Static real-time CT imaging system with paired ray source rings and imaging control method

Abstract

The present invention discloses a static real-time CT imaging system with paired ray source rings, including paired ray source rings and detector rings, wherein on the Z axis, the left ray source ring and the right ray source ring are symmetrically arranged on the left and right sides of the detector ring, and the two ray source rings share one detector ring. The multiple focal points in the two ray source rings arranged in the static real-time CT imaging system can be equivalent to the multiple focal points of the same equivalent ray source ring, and the total number of focal points of the equivalent ray source ring is the sum of the focal points of the left ray source ring and the right ray source ring; thereby, the volume requirements for each ray source in the ray source ring are reduced to a certain extent, and the FOV of the equipment is effectively expanded, and the CT imaging accuracy and quality are improved. The present invention also provides a corresponding imaging control method, which can eliminate the gap area that may exist between the left ring FOV and the right ring FOV by controlling the scanning mode, so that the above-mentioned static real-time CT imaging system meets the use requirements.

Description

Technical Field

[0001] The invention relates to a static real-time CT imaging system with paired ray source rings, and also to an imaging control method implemented by using the static real-time CT imaging system, belonging to the technical field of medical imaging. Background Art

[0002] CT (Computed Tomography) is the abbreviation of computer tomography technology. Its imaging principle is as follows: X-ray beams and highly sensitive X-ray detectors are used to perform layer-by-layer section scanning around a certain part of the human body. The scintillation material on the X-ray detector receives the X-rays that pass through the layer, converts them into visible light, and then converts them into electrical signals by the photoelectric converter. After amplification, they are converted into digital signals through analog / digital conversion and input into the computer for processing. In the computer, the selected layer is divided into several cubes of the same volume, called voxels. After the information obtained from the layer-by-layer section scanning is calculated, the X-ray attenuation coefficient or absorption coefficient of each voxel is obtained, and then arranged into a matrix, namely the voxel digital matrix. The digital information in the voxel digital matrix is ​​converted into small squares with varying grayscales from black to white, which are called pixels on a two-dimensional projection. Arranged in a tomographic manner to form a CT image.

[0003] In order to increase the scanning speed, improve the imaging accuracy and speed, avoid the influence of the centrifugal force caused by mechanical rotation, and reduce the signal tailing effect and overlapping crosstalk during high-speed rotation, the applicant disclosed a static real-time CT imaging system in the Chinese patent No. ZL 201410425061.2. The static real-time CT imaging system includes an annular photon counting detector, an annular scanning X-ray source and a scanning timing controller. Among them, under the control of the scanning timing controller, the annular scanning X-ray source emits a narrow beam of X-rays, which penetrate the object to be measured and project onto the corresponding annular photon counting detector. The annular photon counting detector sends the corresponding exposure information to the data acquisition processing unit and the human-computer interaction unit through the scanning host and the main control unit, and completes the image reconstruction in the data acquisition processing unit and the human-computer interaction unit. In the above-mentioned static real-time CT imaging system, during the scanning process, the annular scanning X-ray source does not need to rotate significantly, and the X-ray projection position is switched in sequence through electronic control, so that the scanning speed is increased by dozens of times, and a dynamic three-dimensional stereo image can be obtained: the photon counting detector is used to obtain absorption data and energy data, and thus achieve real-time data reconstruction.

[0004] In order to meet the actual needs of a large field of view, a static real-time CT imaging system that adapts to the requirements of a large field of view is disclosed in the patent document with the publication number WO2018 / 153382A1. The static real-time CT imaging system includes a multi-focus annular X-ray source and an annular photon detector; wherein the multi-focus annular X-ray source is composed of a plurality of scanning X-ray sources arranged in an annular shape, and the annular photon counting detector is composed of a plurality of photon counting detector modules arranged in an annular shape; each scanning X-ray source emits a wide beam X-ray in turn, which is projected onto the corresponding photon counting detector module after passing through the object to be measured, and a non-reverse geometric imaging method is adopted between the scanning X-ray source and the corresponding photon counting detector module, and each photon counting detector module works in an overlapping manner, and the corresponding exposure information is sent to the data acquisition processing unit, and the real-time reconstruction and visualization reproduction of the image are completed in the data acquisition processing unit. The static real-time CT imaging system emits a wide beam X-ray from a multi-focus annular X-ray source, and the non-reverse geometric imaging method is adopted between the ray source and the detector, which can adapt to the requirements of a large field of view (i.e., the field of view angle FOV reaches about 450 to 500).

