Multi-track spiral CBCT imaging system, calibration model determination method, device and system thereof, computer equipment and storage medium

Abstract

The invention relates to a multi-track spiral CBCT imaging system, a calibration model determination method, device and system thereof, computer equipment and a storage medium. The method comprises the steps of collecting first motion projection data under the condition that a motion correction device is installed in a first imaging area of a bed body and the bed body is controlled to move according to a first preset motion sequence; under the condition that the motion correction device is installed in a second imaging area of the bed body and the bed body is controlled to move according to a second preset motion sequence, second motion projection data are collected; determining a motion parameter matrix according to the first motion projection data and the second motion projection data; and then constructing a correction model based on the motion parameter matrix, a mapping relation between a three-dimensional space coordinate point and a projection coordinate point when the motion correction device moves according to the first preset motion sequence, and a mapping relation between a three-dimensional space coordinate point and a projection coordinate point when the motion correction device moves according to the second preset motion sequence.

Description

Technical Field

[0001] The present application relates to the field of CBCT imaging technology, and in particular to a multi-track spiral CBCT imaging system and a correction model determination method, device and system, computer equipment and storage medium thereof. Background Art

[0002] Cone-beam CT (CBCT) technology has evolved over the years to include various scanning and imaging methods, such as half-cone-beam digital breast tomosynthesis (DBT), circular CBCT, and spiral CBCT. However, existing spiral CBCT scanning methods are suitable for industrial scanning and are not suitable for clinical use. Summary of the Invention

[0003] Based on this, it is necessary to provide a method, device, computer equipment, computer-readable storage medium and computer program product for determining a correction model for multi-track spiral CBCT imaging that can be implemented in clinical applications at low cost to address the above technical problems.

[0004] In a first aspect, the present application provides a method for determining a correction model for multi-track spiral CBCT imaging, comprising:

[0005] collecting first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed close to the ray generating device;

[0006] collecting second motion projection data of the bed moving according to a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area;

[0007] determining a motion parameter matrix of a correction model according to the first motion projection data and the second motion projection data;

[0008] A correction model is constructed according to the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

[0009] In one embodiment, the first imaging area is the imaging area on the bed closest to the radiation generating device.

[0010] In a second aspect, a multi-track spiral CBCT imaging method is provided. The method is applied to a multi-track spiral CBCT imaging system, wherein the multi-track spiral CBCT imaging system includes a motion correction device. The method includes:

[0011] collecting spiral CBCT data of the object to be imaged when the bed moves according to a third preset motion sequence to obtain actual projection data of the object to be imaged;

[0012] Based on the correction model, the actual projection data is corrected into ideal projection data; wherein the correction model is the model determined by the correction model determination method for multi-track spiral CBCT imaging described above;

[0013] Based on the spiral CBCT reconstruction algorithm, the ideal projection data is reconstructed to obtain multiple image sequences;

[0014] Based on the image fusion algorithm, multiple image sequences are weighted to obtain spiral CBCT images.

[0015] In one embodiment, when the third preset motion sequence includes multiple motion sequences, the multiple image sequences are weighted based on an image fusion algorithm to obtain a spiral CBCT image, including:

[0016] According to the fusion formula, multiple image sequences are weighted to obtain spiral CBCT images;

[0017] Among them, the expression of the fusion formula is:

[0018]

[0019] Where, f is the spiral CBCT image, M is the number of image sequences, g(k) is the weight function, k is the number of layers in the image sequence, and f i is the spiral CBCT image corresponding to the i-th motion sequence, f i+1 is the spiral CBCT image corresponding to the i+1th motion sequence;

[0020] The expression of the weight function is:

[0021]

[0022] Where L is the number of layers of the selected single image sequence.

[0023] In a third aspect, a multi-track spiral CBCT correction system is provided, comprising:

[0024] The bed body includes a bed board, a mechanical connecting component and a support portion, wherein the mechanical connecting component connects the bed board and the support portion respectively so that the bed board can translate relative to the support portion; the support portion is used to support the bed board;

[0025] A ray generating device, which is used to generate X-rays;

[0026] The detector is used to receive X-rays and generate spiral CBCT data based on the X-rays; the ray generating device and the detector are arranged on the same vertical plane, and the ray generating device and the detector are arranged opposite to each other;

[0027] A motion correction device, the motion correction device is detachably connected to the bed board; the motion correction device has multiple markers;

[0028] The controller is connected to the bed, the ray generating device, the detector and the motion correction device respectively; the controller is used to drive the mechanical connection parts to move, and the controller is also used to execute the method steps of the correction model determination method for multi-track spiral CBCT imaging.

[0029] In one embodiment, a plurality of markers are arranged in a spiral pattern on the surface of the phantom of the motion correction device.

