HK1195941A - A ct apparatus without a gantry - Google Patents

Description

No frame CT device

Technical Field

The invention relates to a gantry-free CT device, in particular to a gantry-free CT device for security inspection.

Background

Due to the excellent performance of the CT technology in the aspect of material density identification, the application of the CT technology in a security check system is continuously expanded. However, in the CT technology, data at different angles need to be acquired for data reconstruction, and the conventional solution is to acquire X-ray perspective data at different angles by using a slip ring system rotating at a certain speed for reconstruction, so that the appearance of a rotating part causes the equipment to have a complex structure, high running noise, large equipment volume and high operation and maintenance costs. In recent years, with the continuous development of X-ray source technology, especially the appearance of multi-point X-ray sources based on carbon nano technology, a new idea is provided for the CT technology to reconstruct data from different angles.

The triggering time sequence of the ray emission points of the carbon nano X-ray source is controlled through a certain time sequence, if the ray emission points of the X-ray source are enough, the layout of the receiving surface of the detector is effective, the emission and receiving time sequences are controlled reasonably, enough data quantity required by CT data reconstruction can be obtained, and therefore the reconstruction work of the CT technology is achieved without depending on a rotating slip ring system. The non-frame CT technology is provided, the problem of complex data transmission in the prior CT technology is solved, the operation cost is lower, and the reliability is higher. However, the non-gantry CT technology cancels rotating parts, and also puts higher requirements on the layout of the radiation source and the detector of the CT device, and how to reasonably arrange the radiation source and the detector becomes one of the difficulties faced by various non-gantry CT manufacturers.

Since the early gantry-free CT technology is mostly applied to the field of medical examination, the scanned object to be examined is relatively single, and the fixed position in the scanning channel can be ensured, the most common layout mode is that the detector is laid out in a linear or circular arc shape, and CT reconstruction data in different angular directions are acquired through the relative movement of the ray emission point of the multi-point X-ray source and the receiving surface of the detector. Compared with the early gantry-free CT system, no matter the gantry-free CT system is in a linear layout or an arc layout, the influence of a scanning channel on the layout of an X-ray source and a detector is not comprehensively considered, namely, how to ensure a large enough scanning channel under a small-size condition, so that when the gantry-free CT system is applied to the field of security inspection, the overall size of the gantry-free CT system is large, the inspection speed is low, and the requirement of quick inspection in the field of security inspection on the occupied area of the gantry-free CT system cannot be met. In the security check field, the size of the scanning channel and the scanning speed are two important factors influencing the checking effect, so the scanning channel of the security check CT equipment is obviously larger than that of the medical CT equipment, the speed is obviously higher than that of the medical CT system, and in addition, the security check equipment is mostly positioned in a public area, so the radiation protection requirement of the equipment is higher, and the radiation protection requirement brings a plurality of harsh requirements for the design of the security check equipment.

Disclosure of Invention

It is an object of the present invention to provide a gantry-less CT apparatus, which has, for example, a smaller volume, thereby enabling a reduction in the footprint.

According to an aspect of the present invention, there is provided a gantry-less CT apparatus, including: a scanning channel; a stationary X-ray source disposed about the scan channel, the X-ray source comprising a plurality of ray emission points; and a stationary plurality of detector modules arranged around the scan channel, the plurality of detector modules disposed opposite the X-ray source.

According to an aspect of the invention, at least some of the plurality of detector modules are arranged in a substantially L-shape when viewed in a plane intersecting the scanning channel. The plane is substantially perpendicular to the scan path or the plane is tilted with respect to the scan path.

According to an aspect of the invention, at least some of the plurality of radiation emission points of the X-ray source are arranged substantially linearly or doglegged when viewed in a plane intersecting the scan channel. The plane is substantially perpendicular to the scan path or the plane is tilted with respect to the scan path.

According to an aspect of the present invention, a sum of an angle between a line connecting a leading and trailing ray emitting point of the ray emitting points arranged in a substantially straight line shape or a broken line shape and a line connecting a center of the scanning passage and an angle between a line connecting a leading and trailing detector module of the detector modules arranged in a substantially L-shape and a center of the scanning passage is greater than 180 degrees. Thereby ensuring that the data acquisition system can obtain enough scanning data.