[0005] In order to improve the accuracy of CT imaging, in a static real-time CT imaging system, there are certain requirements on the number of X-ray sources arranged in a multi-focus annular X-ray source. However, when a large number of X-ray sources are arranged in a multi-focus annular X-ray source, this puts higher requirements on the volume of the X-ray source, and the volume of the X-ray source needs to be reduced, which brings great difficulties to the manufacture of the X-ray source. Summary of the invention

[0006] The primary technical problem to be solved by the present invention is to provide a static real-time CT imaging system with paired ray source rings.

[0007] Another technical problem to be solved by the present invention is to provide an imaging control method implemented based on the above-mentioned static real-time CT imaging system.

[0008] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0009] According to a first aspect of an embodiment provided by the present invention, a static real-time CT imaging system with a paired ray source ring is provided, characterized in that it includes a paired ray source ring and a detector ring, wherein:

[0010] On the Z axis, the left ray source ring and the right ray source ring are symmetrically arranged on the left and right sides of the detector ring, and the two ray source rings share one detector ring;

[0011] The left ray source ring and the right ray source ring are respectively annular multi-focus X-ray sources with multiple X-ray sources, and the same number of focal points are evenly arranged on the left ray source ring and the right ray source ring, and the focal points of the left ray source ring and the right ray source ring are relatively staggered.

[0012] Preferably, the detector ring is composed of a plurality of photon counting detectors arranged in a ring shape, wherein a plurality of photon counting detectors corresponding to the same X-ray source constitute a photon counting detector module;

[0013] The static real-time CT imaging system also includes a scanning timing controller; the emission timing of multiple focal points in the left ray source ring and the right ray source ring and the acquisition timing of the corresponding photon counting detector modules in the detector ring are controlled by the scanning timing controller.

[0014] Preferably, the multiple X-ray sources in the left ray source ring and the right ray source ring emit X-rays according to a predetermined emission sequence, and the corresponding photon counting detector modules collect exposure information of the X-rays on the photon counting detector modules after passing through the object to be measured in an overlapping manner.

[0015] Preferably, under the action of the scanning timing controller, the multiple X-ray sources in the left ray source ring and the right ray source ring perform axial scanning in any of the following ways:

[0016] ① Expose a ray source on the left, expose a ray source on the right, and then expose another ray source on the left, so that all ray sources are exposed alternately on the left and right to obtain the projection images of all ray sources;

[0017] ② The left ray sources are exposed in turn, and then the right ray sources are exposed in turn to obtain the projection images of all ray sources;

[0018] ③ The left ray source is exposed in turn, and only the projection image of the left ray source is obtained;

[0019] ④ The ray sources on the right are exposed in turn, and only the projection image of the ray sources on the right is obtained.

[0020] Preferably, the multiple focal points in the left ray source ring use one energy level, and the multiple focal points in the right ray source ring use another energy level, so that energy spectrum images of two energy levels can be achieved in one scan.

[0021] Preferably, the static real-time CT imaging system adopts step scanning in the long Z-direction scanning mode to fill the gap area.

[0022] Preferably, the static real-time CT imaging system adopts a spiral scanning method in the long Z-direction scanning method.

[0023] According to a second aspect of the embodiment provided by the present invention, a static real-time CT imaging control method is provided, which is implemented based on the above-mentioned static real-time CT imaging system and includes the following steps:

[0024] The scanning timing controller controls the X-ray sources in the left and right ray source rings and the corresponding photon counting detector modules in the detector ring to work in a predetermined scanning timing:

[0025] The multiple X-ray sources in the left ray source ring and the right ray source ring emit X-rays according to a predetermined emission sequence, and the corresponding photon counting detector modules collect exposure information of the X-rays on the photon counting detector modules after passing through the object to be measured in an overlapping manner.