[0030] In a fourth aspect, a multi-track spiral CBCT imaging system is provided, comprising:

[0031] The bed body includes a bed board, a mechanical connecting component and a support portion, wherein the mechanical connecting component connects the bed board and the support portion respectively so that the bed board can translate relative to the support portion; the support portion is used to support the bed board;

[0032] A ray generating device, which is used to generate X-rays;

[0033] The detector is used to receive X-rays and generate spiral CBCT data based on the X-rays; the ray generating device and the detector are arranged on the same vertical plane, and the ray generating device and the detector are arranged opposite to each other;

[0034] The controller is connected to the bed, the ray generating device and the detector respectively; the controller is used to drive the mechanical connection parts to move, and the controller is also used to execute the method steps of the above-mentioned multi-track spiral CBCT imaging method.

[0035] In a fifth aspect, a correction model determination device for multi-track spiral CBCT imaging is provided, the device comprising:

[0036] a first acquisition module for acquiring first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed near the radiation generating device;

[0037] a second acquisition module for acquiring second motion projection data of the bed moving according to a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area;

[0038] a motion parameter matrix determining module, configured to determine a motion parameter matrix of a correction model based on the first motion projection data and the second motion projection data;

[0039] The correction model construction module is used to construct a correction model according to the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

[0040] In a sixth aspect, the present application further provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements any step in the above-mentioned correction model determination method for multi-track spiral CBCT imaging.

[0041] In a seventh aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any step in the above-mentioned correction model determination method for multi-track spiral CBCT imaging.

[0042] The correction model determination method, device, multi-track spiral CBCT correction system, imaging system, computer device, and computer-readable storage medium for multi-track spiral CBCT imaging can acquire first motion projection data when a motion correction device is installed in a first imaging area of ​​a bed and the bed is controlled to move according to a first preset motion sequence. The first imaging area is an imaging area on the bed near a radiation generating device. The second motion projection data can be acquired when the motion correction device is installed in a second imaging area of ​​the bed and the bed is controlled to move according to a second preset motion sequence. The second imaging area is an imaging area on the bed adjacent to the first imaging area. A motion parameter matrix is ​​determined based on the obtained first and second motion projection data. A correction model is then constructed based on the motion parameter matrix, the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence. The correction model can be used to correct multi-track spiral CBCT imaging, thereby reducing artifact interference and making it suitable for clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments of the present application or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 FIG2 is a diagram illustrating an application environment of a correction model determination method for multi-track spiral CBCT imaging in one embodiment;

[0045] Figure 2 FIG4 is a flow chart of a method for determining a correction model for multi-track spiral CBCT imaging in one embodiment;

[0046] Figure 3 1 is a schematic flow chart of a multi-track spiral CBCT imaging method according to one embodiment;

[0047] Figure 4 is a schematic diagram of a spiral scanning trajectory of a composite motion in one embodiment;

[0048] Figure 5 Schematic diagram of the structure of a multi-track spiral CBCT correction system in one embodiment;

[0049] Figure 6 FIG1 is a structural block diagram of a correction model determination apparatus for multi-track spiral CBCT imaging in one embodiment;

[0050] Figure 7 is a structural block diagram of a multi-track spiral CBCT imaging device in one embodiment;

[0051] Figure 8 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0053] It should be noted that the terms "first", "second", etc. used in this application can be used to describe various elements or structures, but these elements or structures are not limited by these terms. These terms are only used to distinguish the first element or structure from the second element or structure. The terms "including" and "having" used in this application and any variations thereof are intended to cover non-exclusive inclusions. The term "plurality" used in this application refers to two or more. The term "and / or" used in this application refers to one of the solutions, or any combination of multiple solutions.

[0054] Among traditional imaging modalities, circular CBCT scanning is the most common. During this method, the object remains stationary at the center of the scan, while the X-ray source and detector perform a single circular scan around the object to collect projection data. However, this method does not meet Tuy's conditions for accurate reconstruction, resulting in severe cone-angle artifacts in the reconstructed images, which become more pronounced with increasing cone angles.

[0055] To address this issue, some researchers have proposed the spiral CBCT scanning method. During the spiral CBCT scanning method, an object moves at a constant speed while the X-ray source and detector perform multiple continuous circular scans around the object to collect projection data. However, currently, spiral CBCT scanning methods are primarily used for industrial scanning, making clinical application difficult for the following reasons: First, this spiral CBCT scanning method requires slip rings for continuous multi-circle scanning, which require custom customization and are costly; second, this spiral CBCT scanning method requires the bed to move perpendicular to the center of rotation during scanning, and motion repeatability must be guaranteed, placing extremely high demands on mechanical control; third, this spiral CBCT scanning method cannot collect data during the acceleration and deceleration phases of the rotation, or the collected data must be discarded, otherwise artifacts will be generated in the reconstructed image. These factors have limited the clinical application of spiral CBCT scanning.

