Static x-ray source CT imaging system and method based on multi-center scanning structure

Abstract

A medical CT imaging system which relates to the technical field of tomographic imaging and comprises a CT imaging system and method. The CT imaging system comprises: a scanning module, a detection module and a reconstruction module, wherein the scanning module comprises a gantry, a worktable, and an array X-ray source module, wherein the array X-ray source module comprises a plurality of groups of light source assemblies arranged in an axial direction, each group of light source assemblies comprises a plurality of ray source arrays, and the plurality of ray source arrays are arranged in a circle; each ray source array comprises a plurality of ray source units, and rays emitted by each unit cover a portion of an imaged object so as to form a multi-center scanning structure; the detection module comprises a plurality of detectors arranged on the inner side of the gantry; and the reconstruction module is configured to receive projection data, perform image reconstruction, and acquire internal information of an image. The CT imaging system based on a static X-ray source can complete scanning of an imaged object when a light source is stationary, so as to obtain an internal structure of a reconstructed object.

Description

Static X-ray Source CT Imaging System and Method Based on Multicenter Scanning Structure Technical Field

[0001] This application relates to the field of computed tomography, and in particular to a static X-ray source CT imaging system and method based on a multi-center scanning structure. Background Technology

[0002] In recent years, with the development of cold cathode X-ray sources, CT imaging systems have gradually become more characterized by static structures, high resolution, and low dose. Currently, CNT-based CT imaging systems exist, which use uniformly arranged CNTs on a ring to replace rotating heat source structures and complete rotational scanning of the imaging object. However, due to the non-negligible packaging size of current CNTs, the projection data faces the problem of sparse angles during scanning, which limits the high-resolution imaging of cold cathode imaging systems. Furthermore, in the case of sparse angle sampling, using a single-center scanning structure results in uneven X-ray distribution, with gaps in some areas, leading to a decrease in image quality. In addition, although CNTs have a fast time response, when scanned one by one in an integrated X-ray source array, the imaging speed is limited by the detector detection rate, which may still cause motion artifacts and other distortions, resulting in a decrease in image quality.

[0003] To address the aforementioned shortcomings, several technical solutions have been implemented. Researchers have proposed planar cold cathode light sources (CNTs), which, by densely arranging CNTs on a plane, partially solve the CNT packaging problem. However, current planar CNTs have excessively low current and voltage, making addressable emission impossible. To meet detector response requirements, multiple light sources need to be lit simultaneously, but this causes aliasing of projection data. Encoded emission schemes can effectively solve the aliasing problem, but current imaging solutions are only applied to tomographic imaging systems, not CT tomographic systems. Furthermore, the coding scheme design only considers simple coding of a single component under single-energy conditions, without considering multi-component joint coding or coding methods that take energy spectrum into account. In addition, coded area array light sources still face the sparse angle problem. At the algorithmic level, the sparse angle problem has always been a hot topic, and many solutions exist, such as the construction of reconstruction frameworks based on compressed sensing and deep learning, which incorporates prior image information into the algorithm to suppress reconstruction artifacts and improve reconstruction quality. However, these methods generally suffer from the dual-domain problem, meaning they cannot model signals and noise simultaneously in both the projection domain and the image domain, thus failing to obtain high-quality and accurate projection and reconstructed images. Summary of the Invention

[0004] This application provides a static X-ray source CT imaging system and method based on a multi-center scanning structure. It employs multiple array X-ray sources or area sources to form a static ring X-ray source, enabling efficient scanning. When used with a scanning bed, it can achieve the same spiral CT scanning function as conventional clinical CT. In the reconstruction module, an expression based on projection redundancy is introduced, allowing simultaneous modeling of signal and noise in the projection domain, ensuring the accuracy of the reconstructed image. Furthermore, combined with coded luminescence technology, by changing the voltage of the X-ray source module during scanning and utilizing the redundancy between projections, complete projection data can be recovered, realizing the scanning function of multi-energy CT.

[0005] To address the aforementioned technical problems, in a first aspect, embodiments of this application provide a static X-ray source CT imaging system based on a multi-center scanning structure, comprising: a scanning module, a detection module, and a reconstruction module connected in sequence; wherein, the scanning module includes a gantry, a stage, and an array X-ray source module; the gantry has a through slot for the stage to move in or out of the gantry; the array X-ray source module is disposed on the inner surface of the gantry; the array X-ray source module includes multiple sets of source components arranged axially, each set of source components including multiple X-ray source arrays, and the multiple X-ray source arrays forming a 360° angle; the X-ray source array includes multiple X-ray source units, and the X-rays emitted by each unit cover a portion of the imaging object. The X-ray source array comprises one or more of the following: a linear X-ray tube array, an arc-shaped X-ray tube array, and a planar X-ray tube array. The detection module includes several detectors located inside the gantry for detecting the X-ray beam emitted by the array's X-ray source module. The reconstruction module processes the projection data measured by the detection module, expresses projection redundancy information, models signal and noise in the projection domain, and performs image reconstruction to obtain internal image information. The scanning module also includes a scanning control unit. The scanning control unit controls the illumination of the array's X-ray source module during the scanning process and controls the rotation of the detection module to complete projection measurements at different angles.

