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WO2025098141A1 - Système de tomodensitométrie - Google Patents

Système de tomodensitométrie Download PDF

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Publication number
WO2025098141A1
WO2025098141A1 PCT/CN2024/126810 CN2024126810W WO2025098141A1 WO 2025098141 A1 WO2025098141 A1 WO 2025098141A1 CN 2024126810 W CN2024126810 W CN 2024126810W WO 2025098141 A1 WO2025098141 A1 WO 2025098141A1
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WO
WIPO (PCT)
Prior art keywords
scanning
ray source
distributed
detector
segments
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/CN2024/126810
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English (en)
Chinese (zh)
Inventor
陈志强
张丽
沈乐
杨洪恺
孙运达
黄清萍
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tsinghua University
Nuctech Co Ltd
Original Assignee
Tsinghua University
Nuctech Co Ltd
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Filing date
Publication date
Application filed by Tsinghua University, Nuctech Co Ltd filed Critical Tsinghua University
Publication of WO2025098141A1 publication Critical patent/WO2025098141A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A61B6/032—Transmission computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/027—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]

Definitions

  • the present disclosure relates to the field of radiation scanning, and in particular to a CT scanning system.
  • Computed Tomography (CT) scanning technology is widely used in medical examination, security inspection, industrial inspection and other fields.
  • CT scanning systems used in security inspection can detect luggage, parcels and other items.
  • a CT scanning system may include a ray source, a detector, and a computer system.
  • an X-ray source emits X-rays through the object to be detected
  • the detector receives the X-rays passing through the object to be detected and converts them into electrical signals.
  • the electrical signals are amplified and digitized and transmitted to the computer system.
  • the computer system uses an image reconstruction algorithm to process the received data and generate a two-dimensional or three-dimensional image.
  • CT scanning technology combines X-ray imaging and computer image reconstruction technology to provide high-resolution, three-dimensional image data, which can help security personnel accurately detect potential dangerous goods or other security threats.
  • spiral CT scanning technology is increasingly widely used in medical examinations, safety inspections, industrial inspections and other fields.
  • the tomographic image data of the object to be inspected is obtained by continuous rotation scanning.
  • spiral CT scanning technology has the advantages of fast scanning speed and high temporal and spatial resolution.
  • how to further improve the scanning speed of the spiral CT scanning system is one of the important topics that researchers have been paying attention to.
  • the present disclosure provides a CT scanning system and a scanning method thereof.
  • a CT scanning system comprising: a conveying device for moving a scanned object in a scanning channel along a predetermined conveying direction; p scanning segments, each scanning segment comprising a distributed ray source and a detector array, the p scanning segments being arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source comprises m target points, the m target points are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array is used to detect rays emitted from the distributed ray source and passing through the scanned object, and to generate projection data based on the detected rays; and an image reconstruction device, the image reconstruction device being configured to generate a computerized tomography image of the scanned object based on the projection data detected by each detector in the p scanning segments; wherein the distributed ray source of
  • the distributed radiation source of each scanning segment is configured to rotate about a first axis when the scanning object is scanned.
  • the tangent direction is a direction extending along a tangent line tangent to the rotation direction of the distributed ray source.
  • the CT scanning system also includes a controller, which is configured to control at least one of the following aspects of the distributed radiation source: the activation time of the m target points, the duration of the radiation beams emitted by the m target points, the intensity of the radiation beams emitted by the m target points, and the energy of the radiation beams emitted by the m target points.
  • the m target points are arranged at intervals along a first arrangement direction, wherein the first arrangement direction is parallel to the first axis.
  • the distributed radiation source of each scanning segment includes an X-ray generating tube with multiple target points, or the distributed radiation source includes multiple X-ray generating tubes with single target points. X-ray generating tube at point.
  • the detector array of at least one of the scanning segments comprises a single row of detectors.
  • the detector array of at least one of the scanning segments includes n rows of detectors, where n is a positive integer greater than or equal to 2.
  • the detector array of at least one of the scanning segments comprises an area array detector.
  • the detector array of at least one of the scanning segments includes n1 rows of detectors, n1 is a positive integer greater than or equal to 1, and m is greater than n1.
  • the m target points are arranged at intervals along a first arrangement direction, wherein the first arrangement direction is parallel to the first axis; and the n rows of detectors are arranged at intervals along the first arrangement direction.
  • each row of detectors includes a plurality of detector modules, and in a plane perpendicular to the first axis, the plurality of detector modules of at least one row of detectors are arranged continuously along a straight line or an arc.
  • the CT scanning system further comprises a rear collimator, and in at least one of the scanning segments, the rear collimator is located on a side of the detector array facing the distributed radiation source.
  • the back collimator includes a plurality of sub-collimators, and in a plane perpendicular to the first axis, the plurality of sub-collimators are continuously arranged along a straight line or an arc.
  • the ray beam emitted by at least one of the m target points is shaped into a fan beam.
  • each row of detectors includes multiple detector modules, and in a plane perpendicular to the first axis, the multiple detector modules of at least one row of detectors are arranged continuously along an arc line; in a plane perpendicular to the first axis, at least one target point is offset from the center of the arc line.
  • the m target points are arranged at equal intervals along a first arrangement direction with a preset spacing distance dz , wherein the first arrangement direction is parallel to the first axis.
  • the m The i-th target point and the i+1-th target point among the target points are offset in the tangent direction by a first offset od1, wherein i is a positive integer greater than or equal to 2 and less than m.
  • the i-th target point and the i-1-th target point among the m target points are offset in the tangent direction by a second offset od2.
  • the first offset od1 and the second offset od2 are substantially equal.
  • the first offset od1 and the second offset od2 are both determined according to a rotation speed of the distributed radiation source, a moving speed of the conveying device, and a spacing distance between the m target points in the first arrangement direction.
  • the first offset od1 and the second offset od2 are designed so that the rotation angle difference ⁇ of adjacent target points satisfies the following condition:
  • k is a preset coefficient
  • k is a non-integer
  • ⁇ is the rotation speed of the distributed ray source
  • v is the moving speed of the conveying device
  • dz is the spacing distance between the m target points in the first arrangement direction.
  • the radiation beam formed by the m target points forms a scanning range in the region of interest where the scanning object is located, the scanning range including a first position and a second position, the first position being closer to the distributed radiation source than the second position, and the second position being between the first position and the detector array; and the scanning range forms a first straight line segment parallel to the transmission direction at the first position, and the scanning range forms a second straight line segment parallel to the transmission direction at the second position, and the width of the first straight line segment is greater than the width of the second straight line segment.
  • the distributed ray source and the detector array in one scanning segment are relatively arranged according to a first arrangement direction
  • the distributed ray source and the detector array in another scanning segment are relatively arranged according to a second arrangement direction
  • the first arrangement direction and the second arrangement direction intersect along the transmission direction
  • the orthographic projection forms an interval angle, and the interval angle is greater than 0° and less than 180°.
  • the interval angle satisfies the following conditions:
  • k' is a preset coefficient
  • k' is a non-integer
  • Lz is the distance between the two sets of source detection systems in two adjacent scanning segments along the transmission direction
  • q is the moving distance of the transmission device during the time when two adjacent scanning segments rotate by the interval angle
  • pz is the moving distance of the transmission device during the time when the source detection system of any one of the two adjacent scanning segments rotates one circle.