According to an aspect of the invention, the ray beams emitted by the plurality of ray emitting points of the X-ray source are perpendicular to the advancing direction of the object to be inspected along the scanning channel or perpendicular to the scanning channel, or inclined relative to the advancing direction of the object or the scanning channel.

According to an aspect of the invention, the radiation beams emitted by the plurality of radiation emitting points of the X-ray source are in a plane with a radiation receiving surface of the detector module.

According to an aspect of the invention, the radiation receiving faces of the detector modules are adjacent end to end such that radiation emanating from the plurality of radiation emitting points cannot pass between the radiation receiving faces.

According to an aspect of the present invention, a midpoint connecting line of the ray receiving surfaces of the detector receiving module when viewed in a plane intersecting the scanning channel may form two straight lines, and the two straight lines intersect at a point. The plane is substantially perpendicular to the scan path or the plane is tilted with respect to the scan path.

According to an aspect of the invention, the plurality of radiation emission points of the X-ray source and the receiving surfaces of the plurality of detector modules are arranged in the same plane, and the direction of the radiation beam is substantially perpendicular to the receiving surface of the corresponding detector module. The plane is substantially perpendicular to the scan path or the plane is tilted with respect to the scan path.

According to an aspect of the invention, each detector module is capable of receiving radiation emitted by at least one of the plurality of radiation emission points from the X-ray source.

According to an aspect of the invention, the plurality of radiation emission points of the X-ray source and the corresponding radiation emission points and detector modules of the plurality of detector modules are arranged in the same plane. The plane is substantially perpendicular to the scan path or the plane is tilted with respect to the scan path.

According to an aspect of the invention, the plurality of radiation emission points are arranged in at least one row in the direction of the scanning passage.

According to an aspect of the invention, the gantry-less CT apparatus further comprises: and the front collimating device is arranged between the plurality of ray emission points and the detector module.

According to an aspect of the invention, the pre-alignment means is a correction grid.

According to an aspect of the invention, the distance of the front collimator from the receiving surface of the detector module is larger than the distance of the correction grid from the ray emission point.

According to an aspect of the invention, the distance of the front collimator from the receiving face of the detector module is at least 5 times the distance of the correction grid from the radiation emission point.

According to an aspect of the invention, the correction grid shape is a fitted curve shape.

According to an aspect of the invention, the X-ray source is a carbon nanotube X-ray source.

The invention can adopt the carbon nano X-ray source, overcomes the defects of complex structure and large volume of the traditional non-frame CT device by reasonably distributing the X-ray source and the detector module, realizes the miniaturization of CT security check equipment, reduces the occupied area and improves the usability of the non-frame CT system on a security check site.

According to the carbon nano X-ray source-based gantry-less CT system, the carbon nano source is controlled to emit, and the optimal layout of the detector arm support can ensure that enough data required by gantry-less CT can be acquired under the condition of a small width size of equipment, so that the purposes of reducing the occupied area of the gantry-less CT equipment and reducing the equipment cost are achieved.

Drawings

FIG. 1 is a schematic diagram of a gantry-less CT apparatus, according to an embodiment of the present invention;

FIG. 2 is a schematic layout of a source, detector and prearrangement in accordance with an embodiment of the present invention; and

FIG. 3 is a schematic view of an arrangement of a source and a detector according to an embodiment of the invention.

Detailed Description

The invention is further described with reference to the following drawings and detailed description.

