CT Plain Scan Image Reconstruction Method, System, Device and Readable Storage Medium

Abstract

The present invention provides a CT plain scan image reconstruction method, system, device and readable storage medium, which relates to the field of medical image processing and includes: calculating a weight coefficient set corresponding to each collimator in a collimator group to generate a storage table; creating a CT plain scan data set, and obtaining a weight coefficient set corresponding to and matching the collimator of the plain scan in the storage table; obtaining a corresponding weight coefficient based on the plain scan data set according to each voxel position and the rotation angle where the ray is located to perform back-projection weighted summation to obtain the voxel value at the detector position; during the plain scan, the detector moves in the Z direction relative to the scanned object, calculating the voxel value for each position of the detector in the Z direction of the scanned object, generating a three-dimensional image based on the voxel values at each detector position and splicing them in sequence to obtain a reconstructed image, so as to solve the problem that a large amount of computing resources are consumed in the process of reconstructing the image and the requirement for the computer hardware configuration is relatively high.

Description

Technical Field

[0001] The present invention relates to the field of medical image processing, and particularly to a method, a system, a device and a readable storage medium for reconstructing a CT plain scan image. Background Art

[0002] With the continuous development of imaging technology, medical image diagnosis plays an extremely important role in modern medicine, and it plays an important role in clinical diagnosis, teaching and scientific research. CT plain scan, also known as ordinary scan, refers to a scan without intravenous iodine contrast agent. After obtaining the CT plain scan data set, it is necessary to reconstruct the data. Reconstructing a three-dimensional stereoscopic image will consume a large amount of computing resources, thus restricting the reconstruction speed and affecting the clinical use efficiency.

[0003] During the reconstruction process of plain scan data, the corresponding voxel values are mainly obtained by weighted summation of parallel conjugate rays. However, the weighted coefficients used are all calculated in real time, so the proportion of computing resources occupied exceeds half. Currently, to solve this problem, some methods adopt the way of improving computing power. Specifically, for example, using a multi-core CPU or a GPU with parallel computing ability. However, applying this method requires relatively high computer hardware configuration. Summary of the Invention

[0004] In order to overcome the above technical defects, the purpose of the present invention is to provide a method, a system, a device and a readable storage medium for reconstructing a CT plain scan image, which are used to solve the problems of consuming a large amount of computing resources, low efficiency and high requirements for computer hardware configuration during the process of reconstructing an image.

[0005] The present invention discloses a method for reconstructing a CT plain scan image, including the following steps:

[0006] Calculate the weight coefficient sets corresponding to each collimator in a collimator group to generate a storage table;

[0007] Wherein, the weight coefficient set corresponding to any collimator includes several weight coefficient subsets corresponding to the voxel positions of a scanning object, and each weight coefficient subset contains several weight coefficients corresponding to the rays at a rotation angle;

[0008] Create a CT plain scan data set, determine the collimator for plain scan, and obtain the weight coefficient set that matches the collimator for plain scan in the storage table;

[0009] Based on the plain scan data set, obtain a detector position and the voxel positions of the scanning object at the detector position. According to each voxel position and the rotation angle of the rays, obtain the corresponding weight coefficients in the weight coefficient set that matches the collimator for plain scan, and perform back-projection weighted summation to obtain the voxel value at the detector position;

[0010] During the plain scan, the detector moves relative to the scanned object in the Z direction. The voxel values are calculated for each position of the detector in the Z direction of the scanned object, and a three-dimensional image is generated based on the voxel values at each detector position and sequentially stitched together to obtain a reconstructed image.

[0011] Preferably, a set of weight coefficients corresponding to each collimator in a collimator group is calculated to generate a storage table, including the following:

[0012] Obtain a collimator in the collimator group, and obtain the opening parameter of the collimator and the Z-direction length of the detector module;

[0013] A ray at a rotation angle passes through any voxel position to a detector unit on the detector module. Denote the Z-direction position of the detector unit on the detector module as the detection position. Obtain the distance between the detection position and the central detector unit on the detector module, and calculate the weight coefficient corresponding to the voxel position according to the distance and the shape adjustment parameter of the detector module;

[0014] Perform a normalization operation on the weight coefficients of the parallel conjugates based on the weight coefficients corresponding to all pixel positions to obtain the set of weight coefficients corresponding to the collimator;

[0015] Calculate each collimator in the collimator group until the sets of weight coefficients corresponding to all collimators are obtained to generate a storage table.