  • a CT scanning system includes: a conveying device for moving a scanned object in a scanning channel along a predetermined conveying direction; wherein the conveying device includes a conveying surface for placing the scanned object; p scanning segments, each scanning segment includes a distributed ray source and a detector array, and the p scanning segments are arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source includes m targets, and the m targets are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array is used to detect rays emitted from the distributed ray source and passing through the scanned object, and generate projection data based on the detected rays; and an image reconstruction device, wherein the image reconstruction device is configured to generate a computerized tomography image of the scanned object based on the projection data detected by each detector in the
  • a CT scanning system comprising: a conveying device for moving a scanned object in a scanning channel along a predetermined conveying direction; wherein the conveying device comprises a conveying surface for placing the scanned object; p scanning segments, each scanning segment comprising a distributed ray source and a detector array, the p scanning segments being arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source comprises m target points, the m target points are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array is used to detect rays emitted from the distributed ray source and passing through the scanned object, and to generate projection data based on the detected rays; and an image reconstruction device, the image reconstruction device being configured to: generate a computed tomography image of the scanned object based on the projection data detected by each detector in
  • the detector module comprises: in a plane perpendicular to the first axis, a plurality of detector modules of at least one row of detectors are continuously arranged along an arc line; and in a plane perpendicular to the first axis, at least one target point is offset from the center of the arc line.
  • distributed ray source technology rotating spiral CT scanning technology and multi-segment scanning technology are integrated into one, and distributed ray sources are used to replace the single-point ray sources in the traditional spiral CT scanning system, so that high scanning speed CT scanning can be achieved without increasing the number of detector rows.
  • FIG1 is a schematic structural diagram of a CT scanning system according to some exemplary embodiments of the present disclosure.
  • FIG2 schematically shows a side view of a CT scanning system provided by an embodiment of the present disclosure when viewed along a transmission direction;
  • FIG3A is a schematic diagram of a conventional CT scan
  • FIG3B is a scanning principle diagram of CT scanning using a distributed ray source according to an embodiment of the present disclosure
  • FIG4A is a schematic diagram of the structure of a distributed ray source according to some exemplary embodiments of the present disclosure.
  • FIG4B is a schematic structural diagram of the distributed ray source in FIG4A observed from another viewing angle
  • FIG4C schematically shows a waveform diagram of a current used to control the beam output of a distributed ray source
  • FIG5A is a schematic diagram of the structure of a source and a detector combination of a CT scanning system according to an embodiment of the present disclosure, in which a distributed radiation source and a single row of detectors are schematically shown;
  • FIG5B is a schematic diagram of the structure of a source and a detector combination of a traditional CT scanning system, in which a single target radiation source and multiple rows of detectors are schematically shown;
  • FIG5C is a schematic diagram of the structure of the source and detector combination of the CT scanning system according to an embodiment of the present disclosure, in which a distributed ray source and a multi-row detector are schematically shown;
  • FIG5D is a schematic diagram of the structure of the source and detector combination of a traditional CT scanning system, in which a single target is schematically shown. Point ray sources and more rows of detectors;
  • FIG5E is a schematic diagram of the structure of a source and a detector combination of a CT scanning system according to an embodiment of the present disclosure, in which a distributed ray source and a planar array detector are schematically shown;
  • FIG5F is a schematic diagram of the structure of a source and a detector combination of a traditional CT scanning system, in which a single target point ray source and a planar array detector are schematically shown;
  • FIG. 6A to 6D schematically illustrate some arrangements of sources and probes according to some exemplary embodiments of the present disclosure
  • FIG. 7A to 7C schematically illustrate the arrangement of multiple target points of a distributed ray source in a CT scanning system according to some exemplary embodiments of the present disclosure, wherein FIG. 7A is a perspective view of the distributed ray source, FIG. 7B is a schematic view of the source and the probe in one rotation state, and FIG. 7C is a schematic view of the source and the probe in another rotation state;
  • FIG8A schematically shows an arrangement of a source and a probe in a conventional CT scanning system
  • FIG8B schematically shows an exemplary arrangement of a source and a probe in a CT scanning system according to an embodiment of the present disclosure
  • FIG8C schematically shows a schematic diagram of an installation structure of a source and a probe in a CT scanning system according to an embodiment of the present disclosure
  • FIG9 schematically shows a rear collimator included in a CT scanning system according to some exemplary embodiments of the present disclosure
  • FIG. 10A schematically shows a scanning range of a conventional CT scanning system
  • FIG. 10B schematically shows a scanning range of a CT scanning system according to some exemplary embodiments of the present disclosure
  • FIG11 is a flow chart of a CT scanning method according to some exemplary embodiments of the present disclosure.
  • FIG. 12A and FIG. 12B schematically show comparison diagrams of reconstruction results of the CT scanning system according to an embodiment of the present disclosure and a conventional spiral CT system under the same scanning parameters, respectively;
  • FIG13 schematically shows a block diagram of an imaging device of a CT scanning system according to an embodiment of the present disclosure.
  • references to "one embodiment,” “an embodiment,” “an example,” or “an example” mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present disclosure. Therefore, the phrases “in one embodiment,” “in an embodiment,” “an example,” or “an example” appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example.
  • particular features, structures, or characteristics may be combined in one or more embodiments or examples in any appropriate combination and/or subcombination.
  • the term “and/or” as used herein includes any and all combinations of one or more of the associated listed items.
  • spiral CT scanning technology Compared with traditional CT scanning technology, spiral CT scanning technology has the advantages of fast scanning speed and high temporal and spatial resolution. Therefore, spiral CT scanning technology is increasingly widely used in medical inspection, safety inspection, industrial inspection and other fields.
  • the tomographic image data of the object to be inspected is obtained by continuous rotation scanning.
  • a spiral CT scanning system used in security inspection scenarios includes a radiation source, a detector, a scanning channel, a control system, and a computer system.
  • the radiation source and the detector are mounted on a frame through a support.
  • the control system is used to control the scanning parameters and the image acquisition process, such as the scanning speed and dose.
  • the computer system is used to image Image reconstruction, image processing and analysis.
  • the basic principle of spiral CT scanning technology is to obtain a tomographic image of the scanned object through continuous rotation scanning and image reconstruction. Specifically, the scanned object is placed in the scanning channel, such as a suitcase on a baggage conveyor belt.
  • the X-ray source and detector begin to rotate and perform continuous rotation scanning around the scanned object.
  • the X-rays pass through the scanned object, are received by the detector and converted into electrical signals. After amplification and digitization, the electrical signals are transmitted to the computer system.
  • the computer system uses a reconstruction algorithm to process the received data and generate a reconstructed image.
  • the spiral CT scanning system can provide high-resolution tomographic images using continuous rotation scanning and image reconstruction technology.
  • CT scanning equipment For spiral CT scanning equipment used in the field of security inspection, it is difficult to increase the scanning speed by increasing the slip ring speed due to the large size of the scanning channel and the fact that the slip ring speed of the spiral CT scanning equipment is restricted by the mechanics and mechanical properties of the imaging components.