[0056] The correction model determination method for multi-track spiral CBCT imaging provided in the embodiment of the present application can be applied to Figure 1In the application environment shown, the data storage system can store data that the server 102 needs to process. The data storage system can be integrated on the server 102 or placed on a cloud or other network server. A motion correction device is installed in a first imaging area of ​​the bed, and the bed is controlled to move according to a first preset motion sequence to collect first motion projection data; wherein the first imaging area is an imaging area on the bed near the radiation generating device; the motion correction device is installed in a second imaging area of ​​the bed, and the bed is controlled to move according to a second preset motion sequence to collect second motion projection data; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area; based on the obtained first motion projection data and second motion projection data, a motion parameter matrix of the correction model is determined; then, based on the motion parameter matrix, the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence, a correction model is constructed. The server 102 can be an independent physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0057] In an exemplary embodiment, Figure 2 As shown, a correction model determination method for multi-track spiral CBCT imaging is provided, and the method is applied to Figure 1 The server 102 in FIG. 1 is used as an example for explanation, including:

[0058] S202 , collecting first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed close to the ray generating device.

[0059] S204 , collecting second motion projection data of the bed moving according to a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area.

[0060] On the bed surface, the bed can be divided into multiple imaging areas and named sequentially. For example, the first imaging area can be located at the head of the bed, close to the radiation generator. The remaining imaging areas are then arranged sequentially toward the foot of the bed. In this case, the second imaging area is the imaging area close to the radiation generator and adjacent to the first imaging area. Therefore, the distance between the second imaging area and the radiation generator is greater than the distance between the first imaging area and the radiation generator, and the first imaging area is the imaging area closest to the radiation generator.

[0061] Exemplarily, the first imaging area may be any area among the multiple imaging areas except the last imaging area, the second imaging area is the imaging area on the bed adjacent to the first imaging area, and the second imaging area is the last common imaging area.

[0062] S206 , determining a motion parameter matrix of a correction model according to the first motion projection data and the second motion projection data.

[0063] S208, constructing a correction model according to the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

[0064] The first motion projection data can be collected by the ray generating device and the detector. Specifically, after the motion correction device is installed in the first imaging area of ​​the bed, the ray generating device and the detector are driven to work, and the bed is driven to move synchronously according to the first preset motion sequence, so that the projection area of ​​the X-rays generated by the ray generating device includes the first imaging area, the detector receives the X-rays, and generates the first motion projection data based on the X-rays. Correspondingly, the second motion projection data can be collected by the ray generating device and the detector. Specifically, after the motion correction device is installed in the second imaging area of ​​the bed, the ray generating device and the detector are driven to work, and the bed is driven to move synchronously according to the second preset motion sequence, so that the projection area of ​​the X-rays generated by the ray generating device includes the second imaging area, the detector receives the X-rays, and generates the second motion projection data based on the X-rays.

[0065] Specifically, the motion correction device is positioned in the first imaging area of ​​the bed, and after being turned on, the radiation generating device and detector can perform a first rotational motion. Simultaneously, the bed moves according to a first preset motion sequence. After the radiation generating device and detector rotate from an initial rotation angle to a preset angle corresponding to an end rotation angle, the radiation generating device and detector stop rotating, and the bed stops moving. During the detector's operation, the detector synchronously collects the first motion projection data of the motion correction device. The first rotational motion can have a rotational speed of 7.5 degrees per second, and the first preset motion sequence can include a bed-movement motion with a bed-movement speed of 20 mm / s. During the motion, the detector captures data at a rate of 48 frames per second.

[0066] Correspondingly, the motion correction device is set in the second imaging area of ​​the bed, and the ray generating device and the detector can perform a second rotational motion after being turned on. At the same time, the bed moves according to a second preset motion sequence until the ray generating device and the detector rotate from the preset angle corresponding to the end of the rotation to the initial angle for the start of the rotation. The ray generating device and the detector stop the rotational motion and the bed stops moving. During the operation of the detector, the detector synchronously collects the second motion projection data of the motion correction device. The rotation speed of the second rotational motion can be 7.5 degrees / second. The second preset motion sequence can include bed entry and / or bed exit motion, with the bed entry speed being 20mm / s and the bed exit speed being 20mm / s. The acquisition rate of the detector during the motion is 48 frames / second.

[0067] The first motion projection data and the second motion projection data collected can be used to calculate the motion parameters of the ray generating device and the detector during the spiral scanning, and used to correct the subsequently collected object projection data. The correction model used is as follows:

[0068]

[0069] Among them, E is the loss function. is the 3×4 motion parameter matrix to be optimized. u is the horizontal coordinate of the projection coordinate point corresponding to the first motion projection data and the second motion projection data of the motion correction device estimated based on the motion parameter matrix. v is the vertical coordinate of the projection coordinate point corresponding to the first motion projection data and the second motion projection data of the motion correction device estimated based on the motion parameter matrix. is the horizontal coordinate of the projection coordinate point corresponding to the first motion projection data and the second motion projection data of the motion correction device measured in the collected motion projection data, The ordinate of the projection coordinate point corresponding to the first motion projection data and the second motion projection data of the motion correction device measured in the collected motion projection data. Wherein, if there is a marker on the motion correction device, the projection coordinate point can be the projection coordinate point of the motion correction device marker.