[0016] Preferably, obtaining the distance between the detection position and the central detector unit on the detector module includes the following:

[0017] Calculate the distance between the detection position and the central detector unit on the detector module according to the following formula,

[0018]

[0019] where, q i is the distance, z i is the detection position of ray i, where the detection position is when the ray passes through a voxel position to a detector unit on the detector module, and the detector unit is the Z-direction position on the detector module, z cent is the Z-direction position of the central detector unit on the detector module, and dz is the Z-direction length of the detector module.

[0020] Preferably, calculating the weight coefficient corresponding to each voxel position according to the distance and the detector shape adjustment parameter includes the following:

[0021] Calculate the weight coefficient corresponding to any voxel position according to the following formula:

[0022]

[0023] Among them, w (α,z) is the weight coefficient, q i is the distance, Q is the detector module shape adjustment parameter, and dz is the Z-direction length of the detector module.

[0024] Preferably, the normalization operation on the weight coefficients of the parallel conjugates includes the following:

[0025] Determine the weight coefficients of the parallel conjugates according to the rotation angle where the ray is located, and perform normalization calculation according to the following formula:

[0026]

[0027] Among them, w (α,z) , w (α+π,z) are the weight coefficients of a pair of 180° conjugates.

[0028] Preferably, after generating the storage table, it includes the following:

[0029] Correspondingly store the voxel positions and weight coefficients of the rays at each rotation angle, and store them on the hard disk;

[0030] Among them, the storage format of the weight coefficients is The storage space on the hard disk is N 2 ×S×α×4Byte, N is the size of the scanned object in the XY plane, S is the number of rows of detector units on the detector module, α is the angle of a circumferential scan of the detector at a Z-direction position of the scanned object, and 4Bytes stores data in floating-point form.

[0031] Preferably, according to each voxel position and the rotation angle where the ray is located, obtain the corresponding weight coefficient from the weight coefficient set corresponding to the collimator matching the plain scan, so as to perform back-projection weighted summation to obtain the voxel value at the detector position, including the following:

[0032] Calculate the voxel value according to the following formula:

[0033]

[0034] Among them, is the weight coefficient obtained from the storage table, p (α,l,z) is the pixel point of the detector module, (x, y, z) is the geometric spatial position of the voxel of the scanned object, and l represents the position in the channel direction of the detector module.

[0035] The present invention also provides a CT plain scan image reconstruction system, which is used in cooperation with a CT device and includes:

[0036] The first processing module is used to calculate the weight coefficient sets corresponding to the collimators in a collimator group to generate a storage table; wherein, the weight coefficient set corresponding to any collimator includes several weight coefficient subsets corresponding to the voxel positions of the scanned object, and each weight coefficient subset contains several weight coefficients corresponding to the ray at a rotation angle.

[0037] The weight matching module is used to create a CT plain scan data set, determine the collimator for plain scan, and obtain the weight coefficient set corresponding to the collimator for plain scan by matching in the storage table.

[0038] The calculation module is used to obtain a detector position and the voxel positions of the scanned object at the detector position based on the plain scan data set, and obtain the corresponding weight coefficients in the weight coefficient set corresponding to the collimator for plain scan according to the voxel positions and the rotation angle where the ray is located, so as to perform back-projection weighted summation to obtain the voxel value at the detector position.

[0039] The second processing module is used to move the detector relative to the scanned object in the Z direction during plain scan, calculate the voxel values when the detector is at each position in the Z direction of the scanned object, generate a three-dimensional image based on the voxel values at each detector position and splice them in sequence to obtain a reconstructed image.

[0040] The present invention also provides a computer device, which includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the above reconstruction method are implemented.

[0041] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above reconstruction method are implemented.