  • detectors are relatively high-cost components. Increasing the number of detector rows will significantly increase the number of detectors, and accordingly, the cost of the entire CT scanning equipment will also increase significantly.
  • the inventors have found through further research that in spiral CT scanning equipment, the increase in the number of detector rows will bring about problems such as cone angle artifacts, an increase in the spatial solid angle of the beam, and an increase in the complexity of the post-collimator structure.
  • increasing the number of detector rows will increase the spatial solid angle of the beam, thereby increasing the scattering ratio, seriously affecting the image quality and numerical accuracy; moreover, as the spatial solid angle of the beam increases, the radiation protection level needs to be improved, which will increase the weight of the equipment and the length of the scanning channel.
  • non-rotating static multi-ray source CT scanning technology can be used to replace spiral CT scanning technology.
  • multi-ray source CT scanning technology multiple ray sources are arranged around the scanning channel in a certain geometric arrangement, and data similar to spiral scanning is generated for image reconstruction by alternately emitting beams. Since the frequency of alternating beams of multiple ray sources can be very fast, a higher scanning speed can be generated than the scanning speed of slip ring rotation.
  • an embodiment of the present disclosure provides a CT scanning system, wherein the system includes: a conveying device, used to move a scanned object in a scanning channel along a predetermined conveying direction; p scanning segments, each scanning segment includes a distributed ray source and a detector array, the p scanning segments are arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source includes m target points, the m target points are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array is used to detect rays emitted from the distributed ray source and passing through the scanned object, and generate projection data based on the detected rays; and an image reconstruction device, the image reconstruction device is configured to: generate a computerized tomography image of the scanned object based on the projection data detected by each detector in the p scanning segments; wherein the distributed ray source of
  • Fig. 1 is a schematic diagram of the structure of a CT scanning system according to some exemplary embodiments of the present disclosure.
  • the CT scanning system may include: a transmission device 3 , p scanning segments, a scanning channel 31 and an image reconstruction device 4 .
  • the conveying device 3 is used to move the scanning object 30 along a predetermined conveying direction Z in the scanning channel 31 .
  • the conveying device 3 can be realized in the form of belt transmission or chain transmission.
  • the scanning object 30 is placed on the transmission surface of the transmission device 3.
  • p is an integer greater than or equal to 2, that is, the scanning imaging system includes 2 or more scanning segments.
  • 2 scanning segments are exemplarily shown.
  • the p scanning segments may include the h-th scanning segment and the j-th scanning segment, wherein h and j are both positive integers greater than or equal to 1 and less than or equal to p, and h and j are not equal.
  • the 2 scanning segments exemplarily shown in FIG1 may be the h-th scanning segment and the j-th scanning segment.
  • the distributed ray source 1 and the detector array 2 of the hth scanning segment are arranged on both sides of the scanning channel along the first arrangement direction D5
  • the distributed ray source 1 and the detector array 2 of the jth scanning segment are arranged on both sides of the scanning channel along the second arrangement direction D6.
  • the arrangement direction here represents the relative position relationship between the ray source and the detector in a certain scanning segment. It should be understood that since the ray source and the detector in the scanning segment are rotating, the first arrangement direction D5 and the second arrangement direction D6 here can be variable.
  • Each scanning section includes a distributed ray source 1 and a detector array 2.
  • the distributed ray source 1 includes m target points 10, which are configured to be activated in a predetermined order to emit ray beams, where m is a positive integer greater than or equal to 2; the detector array 2 is used to detect rays emitted from the distributed ray source 1 and passing through the scanned object 30, and to generate projection data according to the detected rays.
  • the image reconstruction device 4 is configured to generate a computed tomography image of the scan object 30 based on the projection data of the two scan segments.
  • FIG2 schematically shows a side view of a CT scanning system viewed along a conveying direction provided by an embodiment of the present disclosure.
  • the distributed ray source 1 and the detector array 2 are arranged on both sides of the scanning channel along the first arrangement direction D5. side; in the second scanning segment, the distributed ray source 1 and the detector array 2 are arranged on both sides of the scanning channel along the second arrangement direction D6.
  • first arrangement direction D5 and the second arrangement direction D6 are different.
  • the orthographic projections of the first arrangement direction D5 and the second arrangement direction D6 in a plane perpendicular to the conveying direction intersect at an interval angle ⁇ , which is greater than 0° and less than 180°.
  • the first arrangement direction D5 forms a first inclination angle with the conveying surface, which is greater than 0° and less than 90°; and/or the second arrangement direction D6 forms a second inclination angle with the conveying surface, which is greater than 0° and less than 90°.
  • the CT scanning system of the present disclosure combines distributed ray source technology and rotary spiral CT scanning technology in each scanning segment, and uses distributed ray sources to replace single-point ray sources in traditional spiral CT scanning systems, so that high scanning speed CT scanning can be achieved without increasing the number of detector rows.
  • the equipment can realize multiple sets of source-detector systems to complete the entire circular scan at the same time on the basis of a series of advantages such as multi-source spiral CT mode saving detectors, increasing scanning range, and reducing imaging cone angle, which will multiply the scanning efficiency within a single spiral cycle, thereby further improving the imaging speed and achieving faster imaging speed, thereby achieving higher security inspection efficiency.
  • the CT scanning system uses a distributed radiation source 1.
  • the distributed radiation source 1 includes a plurality of target points 10 that emit radiation beams.
  • the plurality of target points 10 can be arranged in a predetermined geometric shape and a predetermined spacing distance.
  • the predetermined geometric shape can include a straight line, an arc, a plane, a curved surface, and the like.
  • the distributed ray source 1 includes an X-ray generating tube having multiple target points, or the distributed ray source 1 includes multiple X-ray generating tubes having a single target point.
  • FIG. 4A is a schematic diagram of the structure of a distributed radiation source according to some exemplary embodiments of the present disclosure
  • FIG. 4B is a schematic diagram of the structure of the distributed radiation source in FIG. 4A observed from another perspective.
  • the distributed radiation source 1 includes an X-ray generating tube having m target points 10.
  • the m target points 10 are configured to be activated in a predetermined order to emit radiation beams.
  • FIG. 4A and FIG. 4B schematically illustrate the radiation beams emitted by the multiple target points 10. Ray beam.
  • the X-ray generating tube may be an X-ray generator using cold cathode carbon nanotubes.
  • the X-ray generating tube may include a cold cathode carbon nanotube emission unit, an accelerator system, a target material and a cooling system.
  • the cold cathode carbon nanotube emission unit may include a plurality of cold cathode carbon nanotubes as electron emission sources.
  • the carbon nanotubes are fixed in the emission unit by a suitable preparation process and connected to the electron source circuit.
  • the emission characteristics of the cold cathode carbon nanotubes enable them to provide stable electron emission and generate high-intensity electron beams.
  • the accelerator system is used to accelerate the electron beam emitted by the cold cathode carbon nanotubes.
  • the target material is the target of the electron beam, and the electron beam strikes the target material to generate X-ray radiation.
  • the target material may be a metal with a high atomic number, such as tungsten or molybdenum.