[0006] In some exemplary embodiments, a portion of the object is covered by rays emitted from the ray source units in the ray source array, and all ray source units can be lit up to completely cover the imaging object, thus forming a multi-center scanning structure in the assembly.

[0007] In some exemplary embodiments, the X-ray source assembly includes multiple linear / arc X-ray tube arrays that enclose 360°; the linear / arc X-ray tube arrays include multiple X-ray source units, and the X-rays emitted by the X-ray source units in the linear / arc X-ray tube arrays only cover a portion of the imaging object. When all X-ray source units are lit, they can completely cover the imaging object, forming a multi-center scanning structure.

[0008] In some exemplary embodiments, the X-ray source assembly includes multiple area array light sources, and the multiple area array light sources are arranged in a 360° circle; the area array light source includes multiple X-ray source units, each of the X-ray source units in the area array light source covers only a part of the imaging object during irradiation, and the irradiation of all the X-ray source units on the area array light source can completely cover the imaging object, forming a multi-center scanning structure.

[0009] In some exemplary embodiments, the number of the ray source arrays is odd, taking into account the distribution of the light source spacing and the packaging spacing between the ray source arrays, in order to solve the problem of discontinuous data acquisition caused by the seams between the arrays.

[0010] In some exemplary embodiments, in the scanning control unit, multiple X-ray source units in a stationary X-ray source module are simultaneously illuminated in a single projection acquisition by means of encoded light emission, thereby completing the acquisition of the projection.

[0011] In some exemplary embodiments, multiple X-ray source units in a stationary X-ray source module are simultaneously illuminated in a single projection acquisition by means of encoded emission, including: encoded emission is performed under the same array of light sources within the component, or encoded emission is jointly encoded in adjacent arrays within the component, or encoded emission is encoded between components; an encoding scheme is designed based on different optimization objectives and imaging objects; the optimization objectives include: complete coverage of the object in a single encoding and the highest X-ray utilization efficiency.

[0012] In some exemplary embodiments, the detector is an arc-shaped detector; when the X-ray source assembly is a linear or arc-shaped light source X-ray tube array, the stage moves at a constant speed during the scanning process, which, combined with the detector rotation, achieves helical scanning; or, the stage is stationary during the scanning process, which, combined with the detector rotation, achieves cone-beam scanning; when the X-ray source assembly is composed of a surface array light source, by designing the surface array emission timing, helical scanning is achieved by combining the stage being stationary with the detector rotation.

[0013] In some exemplary embodiments, the array X-ray source module combines different voltages with different voltage encoding schemes during the scanning process to form a multi-energy CT scan.

[0014] In some exemplary embodiments, during the encoding and emission process, the detector's acquisition process includes: rotating to the opposite side of the corresponding encoding light source, pausing to acquire data, and continuing to rotate to the next opposite side of the encoding light source; or, during the encoding and emission process, the detector acquires data by rotating at a constant speed.

[0015] In some exemplary embodiments, the detector acquires projection information of all X-ray beams emitted by the X-ray source under the coded template, and the calculation formula for the acquisition process is as follows:

[0016] in, This represents the measurement data on the j-th detector. Let M represent the sampling matrix, where M represents the number of light sources. A 1 in the matrix indicates that the light source at that location was lit in k measurements. This indicates the lighting status of the i-th light source in the k-th sampling case. E represents the energy integral on the j-th detector corresponding to the i-th light source during the k-th illumination. l (e) represents the normalized spectral information of the ray element at 1 kV, I0 represents the total number of photons from the source, A is a known projection matrix, δ(e) represents the mass decay coefficient of matter at energy e, and ρ represents the mass density distribution map. The representation of a ray element at energy 1kV is the measurement data received by the i-th detector from the j-th source at energy spectrum location e; in the case of a single energy spectrum, [Aδ(e)ρ] ij This can be further simplified to [Af] ij f is the linear attenuation coefficient of the reconstructed image.

[0017] In some exemplary embodiments, the reconstruction module processes the acquired measurement data, utilizes the redundancy characteristics of projection, models the signal and noise in the projection domain, designs a reconstruction algorithm, and obtains the internal structural information of the object. Under the single-energy spectrum assumption, the reconstruction algorithm formula is as follows:

[0018] Where T represents the number of sampling angles, K represents the number of encoding schemes, M represents the number of light sources, and N represents the number of detectors. This represents a matrix combining partial differential equations, used to express the redundancy properties of projections and to model the signal. This is a sparse sampling matrix, where 1 indicates that the projection of the point is known, and 0 indicates that the projection of the point is unknown. Let R represent a known sparse projection. ijt Let be the line integral of the attenuation coefficient along the path of the X-ray emitted from the j-th light source at the t-th angle to the i-th detector. The regularization term is designed based on prior image information to reduce the solution space.