As shown in fig. 1 to 3, according to an embodiment of the present invention, a gantry-less CT apparatus includes a scan tunnel 4; a stationary X-ray source 7 comprising a plurality of radiation emission points 71; and a plurality of fixed detector modules 10, the detector modules 10 being mounted on a detector boom 5, the detector boom 5 being disposed opposite the X-ray source 7, and the detector modules 10 being arranged in a substantially L-shape when viewed in a plane intersecting the scan path 4 (which may be substantially perpendicular to the scan path or which may be inclined with respect to the scan path), i.e. with distinct lateral arms 13 and vertical arms 11, and the lateral arms 13 and vertical arms 11 being interconnected without disconnection. The plane formed by the ray emitting point 71 of the X-ray source 7 and the detector arm 5 or the detector module 10 is approximately perpendicular to the traveling direction of the scanning passage 4 or the conveying device 1 or is inclined relative to the traveling direction of the scanning passage 4 or the conveying device 1. A plurality of radiation emission points 71 and the detector boom 5 or the detector modules 10 are arranged around the scanning tunnel 4. As shown in the figure, in a preferred embodiment, the gantry-less CT apparatus further comprises an optical barrier system 3 for detecting the entrance and exit of the object under examination into and out of the scanning passage, an acquisition control unit 6, a computer reconstruction unit 8, and a conveying device 1 for conveying the object under examination 2.

The X-ray source 7 may be a nanotube X-ray source having a plurality of X-ray emission points 71. Furthermore, the X-ray source 7 may also be another suitable X-ray source, as long as it comprises a plurality of controllable radiation emission points. The plurality of ray emission points of the X-ray source 7 are linearly arranged, and may be arranged in a straight line type (shown in fig. 1) or a broken line type (shown in fig. 3). The direction of the radiation emitted by the X-ray emitting point 71 is approximately perpendicular to the traveling direction of the scanning passage 4 or the conveying device 1 or is inclined relative to the traveling direction of the scanning passage 4 or the conveying device 1, and the X-ray emitting point 71 and the receiving surface of the detector module 10 can be in the same plane.

As shown in FIG. 2, all fan-shaped X-ray beams emitted by the X-ray source 7 can fill the effective scanning area 15 in the scanning channel 4 without blind corners. The X-ray beam-out of each ray emission point 71 of the X-ray source 7 is controlled by the acquisition control unit 6, and the emission time, interval and intensity of the X-ray emission points 71 are adjustable. The radiation emission points 71 may be triggered at intervals or continuously. The included angle between the connecting line of the head end ray emission point 9 and the tail end ray emission point 17 of the X-ray source 7 and the center C (of the cross section) of the scanning channel 4 is beta, the included angle between the connecting line of the head end detector module 10 and the tail end detector module 10 in the plurality of detector modules 10 and the center C (of the cross section) of the channel is alpha, and the sum of beta and alpha is more than 180 degrees.

As shown in fig. 2, the detector arm support 5 comprises a horizontal arm 13 and a vertical arm 11, and the horizontal arm and the vertical arm intersect without disconnection. The middle point of the ray receiving surface of the detector receiving module 10 on the detector cross arm 13 is located on one straight line, the middle point of the ray receiving surface of the detector receiving module 10 on the detector vertical arm 11 is located on the other straight line, and the two straight lines intersect at one point. The rays emitted from the plurality of ray emitting points 71 cannot pass between the detector arms 5. In the plane of the radiation emitted by the X-ray emission point 71, the detector modules 10 are connected end to end without disconnection, i.e. all the radiation emitted by the X-ray emission point must pass through the receiving surface of the detector. The detector modules 10 shown in the drawings may be constructed as linear detectors or as area-array detectors.

As shown in fig. 2, the ray emission points 71 are linearly arranged when viewed in a plane intersecting the scanning channel 4, and may be arranged in a linear type (as in fig. 2) or a broken line type (as in fig. 3), and the sum of the included angle β between the first and second ray emission points 9 and 17 in the ray emission points and the connecting line of the channel center C (the center of the cross section of the channel) and the included angle α between the first and second detector modules in the detector modules and the connecting line of the channel center C is greater than 180 degrees, so as to ensure that sufficient tomographic data are obtained for reconstruction. In fig. 3, the direction in which the X-ray source emits the radiation is substantially perpendicular to the conveying direction of the scanning passage 4 or the conveying device 1 or is inclined with respect to the conveying direction of the scanning passage 4 or the conveying device 1, and the direction of the radiation coincides with the direction of the detector receiving plane.

On the detector boom 5, the detector module 10 is capable of receiving at least some of the plurality of radiation emission points 71 from the X-ray source 7, some of which are perpendicular to the receiving surface and some of which are inclined with respect to the receiving surface.