[0026] Preferably, under the action of the scanning timing controller, the multiple X-ray sources in the left ray source ring and the right ray source ring perform axial scanning in any of the following ways:

[0027] ① Expose a ray source on the left, expose a ray source on the right, and then expose another ray source on the left, so that all ray sources are exposed alternately on the left and right to obtain the projection images of all ray sources;

[0028] ② The left ray sources are exposed in turn, and then the right ray sources are exposed in turn to obtain the projection images of all ray sources;

[0029] ③ The left ray source is exposed in turn, and only the projection image of the left ray source is obtained;

[0030] ④ The ray sources on the right are exposed in turn, and only the projection image of the ray sources on the right is obtained.

[0031] Preferably, the multiple focal points in the left ray source ring use one energy level, and the multiple focal points in the right ray source ring use another energy level, so that energy spectrum images of two energy levels can be achieved in one scan.

[0032] Preferably, the static real-time CT imaging system adopts step scanning in the long Z-direction scanning mode to fill the gap area.

[0033] Preferably, the static real-time CT imaging system adopts a spiral scanning method in the long Z-direction scanning method.

[0034] The static real-time CT imaging system with paired ray source rings provided by the present invention has ray source rings symmetrically arranged on the left and right sides of the detector ring, the left ray source ring and the right ray source ring share the detector ring, and the multiple focal points in the two ray source rings can be equivalent to the multiple focal points of the same equivalent ray source ring, and the total number of focal points of the equivalent ray source ring is the sum of the focal points of the left ray source ring and the right ray source ring; thereby, the volume requirements for each ray source in the ray source ring are reduced to a certain extent, and the FOV of the equipment is effectively expanded, and the CT imaging accuracy and quality are improved. The imaging control method for the above-mentioned static real-time CT imaging system provided by the present invention can eliminate the gap area that may exist between the left ring FOV and the right ring FOV by controlling the scanning mode, so that the static real-time CT imaging system provided by the present invention meets the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a static CT imaging system with paired ray source rings provided by the present invention;

[0036] Figure 2 It is a schematic diagram of the FOV of a static CT imaging system with paired ray source rings under ideal conditions;

[0037] Figure 3 It is a schematic diagram of a diamond-shaped FOV;

[0038] Figure 4 It is a schematic diagram of a rectangular FOV;

[0039] Figure 5 It is a schematic diagram of the principle of using step scanning to compensate for the gap area. DETAILED DESCRIPTION

[0040] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] The static real-time CT imaging system provided by the present invention includes a pair of ray source rings, a detector ring 3 and a scanning timing controller in the scanning frame unit. Figure 1As shown, on the Z axis, the left ray source ring 1 and the right ray source ring 2 are symmetrically arranged on the left and right sides of the detector ring 3, and the two ray source rings share one detector ring 3. The left ray source ring 1 and the right ray source ring 2 are respectively annular multi-focus X-ray sources with multiple X-ray sources, and the same number of focal points are evenly arranged on the left ray source ring 1 and the right ray source ring 2, and the focal points of the left ray source ring 1 and the right ray source ring 2 are relatively staggered. The detector ring 3 is composed of multiple photon counting detectors arranged in a ring, wherein the multiple photon counting detectors corresponding to the same X-ray source constitute a photon counting detector module. The emission timing of the multiple focal points in the left ray source ring 1 and the right ray source ring 2 and the collection timing of the corresponding photon counting detector module in the detector ring 3 are controlled by the same scanning timing controller; the multiple X-ray sources in the left ray source ring 1 and the right ray source ring 2 emit X-rays according to the predetermined emission timing, and the corresponding photon counting detector modules in the detector ring 3 collect the exposure information of the X-rays on the photon counting detector module after passing through the object to be measured in an overlapping manner.