[0019] In the multi-energy spectroscopy case, the unknown data is the density information of the material. Assuming the reconstructed material is composed of G different materials, the material matrix of the material is written as:

[0020] Where, δ g (e) represents the mass decay coefficient of the g-th material at energy e. If the image at pixel i belongs to the g-th material, then... Conversely, it equals 0.

[0021] The reconstructed formula after conversion is shown below:

[0022] Where l represents the use of l groups of ray elements with different energies for projection acquisition, T represents the number of sampling angles, K represents the number of encoding schemes, M represents the number of light sources, and N represents the number of detectors. This represents a matrix that combines partial differential equations. This represents the line integral value of the j-th light source corresponding to the i-th detector at the t-th angle at the energy spectrum e of the ray element at an energy of 1kV.

[0023] Secondly, this application also provides a static X-ray source CT imaging method based on a multi-center scanning structure. The method utilizes the static X-ray source CT imaging system based on a multi-center scanning structure described in the above embodiments to perform CT imaging, including the following steps: setting imaging parameters; the imaging parameters include whether the stage on the gantry is moved, whether it is multi-energy scanning, and the loading of the coded emission mode; placing the object to be imaged on the stage; under the coded template, addressably illuminating the X-ray source unit in the component; the detector collects the projection information of all X-ray beams emitted by the X-ray source under the coded template to obtain projection data; and reconstructing the internal structure of the imaged object using a reconstruction module based on the set coded and projection data.

[0024] The technical solution provided in this application has at least the following advantages:

[0025] This application provides a static X-ray source CT imaging system and method based on a multi-center scanning structure. The CT imaging system includes a scanning module, a detection module, and a reconstruction module connected in sequence. The scanning module includes a gantry, a stage, and an array X-ray source module. The gantry has a through slot for the stage to move in or out of the gantry. The array X-ray source module is disposed on the inner surface of the gantry. The X-ray source module includes multiple sets of source components arranged axially. Each set of source components includes multiple X-ray source arrays arranged in a 360° configuration. The X-ray source array contains multiple X-ray source units, and the X-rays emitted by each unit cover... A portion of the imaging object constitutes a multi-center scanning structure; the X-ray source array includes one or more of the following: a linear X-ray tube array, an arc-shaped X-ray tube array, and a planar X-ray source array; the detection module includes several detectors located inside the gantry for detecting the X-ray beam emitted by the array X-ray source module; the reconstruction module receives the projection data measured by the detection module and performs image reconstruction to obtain internal image information; the scanning module also includes a scanning control unit; the scanning control unit controls the illumination status of the array X-ray source module during the scanning process and controls the rotation of the detection module to complete projection measurements at different angles.

[0026] This application provides a static X-ray source CT imaging system and method based on a multi-center scanning structure. First, the multi-center scanning method effectively reduces the problem of uneven angular sampling in single-center scanning, and utilizes the correlation between projections to obtain dense projection data. Second, during the acquisition process, the acquisition time is further shortened by using coded illumination, which helps suppress motion artifacts. Furthermore, specific acquisition templates can be designed according to the imaging object, further mitigating motion artifacts. In addition, this application achieves multi-energy CT scanning by setting different scanning voltages in conjunction with the coding scheme, enabling effective analysis of soft tissues. Moreover, this application employs a wireless transmission mode; the reconstruction module is not limited to local construction but can be uploaded to a cloud platform for efficient data processing and reconstruction using large models. Attached Figure Description

[0027] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0028] Figure 1 is a schematic diagram of the structure and light source components of a static X-ray source CT imaging system based on a multi-center scanning structure according to an embodiment of this application.

[0029] Figure 2 is a schematic diagram of the structure of a CT imaging system provided in an embodiment of this application.

[0030] Figure 3 is a schematic diagram of a linear array or area array polygon scanning structure provided in an embodiment of this application.

[0031] Figure 4 is a schematic diagram of an arc-shaped linear array or area array polygon scanning structure provided in an embodiment of this application.

[0032] Figure 5 is a schematic diagram of a spiral CT scan provided in an embodiment of this application.

[0033] Figure 6 is a schematic diagram of a 7-sided linear light source array CT scan provided in an embodiment of this application.

[0034] Figure 7 is a schematic diagram of a 7-sided linear light source array CT scan provided in another embodiment of this application.

[0035] Figure 8 is a schematic diagram of a 7-sided area array light source CT scan provided in an embodiment of this application.

[0036] Figure 9 is a schematic diagram of the encoding of a radiation source array in a component provided in an embodiment of this application.

[0037] Figure 10 is a schematic diagram of inter-array coding of a radiation source array in a component provided by an embodiment of this application.

[0038] Figure 11 is a schematic diagram of inter-component coding provided in an embodiment of this application. Detailed Implementation

[0039] As can be seen from the background technology, existing cold cathode X-ray sources suffer from low power and sparse scanning angles, so further development is needed for their application in CT imaging systems.