  • the electron beam emitted by the cold cathode carbon nanotube strikes the target material, characteristic X-rays and continuous spectrum X-rays are generated. Since a large amount of heat is generated during the generation of X-rays, a cooling system is required to ensure stable operation of the system.
  • the cooling system can adopt air cooling or liquid cooling to effectively dissipate the heat through the heat sink.
  • the distributed radiation source is described here using an X-ray generating tube using a cold cathode carbon nanotube as an example, but the embodiments of the present disclosure are not limited to this form of X-ray generator, and distributed radiation sources of other suitable structures can be applied to the CT scanning system provided by the embodiments of the present disclosure.
  • FIG. 3A is a scanning principle diagram of a conventional CT scan
  • FIG. 3B is a scanning principle diagram of a CT scan using a distributed ray source according to an embodiment of the present disclosure.
  • a beam of radiation emitted by a single radiation source 1' passes through the object to be detected and then is detected by a detector 2' to form projection data.
  • a single radiation source corresponds to multiple rows of detectors or a planar array detector.
  • the detector array may include n1 rows of detectors or planar array detectors, where n1 is a positive integer greater than or equal to 1; the distributed ray source 1 includes m target points, where m is a positive integer greater than or equal to 2, and m is greater than n1. That is, in the embodiment of the present disclosure, the number of target points of the distributed ray source is greater than the number of rows of the detector array.
  • the ray beams sequentially emitted by the distributed ray source with multiple target points pass through the detection object and are detected by the detector. After detection, projection data is formed.
  • a distributed ray source with multiple targets corresponds to a smaller number of detectors. The "smaller number" here may include the following situations: the number of rows of detectors is reduced compared to traditional CT scanning; or the area of the array detector is reduced compared to traditional CT scanning.
  • the CT scanning using a distributed ray source according to the embodiment of the present disclosure also has the advantages of suppressing cone angle artifacts, reducing scattering effects, and optimizing doses.
  • FIG4C schematically shows a waveform of a current for controlling the output beam of a distributed ray source.
  • the schematically shown current can be applied to a distributed ray source having five target points.
  • the five target points of the distributed ray source output beams alternately according to the timing shown in FIG4C , and each output detector and data acquisition system completes a data acquisition.
  • the distributed ray source 1 may include a smaller number (for example, 4, 3) or a larger number (for example, 6, 9, 10) of target points.
  • the CT scanning system may further include a controller 5 , which is configured to control at least one of the following aspects of the distributed radiation source 1 : the activation moment of the m target points 10 , the duration of the radiation beams emitted by the m target points 10 , the intensity of the radiation beams emitted by the m target points 10 , and the energy of the radiation beams emitted by the m target points 10 .
  • the beam emission of each target point can be controlled according to a predetermined timing.
  • the duration, intensity and energy of the beam emitted by each target point can be independently controlled.
  • the multi-source spiral CT system of the present disclosure includes a distributed X-ray source, a detector, a slip ring and a frame, an object conveying device, a data acquisition system and a data processing system.
  • the distributed X-ray source is the main difference between the present disclosure and the traditional spiral CT.
  • the CT scanning system may further include a data acquisition system 8 and a data processing system 9.
  • the data acquisition system 8 may be configured to have acquisition signal triggering and data transmission functions. Before a target point of the ray source emits a beam, the data acquisition system 8 sends an acquisition signal, and the detector starts integrating (or counting); after the target point stops transmitting the beam, the data acquisition system 8 sends a stop acquisition signal, and the detector completes integrating (or counting).
  • the data acquisition system 8 transmits the result of the detector's acquisition to the subsequent data processing system 9. That is, the detector's acquisition of data and the target point's beam emission are synchronized.
  • the data processing system 9 is configured to correct, reconstruct, automatically identify, process and display the collected data. Correction includes background correction, gain correction and the process of taking negative logarithm transformation into line integral. Reconstruction can use analytical algorithms or iterative algorithms to calculate the attenuation coefficient or CT number of the scanned object. If dual-energy data or energy spectrum data is collected, the density, atomic number information and selected base material coefficient information of the scanned object can also be calculated using dual-energy reconstruction algorithms or energy spectrum reconstruction algorithms. Automatic identification is to perform segmentation, statistics, classification and other operations on the reconstruction results, and compare them with the feature database to determine whether there are components in the scanned object that meet the inspection characteristics, and give a judgment conclusion. Image processing and display are to display the reconstruction results and automatic identification results on the screen in the form of tomographic images or three-dimensional rendering images for users to observe and judge.
  • the distributed radiation source 1 is configured to rotate about a first axis AX1 when a scanning object 30 is scanned, wherein the first axis AX1 is parallel to a transmission direction Z.
  • the CT scanning system also includes a support member 6 (refer to FIG. 8C ) for supporting the distributed radiation source 1 and the detector array 2, and the support member 6 is configured to drive the distributed radiation source 1 and the detector array 2 to rotate around the first axis AX1 when the scanning object 30 is scanned.
  • a support member 6 (refer to FIG. 8C ) for supporting the distributed radiation source 1 and the detector array 2, and the support member 6 is configured to drive the distributed radiation source 1 and the detector array 2 to rotate around the first axis AX1 when the scanning object 30 is scanned.
  • an XYZ space coordinate system is established, as shown in FIG1, the X direction is the width direction of the scanning channel, the Y direction is the height direction of the scanning channel, and the Z direction is the transmission direction of the scanning object in the scanning channel.
  • the ray source 1 or the detector array 2 has a rotational motion, and the rotation direction around the first axis AX1 is represented by the W direction.
  • the D1-D2 direction is established, wherein, in the embodiment shown in FIG1, the first arrangement direction D1 (as shown in FIG7A) is parallel to the direction Z, which is used to represent the arrangement of multiple targets of the distributed ray source in the direction Z; as shown in FIG7B and FIG7C, the tangent direction D2 represents the direction perpendicular to the rotation direction W.
  • the D3-D4 direction is established, wherein, as shown in FIG6A and FIG6B, the second arrangement direction D3 is parallel to the direction Z, which is used to represent the arrangement of multiple rows of detectors in the direction Z; as shown in FIG6C and FIG6D, the third arrangement direction D4 is perpendicular to the direction Z, which is used to represent the arrangement of multiple detector modules of a row of detectors in the direction perpendicular to the direction Z.
  • the support 6 may include a slip ring structure for a CT device.
  • the slip ring structure may include a fixed part, a rotating part, a contactor, and a conductive ring.
  • the fixed part is also called a fixed ring, which can be installed on a fixed part of the CT device (for example, a frame or base of a CT scanning system).
  • the rotating part is also called a rotating ring, and the distributed radiation source 1 and the detector array 2 are connected to the rotating part.
  • the fixed ring is the fixed end of the slip ring, and the rotating ring is the rotating end of the slip ring.
  • the contactor is a group of conductive brushes or contact sheets fixed to the rotating part. They contact the metal ring of the rotating part to establish an electrical connection.
  • the contactor can be made of a conductive material (such as carbon) with good conductivity and wear resistance.
  • the conductive ring is a group of metal rings fixed to the fixed part. They contact the contactor of the rotating part to form an electrical connection.
  • the conductive ring can be made of a highly conductive metal (such as copper) to ensure good electrical transmission.
