameter includes:

[0020] Perform fitting on each environmental parameter and the corresponding radiation source projection map to obtain an initial uniformity calibration relationship;

[0021] Determine a target uniformity calibration relationship according to the initial uniformity calibration relationship.

[0022] In one embodiment, determining a target uniformity calibration relationship according to the initial uniformity calibration relationship includes:

[0023] Process the initial uniformity calibration relationship according to a preset mask to obtain a target uniformity calibration relationship.

[0024] In one embodiment, the environmental parameter includes a size parameter of a radiation surface source and / or a distance between the radiation surface source and a collimator in the medical scanning device.

[0025] In one embodiment, the radiation surface source is obtained after a preset movement of a radiation point source and / or a radiation line source.

[0026] In a second aspect, the present application further provides a calibration device, including:

[0027] A first acquisition module, configured to acquire data to be calibrated of a medical scanning device under target environmental parameters; the data to be calibrated includes a response relationship between an image domain unit corresponding to a to-be-detected object and a detection unit in the medical scanning device, or the data to be calibrated includes an actual projection image detected by the medical scanning device; the medical scanning device includes a collimator;

[0028] A calibration module, configured to calibrate data to be calibrated according to target environmental parameters and a target uniformity calibration relationship to obtain target calibrated data; the target uniformity calibration relationship includes a correspondence between environmental parameters and a radiation source projection map, and the radiation source projection map includes a relative relationship between a theoretical distribution and an actual distribution of radionuclides corresponding to different detection units;

[0029] A first determination module, configured to determine a target reconstructed image according to the target calibrated data.

[0030] In a third aspect, the present application further provides a computer device, including a memory and a processor, where the memory stores a computer program, and when the processor executes the computer program, the steps of any of the above methods are implemented.

[0031] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0032] In a fifth aspect, the present application further provides a computer program product, including a computer program, and when the computer program is executed by a processor, the steps of any of the above methods are implemented.

[0033] For the above calibration method, device, computer device, and readable storage medium, since the target uniformity calibration relationship includes a correspondence between environmental parameters and a radiation source projection map, and the radiation source projection map includes a relative relationship between a theoretical distribution and an actual distribution of radionuclides corresponding to different detection units, after obtaining the data to be calibrated of a medical scanning device under target environmental parameters, the data to be calibrated can be calibrated according to the target environmental parameters and the target uniformity calibration relationship to combine the actual situation of the medical scanning device to obtain target calibrated data. Further, since the data to be calibrated includes a response relationship between an image domain unit corresponding to a to-be-detected object and a detection unit in the medical scanning device, or the data to be calibrated includes an actual projection image detected by the medical scanning device, based on the calibrated target calibrated data, the target reconstructed image can be accurately and flexibly determined, improving the quality of the target reconstructed image. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required to be used in the description of the embodiments of the present application or related technologies. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other related drawings can be obtained without creative efforts based on these drawings.

[0035] Figure 1 It is a schematic diagram of light leakage at a seam.

[0036] Figure 2 It is an application environment diagram of the calibration method in an embodiment;

[0037] Figure 3 It is a schematic flowchart of the calibration method in an embodiment;

[0038] Figure 4 It is a schematic flowchart of obtaining a target reconstructed image in an embodiment;

[0039] Figure 5 It is a schematic flowchart of obtaining a target uniformity correction relationship in an embodiment;

[0040] Figure 6 It is a schematic diagram of adjusting the distance;

[0041] Figure 7 It is a schematic flowchart of obtaining a target uniformity correction relationship in another embodiment;

[0042] Figure 8 It is a schematic diagram of the process of a calibration method in an embodiment;

[0043] Figure 9 It is a schematic diagram of the use of a calibration method in an embodiment;

[0044] Figure 10 It is a schematic diagram of the process of a calibration method in an embodiment;

[0045] Figure 11 It is a schematic diagram of collimators without and with seams in an embodiment;

[0046] Figure 12 It is a schematic diagram of a radiation source projection map in an embodiment;

[0047] Figure 13 It is a schematic diagram of the effect of a calibration in an embodiment;

[0048] Figure 14 It is a schematic diagram of the effect of another calibration in an embodiment;

[0049] Figure 15 It is a structural block diagram of a calibration device in an embodiment. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0051] Single-Photon Emission Computed Tomography (SPECT) is a mature imaging technology in the field of nuclear medicine and has extensive applications in clinical diagnosis and treatment. Taking a medical scanning device as an example, if it is SPECT, the collimator is a key component of SPECT imaging and plays a decisive role in the sensitivity and imaging resolution of the SPECT system.

[0052] Since the collimator plays an important role in the performance of the SPECT system, SPECT also has high requirements for the processing accuracy of the collimator. Traditional parallel-hole collimators, fan-beam collimators, cone-beam collimators, etc. are made by hot melt casting or lead foil stacking. Taking a low-energy parallel-hole collimator as an example, due to its small aperture and wall thickness, the wall thickness is usually on the order of 0.1 millimeters (mm), while the overall size is about 400x500mm. The requirements for the one-time forming processing accuracy are relatively high, the processing difficulty is large, and the processing cost is also high. Therefore, a feasible method is to divide the collimator into several small pieces, process them in blocks, and then splice and synthesize them into a whole. However, the blocks of the collimator are usually connected by a glue layer at the splicing position. The glue layer has a certain thickness, and depending on the process accuracy difference, the thickness of the glue layer may vary from 0.01mm to 1mm.