[0040] To address the aforementioned technical problems, this application provides a static X-ray source CT imaging system based on a multi-center scanning structure, comprising: a scanning module, a detection module, and a reconstruction module connected in sequence; wherein, the scanning module includes a gantry, a stage, and an array X-ray source module; the gantry has a through slot for the stage to move in or out of the gantry; the array X-ray source module is disposed on the inner surface of the gantry; the array X-ray source module includes multiple sets of source components arranged axially, each set of source components including multiple X-ray source arrays, and the multiple X-ray source arrays are arranged in a 360° configuration; the X-ray source array includes multiple X-ray source units, and the X-rays emitted by each unit cover a portion of the imaging object to form multiple X-ray sources. The system comprises a central scanning structure; a radiation source array including one or more of a linear X-ray tube array, an arc-shaped X-ray tube array, and a planar array; a detection module including several detectors located inside the gantry for detecting the X-ray beam emitted by the static array X-ray source module; a reconstruction module for processing the projection data measured by the detection module, expressing projection redundancy information, modeling signal and noise in the projection domain, and reconstructing the image to obtain internal image information; and a scanning module including a scanning control unit for controlling the illumination of the radiation source units during scanning and controlling the rotation of the detection module to complete projection measurements at different angles. The CT imaging system based on a static X-ray source provided in this application can scan an object under static conditions and obtain the reconstructed internal structure of the object.

[0041] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0042] Referring to Figure 1, this application provides a static X-ray source CT imaging system based on a multi-center scanning structure, including: a scanning module, a detection module, and a reconstruction module connected in sequence; wherein, the scanning module includes a gantry, a stage, and an array X-ray source module; the gantry has a through slot for the stage to move in or out of the gantry; the array X-ray source module is disposed on the inner surface of the gantry; the array X-ray source module includes multiple sets of source components arranged along the axial direction, each set of source components includes multiple X-ray source arrays, and the multiple X-ray source arrays are arranged in a 360° circle; the X-ray source array contains multiple X-ray source units, and the X-rays emitted by each unit cover... The X-ray source array comprises a portion of the imaging object, forming a multi-center scanning structure. The X-ray source array includes one or more of the following: a linear X-ray tube array, an arc-shaped X-ray tube array, and a planar X-ray source array. The detection module includes a detector located inside the gantry, used to detect the X-ray beam emitted by the static array X-ray source module. The reconstruction module receives the projection data measured by the detection module and performs image reconstruction to obtain internal image information. The scanning module also includes a scanning control unit. The scanning control unit controls the illumination of the X-ray source units during scanning and controls the rotation of the detection module to complete projection measurements at different angles.

[0043] Specifically, the scanning control unit includes an X-ray controller and a detector rotation controller. The X-ray controller is used to control the lighting of the light source in the static array X-ray source module, and the detector rotation controller is used to control the rotation of the detector.

[0044] It should be noted that the X-ray controller controls the stationary X-ray source module through a control circuit, where the power supply can be a high-voltage power supply under the chip package to power the stationary X-ray source module.

[0045] Specifically, referring to Figure 2, this application provides a medical CT imaging system, including: a gantry 1, an array X-ray source module 2 (also referred to as a stationary X-ray source module), a scanning module, a worktable 3 (also referred to as a scanning bed), a detection module, and a reconstruction module; the gantry 1 has a through slot for installing the array X-ray source module 2 inside; the scanning module is mounted on the gantry and is used to control the array X-ray source module 2 to complete measurements at different angles; the worktable 3 is configured as a platform for moving the subject to be imaged into and out; the detection module 4 is disposed inside the gantry for detecting X-rays; the reconstruction module is used to process the detector's measurement signals to reconstruct the internal structure of the imaged object.

[0046] It should be noted that the reconstruction module is not limited to being set up locally. It receives the data collected by the detection module through wireless transmission and processes the data on the reconstruction workstation to reconstruct the internal structure of the image.

[0047] Figure 3 illustrates a linear or area array polygonal scanning structure; Figure 4 illustrates an arc-shaped linear or area array polygonal scanning structure. Specifically, in some embodiments, the X-ray source assembly includes multiple sets of linear array X-ray tubes, the array of multiple sets of linear array X-ray tubes enclosing a 360° angle, with each set of array light sources corresponding to a different rotation center, forming a multi-center scanning structure.

[0048] In some embodiments, the X-ray source assembly includes multiple linear / arc X-ray tube arrays that are arranged in a 360° configuration. The X-rays emitted by the X-ray source units in the linear / arc X-ray source arrays only cover a portion of the imaging object. When all X-ray source units are lit, the imaging object can be completely covered, forming a multi-center scanning structure.

[0049] In some embodiments, the X-ray source assembly includes multiple area array light sources arranged in a 360° configuration. Each area array light source includes multiple X-ray source units. During irradiation, each X-ray source unit in the area array light source covers only a portion of the imaging object. Irradiation by all X-ray source units on the area array light source can completely cover the imaging object, forming a multi-center scanning structure.