[0042] After adopting the above technical solutions, compared with the prior art, the following beneficial effects are achieved:

[0043] The CT plain scan image reconstruction method, system, device and readable storage medium provided by the present invention pre-calculate the weight coefficients and store them separately in a preset format. After obtaining the CT plain scan module, the corresponding weight coefficients are obtained in the storage table according to the voxel positions and the rotation angle where the ray is located for back-projection weighted summation. Based on the voxel values obtained from each circular scan, a three-dimensional image is generated and spliced in sequence to form a reconstructed image. In the image reconstruction process, it is not necessary to repeatedly calculate each weight coefficient again, and it can be quickly obtained by looking up the table, which simplifies the calculation of the weighting coefficients, so as to solve the problems of consuming a large amount of computing resources, low efficiency, and high requirements for computer hardware configuration in the process of reconstructing images. Description of the Drawings

[0044] Figure 1 Schematic structural diagram of Embodiment 1 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention;

[0045] Figure 2 Schematic flowchart of Embodiment 1 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention;

[0046] Figure 3 Schematic flowchart of Embodiment 1 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention, which is used to reflect the process of calculating the weight coefficient set corresponding to each collimator in a collimator group to generate a storage table;

[0047] Figure 4 Schematic structural diagram of Embodiment 1 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention, which reflects the position where the ray passes through the voxel and hits the detector module;

[0048] Figure 5 Schematic diagram of the distribution of weight coefficients along the Z direction in Embodiment 1 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention, where point A is Figure 4 the weight coefficient corresponding to the ray in

[0049] Figure 6 Schematic diagram of program modules in Embodiment 2 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention;

[0050] Figure 7 Schematic hardware structure diagram of a computer device in Embodiment 3 of the CT plain scan image reconstruction method, system, device and readable storage medium according to the present invention.

[0051] Reference numerals:

[0052] 5 - Image reconstruction system; 51 - First processing module; 52 - Weight matching module; 53 - Calculation module; 54 - Second processing module; 6 - Computer device; 61 - Memory; 62 - Processor. Detailed implementation manners

[0053] The advantages of the present invention are further elaborated below in conjunction with the accompanying drawings and specific embodiments.

[0054] Exemplary embodiments will be described in detail herein, and examples thereof are shown in the accompanying drawings. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0055] The terms used in this disclosure are for the purpose of describing particular embodiments only and are not intended to limit the disclosure. The singular forms "a", "the", and "said" used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0056] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0057] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0058] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a mechanical connection or an electrical connection, or it may be the communication inside two elements. It may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms may be understood according to specific circumstances.

[0059] In the following description, the suffixes such as "module", "component", or "unit" used to represent elements are only for the convenience of the description of the present invention and have no specific meaning in themselves. Therefore, "module" and "component" may be used interchangeably.

[0060] Embodiment 1: This embodiment discloses a method for reconstructing CT plain scan images. For CT plain scan operation, the scanning object needs to be moved to a fixed position, and then the X-ray source and the detector rotate around the scanning object by 360°. The scanning object moves a distance equal to the collimator opening size along the Z direction, and the 360° scan is repeated. For a head scan of a 16-row (2-cm collimator opening) CT, it usually needs to be repeated about 8 times (16-cm Z-direction coverage length). Therefore, in this solution, in order to reduce the computational complexity during the image reconstruction after scanning, the weight coefficients are pre-calculated, and the weight coefficients used for back-projection calculation during the plain scan are repeatedly obtained each time a 360° scan is performed. It should be noted that the above 360° scan is an operation of the detector at a certain position. The detector includes several detector modules, and each detector module includes several detector units. Specifically, the following steps are included:

[0061] S100: Calculate the weight coefficient sets corresponding to the collimators in a collimator group to generate a storage table;

[0062] Among them, the weight coefficient set corresponding to any collimator includes several weight coefficient subsets corresponding to a voxel position of the scanning object, and each weight coefficient subset includes several weight coefficients corresponding to the ray at a rotation angle; that is, the weight coefficients are related to the voxels on the scanning object and the rotation angle of the ray.