[0042] The static real-time CT imaging system provided by the present invention can be equivalent to an equivalent ray source ring with multiple focal points by relatively staggered arrangement of multiple focal points on two ray source rings located on the left and right sides of the detector ring 3, and the number of focal points of the equivalent ray source ring is twice the number of focal points of a single ray source ring. For example, assuming that the left ray source ring 1 and the right ray source ring 2 are respectively evenly arranged with 60 focal points, and the angular interval of each focal point is 6°, and at the same time, the focal points in the left ray source ring 1 and the right ray source ring 2 are relatively staggered, then it is equivalent to an equivalent ray source ring with 120 focal points, and the angular interval between each focal point is 3°. Through the above improvements, without increasing the difficulty of manufacturing the X-ray source, the number of focal points used for imaging in the static real-time CT imaging system is greatly increased, and the imaging accuracy and quality can be greatly improved.

[0043] In the static real-time CT imaging system provided by the present invention, the scanning frame unit may further include an auxiliary mechanism for making the left ray source ring 1 and the right ray source ring 2 swing at a small angle along the circumferential direction in addition to the paired ray source rings, the detector ring 3 and the scanning timing controller. The above-mentioned small angle swing is an angle interpolation for fine reconstruction, which is essentially not a rotational imaging method like ordinary CT. The angle amplitude of the small angle swing is similar to the angle interval between the two focal points.

[0044] The static real-time CT imaging system described above can meet the requirements of a large field of view by emitting X-rays in a time sequence by multiple focal points in the left ray source ring 1 and the right ray source ring 2, and adopting a non-reverse geometric imaging method between the ray source and the photon counting detector module. This is described in detail below.

[0045] In the above-mentioned static real-time CT imaging system, the left ray source ring 1, the right ray source ring 2 and the detector ring 3 are installed on a rotating bracket, and the three are on the same axis, which is the Z axis commonly known in the CT field. Under the control of the scanning timing controller, the multiple X-ray sources in the left ray source ring 1 and the right ray source ring 2 emit X-rays according to a certain timing, and the corresponding photon counting detector modules work in an overlapping manner, wherein the multiple photon counting detectors corresponding to the same X-ray source can be regarded as a photon counting detector module. For example, X-ray source No. 1 works corresponding to photon counting detectors No. 1, 2, 3, 4, and 5, X-ray source No. 2 works corresponding to photon counting detectors No. 2, 3, 4, 5, and 6, scanning X-ray source No. 3 works corresponding to photon counting detectors No. 3, 4, 5, 6, and 7, and so on. The corresponding working mode is full-ring readout, that is, the projection area corresponding to multiple focal points is read out at one time. The focal planes of the left ray source ring 1 and the right ray source ring 2 are respectively located on the left and right sides of the Z-direction center plane of the detector ring 3 in the Z direction. The X-rays emitted by the focal points in the left ray source ring 1 and the right ray source ring 2 are obliquely incident on the detector surface (i.e., each photon counting detector module in the detector ring 3 is not perpendicular to the corresponding incident X-rays), and necessary geometric correction is required during imaging. The specific geometric correction algorithm is a conventional technical means generally mastered by those skilled in the art, and will not be described in detail here.

[0046] The X-ray sources in the left ray source ring 1 and the right ray source ring 2 can be composed of a plurality of independent scanning X-ray sources tightly and evenly arranged in a ring, or a ring X-ray source with multiple focal points evenly distributed on multiple cathodes, or several groups of arc X-ray sources with multiple focal points evenly distributed on multiple cathodes. The detector ring 3 is preferably composed of a plurality of photon counting detectors tightly and evenly arranged in a ring. A plurality of photon counting detectors corresponding to the same X-ray source constitute a photon counting detector module, and a non-reverse geometric imaging method is adopted between the plurality of focal points and the corresponding photon counting detector modules. The number of the plurality of focal points arranged on the circumference may be consistent with the number of the photon counting detectors or may be inconsistent. As described above, the photon counting detectors constituting the detector ring 3 may also be replaced by direct conversion, energy differentiation or scintillator-based integral X-ray detectors.

[0047] When the static real-time CT imaging system is working, the X-ray sources in the left ray source ring 1 and the right ray source ring 2 are controlled by the scanning timing controller to emit X-rays along the circumferential direction according to a certain timing, and its effect is equivalent to the circular rotation of the existing spiral CT.