  • the detector array 2 may include various types of detectors suitable for use in a CT scanning system. For example, based on the number of rows and geometric detector efficiency, the detector array 2 may include a single-row detector, a multi-row detector, or a planar array detector. Based on the way of collecting X-ray signals, the detector array 2 may include an energy deposition detector or a photon counting detector. Based on the detection energy, the detector array 2 may include a single-energy detector, a dual-energy detector, or an energy spectrum detector.
  • Fig. 5A is a schematic diagram of the structure of the source and detector combination of the CT scanning system according to an embodiment of the present disclosure, in which a distributed radiation source and a single row of detectors are schematically shown.
  • Fig. 5B is a schematic diagram of the structure of the source and detector combination of the traditional CT scanning system, in which a single target radiation source and multiple rows of detectors are schematically shown.
  • the detector array 2 in at least one scanning segment, for example, in each scanning segment, includes a single row of detectors 20.
  • the distributed radiation source 1 includes four target points 10.
  • FIG. 5B in a conventional CT scanning system, a radiation source 1' with a single target point and four rows of detectors 2' are provided. Referring to FIG. 5A and FIG.
  • the resolution of radiation scanning provided by the combination of the distributed radiation source 1 with four target points 10 and the single row of detectors 20 in the region where the scanning object 30 is located is higher than that provided by the combination of the single target point radiation source 1' and the four rows of detectors 2' in the region where the scanning object 30 is located.
  • the scanning rate is basically the same. Accordingly, the scanning combination of the distributed radiation source 1 with four target points 10 and the single row of detectors 20 and the scanning combination of the single target radiation source 1' and the four rows of detectors 2' can obtain basically the same image effect. In this case, the detector cost can be reduced to 1/4 compared with the four rows of detectors 2'.
  • the CT scanning system may include a distributed radiation source 1 with m target points and a single-row detector 20.
  • the resolution of radiation scanning provided by the combination of the distributed radiation source 1 with m target points and the single-row detector 20 in the area where the scanning object 30 is located is basically the same as the resolution of radiation scanning provided by the combination of the single-target radiation source 1' and the m-row detectors 2' in the area where the scanning object 30 is located, and the detector cost can be reduced to 1/m.
  • Fig. 5C is a schematic diagram of the structure of the source and detector combination of the CT scanning system according to an embodiment of the present disclosure, in which a distributed radiation source and multiple rows of detectors are schematically shown.
  • Fig. 5D is a schematic diagram of the structure of the source and detector combination of the traditional CT scanning system, in which a single target radiation source and multiple rows of detectors are schematically shown.
  • the detector array 2 includes n rows of detectors, where n is a positive integer greater than or equal to 2.
  • a ray source 1′ with a single target point and 12 rows of detectors 2′ are provided.
  • the resolution of the ray scanning provided by the combination of the distributed ray source 1 with 4 target points 10 and the 3 rows of detectors 20 in the region where the scanned object 30 is located is substantially the same as the resolution of the ray scanning provided by the combination of the ray source 1′ with a single target point and the 12 rows of detectors 2′ in the region where the scanned object 30 is located. Accordingly, the scanning combination of the distributed ray source 1 with 4 target points 10 and the 3 rows of detectors 20 and the scanning combination of the ray source 1′ with a single target point and the 12 rows of detectors 2′ can obtain substantially the same image effect. In this case, the detector cost can be reduced to 1/4 compared with 12 rows of detectors 2'.
  • the CT scanning system may include a distributed radiation source 1 with m target points and n rows of detectors 20.
  • the combination of the distributed radiation source 1 with m target points and the n rows of detectors 20 provides a radiation scanning resolution in the area where the scanning object 30 is located that is comparable to that of a single target point.
  • the cone angle of the ray beam is reduced, and the influence of the cone angle effect on the reconstructed image is also reduced, thereby improving the quality of the reconstructed image.
  • the distributed ray source can be combined with multiple rows of detectors that are far apart, so that the coverage of the ray beam in the direction of object movement (i.e., Z direction) can be increased, thereby improving the scanning speed.
  • Fig. 5E is a schematic diagram of the structure of the source and detector combination of the CT scanning system according to an embodiment of the present disclosure, in which a distributed ray source and a planar array detector are schematically shown.
  • Fig. 5F is a schematic diagram of the structure of the source and detector combination of the traditional CT scanning system, in which a single target point ray source and a planar array detector are schematically shown.
  • the detector array 2 includes a planar array detector 20, and the planar array detector may include multiple rows of detector modules.
  • FIG. 5F in a conventional CT scanning system, a ray source 1′ with a single target point and a planar array detector 2′ are provided, and the planar array detector 2′ includes 24 rows of detector modules.
  • the resolution of the ray scanning provided by the combination of the distributed ray source 1 with 4 target points 10 and the planar array detector 20 in the region where the scanned object 30 is located is substantially the same as the resolution of the ray scanning provided by the combination of the ray source 1′ with a single target point and the planar array detector 2′ in the region where the scanned object 30 is located. Accordingly, the scanning combination of the distributed ray source 1 with 4 target points 10 and the planar array detector 20 and the scanning combination of the ray source 1′ with a single target point and the planar array detector 2′ can obtain substantially the same image effect. In this case, the detector cost can be reduced to 1/4 compared to the planar array detector 2'.
  • the CT scanning system may include a distributed radiation source 1 with m target points and a planar array detector 20 with n rows of detector modules.
  • the resolution is basically the same, but the detector cost can be reduced to 1/m.
  • the distributed ray source is combined with a smaller area array detector, which can reduce the cost of the array detector while achieving high-resolution imaging.
  • 6A to 6D schematically illustrate some arrangements of sources and detectors according to some exemplary embodiments of the present disclosure.
  • FIG6A is an exemplary arrangement of the source and the probe observed along the Y direction.
  • the distributed ray source 1 may include m target points 10, and the m target points 10 are arranged at intervals in a first arrangement direction D1, and the first arrangement direction D1 may be substantially parallel to the first axis AX1.
  • the m target points 10 may be arranged at intervals along a straight line parallel to the first arrangement direction D1.
  • the m target points 10 may be arranged at equal intervals.
  • the m target points are arranged at equal intervals at a preset interval distance dz along the first arrangement direction.
  • n rows of detectors 20 may be arranged in a third arrangement direction D3 , and the third arrangement direction D3 may be substantially parallel to the first axis AX1 .
  • n rows of detectors 20 may be arranged in an equidistant manner.
  • FIG6B is another exemplary arrangement of the source and the probe observed along the Y direction.
  • the distributed ray source 1 may include m target points 10, and the m target points 10 are arranged at intervals in a first arrangement direction D1, and the first arrangement direction D1 may be an arc direction.
  • the m target points 10 may be arranged at intervals along an arc or a curve.
  • the m target points 10 may be arranged at intervals along an arc or a curve at equal intervals.
  • the m target points are arranged at equal intervals along the first arrangement direction at a preset interval distance dz .
  • the n rows of detectors 20 may be arranged in a third arrangement direction D3 , and the third arrangement direction D3 may be substantially parallel to the first axis AX1 .
  • the n rows of detectors 20 may be arranged in an equidistant manner.