[0063] That is, in the above steps, since it is necessary to select a collimator with a suitable aperture according to the actual usage scenario during the plain scan, each collimator is correspondingly associated with a sub-storage table for storing weight coefficients. For the weight coefficients under the same collimator opening size, only the same set of look-up tables needs to be used. During the back-projection calculation of the reconstructed image, first select the corresponding sub-storage table according to the aperture of the collimator, and then look up the specific weight coefficients according to the voxel position and the rotation angle of the ray.

[0064] In the above steps, that is, the weight coefficients are pre-calculated and stored separately, and there is no need to repeat the calculation of each weight coefficient in the subsequent process, so as to solve the problems of consuming a large amount of computing resources, low efficiency, and high requirements for computer hardware configuration during the image reconstruction process. Specifically, calculating the weight coefficient sets corresponding to the collimators in a collimator group to generate a storage table includes the following steps:

[0065] S110: Obtain a collimator in the collimator group, and obtain the opening parameter of the collimator and the Z-direction length of the detector module;

[0066] In the above steps, as required above, the corresponding sub-storage table needs to be selected according to the aperture of the collimator, and the number of times of the 360° scan in the plain scan also needs to be determined according to the aperture of the collimator. Both can be determined according to the opening parameters of the collimator. It should be noted that the Z-direction length of the detector module is mainly used in the following step S120 to determine the specific position where the ray reaches the detector module, so as to calculate the corresponding weight coefficient.

[0067] S120: The ray at a rotation angle passes through any voxel position to the detector unit on the detector module. Denote the Z-direction position of the detector unit on the detector module as the detection position, obtain the distance between the detection position and the central detector unit on the detector module, and calculate the weight coefficient corresponding to the voxel position according to the distance and the shape adjustment parameter of the detector module;

[0068] In the above steps, for explanation, a plurality of detector modules are arranged on the detector. The arrangement direction of the detector modules is the X direction, and the direction perpendicular to the X direction and pointing to the center of the detector is the Y direction. A plurality of detector units are provided on each detector module. The detector units are arranged one by one in sequence on the detector module. The arrangement direction of the detector units is the Z direction. The above detection position is the position where the ray passing through the voxel of the scanned object hits the detector module, that is, specifically reflected in the position of the detector unit on the detector module.

[0069] Specifically, as the acquisition of the weight coefficient is related to the voxel position, and more specifically, it is related to the distance from the position where the ray hits the detector module after passing through the voxel to the central detector unit on the detector module. Therefore, the obtaining of the distance between the detection position and the central detector unit on the detector module in the above steps includes the following:

[0070] Calculate the distance between the detection position and the central detector unit on the detector module according to the following formula,

[0071]

[0072] where q i is the distance, z i is the detection position of ray i. Among them, the detection position is when the ray passes through a voxel position to the detector unit on the detector module, and the detector unit is at the Z-direction position on the detector module. z cent is the Z-direction position of the central detector unit on the detector module, and dz is the Z-direction length of the detector module.

[0073] Furthermore, based on the calculated distance between the detection position and the central detector unit on the detector module, the calculation of the weight coefficient corresponding to each voxel position according to the distance and the detector shape adjustment parameter includes the following:

[0074] Calculate the weight coefficient corresponding to any voxel position according to the following formula:

[0075]

[0076] where w (α,z) is the weight coefficient, q i is the distance, Q is the detector module shape adjustment parameter, and dz is the Z-direction length of the detector module.

[0077] S130: Normalize the weight coefficients of the parallel conjugates based on the weight coefficients corresponding to all pixel positions to obtain the set of weight coefficients corresponding to the collimator;

[0078] In this embodiment, the back-projection algorithm is mostly used in the CT plain scan reconstruction. The weighted summation of the parallel conjugate rays is used to obtain the corresponding voxel values. Therefore, it is necessary to normalize the weight coefficients of the parallel conjugates. The parallel conjugate rays are the parallel rays that appear in pairs. Therefore, the above normalization operation on the weight coefficients of the parallel conjugates includes the following:

[0079] Determine the weight coefficients of the parallel conjugates according to the rotation angle where the rays are located. Since the weight coefficients are obtained according to the detector module shape adjustment parameter, the weight coefficients of the parallel conjugates can be screened based on this;

[0080] Perform normalization calculation according to the following formula:

[0081]

[0082] where w (α,z) , w (α+π,z) are the weight coefficients of a pair of 180° conjugates.