[0048] The X-ray sources (i.e., multiple focal points) in the left ray source ring 1 and the right ray source ring 2 can realize an axial scan in the following multiple ways, and can simultaneously obtain the left ring FOV 6 and the right ring FOV 7, or can only obtain the left ring FOV 6 or the right ring FOV 7. Specifically, the following four axial scan methods are included:

[0049] ① Expose a ray source on the left, expose a ray source on the right, and then expose another ray source on the left, so that all ray sources are exposed alternately on the left and right to obtain the projection images of all ray sources;

[0050] ② The left ray sources are exposed in turn, and then the right ray sources are exposed in turn to obtain the projection images of all ray sources;

[0051] ③ The left ray source is exposed in turn, and only the projection image of the left ray source is obtained;

[0052] ④ The ray sources on the right are exposed in turn, and only the projection image of the ray sources on the right is obtained.

[0053] In addition, in the axial scanning modes ①②③④, the emission timing of single or multiple focal points in different areas of a single ray source ring can also adopt a scanning timing of emitting X-rays simultaneously or in time-sharing, point by point or alternately, line by line or alternately. Each X-ray source in the left ray source ring 1 and the right ray source ring 2 can emit X-rays sequentially along the circumferential direction, or can emit X-rays sequentially with several X-ray sources spaced apart. The X-ray sources in the left ray source ring 1 and the right ray source ring 2 can emit X-rays only from a single X-ray source, or can emit X-rays in parallel from multiple X-ray sources at the same time. The maximum number of X-ray sources emitting X-rays in parallel is based on the premise that the X-rays emitted in parallel do not interfere with each other on the photon counting detector, and the circumferential distribution of the X-ray sources emitting X-rays in parallel is preferably uniformly distributed around the circumference.

[0054] The X-rays emitted by the X-ray sources in the left ray source ring 1 and the right ray source ring 2 pass through the object to be measured and then irradiate the corresponding photon counting detector module in the detector ring 3. The data acquisition and processing unit is composed of multiple distributed subsystems, and an embedded GPU is integrated in the subsystem. The photon counting detector collects and reconstructs the received X-ray information by the data acquisition and processing unit, and the reconstructed image information is then transmitted to the image data storage unit and the human-computer interaction unit, and the image storage and visual reproduction are completed in the image data storage unit and the human-computer interaction unit. Of course, it is also possible to follow the existing CT data acquisition and processing method: the data acquisition and processing unit only collects data, and then transmits the data information to the image data storage unit for reconstruction and storage.

[0055] In the prior art, the number of focal points in a multi-focus annular X-ray source determines the maximum circumferential projection density during static scanning. This projection density sometimes cannot meet some medical imaging requirements with higher requirements. In order to increase the maximum circumferential projection density, on the one hand, the static real-time CT imaging system provided by the present invention increases the number of focal points used for imaging by setting two ray source rings, and on the other hand, the static real-time CT imaging system provided by the present invention can also increase the number of scanning focal points by using an interpolation scanning method. The interpolation scanning method makes the circumferential projection density higher, can realize the energy spectrum scanning function, and the multi-focus parallel scanning speed is faster. When performing interpolation scanning, the multi-focus annular X-ray source rotates at a uniform speed through an angle range not less than that between two adjacent focal points. During the movement time through this angle range, the multi-focus annular X-ray source completes multiple X-ray emissions, which is equivalent to adding multiple focal points between the two focal points. During the rotation process, a single focus emits X-rays several times, which is several interpolation scans. When performing interpolation scanning, only the left ray source ring 1 and the right ray source ring 2 can swing at a small angle along the circumferential direction, or the left ray source ring 1, the right ray source ring 2 and the detector ring 3 can swing relatively along the circumferential direction, or the rotating bracket as a whole does not move, and the scanning bed carrying the human body swings along the circumferential direction.