[0070] By minimizing the loss function E, the sum of the uv norm of the estimated projection coordinate point and the measured projection coordinate point is minimized, thereby obtaining the optimal parameter matrix , thereby obtaining the motion parameters of the spiral scan. The relationship between u, v and the 3×4 motion parameter matrix to be optimized can be described by the following formula:

[0071]

[0072] Where x, y, and z are the known spatial coordinates of the motion correction device. w is a normalization factor. Where x, y, and z are the known spatial coordinates of the marker on the motion correction device if one is present.

[0073] After obtaining the motion parameter matrix for the spiral scan, a mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points during the first and second rotational scans is established. This allows the collected object projection data (actual projection data) to be corrected to the theoretical coordinate point positions, thereby obtaining ideal projection data. Therefore, a correction model can be constructed based on the motion parameter matrix, as well as the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

[0074] Therefore, the correction model determination method for multi-track spiral CBCT imaging can acquire first motion projection data when the motion correction device is installed in a first imaging area of ​​the bed and the bed is controlled to move according to a first preset motion sequence; wherein the first imaging area is an imaging area on the bed near the radiation generating device; and when the motion correction device is installed in a second imaging area of ​​the bed and the bed is controlled to move according to a second preset motion sequence, second motion projection data can be acquired; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area; based on the obtained first motion projection data and second motion projection data, a motion parameter matrix is ​​determined; and then a correction model is constructed based on the motion parameter matrix, the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional spatial coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence. Through the correction model, multi-track spiral CBCT imaging can be corrected, thereby reducing artifact interference and being suitable for clinical application.

[0075] In an exemplary embodiment, the first imaging area is the imaging area on the bed closest to the radiation generating device. Such an arrangement can ensure the reliability of the imaging area of ​​the bedside area of ​​the bed.

[0076] Furthermore, such a setting can also determine the correction model while reducing the bed movement distance, thereby reducing energy consumption.

[0077] In one embodiment, the initial rotation angle may be -20 degrees; the preset angle corresponding to the end of rotation may be 380 degrees. Where 0 degrees is the angle corresponding to the upward direction with a line perpendicular to the horizontal plane as the axis, and the positive direction of rotation is counterclockwise when viewed from the bed entry direction. Specifically, the first rotational motion is a counterclockwise circular rotation of the radiation generating device and detector around the rotation center when viewed from the bed entry direction. The second rotational motion is a clockwise rotation in the opposite direction of the first rotational motion.

[0078] It should be noted that in this embodiment, the rotation range from -20 degrees to 380 degrees is because it takes a period of time for the ray generating device to start emitting X-rays to reach a dose stable state. A certain angle range is reserved to allow the beam to pass through the dose unstable state. The data actually used is the dose stable data from 0 degrees to 360 degrees.

[0079] In an exemplary embodiment, Figure 3 As shown, a multi-track spiral CBCT imaging method is applied to a multi-track spiral CBCT imaging system, wherein the multi-track spiral CBCT imaging system includes a motion correction device; the method includes:

[0080] S302 : Acquire spiral CBCT data of the object to be imaged when the bed moves according to a third preset motion sequence, so as to obtain actual projection data of the object to be imaged.

[0081] S304 , based on the correction model, correct the actual projection data to ideal projection data; wherein the correction model is the model determined by the correction model determination method for multi-track spiral CBCT imaging described above.

[0082] S306 , reconstructing the ideal projection data based on a spiral CBCT reconstruction algorithm to obtain multiple image sequences.

[0083] S308 , weighting the multiple image sequences based on an image fusion algorithm to obtain a spiral CBCT image.

[0084] The radiation generator and detector sequentially scan each imaging area of ​​the bed at a preset scanning speed in a rotational motion sequence. A rotational motion sequence refers to a random combination of at least one first rotational motion and / or at least one second rotational motion. Accordingly, the bed can synchronously move the imaging object forward or backward at the bed motion speed. The preset scanning speed can be 7.5 degrees / second, and the bed motion speed can be 20 mm / s.

[0085] The composite motion of this rotational motion sequence and the bed motion is equivalent to a spiral scan, but the resulting spiral scan trajectory is somewhat different from the traditional spiral scan trajectory. In this embodiment, for ease of explanation, a motion sequence with a length of 2 is used for illustration. Figure 4 As shown in the figure, two possible scanning trajectories of the motion sequence are shown, where the arrows point to the direction of bed entry; S0, S1, and S2 are nodes in the composite spiral scanning trajectory, which are used to indicate how many times the first rotational motion and the second rotational motion are involved in this scanning segment, from which the movement of the bed can also be analyzed.