  • FIG6C is an exemplary arrangement of sources and detectors observed along the Z direction.
  • the detector array 2 may include a single row of detectors, multiple rows of detectors, or a planar array of detectors.
  • each row of detectors or planar array of detectors includes multiple detector modules 21, and in a plane perpendicular to the first axis, multiple detector modules 21 of at least one row of detectors are arranged along a fourth direction.
  • the fourth arrangement direction D4 may be an arc direction, that is, the plurality of detector modules 21 may be continuously arranged along an arc or a curve.
  • the m target points 10 may be arranged in intervals in a first arrangement direction D1 , and the first arrangement direction D1 may be a straight line direction or a curved line direction.
  • FIG6D is another exemplary arrangement of sources and detectors observed along the Z direction.
  • the detector array 2 may include a single-row detector, multiple rows of detectors, or a planar array detector.
  • each row of detectors or planar array detectors includes a plurality of detector modules 21, and in a plane perpendicular to the first axis, the plurality of detector modules 21 of at least one row of detectors are arranged continuously along a fourth arrangement direction D4.
  • the fourth arrangement direction D4 may be a straight line direction perpendicular to the first axis AX1. That is, the plurality of detector modules 21 may be arranged continuously along a straight line.
  • the m target points 10 may be arranged in intervals in a first arrangement direction D1 , and the first arrangement direction D1 may be a straight line direction or a curved line direction.
  • Figures 6A to 6D exemplarily show some arrangements of source and probe combinations.
  • the embodiments of the present disclosure are not limited to the several arrangements listed here. In the absence of conflict, the several arrangements listed in Figures 6A to 5D can be combined with each other, and the embodiments of the present disclosure can also include other suitable arrangements.
  • FIG7A to FIG7C schematically illustrate the arrangement of multiple target points of a distributed ray source in a CT scanning system according to some exemplary embodiments of the present disclosure, wherein FIG7A is a perspective view of a distributed ray source, FIG7B is a schematic view of a source and a probe in one rotation state, and FIG7C is a schematic view of a source and a probe in another rotation state. It should be noted that FIG7B and FIG7C are schematic views of a source and a probe observed along the Z direction, respectively.
  • the tangent direction D2 is a direction extending along a tangent line tangent to the rotation direction W of the distributed ray source 1.
  • the tangent direction D2 is a direction extending along a tangent line tangent to the rotation direction W of the distributed ray source 1.
  • the three target points 10 are schematically shown.
  • the three target points are marked as the first target point 11, the second target point 12, and the third target point 13.
  • At least two of the m target points are offset in the tangent direction D2 by a first offset od1.
  • At least two of the m target points (e.g., the second target point 12 and the third target point 13) are offset in the tangent direction D2 by a second offset od2.
  • the first offset od1 and the second offset od2 are substantially equal.
  • substantially equal includes the situation where two quantities are strictly equal or the two quantities are equal in an engineering sense. For example, when the ratio between the two quantities is in the range of 0.8 to 1.2, the two quantities can be considered to be substantially equal.
  • the coordinates of the i-th target point mi in the XYZ coordinate system are ( xi , yi , z ).
  • the Z coordinates z of the m target points are an arithmetic progression with a tolerance of dz , where dz is an equally spaced distance.
  • ⁇ i is the distance from the target point mi to the rotation center O (i.e., the orthographic projection point of the first axis AX1 on a plane perpendicular to the Z direction).
  • ⁇ i is the rotation angle of the target point mi, i.e., the angle of the line connecting the target point mi and the rotation center O relative to the direction Y.
  • the coordinates xi , yi of the i-th target point mi in the XYZ coordinate system can be calculated by the following formula:
  • some of the target points 10 are arranged in a staggered manner in the tangent direction, that is, ⁇ i and ⁇ i are designed to have different values, so that some of the target points 10 are located at different positions on a plane perpendicular to the Z direction.
  • ⁇ i and ⁇ i are designed to have different values, so that some of the target points 10 are located at different positions on a plane perpendicular to the Z direction.
  • all m target points 10 can be arranged in a staggered manner in the tangent direction, that is, any two target points among the m target points 10 are offset in the tangent direction D2.
  • the offset between adjacent target points 10 is determined according to the rotation speed ⁇ of the distributed radiation source, the moving speed v of the transmission device and the interval distance dz of the target points in the Z direction. That is, the first offset od1 and the second offset od2 are root mean square. It is determined according to the rotation speed ⁇ of the distributed radiation source, the moving speed v of the conveying device and the spacing distance dz of the targets in the first arrangement direction D1 (parallel to the Z direction).
  • ⁇ kv ⁇ / dz
  • the ray beams emitted by multiple target points staggered in the tangent direction can irradiate the scanned object from different angles, and then the projection data detected by the detector can contain redundant information, thereby improving the image quality.
  • the distributed ray source and the detector array in one scanning segment are relatively arranged according to a first arrangement direction
  • the distributed ray source and the detector array in another scanning segment are relatively arranged according to a second arrangement direction
  • the orthographic projections of the first arrangement direction and the second arrangement direction along the transmission direction intersect to form an interval angle, and the interval angle is greater than 0° and less than 180°.
  • the interval angle ⁇ formed by the distributed radiation source 1 and the detector array 2 in the first scanning segment intersecting the first arrangement direction D5 and the second arrangement direction D6 of the second scanning segment is determined according to the moving speed of the conveying device 3, the rotation speed of the distributed radiation source 1 and the distance between adjacent scanning segments.
  • k' is a preset coefficient
  • k' is a non-integer
  • Lz is the distance between the two sets of source detection systems in two adjacent scanning segments along the transmission direction
  • q is the moving distance of the transmission device during the time when two adjacent scanning segments rotate by the interval angle
  • pz is the moving distance of the transmission device during the time when the source detection system of any one of the two adjacent scanning segments rotates one circle.
  • the distance moved by the conveying device 3 is q, and the difference between the z-direction distances of the two source-detection systems minus q should be between integer multiples of the distance moved by the conveying device 3 (such as a belt) when the source-detection system rotates one circle. In this way, during the continuous spiral scanning process, the overlap of the X-ray projection paths can be prevented.
  • Figure 8A schematically shows the arrangement of the source and the probe in a traditional CT scanning system
  • Figure 8B schematically shows an exemplary arrangement of the source and the probe in a CT scanning system according to an embodiment of the present disclosure
  • Figure 8C schematically shows a schematic diagram of the installation structure of the source and the probe in a CT scanning system according to an embodiment of the present disclosure.
  • each row of detectors 20 may include a plurality of detector modules 21, and in a plane perpendicular to the first axis AX1, a plurality of detector modules 21 of at least one row of detectors are arranged continuously along an arc line RL2.
  • the arc line RL2 has a center O2.
  • at least one target point 10 is offset from the center O2 of the arc line. That is, in an embodiment of the present disclosure, the detector modules 21 are not arranged along an arc with the target point as the center. That is, the detectors may be arranged non-centripetally relative to the target point of the radiation source.
  • the detector needs to be arranged centripetally relative to the target point of the radiation source, that is, the detector module 21 ′ is arranged along an arc line with the target point 2 ′ as the center.