[0056] The static real-time CT imaging system can realize energy spectrum scanning in various ways by using the multi-focus in the left ray source ring 1 and the right ray source ring 2. First, the left ray source ring 1 and the right ray source ring 2 can use the energy instantaneous switching of a single X-ray source to perform energy spectrum scanning, and can instantaneously switch between multiple energy levels (for example, switching between 100kV, 120kV, and 140kV). The specific number of switched energy levels is determined by the design requirements. After a certain X-ray source performs energy spectrum scanning by instantaneous energy switching, the next X-ray source under the scanning timing control performs energy spectrum scanning in the same way until the entire scanning work is completed. Secondly, the left ray source ring 1 and the right ray source ring 2 can use circular intermittent energy switching for energy spectrum scanning, that is, after each X-ray source of the left ray source ring 1 and the right ray source ring 2 completes a circular scan at the same energy level under timing control, then all switch to another energy level, and repeat the next circular scan until all energy level switching is completed. Thirdly, the left ray source ring 1 and the right ray source ring 2 can also use a circular multi-energy spectrum scanning method to perform energy spectrum scanning, that is, the scanning X-ray sources distributed on the circumference are divided into several groups, each group is unified into one energy level, and after completing a circular scan under timing control, the energy level of each group of scanning X-ray sources is switched to the corresponding next energy level, and the next circular scan is repeated until all energy level switching is completed. Finally, the left ray source ring 1 and the right ray source ring 2 can also use two different energy levels at the same time. Specifically, the multiple focal spots in the left ray source ring 1 use one energy level (A kV), and the multiple focal spots in the right ray source ring 2 use another energy level (B kV, B≠A), and one scan realizes energy spectrum images of two energy levels.

[0057] It should be noted that the photon counting detector in the present invention can also be replaced by an integrating detector to achieve the same function. However, the imaging effect of the integrating detector is inferior to that of the photon counting detector. However, since the integrating detector technology is relatively mature, its function is relatively stable.

[0058] The structure and scanning method of the static real-time CT imaging system with paired ray source rings provided by the present invention are introduced above. The FOV of the static real-time CT imaging system with paired ray source rings is introduced in detail below.

[0059] like Figure 1As shown, there is inevitably an edge area 5 that cannot be sensitive to light between the left ray source ring 1 and the detector ring 3 and between the right ray source ring 2 and the detector ring 3. The two edge areas 5 are located on both sides of the photosensitive area 4 of the detector ring 3. The size of the edge area 5 is determined by the specific design adopted when the detector ring 3 is implemented. Due to the existence of the edge area 5, the FOV reconstructed under this structure is not continuous, and is divided into a left ring FOV 6, a blank area 8 and a right ring FOV 7, wherein the blank area 8 is a blank area formed because both the left ray source ring 1 and the right ray source ring 2 are not covered by X-rays. In actual design, the smaller the edge area 5, the better. The smaller the edge area 5, the smaller the area of ​​the blank area 8. Ideally, after eliminating the edge area 5, the FOV of the device will be composed of the left ring FOV 6 and the right ring FOV 7. At this time, there is no blank area 8, as shown in FIG. Figure 2 shown.

[0060] By performing FOV compensation algorithm processing, the left ring FOV 6 and the right ring FOV 7 can be changed from an asymmetric rhombus (such as Figure 3 as shown) into a rectangular shape (as shown Figure 4 The left and right boxes in the figure). If an analytical algorithm is used, such as traditional filtered back projection, a compensation algorithm is needed to correct the rhombus to a rectangle. For a specific compensation algorithm, see Zikuan Chen et al., "Compensating the intensity fall-off effect in cone-beam tomography by an empirical weight formula" [J], Appl Opt. 2008 November 10; 47(32): 6033–6039. If an iterative algorithm is used, the directly reconstructed FOV is a cylinder with a rectangular cross section, and no algorithm compensation is required.

[0061] like Figure 1 As shown, since there is inevitably an edge area 5 that cannot be photosensitive between the left ray source ring 1 and the detector ring 3 and between the right ray source ring 2 and the detector ring 3, the reconstructed FOV is not continuous, and there is a gap area 8 between the left ring FOV 6 and the right ring FOV 7. The above-mentioned gap area 8 can be eliminated by different scanning methods.

[0062] For example, Figure 5 As shown, when the static real-time CT imaging system uses step scanning in the long Z-direction scanning mode, the gap area 8 can be compensated. Specifically, when the step length is similar to the average width of the left ring FOV 6, the right ring FOV 7 and the gap area 8, in each scan, the left ring FOV 6 and the right ring FOV 7 are approximately located at the following positions.

[0063] ① The first scan S-1 completes the scanning of the left ring FOV 6, the blank area 8 and the right ring FOV 7.