[0083] S140: Calculate each collimator in the collimator group until the set of weight coefficients corresponding to all collimators is obtained to generate a storage table.

[0084] In the above steps, as described above, each collimator corresponds to a sub-storage table. After merging, a storage table is generated and stored separately. Further, for further facilitation of acquisition, the storage table is stored on the hard disk or at a preset address. Specifically, after the storage table is generated in the above steps, the following operations are included:

[0085] Correspondingly store the voxel positions and weight coefficients of the rays at each rotation angle and store them on the hard disk; where the storage format of the weight coefficients is The storage space on the hard disk is N 2×S×α×4Byte, where N is the size of the scanning object in the XY plane, S is the number of rows of detector units on the detector module, α is the angle of circumferential scanning in one Z - direction position of the detector around the scanning object, and 4Bytes stores data in floating - point form.

[0086] Based on the above storage method, during the reconstruction calculation process, the weight coefficient set can be read into the hard disk to simplify the calculation of the weighting coefficients, and the required weight coefficients can be obtained by looking up the table according to the (x, y, z, α) coordinates.

[0087] S200: Create a non - contrast CT dataset, determine the collimator for non - contrast scanning, and obtain the weight coefficient set corresponding to the collimator for non - contrast scanning in the storage table;

[0088] In the above steps, when reconstructing the image, select the coefficient set under the corresponding collimator and read it into the memory. It should be noted that during non - contrast scanning, the weight coefficients between circles are repeatedly calculated. Only the weight coefficients used in one - circle reconstruction process need to be saved on the hard disk, and the weight coefficients can be quickly obtained through the look - up table method.

[0089] S300: Based on the non - contrast CT dataset, obtain a detector position and the voxel positions of the scanning object at the detector position. Obtain the corresponding weight coefficients from the weight coefficient set corresponding to the collimator for non - contrast scanning according to the voxel positions and the rotation angle of the ray, so as to perform back - projection weighted summation to obtain the voxel value at the detector position;

[0090] Specifically, in the above steps, obtaining the corresponding weight coefficients from the weight coefficient set corresponding to the collimator for non - contrast scanning according to the voxel positions and the rotation angle of the ray, so as to perform back - projection weighted summation to obtain the voxel value at the detector position, includes the following:

[0091] Calculate the voxel value according to the following formula:

[0092]

[0093] where, is the weight coefficient obtained from the storage table, p (α,l,z) is the pixel point of the detector module, (x, y, z) is the geometric spatial position of the voxel of the scanning object, and l represents the position in the channel direction of the detector module.

[0094] During the process of calculating the voxel value according to the above formula, It can be directly retrieved from the storage table according to the (x, y, z, α) coordinates. To improve the reconstruction speed, two aspects can be considered. One is to increase the computing power of the computer, such as using a multi-core CPU or a GPU with parallel computing capabilities. The other is to effectively improve the reconstruction speed by simplifying the calculation process of the weight coefficients. Different from the first aspect commonly used in the prior art, this embodiment is based on the second aspect. After obtaining the weight coefficients, the above voxel values can be obtained directly by weighted summation, greatly simplifying the amount of calculation and thus effectively improving the reconstruction speed.

[0095] S400: During the plain scan, the detector moves relative to the scanned object in the Z direction. The voxel values are calculated for each position of the detector in the Z direction of the scanned object, and a three-dimensional image is generated based on the voxel values at each detector position and stitched in sequence to obtain the reconstructed image.

[0096] As an explanation, plain scan reconstruction is to calculate the three-dimensional images corresponding to each circle independently, and then stitch them together into a complete three-dimensional stereoscopic image. Thus, when the detector moves relative to the scanned object in the Z direction, that is, after the relative position between the scanned object and the detector changes, an X-ray source and the detector rotate 360 degrees around the scanned object, that is, one circle of detection. The voxel values are calculated for each weight, and a three-dimensional image is generated based on this and stitched to form a complete reconstructed image.