[0053] Figure 1 As a schematic diagram of light leakage at the seam, as Figure 1 (a) and Figure 1 (b) show, once the glue layer in the collimator is too thick, more gamma rays will pass through the gaps in the glue layer and be detected by the detector, resulting in linear artifacts in the image. Moreover, when the distance between the radiation source and the seam is different, the solid angle of the radiation source relative to the seam also changes. Therefore, on the premise that the activity of the radiation source is constant and gamma rays are emitted isotropically, when the distance between the radiation source and the seam decreases, the number of gamma photons actually incident on the seam increases with the increase of the solid angle, resulting in a change in the relative intensity distribution on the actually measured projection image. It can be seen that an overly thick glue layer will cause light leakage, lead to gamma ray penetration, affect the uniformity of the collimator, make the imaging uniformity poor, and thus affect the quality of the finally obtained reconstructed image.

[0054] Based on this, it is necessary to provide a correction method that can improve the quality of the obtained reconstructed image for the above technical problems, and the following will introduce this correction method.

[0055] Figure 2 As an application environment diagram of the correction method in an embodiment, in an exemplary embodiment, a computer device is provided. This computer device can be a server, and its internal structure diagram can be as Figure 2As shown in the figure. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, 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 the computer program in the non-volatile storage medium. The database of the computer device is used to store relevant data. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a calibration method is implemented.

[0056] Those skilled in the art can understand that Figure 2 the structure shown in the figure is only a block diagram of some structures 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 those shown in the figure, or combine some components, or have a different component layout.

[0057] In this embodiment, the method is exemplified by being applied to a server. It can be understood that the method can also be applied to a terminal, and can also be applied to a system including a terminal and a server, and is implemented through the interaction between the terminal and the server. Among them, the terminal can be, but is not limited to, various personal computers, laptop computers, smart phones, and tablet computers. The server can be implemented by an independent server or a server cluster composed of multiple servers.

[0058] Figure 3 is a schematic flowchart of the calibration method in an embodiment. In an exemplary embodiment, as Figure 3 shown, a calibration method is provided. Taking the method applied to the Figure 2 computer device in the figure as an example, it includes the following S301 to S303.

[0059] S301, obtain the data to be calibrated of the medical scanning device under the target environmental parameters; the data to be calibrated includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the data to be calibrated includes the actual projection image detected by the medical scanning device.

[0060] In this embodiment, the computer device first needs to obtain the data to be corrected. Among them, the computer device can obtain the data to be corrected from a medical scanning device or from other devices. The data to be corrected is the data to be corrected by the medical scanning device under the target environmental parameters. The medical scanning device includes a collimator.

[0061] Among them, the medical scanning device can be a scanning device including a collimator. Exemplarily, the medical scanning device can be a positron emission tomography (PET) or SPECT. The collimator in the medical scanning device can include but is not limited to a parallel hole collimator, a fan beam hole collimator, a cone beam hole collimator, a pinhole collimator. The aperture shape of the collimator can be any shape such as a regular hexagon, a square, a circle, etc. The collimator can also be divided into low-energy, medium-energy, and high-energy collimators according to the energy of the radiation source. The material of the collimator can include but is not limited to lead, tungsten.

[0062] The target environmental parameters are the environmental parameters actually used by the medical scanning device. In one embodiment, optionally, the environmental parameters include the size parameter of the radiation surface source and / or the distance between the radiation surface source and the collimator in the medical scanning device. In this way, different imaging scenarios can be flexibly adapted through different environmental parameters. And because the environmental parameters include the size parameter of the radiation surface source and / or the distance between the radiation surface source and the collimator in the medical scanning device, therefore, it is beneficial to perform accurate correction according to the target uniformity correction relationship subsequently. The following will take the environmental parameters including the above-mentioned size parameter and distance as an example.

[0063] Among them, the radiation surface source is the surface source formed by the radiation source, which can be circular, square or other irregular shapes. The radiation source includes but is not limited to technetium-99m (Tc-99m), cobalt-57 (Co-57) or any other type of radiation source. Exemplarily, a uniform flat source can be made of Tc-99m, Co-57 or any type of radiation source as the radiation surface source.

[0064] In one embodiment, optionally, the radiation surface source can also be obtained after a preset movement of the radiation point source and / or the radiation line source. For example, a uniform surface source can be equivalently generated as the radiation surface source by moving the radiation line source back and forth or moving the radiation point source in a "zigzag" shape, etc. In the above embodiment, since the radiation surface source is obtained after a preset movement of the radiation point source and / or the radiation line source, therefore, the radiation surface source can be obtained flexibly.