  • the rotation ranges RR1 and RR2 of the slip ring are schematically shown in Fig. 8A and Fig. 8B, respectively.
  • the rotation range RR2 of the slip ring in the embodiment of the present disclosure is reduced, that is, the rotation radius of the slip ring is reduced, so that the size of the CT scanning device can be reduced and the weight of the device can be reduced.
  • the CT scanning system may further include a rear collimator 25, which is located on the side of the detector array 2 facing the distributed ray source 1.
  • the rear collimator 25 includes a plurality of sub-collimators, and in a plane perpendicular to the first axis, the plurality of sub-collimators are continuously arranged along a straight line or an arc.
  • an anti-scattering post-collimator is used to suppress the influence of scattered photons on image quality.
  • the inventor has found through research that for multi-row detectors and planar array detectors, the post-collimator has a complex structure, is difficult to process, and has a high cost.
  • a distributed ray source is applied to a spiral CT scanning system, a single-row detector can be used. Accordingly, the structural complexity of the post-collimator can be reduced, the processing difficulty can be reduced, and the cost can be reduced.
  • FIG. 10A schematically shows a scanning range of a conventional CT scanning system
  • FIG. 10B schematically shows a scanning range of a CT scanning system according to some exemplary embodiments of the present disclosure.
  • a conventional CT scanning system includes a single target radiation source 1′.
  • ROI region of interest
  • the ray beams formed by the m target points 10 of the distributed ray source 1 form a scanning range in the region of interest ROI where the scanned object 30 is located, and the scanning range includes a first position P1 and a second position P2, wherein the first position P1 is closer to the distributed ray source 1 than the second position P2, and the second position P2 is located between the first position P1 and the detector array 2.
  • the scanning range forms a first straight line segment LS1 parallel to the transmission direction at the first position P1
  • the scanning range forms a second straight line segment LS2 parallel to the transmission direction at the second position P2, and the width of the first straight line segment LS1 is greater than the width of the second straight line segment LS2.
  • a ratio of a width of the first straight line segment LS1 to a width of the second straight line segment LS2 is greater than 1 and less than or equal to 1.5.
  • the wide width (i.e., the width at the first position) and the narrow width (i.e., the width at the second position) of the ray coverage in the region of interest ROI are not less than the wide width and the narrow width of the ray coverage in the single-source spiral CT mode shown in FIG10A. Therefore, in the CT scanning system provided in the embodiment of the present disclosure, a scanning speed not lower than the original single-source spiral CT can be obtained while greatly saving detectors, and the scanning path formed by multiple sources is denser, which brings greater advantages in imaging quality.
  • the ray beam emitted by at least one of the m target points 10 is shaped into a fan beam.
  • the ray beams emitted by the m target points 10 can all be shaped into fan beams. Therefore, for each target point of the distributed ray source, an inclined fan beam is formed relative to the detector, so the scattered signal intensity is smaller than the cone beam formed by a single-source multi-row detector, which is beneficial to reduce the radiation protection pressure of the CT scanning equipment.
  • some exemplary embodiments of the present disclosure provide a CT scanning system, wherein the system includes: a conveying device, used to move the scanned object in a scanning channel along a predetermined conveying direction; p scanning segments, each scanning segment includes a distributed ray source 1 and a detector array 2, and the p scanning segments are arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source 1 includes m target points, and the m target points are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array 2 is used to detect the ray beams emitted from the distributed ray source 1 and passing through the scanning channel.
  • the distributed ray source technology and the rotating spiral CT scanning technology are integrated, and the distributed ray source is used to replace the single-point ray source in the traditional spiral CT scanning system, so that high scanning speed CT scanning can be achieved without increasing the number of detector rows.
  • some target points of the distributed ray source are arranged in a staggered manner in the tangent direction of the rotation direction. Through such a staggered arrangement, the ray projection data contains lower information redundancy and higher information quality.
  • the equipment can realize multiple sets of source detection systems to complete the entire circular scanning at the same time on the basis of a series of advantages such as lower information redundancy and higher information quality. This will multiply the scanning efficiency within a single spiral cycle, thereby further improving the imaging speed, achieving a faster imaging speed, and thus achieving higher security inspection efficiency.
  • Some other exemplary embodiments of the present disclosure further provide a CT scanning system, wherein the system comprises: a conveying device, used to move a scanned object in a scanning channel along a predetermined conveying direction; wherein the conveying device comprises a conveying surface for placing the scanned object; p scanning segments, each scanning segment comprises a distributed ray source 1 and a detector array 2, and the p scanning segments are arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, a detector array 2 is arranged at intervals;
  • the distributed radiation source 1 includes m target points, which are configured to be activated in a predetermined order to emit radiation beams, and m is a positive integer greater than or equal to 2;
  • the detector array 2 is used to detect the rays emitted from the distributed radiation source 1 and passing through the scanned object, and generate projection data based on the detected rays; and an image reconstruction device, which is configured to: generate a computerized to
  • the distributed ray source technology and the rotating spiral CT scanning technology are integrated, and the distributed ray source is used to replace the single-point ray source in the traditional spiral CT scanning system, so that CT scanning with a high scanning speed can be achieved without increasing the number of detector rows. Further, by setting a post-collimator, the influence of scattered photons on image quality can be suppressed.
  • the distributed ray source is applied to the spiral CT scanning system, and a single-row detector can be used. In this way, the structural complexity of the post-collimator can be reduced, its processing difficulty can be reduced, and its cost can be reduced.
  • the equipment has a series of advantages such as reducing the structural complexity of the post-collimator, low processing difficulty, and low cost, and realizes that multiple sets of source-detection systems complete the entire circumferential scanning at the same time, which will multiply the scanning efficiency within a single spiral cycle, thereby further improving the imaging speed, achieving a faster imaging speed, and thus achieving a higher security inspection efficiency.
  • Some other exemplary embodiments of the present disclosure further provide a CT scanning system, wherein the system includes: a conveying device, used to move a scanned object in a scanning channel along a predetermined conveying direction; wherein the conveying device includes a conveying surface for placing the scanned object; p scanning segments, each scanning segment includes a distributed ray source 1 and a detector array 2, the p scanning segments are arranged at intervals along the conveying direction, wherein p is a positive integer greater than or equal to 2, and in each scanning segment, the distributed ray source 1 includes m target points, the m target points are configured to be activated in a predetermined order to emit a ray beam, and m is a positive integer greater than or equal to 2; the detector array 2 is used to detect rays emitted from the distributed ray source 1 and passing through the scanned object, and generate projection data based on the detected rays; and an image reconstruction device, the image reconstruction device is configured to: generate a scanned object according to the projection data detected by each detector
  • the distributed ray source technology and the rotating spiral CT scanning technology are integrated into one, and the distributed ray source is used to replace the single-point ray source in the traditional spiral CT scanning system, so that high scanning speed CT scanning can be achieved without increasing the number of detector rows. Furthermore, the non-centripetal arrangement of the detector relative to the target is conducive to reducing the size of the CT scanning equipment and reducing the weight of the equipment.
  • the equipment has a series of advantages such as reducing the size of the CT scanning equipment and reducing the weight of the equipment, and realizes multiple sets of source-detection systems to complete the entire circular scan at the same time, which will multiply the scanning efficiency within a single spiral cycle, thereby further improving the imaging speed, achieving a faster imaging speed, and thus achieving higher security inspection efficiency.