[0097] Embodiment 2: This embodiment provides a CT plain scan image reconstruction system 5, which is used in cooperation with a CT device and includes:

[0098] A first processing module 51, configured to calculate a weight coefficient set corresponding to each collimator in a collimator group to generate a storage table; wherein, the weight coefficient set corresponding to any collimator includes several weight coefficient subsets corresponding to a voxel position of the scanned object, and each weight coefficient subset contains several weight coefficients corresponding to a ray at a rotation angle;

[0099] The first processing module 51 obtains the distance between the detection position and the central detector unit on the detector module, and calculates the weight coefficient corresponding to the voxel position according to the distance and the shape adjustment parameter of the detector module, where the detection position is when the ray passes through any voxel position to the detector unit on the detector module, and the detector unit is located at the Z-direction position on the detector module.

[0100] A weight matching module 52, configured to create a CT plain scan data set, determine the collimator for the plain scan, and obtain the weight coefficient set matching the collimator for the plain scan in the storage table;

[0101] A calculation module 53, configured to obtain a detector position and the voxel positions of a scanned object at the detector position based on the plain scan data set, obtain corresponding weight coefficients from a weight coefficient set that matches and corresponds to the collimator of the plain scan according to the voxel positions and the rotation angle where the ray is located, so as to perform back-projection weighted summation to obtain the voxel value at the detector position;

[0102] A second processing module 54, configured to move the detector relative to the scanned object in the Z direction during the plain scan, calculate the voxel values at each position of the detector in the Z direction of the scanned object, generate a three-dimensional image based on the voxel values at each detector position, and splice them in sequence to obtain a reconstructed image.

[0103] In this embodiment, the first processing module 51 calculates the weight coefficient sets corresponding to the respective collimators in the collimator group according to a preset formula, such as that described in step S100 in Embodiment 1, and then stores them in a hard disk in a preset format After obtaining the CT plain scan module, the weight matching module 52 filters out a sub-storage table that is consistent with the current collimator opening parameter, and then based on the calculation module 53, corresponding weight coefficients are obtained from the foregoing sub-storage table according to the voxel positions and the rotation angle where the ray is located to perform weighted summation to obtain the voxel value obtained by the current circle detection. The scanned object moves a distance equal to the collimator opening size along the Z direction, and a 360° scan (circle scan) is repeated. Thus, the second processing module 54 generates a three-dimensional image based on the voxel values obtained by each circle scan and splices them in sequence into a reconstructed image. Thus, based on the above steps, the pre-calculated weight coefficients are stored in the computer memory (hard disk or other storage addresses), and the weight coefficient calculation process is simplified by means of table lookup, and the coefficients are directly read to accelerate the reconstruction process.

[0104] Embodiment 3:

[0105] To achieve the above object, the present invention further provides a computer device 6, which may include multiple computer devices. The components of the CT plain scan image reconstruction system 5 in Embodiment 2 may be distributed in different computer devices 9. The computer device 9 may be a smart phone, a tablet computer, a notebook computer, a desktop computer, a rack server, a blade server, a tower server, or a cabinet server (including an independent server or a server cluster composed of multiple servers) that executes a program, etc. The computer device in this embodiment at least includes, but is not limited to: a memory 91, a processor 92, and a cached CT plain scan image reconstruction system 5 that can communicate with each other through a system bus. It should be noted that only the computer device with components is shown, but it should be understood that it is not required to implement all the shown components, and more or fewer components may be alternatively implemented.

[0106] In this embodiment, the memory 61 may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function. The data storage area may store a storage table containing weight coefficients of a user in the computer device. In addition, the memory 61 may include a high-speed random access memory and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the memory 61 may optionally include a memory 61 remotely provided with respect to the processor, and these remote memories may be connected to the PET system through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0107] In some embodiments, the processor 62 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chips. The processor 92 is generally used to control the overall operation of the computer device. In this embodiment, the processor 62 is used to run the program code stored in the memory 61 or process data, such as running the CT plain scan image reconstruction system 5 to implement the CT plain scan image reconstruction method of Embodiment 1.