[0086] like Figure 4 As shown in (a), the rotational motion sequence is "first rotational motion-first rotational motion", and the movement of the bed is "S0-S1-S1-S2". From the direction of entering the bed, S0-S1 is the spiral trajectory formed by the first first rotational motion, and S1-S2 is the spiral trajectory formed by the second first rotational motion. Specifically, a counterclockwise rotation is performed first, and then a counterclockwise rotation is performed again, for a total of two rotations. At this time, the movement of the bed is that during the first counterclockwise rotation, the bed moves from the S0 position to the S1 position, at which point the first counterclockwise rotation ends; during the second counterclockwise rotation, the bed moves from the S1 position to the S2 position, at which point the second counterclockwise rotation ends.

[0087] like Figure 4 As shown in (b), the rotational motion sequence is "first rotational motion - second rotational motion," and the bed's motion is "S0-S1-S2-S1." From the bed's entry direction, S0-S1 is the spiral trajectory formed by the first rotational motion, and S2-S1 is the spiral trajectory formed by the second rotational motion. That is, there is a counterclockwise rotation followed by a clockwise rotation, for a total of two rotations. The bed's motion at this point is as follows: during the counterclockwise rotation, the bed moves from position S0 to position S1, at which point the rotation ends, and the bed continues forward to position S2, ending the first stage. Then, clockwise rotation begins, and the bed moves backward from position S2 to position S1, at which point the rotation ends, ending the second stage.

[0088] like Figure 4 As shown in (c), the rotational motion sequence is "first rotational motion - second rotational motion", and the movement of the bed is "S0-S1-S1-S2". From the bed entry direction, S0-S1 is the spiral trajectory formed by the first rotational motion, and S1-S2 is the spiral trajectory formed by the second rotational motion. Specifically, there is a counterclockwise rotation, followed by a clockwise rotation, for a total of two rotations. At this time, the movement of the bed is that during the counterclockwise rotation, the bed moves from position S0 to position S1, at which point the counterclockwise rotation ends; during the clockwise rotation, the bed moves from position S1 to position S2, at which point the clockwise rotation ends.

[0089] like Figure 4 As shown in (d), the rotational motion sequence is "first rotational motion-first rotational motion," and the bed's motion is "S0-S1-S2-S1." From the bed's entry direction, S0-S1 forms the spiral trajectory formed by the first first rotational motion, and S2-S1 forms the spiral trajectory formed by the second first rotational motion. This means two counterclockwise rotations are performed, one after the other. The bed's motion is as follows: during the first counterclockwise rotation, the bed moves from position S0 to position S1, ending the rotation. The bed then moves forward to position S2, concluding the first stage. Then, the second counterclockwise rotation begins, with the bed moving backward from position S2 to position S1, ending the rotation and the second stage.

[0090] from Figure 4 It can be seen that the equivalent spiral scanning trajectories of (a) and (b) are similar to the traditional spiral scanning trajectories, but the equivalent spiral scanning trajectories of (c) and (d) are significantly different from the traditional spiral scanning trajectories.

[0091] It should be noted that the first rotational motion, the second rotational motion, and the bed motion can be arbitrarily combined to form a customized composite motion sequence. During scanning according to the motion sequence, the detector synchronously collects and stores the actual projection data of the imaging area at an acquisition rate of 48 frames per second. The collected actual projection data is corrected to ideal projection data by the correction model, and then the final spiral CBCT image is reconstructed by the spiral CBCT reconstruction algorithm and image fusion algorithm. The reconstruction is a three-dimensional image reconstruction. It can be seen that this multi-track spiral CBCT imaging method can perform image reconstruction and image fusion based on the corrected projection data, thereby obtaining a clear spiral CBCT image.

[0092] Furthermore, this multi-track spiral CBCT imaging method enables multi-track spiral CBCT scanning without slip rings, reducing mechanical complexity and hardware costs. This multi-track spiral CBCT imaging method also reduces the mechanical control difficulty of the rotational motion sequence and the preset motion sequence of the bed based on the motion parameter matrix determined by the correction model determination method for multi-track spiral CBCT imaging. Finally, based on the fusion formula, it effectively reduces the interference of artifacts.

[0093] In an exemplary embodiment, when the third preset motion sequence includes multiple motion sequences, the multiple image sequences are weighted based on an image fusion algorithm to obtain a spiral CBCT image, including:

[0094] According to the fusion formula, multiple image sequences are weighted to obtain spiral CBCT images.