  • FIG11 is a flow chart of the CT scanning method according to some exemplary embodiments of the present disclosure.
  • the CT scanning method may include steps S110 to S150. It should be noted that steps S110 to S150 are not a restriction on the order of the CT scanning method. In the absence of conflict, the CT scanning method may be executed in parallel or in a sequence different from that described in the text.
  • step S110 the conveying device 3 drives the scanning object 30 to move along a predetermined conveying direction Z in the scanning channel 31 .
  • step S120 the scanning object is controlled to pass through p scanning areas formed by p scanning segments in sequence, wherein, before the scanning object enters the scanning range of the h-th scanning segment among the p scanning segments, the m target points 10 included in the distributed radiation source 1 in the h-th scanning segment are controlled to be activated in a predetermined order to emit a radiation beam, thereby forming a scanning area, wherein h is a positive integer greater than or equal to 1 and less than or equal to p, and m is a positive integer greater than or equal to 2.
  • step S130 the scanning object 30 is made to pass through the hth scanning area.
  • step S140 when the scanned object 30 passes through the hth scanning area, the detector array 2 is used to detect the rays emitted from the distributed ray source 1 and passing through the scanned object. And generate projection data based on the detected rays.
  • step S150 a computer tomography image of the scanned object 30 is generated according to a plurality of projection data formed by the detectors in the p scanning segments.
  • the distributed ray source 1 and the detector array 2 are configured to rotate around the first axis AX1 when the scanning object 30 is scanned, and the scanning object 30 moves through the scanning area during scanning.
  • the distributed ray source 1 At least two of the m target points 10 are offset in the tangent direction D2. Some of the target points of the distributed ray source 1 are staggered in the tangent direction of the rotation direction. Through such staggered arrangement, the ray projection data contains lower information redundancy and higher information quality.
  • the distributed ray source 1 may have five target points that can independently emit beams, and the detector array 2 is a single row of detectors.
  • the scanning method can be performed according to the following steps: The CT scanning system is started, and the slip ring in each scanning section starts to rotate; the scanning object enters the scanning channel through the entrance of the conveying device 3.
  • the scanned object is made to pass through p scanning areas formed by p scanning segments in sequence.
  • h is a positive integer greater than or equal to 1 and less than or equal to p
  • m is a positive integer greater than or equal to 2
  • the 5 source points of the ray source emit beams alternately according to the timing shown in FIG4C, and each output detector and data acquisition system complete a data acquisition.
  • the ray source 1 completes 360 rounds of beam emission, that is, the detector collects 5 ⁇ 360 lines of projection data; after passing through p scanning segments in sequence, the detector projection data in the p scanning segments is obtained; the processing system performs data processing; the scanned object 30 leaves the exit of the conveying device 3, and the scanning is completed.
  • the number of target points, the number of detector rows, the number of beams emitted by the ray source during one rotation of the slip ring, and other geometric parameters in each scanning segment can be adjusted according to different practical application requirements.
  • the arrangement of the source and the detector and the geometric parameters should comply with the requirement that the X-ray covers the area to be reconstructed without duplication or omission, and meet the data conditions for realizing spiral CT reconstruction.
  • FIG. 12A Comparative images of reconstruction results of the CT scanning system according to the embodiment of the present disclosure and the conventional spiral CT system under the same scanning parameters are shown in FIG12A and FIG12B.
  • CT scanning at a high scanning speed can be achieved without increasing the number of detector rows, and the quality of the reconstructed image can be guaranteed at a high scanning speed.
  • FIG13 schematically shows a block diagram of an imaging device of a CT scanning system according to an embodiment of the present disclosure.
  • the imaging device 4 of the CT scanning system may include a processor 401, which may perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage part 408 into a random access memory (RAM) 403.
  • the processor 401 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and/or a related chipset and/or a dedicated microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc.
  • the processor 401 may also include an onboard memory for caching purposes.
  • the processor 401 may include a single processing unit or multiple processing units for performing different actions of the method flow according to the embodiment of the present disclosure.
  • RAM 403 various programs and data required for the operation of electronic device 400 are stored.
  • Processor 401, ROM 402 and RAM 403 are connected to each other through bus 404.
  • Processor 401 performs various operations of the method flow according to the embodiment of the present disclosure by executing the programs in ROM 402 and/or RAM 403. It should be noted that the program can also be stored in one or more memories other than ROM 402 and RAM 403.
  • Processor 401 can also perform various operations of the method flow according to the embodiment of the present disclosure by executing the programs stored in one or more memories.
  • the electronic device 400 may further include an input/output (I/O) interface 405, which is also connected to the bus 404.
  • the electronic device 400 may further include one or more of the following components connected to the I/O interface 405: an input part 406 including a keyboard, a mouse, etc.; an output part 407 including devices such as a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage part 408 including a hard disk, etc.; and a communication part 409 including a network interface card such as a LAN card, a modem, etc.
  • the communication part 409 performs communication processing via a network such as the Internet.
  • a drive 410 is also connected to the I/O interface 405 as needed.
  • Removable media 411 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., are installed in the drive 410 as needed. on which a computer program read out can be installed into the storage section 408 as needed.
  • each box in the flow chart or block diagram can represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of a code contains one or more executable instructions for realizing the specified logical function.
  • the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved.
  • each box in the block diagram or flow chart, and the combination of the boxes in the block diagram or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

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Abstract

L'invention concerne un système de tomodensitométrie comprenant : un dispositif de transport (3) utilisé pour permettre à un objet à balayer (30) de se déplacer dans une direction de transport prédéfinie dans un canal de balayage (31) ; p segments de balayage, chaque segment de balayage comprenant une source de rayonnement distribué (1) et un réseau de détecteurs (2), les p segments de balayage étant espacés dans la direction de transport, p étant un nombre entier positif supérieur ou égal à 2, dans chaque segment de balayage, la source de rayonnement distribué (1) comprenant m cibles, les m cibles étant configurées pour être activées dans un ordre prédéterminé de manière à émettre des faisceaux de rayonnement, m étant un nombre entier positif supérieur ou égal à 2, et les réseaux de détecteurs (2) étant utilisés pour détecter les rayonnements émis par les sources de rayonnement distribué (1) et passant à travers l'objet à balayer (30), et générer des données de projection sur la base des rayonnements détectés ; et un dispositif de reconstruction d'image (4) pour générer une image de tomodensitométrie de l'objet à balayer (30) sur la base des données de projection détectées par chaque réseau de détecteurs (2) dans les p segments de balayage. La source de rayonnement distribué (1) d'au moins un segment de balayage est conçue pour tourner autour d'un premier axe parallèle à la direction de transport lorsque l'objet à balayer (30) est balayé.
PCT/CN2024/126810 2023-11-09 2024-10-23 Système de tomodensitométrie Pending WO2025098141A1 (fr)

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CN117517358A (zh) * 2023-11-09 2024-02-06 清华大学 Ct扫描系统
CN119224018B (zh) * 2024-12-04 2025-02-28 清华大学 Ct成像系统

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