As shown in fig. 2, the radiation emitting points 71 are arranged in a row when viewed in a plane intersecting the scanning passage 4, and the detector modules 10 are arranged in a row, and the radiation outgoing direction may be substantially perpendicular to the conveying direction of the scanning passage 4 or the conveying device 1 or inclined with respect to the conveying direction of the scanning passage 4 or the conveying device 1. The detector receiving faces may be arranged in a single row or in multiple rows in the direction of travel of the baggage conveyor system. If the alignment is multi-row, the corresponding pre-alignment devices need to be multi-row structures.

As shown in fig. 2, the gantry-less CT apparatus according to the present invention further includes: a collimator 16 for controlling the dose of the radiation beam, the collimator 16 being arranged between the plurality of radiation emission points 71 and the plurality of detector modules 10. The lead device 16 may be a calibration grid that fits a curve or other suitable calibration grid. The distance of the pre-collimator 16 from the receiving surface of the detector module 10 is at least 5 times the distance of the radiation emission point 71 from the pre-collimator 16.

In the fixed-gantry frameless CT apparatus shown in fig. 3, the detector arm support 5 is an L-shaped structure, or the detector modules 10 are arranged in a substantially L-shape, the radiation emission points 71 of the X-ray source 7 may also be arranged in a zigzag manner, and the sum of the included angle β between the connection lines of the first and second end radiation emission points 9 and 17 of the radiation emission points 71 and the channel center C and the included angle α between the connection lines of the first and second end detector modules 10 of the detector modules 10 and the channel center C is greater than 180 degrees. Alternatively, detector modules 12 may be arranged in other shapes, such as semi-circular, U-shaped, circular arc, parabolic, curved, and the like. The radiation emission points 71 of the X-ray source 7 may also be arranged in an L-shape, U-shape, semi-circle, circular arc, parabolic shape, curved shape, etc.

The X-ray energy reaching the detector modules 10 on the detector boom 5 may come from a single radiation emission point 71 of the X-ray source 7 or from a combination of several radiation emission points 71 of the X-ray source 7 within a certain period of time. The intensity of the X-rays emitted by the X-ray source 7 at the different radiation emission points 71 can be programmed. The number of radiation emission points of the X-ray source 7 and the size of the transverse and vertical arms of the detector are related to the size of the effective scanning area 15 within the scanning passage 4. The X-ray beams emitted by all the radiation emission points 71 cover the scanning channel 4.

The triggering mode of the X-ray emission points 71 is related to the acquisition control mode of the fixed-gantry frameless CT apparatus, and whether the triggering of a single X-ray emission point 71 is controlled by the acquisition control unit 6 of the frameless CT apparatus. Under the command of the acquisition control unit 6, the radiation emission points 71 of the X-ray source 7 may sequentially emit X-rays, and the radiation emission point emission interval and frequency are governed by the command of the acquisition control unit 6.

In the gantry-less system of the present invention, the acquisition control unit 6 is controlled via a Can bus, including control of the X-ray source 7, control of the detector module 10. When the checked luggage 2 triggers the light barrier system 3, the computer system 8 transmits a control command to the acquisition control unit 6 through a protocol, the acquisition control unit requests the detector module 10 to start acquisition, issues the acquisition start command and transmits and corrects the acquired data by analyzing the command of the acquisition control unit 6, and the data acquired by the detector module 10 is transmitted to the computer reconstruction unit 8.

The computer reconstruction unit 8 is a key device for realizing analysis, reconstruction and feature identification of data of the frameless CT device, when the acquired data are transmitted to the computer reconstruction unit 8, the computer reconstruction unit 8 firstly classifies the data according to the format of a data packet, determines the source of the data, establishes a feature matrix based on the scanned luggage in a scanning area, then solves a corresponding feature value in the feature matrix, obtains whether the substance is a substance to be specially concerned by comparing the feature value with the feature value of a specific substance in a database, and further provides a prompt for alarming or not.

The scanning tunnel 4 functions to provide a tunnel through which the scanned baggage 2 travels and shielding walls for extraneous X-rays. The shielding wall is made of radiation-proof materials, and the radiation-proof materials can be heavy metals such as lead or steel.