[0095] Among them, the expression of the fusion formula is:

[0096]

[0097] Where, f is the spiral CBCT image, M is the number of image sequences, g(k) is the weight function, k is the number of layers in the image sequence, and f i is the spiral CBCT image corresponding to the i-th motion sequence, f i+1 is the spiral CBCT image corresponding to the i+1th motion sequence. For example, the value of M can be 2, that is, two spiral scans are performed (the rotational motion sequence includes two motion sequences), two sets of actual projection data are collected, and two spiral CBCT images are reconstructed.

[0098] The expression of the weight function is:

[0099]

[0100] Wherein, L is the number of layers of the selected single image sequence. Exemplarily, the value of L may be 512.

[0101] In an exemplary embodiment, Figure 5 As shown, a multi-track spiral CBCT correction system 50 includes: a bed 502, a ray generating device 504, a detector 506, a motion correction device 508 and a controller ( Figure 5 not shown).

[0102] The bed body 502 includes a bed plate 5022, a mechanical connection component ( Figure 5 The mechanical connection components are connected to the bed plate 5022 and the support portion 5024 respectively, so that the bed plate 5022 can move relative to the support portion 5024; the support portion 5024 is used to support the bed plate 5022. Figure 5 Four imaging areas are shown in Figure 5 Area A) and position arrangement in it, it should be understood that Figure 5 The number of imaging areas is just for reference.

[0103] The ray generating device 504 is used to generate X-rays.

[0104] The detector 506 is used to receive X-rays and generate spiral CBCT data based on the X-rays; the ray generator 504 and the detector 506 are arranged on the same vertical plane, and the ray generator 504 and the detector 506 are arranged opposite to each other. The detector 506 is a flat panel detector. Figure 5 The dotted line B shown is the movement trajectory of the ray generating device 504 and the detector 506.

[0105] The motion correction device 508 is detachably connected to the bed board 5022 ; there are multiple markers on the motion correction device 508 .

[0106] The controller is connected to the bed 502, the ray generating device 504, the detector 506 and the motion correction device 508 respectively; the controller is used to drive the mechanical connection components to move, and the controller is also used to execute the method steps of the correction model determination method for multi-track spiral CBCT imaging.

[0107] The maximum angular range of rotation for the radiation generator 504 and detector 506 is -20 degrees to 380 degrees, with 0 degrees being the axis pointing upward, perpendicular to the horizontal plane. The positive direction of rotation is counterclockwise, as viewed from the bedside entry direction. Specifically, the first rotational motion is a counterclockwise circular rotation of the radiation generator 504 and detector 506 around the rotation center, as viewed from the bedside entry direction. The second rotational motion is a clockwise rotation, in the opposite direction of the first rotational motion. The rotational axis of the radiation generator 504 and detector 506 is the horizontal center axis of the bedplate 5022.

[0108] It should be noted that in this embodiment, the rotation range from -20 degrees to 380 degrees is because it takes a period of time for the X-ray beam generated by the ray generating device 504 to reach a dose stable state. A certain angle range is reserved to allow the beam to pass through the dose unstable state. The data actually used is the dose stable data from 0 degrees to 360 degrees.

[0109] The ray generating device 504 and the detector 506 are installed 180 degrees relative to each other and 1100 mm apart, wherein the ray generating device 504 is 650 mm away from the rotation center.

[0110] In an exemplary embodiment, the plurality of markers are arranged in a spiral shape on the surface of the phantom of the motion correction device 508 .

[0111] Specifically, the motion correction device 508 consists of a motion correction phantom 5082 (the phantom of the motion correction device 508) and an assembly device 5084. Markers representing known spatial coordinates are arranged on the surface of the motion correction phantom. These markers are typically steel balls. The steel balls may have a diameter of 2 mm and are arranged in a spiral pattern on the surface of the motion correction phantom. The assembly device is used to secure the motion correction phantom and lock it to the bed plate 5022.

[0112] Specifically, the edge of the bed plate 5022 has a long slot, into which the assembly device can slide and lock, and can also drive the motion correction phantom to move and lock. Once the correction model is determined, the motion correction device 508 can be moved to the first and second imaging areas. For imaging, the assembly device is removed to place the object to be imaged on multiple imaging areas on the bed 502, thereby sequentially scanning each imaging area of ​​the bed 502. As each imaging area is scanned, the radiation generator 504 and detector 506 rotate, while the bed 502 moves along a predetermined path (a third preset motion sequence) across the center of rotation.

[0113] In one embodiment, the locking of the assembly device is achieved by means of screws.

[0114] Specifically, the motion correction device 508 is pushed to the first imaging area and the positioning screw is tightened to press against the card slot to lock the assembly device; correspondingly, when the motion correction device 508 needs to be moved, the positioning screw is screwed so that the assembly device can move freely on the card slot and move to the second imaging area, and then the positioning screw is tightened to press against the card slot to lock the assembly device.