[0050] In some embodiments, considering the distribution of light source spacing and the packaging spacing between the X-ray source arrays, the number of X-ray source arrays is odd to address the intermittent data acquisition caused by the seams between the arrays.

[0051] In some embodiments, in the scanning control unit, multiple light sources in a stationary X-ray source module are simultaneously illuminated in a single projection acquisition by means of encoded light emission, thereby completing the acquisition of the projection.

[0052] In some embodiments, multiple X-ray source units in a stationary X-ray source module are simultaneously illuminated in a single projection acquisition by means of coded emission, including: coded emission is coded under the same array of light sources within the component, or coded emission is jointly coded in adjacent arrays within the component, or coded emission is coded between components; an encoding scheme is designed based on different optimization objectives and imaging objects; the optimization objectives include: complete coverage of the object in a single encoding and the highest X-ray utilization efficiency.

[0053] Specifically, coded emission can be performed under the same array of light sources within a component, or jointly coded between adjacent arrays within a component; it can also be coded between components. The design of the coding scheme depends on specific optimization objectives, such as meeting the requirement of complete coverage of the object in a single coding operation; or the requirement of maximizing ray utilization efficiency; or a specific coding scheme designed according to the imaging object.

[0054] In some embodiments, the detector's acquisition process can be divided into the following stages: rotating to the opposite side of the corresponding coded light source, pausing to acquire data, and then continuing to rotate to the next opposite side of the coded light source.

[0055] In some embodiments, the detector rotates at a constant speed to collect data.

[0056] It should be noted that the coded emission method can be preset to a fixed acquisition template, or a specific acquisition template can be designed according to the imaging object, or an acquisition template can be designed according to different energies.

[0057] In some embodiments, the detector is an arc-shaped detector; when the X-ray source assembly is a linear or arc-shaped X-ray tube array, the stage moves at a constant speed during scanning, which, combined with the detector rotation, achieves helical scanning; or...

[0058] When the X-ray source assembly is a linear or arc-shaped X-ray tube array, the stage remains stationary during scanning, which, combined with the detector rotation, enables cone-beam scanning; or...

[0059] When the X-ray source assembly is a planar array light source, by designing the planar array emission timing sequence, spiral scanning can be achieved by combining it with detector rotation when the worktable is stationary.

[0060] Figure 5 shows a schematic diagram of a spiral CT scan, in which the object under test moves along the axial direction and the detector rotates around the object under test.

[0061] Figures 6 and 7 show schematic diagrams of a 7-sided linear light source array CT scan, in which the object under test moves along the axial direction and the detector rotates around the object under test.

[0062] Figure 8 shows a schematic diagram of a hexagonal array light source CT scan, in which the object under test moves along the axial direction and the detector rotates around the object under test.

[0063] In some embodiments, coded light emission can be coded under the same array of light sources within the component, or jointly coded between adjacent arrays within the component; or coded between components.

[0064] Figure 9 shows a schematic diagram of the X-ray source array encoding in a component. During the acquisition process, the detector can rotate to the position opposite the encoded light source, and then perform the projection acquisition process after coming to a stop.

[0065] Figure 10 shows a schematic diagram of the encoding between the X-ray source arrays in one component. During the acquisition process, the detector can rotate at a constant speed to perform projection acquisition.

[0066] Figure 11 shows a schematic diagram of inter-component coding. During the acquisition process, multiple ray units between components are illuminated at once, and the detector can rotate at a constant speed to perform projection acquisition.

[0067] In some embodiments, the array X-ray source module changes between high and low voltages during the scanning process. The high voltage corresponds to one set of encoding schemes, and the low voltage corresponds to another set of encoding schemes, thereby constituting a dual-energy CT scan.

[0068] When using a dual-energy CT scanning structure, after solving for the aliased projection data and interpolating using partial differential relationships, a unified iterative framework is used to simultaneously solve for spectral information and reconstruct the image.

[0069] In some embodiments, the worktable includes a scanning bed with a head and neck fixation device, which can be used to perform specific head and neck CT scans.

[0070] In addition, this application embodiment also provides a static X-ray source CT imaging method based on a multi-center scanning structure. The method uses the static X-ray source CT imaging system based on a multi-center scanning structure described in the above embodiment for CT imaging, including the following steps: setting imaging parameters; the imaging parameters include whether the stage in the gantry is translated, whether it is a multi-energy scan, and the loading of the coded emission mode; placing the object to be imaged on the stage; addressably illuminating the X-ray source in the component under the coded template; the detector acquiring the projection information of all X-ray beams emitted by the X-ray source under the coded template to obtain projection data; de-aliasing based on the set coded and projection data, and interpolating using the redundancy of the projection data; reconstructing using the interpolated data to obtain the internal structure of the imaged object.