[0065] The following takes the radiation surface source as circular as an example. The size parameter of the radiation surface source can be the radius. It can be understood that the size parameter of the radiation surface source can also be other parameters such as the side length, area, etc. that can characterize the size of the radiation surface source.

[0066] Furthermore, denote the radius of the currently used radiation surface source as R*, and the distance between the currently used radiation surface source and the collimator in the medical scanning device as D*. That is to say, the target environmental parameters may include the radius R* and the distance D*. Furthermore, the computer device may obtain the data to be corrected corresponding to the medical scanning device when the radius of the radiation surface source is R* and the distance between the radiation surface source and the collimator in the medical scanning device is D*.

[0067] Optionally, the data to be corrected may include the response relationship between the image domain units corresponding to the object to be measured and the detection units in the medical scanning device. The image domain units are the units obtained by dividing the object to be measured. For example, the object to be measured may be divided into image domain units 1 to 10. The object to be measured is also the object that needs to be scanned. The detection units are the units obtained by dividing the detectors on the medical scanning device, and may also be referred to as projection units. For example, the detectors may be divided into detection units 1 to 10.

[0068] Among them, the above response relationship may be calculated in advance, or the response relationship sent by other devices may be obtained. The response relationship may be the system matrix (also referred to as the system response matrix) in the system matrix calculation process, that is, the response distribution map corresponding to each image domain unit and the detection unit. Continuing with the above example, if the image domain units include image domain units 1 to 10 and the detection units include detection units 1 to 10, then the system matrix is a 10×10 matrix, and the elements in the matrix represent the response distribution between each image domain unit and each detection unit.

[0069] Alternatively, the data to be corrected may also include the actual projection image detected by the medical scanning device. Among them, the actual projection image may be a two-dimensional planar image generated by a plain film imaging experiment, or a two-dimensional projection image measured by a three-dimensional tomographic imaging experiment. Optionally, the computer device may obtain the actual projection image by counting the detectors.

[0070] S302. Correct the data to be corrected according to the target environmental parameters and the target uniformity correction relationship to obtain the target corrected data; the target uniformity correction relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map.

[0071] In this embodiment, the computer device can determine the target uniformity correction relationship. Among them, the target uniformity correction relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map.

[0072] Among them, the target uniformity correction relationship can be a functional relationship, a tabular relationship, a mathematical expression, etc., which is not limited in this embodiment. Optionally, the target uniformity correction relationship can be obtained from a preset storage space. The target uniformity correction relationship can also be a correction relationship obtained after obtaining the projection maps of the radiation source corresponding to different environmental parameters. For example, different environmental parameters can be simulated, and the medical scanning device can perform counting under the environmental parameters to obtain the projection maps of the radiation source corresponding to the environmental parameters, and the mapping relationship between the projection maps of the radiation source corresponding to the environmental parameters can be used as the target uniformity correction relationship.

[0073] Exemplarily, the target uniformity correction relationship can include the correspondence between different environmental parameters and the projection maps of the radiation source corresponding to each environmental parameter. Continuing with the above example, the target correspondence relationship can include the projection map of the radiation source corresponding to a radius of R1 and a distance of D1 between the radiation surface source and the collimator in the medical scanning device. The projection map of the radiation source corresponding to a radius of R2 and a distance of D2 between the radiation surface source and the collimator in the medical scanning device. ……, with a radius of R j and a distance of D i between the radiation surface source and the collimator in the medical scanning device. where both i and j are integers greater than or equal to 1.

[0074] The projection map of the radiation source includes the distribution responses of the radionuclides corresponding to different detection units. Optionally, the projection map of the radiation source includes the relative relationship between the theoretical distribution and the actual distribution of the radionuclides corresponding to each detection unit. Among them, the theoretical distribution can be the distribution of the radionuclides determined according to the structural parameters of the collimator in the medical scanning device. The actual distribution can be the actually measured distribution of the radionuclides.

[0075] Exemplarily, the theoretical distribution can be the estimated radiation intensity value detected by the detection unit, and the actual distribution can be the actually measured radiation intensity value detected by the detection unit. The relative relationship between the theoretical distribution and the actual distribution includes, but is not limited to, the ratio, difference, and percentage difference between the theoretical distribution and the actual distribution, which is not limited in this embodiment.

[0076] Furthermore, after the computer device determines the data to be corrected, it can correct the data to be corrected according to the target environmental parameters and the target uniformity correction relationship to obtain the target corrected data.

[0077] Optionally, the computer device may apply or impose the target uniformity correction relationship on the data to be corrected to obtain the target corrected data. Further optionally, the computer device may determine the target radiation source projection map according to the target environmental parameters and the target uniformity correction relationship, and perform operations on the data to be corrected corresponding to the same detection unit and the target radiation source projection map, such as multiplying or dividing, to obtain the target corrected data.

[0078] It can be understood that if the data to be corrected is the actual projection image detected by the medical scanning device, the target corrected data is also the actual projection image after correction. If the data to be corrected is the response relationship between the image domain unit and the detection unit, the target corrected data is also the response relationship after correction.

[0079] S303. Determine the target reconstructed image according to the target corrected data.