[0115] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily performed in sequence in the order indicated by the arrows. Unless clearly stated herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of the steps or stages in other steps or other steps. It is understandable that the various steps in different embodiments can be freely combined as needed, and the various non-contradictory schemes formed by the combination all fall within the scope of protection of this application.

[0116] Based on the same inventive concept, embodiments of the present application also provide a correction model determination device for multi-track spiral CBCT imaging, which is used to implement the aforementioned correction model determination method for multi-track spiral CBCT imaging. The solution provided by this device is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more embodiments of the correction model determination device for multi-track spiral CBCT imaging provided below can be found in the limitations of the correction model determination method for multi-track spiral CBCT imaging described above and will not be repeated here.

[0117] In an exemplary embodiment, Figure 6 As shown, a correction model determination device 600 for multi-track spiral CBCT imaging is provided, comprising: a first acquisition module 602, a second acquisition module 604, a motion parameter matrix determination module 606 and a correction model construction module 608, wherein:

[0118] The first acquisition module 602 is used to acquire first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed close to the ray generating device.

[0119] The second acquisition module 604 is used to acquire second motion projection data of the bed moving according to a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area.

[0120] The motion parameter matrix determination module 606 is configured to determine a motion parameter matrix of a correction model according to the first motion projection data and the second motion projection data.

[0121] The correction model construction module 608 is used to construct a correction model based on the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

[0122] In an exemplary embodiment, the first imaging area is an imaging area on the bed that is closest to the radiation generating device.

[0123] In an exemplary embodiment, Figure 7 As shown, a multi-track spiral CBCT imaging device 700 is provided, which is applied to a multi-track spiral CBCT imaging system, and the multi-track spiral CBCT imaging system includes a motion correction device; the device 70 includes: a data acquisition module 702, a correction module 704, a reconstruction module 706 and a fusion module 708.

[0124] The data acquisition module 702 is used to acquire spiral CBCT data of the object to be imaged when the bed moves according to a third preset motion sequence, so as to obtain actual projection data of the object to be imaged.

[0125] The correction module 704 is used to correct the actual projection data into ideal projection data based on the correction model; wherein the correction model is the model determined by the correction model determination method for multi-track spiral CBCT imaging described above.

[0126] The reconstruction module 706 is used to reconstruct the ideal projection data based on the spiral CBCT reconstruction algorithm to obtain multiple image sequences.

[0127] The fusion module 708 is used to perform weighting on multiple image sequences based on an image fusion algorithm to obtain a spiral CBCT image.

[0128] In an exemplary embodiment, when the third preset motion sequence includes multiple motion sequences, the fusion module 708 includes: a weighting module.

[0129] The weighting module is used to weight multiple image sequences according to a fusion formula to obtain a spiral CBCT image.

[0130] Among them, the expression of the fusion formula is:

[0131]

[0132] Where, f is the spiral CBCT image, M is the number of image sequences, g(k) is the weight function, k is the number of layers in the image sequence, and f i is the spiral CBCT image corresponding to the i-th motion sequence, f i+1 is the spiral CBCT image corresponding to the i+1th motion sequence;

[0133] The expression of the weight function is:

[0134]

[0135] Where L is the number of layers of the selected single image sequence.

[0136] Each module in the aforementioned correction model determination device 600 for multi-track spiral CBCT imaging and multi-track spiral CBCT imaging device 700 may be implemented in whole or in part via software, hardware, or a combination thereof. Each module may be embedded in or independent of a processor within a computer device in the form of hardware, or may be stored in the form of software within a memory within the computer device, allowing the processor to call and execute the corresponding operations of each module.

[0137] In an exemplary embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as shown in FIG. Figure 8As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected via a system bus, and the communication interface is connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store first motion projection data and second motion projection data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal via a network connection. When the computer program is executed by the processor, a correction model determination method and / or a multi-track spiral CBCT imaging method for multi-track spiral CBCT imaging is implemented.

[0138] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0139] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the steps of any of the above-mentioned correction model determination methods for multi-track spiral CBCT imaging are implemented.

[0140] 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 computer program implements the steps of any of the above-mentioned methods for determining a correction model for multi-track spiral CBCT imaging.

[0141] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps of any one of the above-mentioned correction model determination methods for multi-track spiral CBCT imaging.

[0142] In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and the processor implements the steps of any one of the above-mentioned multi-track spiral CBCT imaging methods when executing the computer program.

[0143] 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 computer program implements the steps of any one of the above-mentioned multi-track spiral CBCT imaging methods.

[0144] In one embodiment, a computer program product is provided, comprising a computer program, which implements the steps of any one of the above-mentioned multi-track spiral CBCT imaging methods when executed by a processor.