[0108] It should be noted that only the computer device 6 with components 61 - 62 is shown, but it should be understood that it is not required to implement all the shown components, and more or fewer components may be alternatively implemented.

[0109] In this embodiment, the CT plain scan image reconstruction system 5 stored in the memory 61 may also be divided into one or more program modules. The one or more program modules are stored in the memory 61 and are executed by one or more processors (in this embodiment, the processor 62) to complete the present invention.

[0110] Embodiment 4:

[0111] To achieve the above object, this embodiment also provides a computer-readable storage medium, which includes a plurality of storage media, such as flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory, etc.), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disc, server, App application mall, etc. A computer program is stored thereon, and when the program is executed by the processor 92, corresponding functions are implemented. The computer-readable storage medium of this embodiment is used to store the CT plain scan image reconstruction system 5, and when it is executed by the processor 92, the CT plain scan image reconstruction method of Embodiment 1 is implemented.

[0112] It should be noted that the embodiments of the present invention have better implementability and do not impose any form of limitation on the present invention. Any person skilled in the art may use the technical content disclosed above to change or modify it into equivalent effective embodiments. However, as long as it does not depart from the content of the technical solution of the present invention, any modification, equivalent change or modification made to the above embodiments according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A CT plain scan image reconstruction method, characterized in that, Comprising the following: Calculating a set of weight coefficients corresponding to each collimator in a collimator group to generate a storage table; Wherein, the set of weight coefficients corresponding to any collimator includes several subsets of weight coefficients corresponding to a voxel position of the scanned object, and each subset of weight coefficients contains several weight coefficients corresponding to the rotation angle where the ray is located; Creating a CT plain scan data set, determining the collimator for the plain scan, and obtaining the set of weight coefficients matching the collimator for the plain scan in the storage table; Based on the CT plain scan data set, obtaining a detector position and the voxel positions of the scanned object at the detector position, and obtaining the corresponding weight coefficients in the set of weight coefficients matching the collimator for the plain scan according to the voxel positions and the rotation angle where the ray is located, so as to perform back-projection weighted summation to obtain the voxel value at the detector position; In the plain scan, the detector moves relative to the scanned object Z and moves in the [direction], calculates the voxel values at each position of the detector in the Z direction of the scanned object, generates a three-dimensional image based on the voxel values at each detector position, and splices them in sequence to obtain a reconstructed image; Where Calculating a set of weight coefficients corresponding to each collimator in a collimator group to generate a storage table, including the following: Obtaining a collimator in the collimator group, and obtaining the opening parameter of the collimator and the Z-direction length of the detector module; A ray at a rotation angle passes through any voxel position to a detector unit on the detector module, and it is recorded that the detector unit is located on the detector module at the Z position as the detection position, obtain the distance between the detection position and the central detector unit on the detector module, and calculate the weight coefficient corresponding to the voxel position according to the distance and the shape adjustment parameter of the detector module; Normalizing the weight coefficients of parallel conjugates based on the weight coefficients corresponding to all pixel positions to obtain the set of weight coefficients corresponding to the collimator; Calculating for each collimator in the collimator group until the sets of weight coefficients corresponding to all collimators are obtained to generate a storage table; Obtaining the distance between the detection position and the central detector unit on the detector module, including the following: Calculating the distance between the detection position and the central detector unit on the detector module according to the following formula ； where q i is the distance, z i is the detection position of ray i, where the detection position is when the ray passes through a voxel position to a detector unit on the detector module, and the detector unit is located at the Z-direction position on the detector module, z cent is the Z-direction position of the central detector unit on the detector module, dz is the Z longitudinal length of the detector module; Calculating the weight coefficients corresponding to each voxel position according to the distance and the detector shape adjustment parameter, including the following: Calculating the weight coefficient corresponding to any voxel position according to the following formula: ； Among them, w (a,z) is the weight coefficient, q i is the distance, Q is the detector module shape adjustment parameter, dz is the Z axial length of the detector module.

2. The reconstruction method according to claim 1, wherein Normalizing the weight coefficients of parallel conjugates, including the following: Determining the weight coefficients of parallel conjugates according to the rotation angle where the ray is located, Performing normalization calculation according to the following formula: ； where, w (a,z) , w (a+π,z) are a pair of conjugate weight coefficients of 180°.