[0080] In this embodiment, after obtaining the target corrected data, the target reconstructed image can be obtained based on the target corrected data. For example, if the data to be corrected is the actual projection image detected by the medical scanning device, the computer device may reconstruct the target corrected data to obtain an initial reconstructed image, and perform processing such as filtering, noise reduction, and cropping on the initial reconstructed image to obtain the target reconstructed image.

[0081] In an exemplary embodiment, optionally, the computer device may further display the target reconstructed image.

[0082] In the above correction method, since the target uniformity correction relationship includes the correspondence between the environmental parameters and the radiation source projection map, and the radiation source projection map includes the relative relationship between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units, after obtaining the data to be corrected of the medical scanning device under the target environmental parameters, the data to be corrected can be corrected according to the target environmental parameters and the target uniformity correction relationship in combination with the actual situation of the medical scanning device to obtain the target corrected data. Further, since the data to be corrected includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the data to be corrected includes the actual projection image detected by the medical scanning device, the target reconstructed image can be accurately and flexibly determined according to the corrected target corrected data, improving the quality of the target reconstructed image.

[0083] In an exemplary embodiment, optionally, the radiation source projection map includes the ratio between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units. The above S302 can be implemented in the following manner:

[0084] Determine the target radiation source projection map according to the target environmental parameters and the target uniformity correction relationship, and multiply the data to be corrected corresponding to the same detection unit by the target radiation source projection map to obtain the target corrected data.

[0085] In this embodiment, the radiation source projection map may include the ratio between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units. For example, taking the m-th detection unit as an example, the radiation source projection map includes the theoretical distribution I of the m-th detection unit est,m and the actual distribution I mea,m between the ratios

[0086] After determining the target environmental parameters, the target radiation source projection map can be determined according to the target environmental parameters and the target uniformity correction relationship.

[0087] Optionally, when the environmental parameters in the target uniformity correction relationship include the target environmental parameters, the computer device can determine the target radiation source projection map corresponding to the target environmental parameters from the target uniformity correction relationship. For example, the computer device can determine the target radiation source projection map by searching. Continuing the above example, assuming R* = R1 and D* = D1, the computer device can determine the target radiation source projection map as

[0088] In some embodiments, when the environmental parameters in the target uniformity correction relationship do not include the target environmental parameters, the computer device can determine the target radiation source projection map according to the difference between the environmental parameters in the target uniformity correction relationship and the target environmental parameters. Further optionally, the computer device can determine the environmental parameter with the smallest difference from the target environmental parameters in the target uniformity correction relationship, and use the radiation source projection map corresponding to the environmental parameter with the smallest difference as the target radiation source projection map.

[0089] Furthermore, the computer device can multiply the data to be corrected by the target radiation source projection map to obtain the target corrected data. Among them, the computer device can multiply the data to be corrected corresponding to the same detection unit by the target radiation source projection map to obtain the target corrected data.

[0090] In the above embodiment, since the radiation source projection map includes the ratio between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units, after multiplying the data to be corrected corresponding to the same detection unit by the target uniformity correction relationship, the corrected target corrected data can be obtained.

[0091] Figure 4 It is a schematic flowchart of the process for obtaining the target reconstructed image in an embodiment. In an exemplary embodiment, such as Figure 4As shown, S303 includes S401 to S402.

[0092] S401, if the data to be corrected includes the actual projection image, then reconstruct the target correction data to obtain the target reconstructed image.

[0093] In this embodiment, if the data to be corrected includes the actual projection image detected by the medical scanning device, then the target correction data is the corrected actual projection image, and the computer device can reconstruct the corrected actual projection image to obtain the target reconstructed image, that is, reconstruct the target correction data to obtain the target reconstructed image. For example, the computer device can use a preset reconstruction algorithm to reconstruct the corrected actual projection image to obtain the target reconstructed image. Further optionally, the computer device can reconstruct the corrected actual projection image to obtain the target reconstructed image according to the response relationship between the image domain unit and the detection unit. For example, the computer device can use a preset reconstruction algorithm to reconstruct the corrected actual projection image according to the system matrix to obtain the target reconstructed image. Among them, the preset reconstruction algorithm includes but is not limited to the Ordered Subsets Expectation Maximization (OSEM) algorithm.

[0094] S402, if the data to be corrected includes the response relationship, then reconstruct the actual projection image detected by the medical scanning device according to the target correction data to obtain the target reconstructed image.

[0095] In this embodiment, if the data to be corrected includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, then the target correction data is the corrected response relationship, and then the computer device can use the corrected response relationship to reconstruct the actual projection image detected by the medical scanning device to obtain the target reconstructed image, that is, the computer device can reconstruct the actual projection image detected by the medical scanning device according to the target correction data to obtain the target reconstructed image. Further optionally, the computer device can use a preset reconstruction algorithm to reconstruct the corrected actual projection image according to the response relationship between the image domain unit and the detection unit to obtain the target reconstructed image.

[0096] It can be understood that when the data to be corrected includes the actual projection image, the actual projection image is corrected and the response relationship remains unchanged; when the data to be corrected includes the response relationship, the response relationship is corrected and the actual projection image remains unchanged.