[0145] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the 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-mentioned methods. In particular, any reference to memory, database, or other media 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), magnetic 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 take various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the various embodiments provided herein may be, but are not limited to, general-purpose processors, central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), programmable logic devices (PLDs), quantum computing-based data processing logic devices, artificial intelligence (AI) processors, and the like.

[0146] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, 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, they should be considered to be within the scope of this application.

[0147] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for determining a correction model for multi-track spiral CBCT imaging, characterized in that: The method comprises: collecting first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed close to the ray generating device; collecting second motion projection data of the bed moving according to a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area; determining a motion parameter matrix of a correction model according to the first motion projection data and the second motion projection data; The correction model is constructed according to the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

2. The method according to claim 1, characterized in that The first imaging area is an imaging area on the bed that is closest to the ray generating device.

3. A multi-track spiral CBCT imaging method, characterized in that: The method is applied to a multi-track spiral CBCT imaging system, wherein the multi-track spiral CBCT imaging system includes a motion correction device; the method includes: collecting spiral CBCT data of the object to be imaged when the bed moves according to a third preset motion sequence to obtain actual projection data of the object to be imaged; Based on a correction model, the actual projection data is corrected into ideal projection data; wherein the correction model is a model determined by the correction model determination method for multi-track spiral CBCT imaging according to any one of claims 1-2; reconstructing the ideal projection data based on a spiral CBCT reconstruction algorithm to obtain multiple image sequences; Based on an image fusion algorithm, the multiple image sequences are weighted to obtain a spiral CBCT image.

4. The method according to claim 3, characterized in that In a case where the third preset motion sequence includes a plurality of motion sequences, weighting the plurality of image sequences based on an image fusion algorithm to obtain a spiral CBCT image includes: weighting the plurality of image sequences according to a fusion formula to obtain a spiral CBCT image; The fusion formula is expressed as follows: Wherein, f is the spiral CBCT image, M is the number of the image sequence, g(k) is the weight function, k is the number of layers of the image sequence, and f i is the spiral CBCT image corresponding to the i-th motion sequence, f i+1 is the spiral CBCT image corresponding to the i+1th motion sequence; The expression of the weight function is: Where L is the number of layers of the selected single image sequence.

5. A multi-track spiral CBCT correction system, characterized in that: include: A bed body, the bed body comprising a bed board, a mechanical connecting component and a support portion, the mechanical connecting component respectively connecting the bed board and the support portion so that the bed board can translate relative to the support portion; the support portion is used to support the bed board; A ray generating device, wherein the ray generating device is used to generate X-rays; a detector, the detector being configured to receive the X-rays and generate spiral CBCT data based on the X-rays; the ray generating device and the detector being disposed on the same vertical plane, and the ray generating device and the detector being disposed opposite to each other; A motion correction device, the motion correction device being detachably connected to the bed board; the motion correction device having a plurality of markers; A controller, wherein the controller is respectively connected to the bed, the ray generating device, the detector and the motion correction device; the controller is used to drive the mechanical connection components to move, and the controller is also used to perform the method steps described in any one of claims 1-2.

6. The multi-track spiral CBCT correction system according to claim 5, characterized in that: The multiple markers are arranged in a spiral shape on the surface of the phantom of the motion correction device.

7. A multi-track spiral CBCT imaging system, characterized in that: include: A bed body, the bed body comprising a bed board, a mechanical connecting component and a support portion, the mechanical connecting component respectively connecting the bed board and the support portion so that the bed board can translate relative to the support portion; the support portion is used to support the bed board; A ray generating device, wherein the ray generating device is used to generate X-rays; a detector, the detector being configured to receive the X-rays and generate spiral CBCT data based on the X-rays; the ray generating device and the detector being disposed on the same vertical plane, and the ray generating device and the detector being disposed opposite to each other; A controller, the controller being connected to the bed, the ray generating device and the detector respectively; The controller is used to drive the mechanical connection component to move, and the controller is also used to execute the method steps described in any one of claims 3-4.

8. A correction model determination device for multi-track spiral CBCT imaging, characterized in that: The device comprises: a first acquisition module, configured to acquire first motion projection data of the bed moving according to a first preset motion sequence when the motion correction device is in a first imaging area of ​​the bed; wherein the first imaging area is an imaging area on the bed near the radiation generating device; a second acquisition module, configured to acquire second motion projection data of the bed moving in a second preset motion sequence when the motion correction device is in a second imaging area of ​​the bed; wherein the second imaging area is an imaging area on the bed adjacent to the first imaging area; a motion parameter matrix determining module, configured to determine a motion parameter matrix of a correction model based on the first motion projection data and the second motion projection data; A correction model construction module is used to construct the correction model according to the motion parameter matrix and based on the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the first preset motion sequence, and the mapping relationship between the three-dimensional space coordinate points and the projection coordinate points when the motion correction device moves according to the second preset motion sequence.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 2 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 2 are implemented.

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