[0064] ② The bed moves to the left for a distance to perform the second scan S-2. At this time, the corresponding left ring FOV6 of the first scan moves out of the scanning area, the empty area 8 of the first scan is located at the left ring FOV 6 position, and the right ring FOV 7 of the first scan is located at the empty area 8.

[0065] ③ The bed moves to the left for a distance to perform the third scan S-3. At this time, the left ring FOV 6 corresponding to the first scan moves out of the scanning area, and the idle area 8 of the first scan also moves out of the scanning area. The right ring FOV 7 of the first scan is located in the left ring FOV 6. Since the adjacent focal points in the left and right ray source rings are spaced by half the ray source spacing angle in a single ray source ring, the two scans can increase the reconstructed image quality.

[0066] ④Scan in the above order to obtain a longer Z-direction scan.

[0067] The positions of the left ring FOV 6 and the right ring FOV 7 corresponding to the above scanning process are shown in Table 1 below. The Z direction is divided into continuous A, B, C, D... segments. Then, in the long Z direction scanning process, except for the A and B segments, the other segments of the A, B, C, D... segments are covered once by the left ring FOV 6 and the right ring FOV 7 respectively, thereby realizing continuous Z direction scanning.

[0068] Table 1 The positions of the left ring FOV and the right ring FOV at each scan

[0069]

[0070]

[0071] In addition, when the static real-time CT imaging system uses a spiral scanning method in the long Z-direction scanning mode, the imaging effect is completely unaffected by the idle area.

[0072] In summary, the static real-time CT imaging system with paired ray source rings provided by the present invention has ray source rings symmetrically arranged on the left and right sides of the detector ring, the left ray source ring and the right ray source ring share the detector ring, and the multiple focal points in the two ray source rings can be equivalent to the multiple focal points of the same equivalent ray source ring, and the total number of focal points of the equivalent ray source ring is the sum of the focal points of the left ray source ring and the right ray source ring; thereby, while increasing the number of focal points, the volume requirements for each ray source in the ray source ring are reduced to a certain extent, and the FOV of the equipment is effectively expanded, improving the CT imaging accuracy and quality. The imaging control method for the above-mentioned static real-time CT imaging system provided by the present invention can eliminate the gap area that may exist between the left ring FOV and the right ring FOV by controlling the scanning mode, so that the static real-time CT imaging system provided by the present invention meets the use requirements.

[0073] The above is a detailed description of a static real-time CT imaging system with paired ray source rings and an imaging control method provided by the present invention. For a person skilled in the art, any obvious changes made to it without departing from the essential spirit of the present invention will constitute an infringement of the patent right of the present invention and will bear the corresponding legal liability.

Claims

1. A static real-time CT imaging control method is implemented based on a static real-time CT imaging system, wherein the static real-time CT imaging system comprises a pair of ray source rings and a detector ring, wherein on the Z axis, a left ray source ring and a right ray source ring are symmetrically arranged on the left and right sides of the detector ring, and the two ray source rings share one detector ring, and wherein the method comprises: The steps include: Controlling the X-ray sources in the left ray source ring and the right ray source ring and the corresponding photon counting detector modules in the detector ring to operate in a predetermined scanning sequence; The multiple X-ray sources in the left ray source ring and the right ray source ring emit X-rays according to a predetermined emission sequence, and the adjacent focal points in the left and right ray source rings are spaced apart by half the ray source spacing angle in a single ray source ring. The corresponding photon counting detector modules collect exposure information of the X-rays on the photon counting detector modules after passing through the object to be measured in an overlapping manner. Each X-ray source in the left ray source ring and the right ray source ring sequentially emits X-rays along the circumferential direction, or sequentially emits X-rays at intervals of several X-ray sources. The step length of the bed movement is equal to the average width of the left ring FOV, the right ring FOV and the blank area, and in each scan, the left ring FOV and the right ring FOV are located at the following positions: ① The first scan completes the scanning of the left ring FOV, the empty area and the right ring FOV; ② The bed moves to the left for a distance to perform the second scan. At this time, the left ring FOV of the corresponding first scan moves out of the scanning area, the empty area of ​​the first scan is located at the left ring FOV position, and the right ring FOV of the first scan is located in the empty area; ③ The bed moves to the left for a distance to perform the third scan. At this time, the left ring FOV corresponding to the first scan moves out of the scanning area, and the idle area of ​​the first scan also moves out of the scanning area. The right ring FOV of the first scan is located in the left ring FOV; ④Scan in the above order to obtain a longer Z-direction scan.