[0097] In the above embodiments, when the data to be corrected includes the actual projection image, the target corrected data can be reconstructed to obtain the target reconstructed image. After directly correcting the generated actual projection image, a target reconstructed image with better quality can be obtained through the corrected actual projection image. When the data to be corrected includes the response relationship, the actual projection image detected by the medical scanning device is reconstructed according to the target corrected data to obtain the target reconstructed image. In this way, in the process of system matrix calculation, that is, in the projection model, the target uniformity correction relationship is considered, and thus a target reconstructed image with better quality can be obtained.

[0098] The following describes the process of obtaining the target uniformity correction relationship. Figure 5 FIG. is a schematic flowchart of a process for obtaining a target uniformity correction relationship in an embodiment. In an exemplary embodiment, as Figure 5 shown, the above correction relationship includes S501 to S502.

[0099] S501, obtain the radiation source projection maps corresponding to different environmental parameters.

[0100] In this embodiment, different environmental parameters can be set, and the radiation source projection maps corresponding to different environmental parameters are obtained based on the medical scanning device. Exemplarily, a uniform flat source made of Tc-99m, Co-57 or any type of radiation source can be used as the radiation surface source, and different j sizes of radiation surface sources can be set, for example, small, medium and large sizes of radiation surface sources can be set.

[0101] In some application scenarios, the size parameters of the radiation surface source can be set according to different imaging objects.

[0102] In one embodiment, optionally, the maximum size of the radiation surface source does not exceed the region of interest (Field of View, FOV) of the imaging of the medical scanning device.

[0103] In some embodiments, a uniform surface source can also be equivalently generated as the radiation surface source by moving the radiation source back and forth or moving the point radiation source in a "zigzag" manner.

[0104] Then, the radiation surface sources with radii of R j can be selected in sequence, and the selected radiation surface sources are placed at different distances D i from the surface of the collimator, and the counts are accumulated by the medical scanning device at different distances D i to obtain the radiation source projection maps corresponding to the environmental parameters wherein. The distances can be evenly distributed or unevenly distributed.

[0105] Optionally, it is possible to determine whether the medical scanning device has accumulated sufficient counts based on quality metrics such as the scanning duration of the medical scanning device or the clarity of the radiation source projection map, and obtain the radiation source projection map corresponding to the environmental parameter only when sufficient counts have been accumulated.

[0106] Optionally, it is possible to keep the detector in the medical scanning device stationary and adjust the distance between the radiation surface source and the collimator surface to achieve different heights D. i 。 Figure 6 As a schematic diagram for adjusting the distance, as Figure 6 shown, in one embodiment, a bracket can be provided between the radiation surface source and the collimator, and by adjusting the position of the radiation surface source on the bracket, the distance between the radiation surface source and the collimator surface can be adjusted. Among them, the height of the bracket can vary according to requirements.

[0107] Optionally, the radiation surface source can also be placed on the scanning bed of the medical scanning device, and the distance between the radiation surface source and the collimator surface can be adjusted by adjusting the height of the scanning bed. It is also possible to adjust the distance between the radiation surface source and the detector by adjusting the radial distance of the detector, etc., thereby adjusting the distance between the radiation surface source and the collimator surface.

[0108] S502. Determine the target uniformity correction relationship based on each environmental parameter and the radiation source projection map corresponding to each environmental parameter.

[0109] In this embodiment, optionally, the computer device can determine the target uniformity correction relationship based on the mapping relationship between each environmental parameter and each radiation source projection map. Exemplarily, the computer device can determine a correction look-up table based on each environmental parameter and the radiation source projection map corresponding to each environmental parameter, and use the correction look-up table as the target uniformity correction relationship.

[0110] In the above embodiment, since it is possible to obtain the radiation source projection maps corresponding to different environmental parameters, therefore, based on each environmental parameter and the radiation source projection map corresponding to each environmental parameter, the target uniformity correction relationship can be accurately and efficiently determined.

[0111] Figure 7 As a schematic flowchart of another process for obtaining the target uniformity correction relationship in one embodiment, in an exemplary embodiment, as Figure 7 shown, S502 includes S701 to S702.

[0112] S701. Fit each environmental parameter and the corresponding radiation source projection map to obtain an initial uniformity correction relationship.

[0113] In this embodiment, after obtaining the radiation source projection maps corresponding to the respective environmental parameters, the computer device will fit the respective environmental parameters and the radiation source projection maps corresponding to the respective environmental parameters to obtain an initial uniformity correction relationship. In this way, the radiation source projection maps in the initial uniformity correction relationship can vary with the environmental parameters.

[0114] Optionally, the computer device will perform two-dimensional fitting on the respective environmental parameters and the radiation source projection maps corresponding to the respective environmental parameters to obtain an initial uniformity correction relationship. Further optionally, the computer device can fit the radiation source projection maps corresponding to the respective environmental parameters through a preset fitting method to obtain an initial uniformity correction relationship. The preset fitting method can include, but is not limited to, polynomial fitting, neural network fitting, etc.