[0071] In some embodiments, the detector acquires the projection information of all X-ray beams emitted by the X-ray source under the coded template, and the calculation formula for the acquisition process is as follows:

[0072] in, This represents the measurement data on the j-th detector. Let M represent the sampling matrix, where M represents the number of light sources. A 1 in the matrix indicates that the light source at that location was lit in k measurements. This indicates the lighting status of the i-th light source in the k-th sampling case. E represents the energy integral on the j-th detector corresponding to the i-th light source during the k-th illumination. l (e) represents the normalized spectral information of the ray element at 1 kV, I0 represents the total number of photons from the source, A is a known projection matrix, δ(e) represents the mass decay coefficient of matter at energy e, and ρ represents the mass density distribution map. The representation of a ray element at energy 1kV is the measurement data received by the i-th detector from the j-th source at energy spectrum location e; in the case of a single energy spectrum, [Aδ(e)ρ] ij This can be further simplified to [Af] ij f is the linear attenuation coefficient of the reconstructed image.

[0073] In some embodiments, the detector receives information about all the X-ray beams emitted by the X-ray source under the coded template to obtain projection data, including: under different coded templates, the detector samples the projection information of all the X-ray beams emitted by the X-ray source to obtain projection data.

[0074] The following section uses monoenergy spectroscopy as an example to introduce the specific process of the reconstruction scheme based on coded luminescence.

[0075] The reconstruction scheme based on encoded luminescence can be composed of two subproblems: first, the projection solution aliasing based on encoded luminescence, and second, the projection interpolation based on partial differential equations.

[0076] Where T represents the number of sampling angles, K represents the number of encoding schemes, M represents the number of light sources, and N represents the number of detectors. This represents the matrix that combines partial differential equations. It is worth noting that... This is a sparse sampling matrix, where 1 indicates that the projection of a point is known, and 0 indicates that the projection of a point is unknown. Let R represent a known sparse projection. ijt This represents the line integral value of the j-th light source corresponding to the i-th detector at the t-th angle. This represents a regularization term designed based on image priors, used to reduce the solution space. It can be designed using deep learning or compressed sensing techniques.

[0077] If dual-energy CT scanning is used, the similarity between different energies can be further utilized to constrain the solution. The above equation can be used in an iterative manner to ultimately obtain a high-quality reconstructed image.

[0078] Specifically, during the projection generation process, the X-ray source is illuminated in an addressable manner using a control circuit. Assuming the X-ray source is monoenergetic, according to Bayes' theorem, f can be calculated by maximizing the posterior probability:

[0079] Where prob(I|f) is the likelihood function term, and prob(f) is the prior term. In the case of monoenergetic light, the light source emits a certain number of photons along a certain path, and the number of attenuated photons received at the detector follows a Poisson distribution. Since each point source is independent and follows a Poisson distribution, the Poisson distribution model is used to describe the measurement projection acquisition process:

[0080] in This indicates the lighting status of the i-th light source under the k-th lighting mode. Let be the number of photons received by the j-th detector from the i-th light source under ideal conditions. This represents the total number of photons received by the j-th detector under ideal conditions in the current emission mode k. This represents the actual number of photons received by the detector.

[0081] From a scanning perspective, based on different encoding schemes, the Poisson log-likelihood function prob(I|f) can be described as:

[0082] Among them, L(I k |f) can be represented as:

[0083] Ignoring terms irrelevant to the reconstructed image f, the above equation can be written as:

[0084] Because Q1(f) contains nonlinearity, it is difficult to optimize. To efficiently optimize the objective function, a Majorization-Minimization (MM) algorithm is used to construct a substitute function. The substitute function is constructed as follows:

[0085] In the formula f z This represents the image reconstruction result at the z-th iteration. Since the function Q1(f) is a convex function, the convergence of the algorithm can be guaranteed. Based on Q2(f; f z The reconstructed image is updated using Newton's descent method.

[0086] in These represent the current reconstructed image f. z Below are the first and second derivatives of the substitution function Q2:

[0087] In summary, the final update is f z It can be obtained from the following formula:

[0088] Where α represents the update step size. Regarding The design can use TV regularization as a priori to constrain the solution space.

[0089] In solving the second subproblem, the P matrix can be described by the following formula:

[0090] Specifically, the first-order partial differential and the second-order partial differential can be defined as follows:

[0091] in, Let τ be the partial differential value of the current ray at different centers of rotation, where the centers of rotation are determined by the current ray and the intersecting rays, and τ is the distance between the two centers of rotation. The P-matrix represents the differential of adjacent parallel beam rays. It can be directly discretized using finite difference methods or described using a deep network. In summary, a complete reconstruction scheme is obtained, as shown in Table 1.