2. The static real-time CT imaging control method according to claim 1, characterized in that: The X-ray sources in the left ray source ring and the right ray source ring emit X-rays only in a single X-ray source, or, At the same time, multiple X-ray sources emit X-rays in parallel. The maximum number of X-ray sources emitting X-rays in parallel is based on the premise that the X-rays emitted in parallel do not interfere with each other on the photon counting detector. The X-ray sources emitting X-rays in parallel are evenly distributed on the circumference.

3. The static real-time CT imaging control method according to claim 1, characterized in that: The multiple X-ray sources in the left ray source ring and the right ray source ring are scanned in any of the following ways: ① a ray source on the left is exposed, a ray source on the right is exposed, and then a ray source on the left is exposed again, so that all ray sources are exposed alternately left and right to obtain projection images of all ray sources; ② the ray sources on the left are exposed in turn, and then the ray sources on the right are exposed in turn to obtain projection images of all ray sources; ③ the ray sources on the left are exposed in turn to obtain only the projection images of the ray sources on the left; ④ the ray sources on the right are exposed in turn to obtain only the projection images of the ray sources on the right.

4. The static real-time CT imaging control method according to claim 1, characterized in that The method comprises the following steps: a plurality of focal points in a left ray source ring use one energy level, a plurality of focal points in a right ray source ring use another energy level, and energy spectrum images of two energy levels are realized in one scan.

5. The static real-time CT imaging control method according to any one of claims 1 to 4, characterized in that The method comprises the following steps: the static real-time CT imaging system adopts step scanning in the long Z-direction scanning mode to fill the gap area.

6. The static real-time CT imaging control method according to any one of claims 1 to 4, characterized in that The method comprises the following steps: the static real-time CT imaging system adopts a spiral scanning mode in a long Z-direction scanning mode.

7. A static real-time CT imaging system with paired radiation source rings, characterized in that It comprises a pair of ray source rings and detector rings, wherein on the Z axis, the left ray source ring and the right ray source ring are symmetrically arranged on the left and right sides of the detector ring, and the two ray source rings share one detector ring; the left ray source ring and the right ray source ring are respectively annular multi-focus X-ray sources with multiple X-ray sources, and the same number of focal points are evenly arranged on the left ray source ring and the right ray source ring, and the focal points of the left ray source ring and the right ray source ring are relatively staggered; The detector ring is composed of a plurality of photon counting detectors arranged in a ring shape, wherein a plurality of photon counting detectors corresponding to the same X-ray source constitute a photon counting detector module; The static real-time CT imaging system also includes a scanning timing controller; the emission timing of multiple focal points in the left ray source ring and the right ray source ring and the acquisition timing of the corresponding photon counting detector module in the detector ring are controlled by the scanning timing controller, The static real-time CT imaging system is used to implement the static real-time CT imaging control method as described in any one of claims 1 to 5.

8. The static real-time CT imaging system according to claim 7, characterized in that: The multiple X-ray sources in the left ray source ring and the right ray source ring emit X-rays according to a predetermined emission sequence, and the corresponding photon counting detector modules collect exposure information of the X-rays on the photon counting detector modules after passing through the object to be measured in an overlapping manner.

9. The static real-time CT imaging system according to claim 7, characterized in that: Multiple focal points in the left ray source ring use one energy level, and multiple focal points in the right ray source ring use another energy level, so that energy spectrum images of two energy levels can be achieved in one scan.

10. The static real-time CT imaging system according to claim 7, characterized in that: The static real-time CT imaging system adopts step scanning in the long Z-direction scanning mode to fill the gap area.

11. The static real-time CT imaging system according to claim 7, characterized in that: The static real-time CT imaging system adopts a spiral scanning mode in the long Z-direction scanning mode.

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