[0115] S702. Determine a target uniformity correction relationship according to the initial uniformity correction relationship.

[0116] Furthermore, after obtaining the initial uniformity correction relationship, the target uniformity correction relationship can be determined according to the initial uniformity correction relationship. Optionally, the computer device can directly use the initial uniformity correction relationship as the target uniformity correction relationship, or the computer device can perform post-processing on the initial uniformity correction relationship to obtain the target uniformity correction relationship. The preprocessing includes, but is not limited to, filtering, noise reduction, cropping, masking, and this embodiment is not limited thereto.

[0117] In the above embodiment, since the respective environmental parameters and the corresponding radiation source projection maps can be fitted to obtain the initial uniformity correction relationship, therefore, according to the initial uniformity correction relationship, a more accurate and comprehensive target uniformity correction relationship can be determined.

[0118] In an exemplary embodiment, optionally, after obtaining the target uniformity correction relationship, the target uniformity correction relationship can be stored in a preset storage space so as to obtain the target uniformity correction relationship from the preset storage space when correction is required. The preset storage space can be the storage space on the computer device or the storage space on other devices, and it includes, but is not limited to, any storage medium.

[0119] In one of the embodiments, optionally, the above S702 can be implemented in the following manner:

[0120] Process the initial uniformity correction relationship according to a preset mask to obtain the target uniformity correction relationship.

[0121] In this embodiment, the preset mask can be determined according to actual requirements and is used to remove interference events in the initial uniformity correction relationship. In this way, after processing the initial uniformity correction relationship according to the preset mask, a target uniformity correction relationship that meets the requirements and is relatively accurate can be obtained.

[0122] Exemplarily, a preset mask can be used to remove areas other than the preset area in the radiation source projection map. For example, after the computer device processes the initial uniformity correction relationship according to the preset mask, only the central area of the radiation source projection map in the initial uniformity correction relationship is retained to obtain the target uniformity correction relationship.

[0123] To more clearly introduce the correction method of the present application, it is described herein in conjunction with Figures 8 - 10 for illustration. Figure 8 is a schematic diagram of the process of a correction method in an embodiment. As Figure 8 shown, the computer device can execute this correction method according to the following process.

[0124] S801, obtain radiation source projection maps corresponding to different environmental parameters.

[0125] S802, fit each environmental parameter and the corresponding radiation source projection map to obtain an initial uniformity correction relationship.

[0126] S803, determine the target uniformity correction relationship according to the initial uniformity correction relationship. For example, the initial uniformity correction relationship can be processed according to a preset mask to obtain the target uniformity correction relationship.

[0127] S804, obtain the data to be corrected of the medical scanning device under the target environmental parameters.

[0128] S805, correct the data to be corrected according to the target environmental parameters and the target uniformity correction relationship to obtain the target corrected data.

[0129] S806, determine the target reconstructed image according to the target corrected data. Among them, if the data to be corrected includes the actual projection image, the target corrected data is reconstructed to obtain the target reconstructed image. If the data to be corrected includes the response relationship, the actual projection image detected by the medical scanning device is reconstructed according to the target corrected data to obtain the target reconstructed image.

[0130] The processes of S801 to S806 can refer to the above embodiments and will not be elaborated here. It can be understood that in one embodiment, S801 to S803 are the previous offline processes, and S804 to S806 are the actual usage processes.

[0131] Figure 9 is a schematic diagram of the use of a correction method in an embodiment. As Figure 9As shown, in one embodiment, the medical scanning device acquires the data to be corrected under target environmental parameters (such as setting the distance D between the radiation surface source and the collimator surface) through a detector, obtains the target uniformity correction relationship from a preset storage space, and performs data processing on the data to be corrected based on a correction method. The process of data processing is also the process of correcting the data to be corrected according to the target environmental parameters and the target uniformity correction relationship to obtain the target corrected data, and determining the target reconstructed image based on the target corrected data. Furthermore, the target reconstructed image can be displayed on a display device.

[0132] Figure 10 FIG. is a schematic diagram of the process of a correction method in one embodiment. Taking the data to be corrected including the actual projection image as an example, radioactive surface sources with different radii can be prepared first, and the radioactive surface source with a radius of R j is placed at different distances D from the collimator i , then the corresponding radioactive source projection images are measured, and then the target uniformity correction relationship is generated by fitting, and according to the actually used radius R* and distance D*, the target radioactive source projection image corresponding to the radius R* and distance D* is determined from the target uniformity correction relationship.

[0133] Furthermore, in one application scenario, the uniformity of the actual projection image can be corrected. For example, the target radioactive source projection image is multiplied by the flat film image or the actual projection image in tomographic imaging to obtain the projection image after uniformity correction, and the target reconstructed image is obtained by reconstructing the projection image after uniformity correction.

[0134] In another application scenario, the uniformity of the response relationship can be corrected. For example, the target radioactive source projection image is multiplied by the system response matrix in the layer reconstruction algorithm to obtain the system response matrix after uniformity correction, and the target reconstructed image is obtained by reconstructing the actual projection image detected by the medical scanning device according to the system response matrix after uniformity correction. Among them, the response relationship includes the system response matrix.