[0092] Based on the above technical solutions, this application provides a static X-ray source CT imaging system and method based on a multi-center scanning structure. The CT imaging system includes: a scanning module, a detection module, and a reconstruction module connected sequentially; wherein, the scanning module includes a gantry, a stage, and an array X-ray source module; the gantry has a through slot for the stage to move in or out of the gantry; the array X-ray source module is disposed on the inner surface of the gantry; the array X-ray source module includes multiple sets of source components arranged axially, each set of source components including multiple X-ray source arrays, and the multiple X-ray source arrays are arranged in a 360° configuration; the X-ray source array contains multiple X-ray source units, each unit emitting X-rays... The emitted X-rays cover a portion of the imaging object to form a multi-center scanning structure; the X-ray source assembly includes one or more of the following: a linear X-ray tube array, an arc-shaped X-ray tube array, and a surface array X-ray source; the detection module includes several detectors disposed inside the gantry for detecting the X-ray beam emitted by the static array X-ray source module; the reconstruction module receives the projection data measured by the detection module and performs image reconstruction to obtain internal image information; the scanning module also includes a scanning control unit; the scanning control unit controls the illumination status of the array X-ray source module during the scanning process and controls the rotation of the detection module to complete projection measurements at different angles.

[0093] Table 1. Generation process of reconstruction scheme based on encoded luminescence

[0094] The static X-ray source CT imaging system and method based on a multi-center scanning structure provided in this application replace the traditional CT imaging system based on a rotating light source. Unlike current static X-ray source CT imaging systems, this application employs a multi-center scanning structure. By fully utilizing the redundancy characteristics of projection, it achieves synchronous modeling of signal and noise in the projection domain, constructing a unified reconstruction framework and solving the sparse angle problem of current X-ray source CT imaging systems. This application can obtain high-quality reconstructed images even with sparse sampling. This application uses a coded emission scheme, which, through simultaneous emission from multiple point sources, can further reduce the power of the static X-ray source and lower the manufacturing difficulty and cost of the X-ray tube. Furthermore, this application is applicable to various scanning methods. For example, by setting a head fixation frame on the scanning bed, a head and neck scanning method can be achieved; by setting different energies for the X-ray source array and combining it with coded emission, rapid multi-energy CT imaging can be achieved without changing the number of acquisition angles.

[0095] Compared with existing technologies, the static X-ray source CT imaging system based on a multi-center scanning structure provided in this application has the following advantages:

[0096] 1. By adopting a multi-center scanning method, the problem of uneven sparse angle sampling in single-center scanning can be effectively reduced, and dense projection data can be obtained by utilizing the correlation between projections.

[0097] 2. During the acquisition process, the acquisition time is further shortened by using coded illumination, which helps to suppress motion artifacts. Furthermore, specific acquisition templates can be designed according to the imaging object, which helps to further improve image resolution.

[0098] 3. By setting different scanning voltages and coordinating them with the encoding scheme, multi-energy CT scanning can be achieved, enabling effective identification of soft tissues.

[0099] 4. Using a wireless transmission mode, the reconstruction module is not limited to local construction and can be uploaded to the cloud platform, using a large model for efficient data processing and reconstruction.

[0100] Those skilled in the art will understand that the above-described embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this application. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A static X-ray source CT imaging system based on a multi-center scanning structure, characterized in that, include: The scanning module, detection module, and reconstruction module are connected in sequence; among them, The scanning module includes a frame, a worktable, and an array X-ray source module; the frame has a through slot for the worktable to move in or out of the frame; the array X-ray source module is disposed on the inner surface of the frame. The array X-ray source module includes multiple sets of source components arranged along the axial direction. Each set of source components includes multiple X-ray source arrays, and the multiple X-ray source arrays form a 360° circle. The X-ray source array includes multiple X-ray source units, and the X-rays emitted by each unit cover a part of the imaging object to form a multi-center scanning structure. The X-ray source array includes one or more of the following: linear X-ray tube array, arc-shaped X-ray tube array, and area array X-ray source. The detection module includes a detector located inside the frame for detecting the X-ray beam emitted by the array X-ray source module; The reconstruction module is used to process the projection data measured by the detection module, express the projection redundancy information, model the signal and noise in the projection domain, and perform image reconstruction to obtain the internal information of the image. The scanning module also includes a scanning control unit; the scanning control unit is used to control the illumination of the X-ray source unit of the array X-ray source module during the scanning process, and to control the rotation of the detection module to complete projection measurements at different angles.

2. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, The X-rays emitted by the X-ray source units in the X-ray source array cover a portion of the object. When all the X-ray source units are lit, the imaging object can be completely covered, forming a multi-center scanning structure in the assembly.

3. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, The X-ray source assembly includes multiple linear / arc X-ray tube arrays, which are arranged in a 360° circle. Each linear / arc X-ray tube array includes multiple X-ray source units. The X-rays emitted by the X-ray source units in the linear / arc X-ray tube array cover a portion of the imaging object. When all the X-ray source units in the linear / arc X-ray tube array are lit, they can completely cover the imaging object, forming a multi-center scanning structure.

4. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, The X-ray source assembly includes multiple area array light sources, which are arranged in a 360° circle. Each area array light source includes multiple X-ray source units. Each X-ray source unit in the area array light source covers a portion of the imaging object during irradiation. The irradiation of all X-ray source units in the area array light source can completely cover the imaging object, forming a multi-center scanning structure.

5. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, Considering the spacing between light sources and the packaging spacing between the X-ray source arrays, the number of X-ray source arrays is odd to solve the problem of discontinuous data acquisition caused by the seams between the arrays.

6. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, In the scanning control unit, multiple X-ray source units in a stationary X-ray source module are simultaneously illuminated in a single projection acquisition by means of encoded light emission, thereby completing the acquisition of the projection.

7. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 6, characterized in that, By using encoded emission, multiple X-ray source units in a static X-ray source module are simultaneously illuminated in a single projection acquisition, including: Encoded emission is performed under the same array of light sources within the component, or coded emission is jointly encoded in adjacent arrays within the component, or coded emission is encoded between components; Based on different optimization objectives and imaging objects, coding schemes are designed; the optimization objectives include: complete coverage of the object in a single coding operation and the highest ray utilization efficiency.

8. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, The detector is an arc-shaped detector; When the X-ray source assembly is a linear or arc-shaped X-ray tube array, the stage moves at a constant speed during the scanning process, which, combined with the rotation of the detector, achieves helical scanning; or, the stage remains stationary during the scanning process, which, combined with the rotation of the detector, achieves cone-beam scanning. When the X-ray source assembly is composed of a planar array light source, by designing the planar array emission timing sequence, and combining it with the detector rotation while the worktable is stationary, spiral scanning can be achieved.

9. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1 or 6, characterized in that, The array X-ray source module combines different voltages with different voltage encoding schemes during the scanning process to form a multi-energy CT scan.

10. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1 or 6, characterized in that, During the encoding and emission process, the detector's acquisition process includes: Rotate to the opposite side of the corresponding coded light source, pause to collect data, and then continue rotating to the next opposite position of the coded light source; or, During the encoding and emission process, the detector rotates at a constant speed to collect data.

11. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 6, characterized in that, The detector acquires the projection information of all X-ray beams emitted by the X-ray source under the coded template. The calculation formula for the acquisition process is as follows: in, This represents the measurement data on the j-th detector. Let M represent the sampling matrix, where M represents the number of light sources. A 1 in the matrix indicates that the light source at that location was lit in k measurements. This indicates the lighting status of the i-th light source in the k-th sampling case. E represents the energy integral on the j-th detector corresponding to the i-th light source during the k-th illumination. l (e) represents the normalized spectral information of the ray element at 1 kV, I0 represents the total number of photons from the source, A is a known projection matrix, δ(e) represents the mass decay coefficient of matter at energy e, and ρ represents the mass density distribution map. The representation of the ray unit at energy 1 kV is the measurement data received by the j-th light source from the i-th detector at energy spectrum e; in the case of a single energy spectrum, [Aδ(e)ρ] ij Further simplified to [Af] ij f is the linear attenuation coefficient of the reconstructed image.

12. The static X-ray source CT imaging system based on a multi-center scanning structure according to claim 1, characterized in that, The reconstruction module processes the acquired measurement data, utilizes the redundancy information of the projection, models the signal and noise in the projection domain, designs a reconstruction algorithm, and obtains the internal structural information of the object. Under the single-energy spectrum assumption, the reconstruction algorithm formula is as follows: Where T represents the number of sampling angles, K represents the number of encoding schemes, M represents the number of light sources, and N represents the number of detectors. This represents a matrix combining partial differential equations, used to express the redundancy properties of projections and to model the signal. This is a sparse sampling matrix, where 1 indicates that the projection of the point is known, and 0 indicates that the projection of the point is unknown. Let R represent a known sparse projection. ijt Let be the line integral of the attenuation coefficient along the path of the X-ray emitted from the j-th light source at the t-th angle to the i-th detector. The regularization term is designed based on prior image information to reduce the solution space; In the multi-energy spectroscopy case, the unknown data is the density information of the material. Assuming the reconstructed material is composed of G different materials, the material matrix of the material is written as: Where, δ g (e) represents the mass decay coefficient of the g-th material at energy e. If the image at pixel i belongs to the g-th material, then... Conversely, it equals 0; The reconstructed formula after conversion is shown below: Where l represents the use of l groups of ray elements with different energies for projection acquisition, T represents the number of sampling angles, K represents the number of encoding schemes, M represents the number of light sources, and N represents the number of detectors. This represents a matrix that combines partial differential equations. This represents the line integral value of the j-th light source corresponding to the i-th detector at the t-th angle at the energy spectrum e of the ray element at an energy of 1kV.

13. A static X-ray source CT imaging method based on a multi-center scanning structure, wherein CT imaging is performed using a static X-ray source CT imaging system based on a multi-center scanning structure as described in any one of claims 1 to 12, characterized in that, Includes the following steps: The imaging parameters are set, including whether the gantry is translated, whether dual-energy scanning is used, and the loading of the coded emission mode. Place the object to be imaged on the worktable; under the encoding template, illuminate the addressable X-ray source of the X-ray source unit; The detector collects the projection information of all the X-ray beams emitted by the X-ray source under the coded template to obtain projection data; The image reconstruction module processes the acquired data to reconstruct the internal organizational structure information of the object.

Images