3. The reconstruction method according to claim 1, wherein After generating the storage table, including the following: Correspondingly storing the voxel positions and weight coefficients at each rotation angle where the ray is located, and storing them on the hard disk; Among them, the storage format of the weight coefficient is , the storage space on the hard disk is , N is XY the size of the scanning object in the plane, S is the number of rows of detector units on the detector module, α is the angle of a circumferential scan of the detector at a Z-direction position of the scanning object, 4Bytes stores data in floating-point form.

4. The reconstruction method according to claim 1, characterized in that, Obtaining the corresponding weight coefficients in the set of weight coefficients matching the collimator for the plain scan according to the voxel positions and the rotation angle where the ray is located, so as to perform back-projection weighted summation to obtain the voxel value at the detector position, including the following: Calculating the voxel value according to the following formula: ； Among them, is the weight coefficient obtained from the storage table, P (a, l, z) is the pixel point of the detector module, ([[]] x , y , z ) is the geometric spatial position of the voxel of the scanned object, l represents the position in the channel direction of the detector module.

5. A CT plain scan image reconstruction system, which is used in cooperation with a CT device, is characterized in that Including: A first processing module, configured to calculate a set of weight coefficients corresponding to each collimator in a collimator group to generate a storage table; wherein, the set of weight coefficients corresponding to any collimator includes several subsets of weight coefficients corresponding to a voxel position of the scanned object, and each subset of weight coefficients contains several weight coefficients corresponding to a rotation angle where the ray is located; A weight matching module, configured to create a CT plain scan data set, determine the collimator for the plain scan, and obtain the set of weight coefficients matching the collimator for the plain scan in the storage table; A calculation module, configured to obtain a detector position and the voxel positions of a scanned object at the detector position based on the plain scan dataset, and obtain corresponding weight coefficients from a set of weight coefficients corresponding to and matched with the collimator of the plain scan according to the voxel positions and the rotation angles where the rays are located, so as to perform back-projection weighted summation to obtain the voxel values at the detector position; A second processing module, configured to move the detector relative to the scanned object in the Z direction during the plain scan, calculate the voxel values when the detector is at each position in the Z direction of the scanned object, generate a three-dimensional image based on the voxel values at each detector position and splice them in sequence to obtain a reconstructed image; wherein calculate the set of weight coefficients corresponding to each collimator in a collimator group to generate a storage table, including the following: Obtain a collimator in the collimator group, and obtain the opening parameter of the collimator and the Z-direction length of the detector module; A ray at a rotation angle passes through any voxel position to a detector unit on the detector module, and the detector unit is recorded as being on the detector module at the Z position as the detection position, obtain the distance between the detection position and the central detector unit on the detector module, and calculate the weight coefficient corresponding to the voxel position according to the distance and the shape adjustment parameter of the detector module; Perform a normalization operation on the weight coefficients of the parallel conjugates based on the weight coefficients corresponding to all pixel positions to obtain the set of weight coefficients corresponding to the collimator; Perform calculations on each collimator in the collimator group until the sets of weight coefficients corresponding to all collimators are obtained to generate a storage table; Obtain the distance between the detection position and the central detector unit on the detector module, including the following: Calculate the distance between the detection position and the central detector unit on the detector module according to the following formula ； where q i is the distance, z i is the detection position of the ray i wherein the detection position is when the ray passes through a voxel position to a detector unit on the detector module, and the detector unit is at the Z-direction position on the detector module, z cent is the Z-direction position of the central detector unit on the detector module, dz is the Z longitudinal length of the detector module; Calculating the weight coefficients corresponding to each voxel position according to the distance and the detector shape adjustment parameter includes the following: Calculate the weight coefficient corresponding to any voxel position according to the following formula: ； Among them, w (a,z) is the weight coefficient, q i is the distance, Q is the detector module shape adjustment parameter, dz is the Z longitudinal length of the detector module.

6. A computer device, characterized in that, The computer device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the steps of the reconstruction method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the reconstruction method according to any one of the above claims 1-4 are implemented.

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