[0135] Figure 11 FIG. is a schematic diagram of a collimator without seams and with seams in one embodiment. As Figure 11 shown, taking the Low Energy High Resolution (LEHR) collimator commonly used in SPECT as an example, Figure 11 (a) shows a collimator without seams, Figure 11 (b) shows a collimator with seams. As Figure 11 (b) shows, this collimator is composed of four small pieces spliced together, there is a certain gap at the cross splicing, the gap width is about 0.2 mm, and the wall thickness and hole length of the collimator holes of the four small pieces are different.

[0136] Figure 12 Schematic diagram of the projection image of the radiation source in one embodiment, as Figure 12 shown, three kinds of uniformly distributed flat Tc-99m sources with different radii (radius 120 / 150 / 200 mm, height H = 2 mm) are respectively placed on the surface of the collimator with seams (D = 0 mm) and at a certain height from the collimator with seams (D = 200 mm), events are collected, and the corresponding radiation source projection images (also called flat source projection images) are obtained. The pixel unit size is 1 mm x 1 mm.

[0137] According to Figure 12 it can be seen that when the radius R of the uniformly distributed flat source and the distance D to the collimator are significantly different, the changes in the wall thickness and length of the collimator holes will not significantly affect the distribution of the radiation source projection image, but the cross artifacts at the seams will vary with the changes in the radius R and the distance D.

[0138] Figure 13 Schematic diagram of the effect of a kind of correction in one embodiment, as Figure 13 shown, a simulation of the imaging experiment of a Tc-99m bucket source (radius R = 60 mm, distance D = 120 mm) is carried out. The projection radius is about 200 mm, and 64 groups of projections are collected at intervals of 5.625° within 360°. The actual projection images are respectively corrected for uniformity according to the radiation source projection images corresponding to different distances D and radii R. The corrected actual projection image is as shown in 13.

[0139] According to Figure 13 it can be seen that if no uniformity correction is performed, a cross-shaped high-brightness artifact will be generated at the center of the actual projection image. If the radiation source projection image used for correction does not match the D set in the imaging experiment, the cross artifacts in the projection image cannot be completely compensated. After correction using the radiation source projection image corresponding to the matching distance D and radius R in the imaging experiment, the cross artifacts in the corrected actual projection image are almost completely compensated.

[0140] Figure 14 Schematic diagram of the effect of another kind of correction in one embodiment. For Figure 13 the uncorrected actual projection image and the corrected actual projection image in Figure 14 are reconstructed using the OSEM algorithm, and the reconstructed image of the bucket source along the axial direction of the distribution can be obtained, as

[0141] shown. Figure 14 Combined with

[0142] it can be seen that if no uniformity correction is performed, a significant convex peak will be generated at the center of the bucket source reconstructed image, and the uniformity is poor. After correction using a suitable radiation source projection image, the uniformity of the bucket source reconstructed image is relatively optimal.

[0142] In summary, the present application proposes a method for uniformity correction of a nuclear medicine system, which solves the problem that the traditional uniformity correction method is not applicable to the SPECT mosaic collimator, can effectively improve the artifacts caused by the seams in the mosaic collimator, improve the image quality, and ensure reliable quantitative imaging. In this way, the collimator production can adopt the method of manufacturing in multiple times and then splicing. The size of the collimator manufactured each time does not have to be greater than or equal to the scanning FOV, which reduces the production cost of the collimator and realizes cost reduction and efficiency improvement of the clinical SPECT system.

[0143] It should be noted that the above examples are based on the SPECT mosaic collimator, but the correction method provided in the present application is applicable to any scenario where there may be gaps in the collimator due to human or non-human reasons, and other medical scanning devices including collimators.

[0144] It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps does not have a strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or steps in other steps.

[0145] Based on the same inventive concept, the embodiments of the present application also provide a correction device for implementing the above-mentioned correction method. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more of the following correction device embodiments can refer to the limitations on the correction method in the above text, and will not be repeated here.

[0146] Figure 15 For the structural block diagram of the correction device in an embodiment, in an exemplary embodiment, as Figure 15 shown, a correction device 1500 is provided, including: a first acquisition module 1501, a correction module 1502, and a first determination module 1503, where:

[0147] The first acquisition module 1501 is configured to acquire the data to be corrected of the medical scanning device under the target environmental parameters; the data to be corrected includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the data to be corrected includes the actual projection image detected by the medical scanning device.

[0148] A calibration module 1502, configured to calibrate the data to be calibrated according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibrated data; the target uniformity calibration relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map.

[0149] A first determination module 1503, configured to determine a target reconstructed image according to the target calibrated data.

[0150] In the above calibration device, since the target uniformity calibration relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map, and the radiation source projection map includes the relative relationship between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units, after obtaining the data to be calibrated of the medical scanning device under the target environmental parameters, the data to be calibrated can be calibrated according to the target environmental parameters and the target uniformity calibration relationship, so as to calibrate the data to be calibrated in combination with the actual situation of the medical scanning device to obtain the target calibrated data. Further, since the data to be calibrated includes the response relationship between the image domain units corresponding to the object to be measured and the detection units in the medical scanning device, or the data to be calibrated includes the actual projection image detected by the medical scanning device, therefore, according to the calibrated target calibrated data, the target reconstructed image can be accurately and flexibly determined, and the quality of the target reconstructed image is improved.

[0151] Optionally, the radiation source projection map includes the ratio between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units; the calibration module 1502 is configured to determine a target radiation source projection map according to the target environmental parameters and the target uniformity calibration relationship, and multiply the data to be calibrated corresponding to the same detection unit by the target radiation source projection map to obtain the target calibrated data.

[0152] Optionally, the first determination module 1503 includes:

[0153] A first determination unit, configured to reconstruct the target calibrated data to obtain a target reconstructed image if the data to be calibrated includes an actual projection image.

[0154] A second determination unit, configured to reconstruct the actual projection image detected by the medical scanning device according to the target calibrated data to obtain a target reconstructed image if the data to be calibrated includes a response relationship.

[0155] Optionally, the calibration device 1500 further includes:

[0156] A second acquisition module, configured to acquire the radiation source projection maps corresponding to different environmental parameters.

[0157] A second determination module, configured to determine a target uniformity calibration relationship according to each environmental parameter and the radiation source projection map corresponding to each environmental parameter.

[0158] Optionally, the second determination module includes:

[0159] A fitting unit, configured to fit the radiation source projection maps corresponding to the environmental parameters to obtain an initial uniformity correction relationship.

[0160] A determination unit, configured to determine a target uniformity correction relationship according to the initial uniformity correction relationship.

[0161] Optionally, the second determination module is configured to process the initial uniformity correction relationship according to a preset mask to obtain a target uniformity correction relationship.

[0162] Optionally, the environmental parameters include the size parameter of the radiation surface source and / or the distance between the radiation surface source and the collimator in the medical scanning device.

[0163] Optionally, the radiation surface source is obtained after a preset movement of the radiation point source and / or the radiation line source.

[0164] Each module in the above correction device can be implemented in whole or in part by software, hardware, and their combination. Each of the above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0165] In one embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0166] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0167] In one embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0168] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in this application can be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, data processing logics based on quantum computing, artificial intelligence (AI) processors, etc., without limitation.

[0169] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this application.

[0170] The above-described embodiments merely represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A calibration method, characterized in that, The method includes: Obtaining calibration data of a medical scanning device under target environmental parameters; the calibration data includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the calibration data includes the actual projection image detected by the medical scanning device; Calibrating the calibration data according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibration data; the target uniformity calibration relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map; Determining a target reconstruction image according to the target calibration data.

2. The method according to claim 1, wherein The radiation source projection map includes the ratio between the theoretical distribution and the actual distribution of the radionuclides corresponding to different detection units; the calibrating the calibration data according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibration data includes: Determining a target radiation source projection map according to the target environmental parameters and the target uniformity calibration relationship; Multiplying the calibration data corresponding to the same detection unit by the target radiation source projection map to obtain the target calibration data.

3. The method according to claim 1, wherein The determining a target reconstruction image according to the target calibration data includes: If the calibration data includes the actual projection image, reconstructing the target calibration data to obtain the target reconstruction image; If the calibration data includes the response relationship, reconstructing the actual projection image detected by the medical scanning device according to the target calibration data to obtain the target reconstruction image.

4. The method according to any one of claims 1 to 3, characterized in that, The method further includes: Obtaining the radiation source projection maps corresponding to different environmental parameters; Determining the target uniformity calibration relationship according to each of the environmental parameters and the radiation source projection maps corresponding to each of the environmental parameters.

5. The method according to claim 4, characterized in that, The determining the target uniformity calibration relationship according to each of the environmental parameters and the radiation source projection maps corresponding to each of the environmental parameters includes: Fitting each of the environmental parameters and the corresponding radiation source projection maps to obtain an initial uniformity calibration relationship; Determining the target uniformity calibration relationship according to the initial uniformity calibration relationship.

6. The method according to any one of claims 1 to 3, characterized in that, The environmental parameters include the size parameter of the radiation surface source and / or the distance between the radiation surface source and the collimator in the medical scanning device.

7. The method according to claim 6, wherein The radiation surface source is obtained by performing a preset movement on a radiation point source and / or a radiation line source.

8. A calibration device, characterized in that, The device includes: A first obtaining module, configured to obtain calibration data of a medical scanning device under target environmental parameters; the calibration data includes the response relationship between the image domain unit corresponding to the object to be measured and the detection unit in the medical scanning device, or the calibration data includes the actual projection image detected by the medical scanning device; A calibration module, configured to calibrate the calibration data according to the target environmental parameters and the target uniformity calibration relationship to obtain target calibration data; the target uniformity calibration relationship includes the corresponding relationship between the environmental parameters and the radiation source projection map; A first determining module, configured to determine a target reconstruction image according to the target calibration data.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method according to any one of claims 1 to 7.

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