During the inspection process, the checked luggage 2 is carried into the scanning channel 4 by the conveyor belt of the conveying device 1 at a certain speed, when the checked luggage 2 touches the light barrier system 3 or the photoelectric sensor 3, the X-ray source 7 enters a beam-out preparation state, when the luggage 2 enters the scanning effective area 15, the acquisition control unit 6 controls the ray emission point 71 of the X-ray source 7 to emit an electron beam according to a preset time sequence, the X-ray is continuously or intermittently generated, meanwhile, the acquisition control unit 6 issues an acquisition starting command, the corresponding position of the detector module 10 starts to acquire data, the time point of the acquired data and the position point of the detector module 10 are recorded, the acquired data are transmitted to the computer reconstruction unit 8 through a special cable (for example, an optical fiber), the computer reconstruction unit 8 compares the control ray emission point instruction information and the acquired data information in the same moment, the data at the corresponding position is then reconstructed by performing the correction and data processing, a matrix based on the material properties of the scanned baggage 2 is established, the matrix is solved in reverse by a calculation module in the computer reconstruction unit 8, one or more material properties of the material of the scanned baggage 2 at the corresponding position are obtained, and material property data in a tomographic position is established. Along with the movement of the luggage 2 at a certain speed, the computer reconstruction unit 8 can obtain material characteristic data of the whole luggage layer by layer, carry out centralized analysis and judgment on the fault data characteristic through a special recognition algorithm, compare with a material characteristic table in the existing database, obtain a conclusion whether the scanned luggage 2 contains the specific material concerned by the user, and display the conclusion through a display connected with a computer system.

In the invention, the acquired data of the scanned luggage under different time sequences is obtained by converting the ray emitting points and the scanning acquisition regions by utilizing the conversion of the positions of the ray emitting points 71 of the X-ray source 7, and further the tomography of the scanned luggage can be realized by utilizing the traditional Computed Tomography (CT) technology under the condition of not rotating the scanned object or the detector and the X-ray source.

In the process of computer reconstruction, the accuracy of the computer reconstruction of tomographic data is related to the angle from which the scanned baggage is viewed. The invention can adopt an X-ray source based on carbon nano materials, the distances between the ray emission points can be the same within a certain length range, the program control can be carried out by the acquisition control unit 6, and the sequence of the ray emitted by the ray emission points can be arranged along a straight line or a broken line. The detector can be divided into a linear detector or a planar array detector, so that the problem of cost and system identification accuracy is solved to the greatest extent.

Typically, the scanned baggage passes through the scanning zone at a certain speed. For the occasion with high scanning requirement, the scanned material can also be kept still in the scanning area, and then the static scanning is continued after moving for a section of displacement until the scanning is finished. The computer system distinguishes the material by identifying material characteristics of the baggage sections. In identifying a substance, the system should include at least one substance property, such as density and atomic number.

The invention takes full consideration of the application of CT technology in the security inspection field, comprehensively considers the scanning channel, the carbon nano-ray source and the detector system, solves the problems of large equipment and low acquisition precision of the CT system without a frame, and realizes the rapidness and miniaturization of the CT technology.

Claims (20)

1. A gantry-less CT apparatus, comprising:

a scanning channel;

a stationary X-ray source disposed about the scan channel, the X-ray source comprising a plurality of ray emission points; and

a stationary plurality of detector modules arranged around the scan channel, the plurality of detector modules disposed opposite the X-ray source.

2. The gantry-less CT apparatus of claim 1, wherein

At least some of the plurality of detector modules are arranged in a substantially L-shape, semi-circle shape, U-shape, circular arc shape, parabolic shape, or curved shape when viewed in a plane intersecting the scan channel.

3. The gantry-less CT apparatus of claim 1 or 2, wherein

At least some of the plurality of ray emission points of the X-ray source are arranged substantially linearly or doglegged when viewed in a plane intersecting the scan channel.

4. The frameless CT device of claim 3, wherein

The sum of the included angle between the connecting line of the head and tail end ray emission points in the ray emission points which are arranged in a linear shape or a broken line shape and the center of the scanning channel and the included angle between the connecting line of the head and tail end detector modules in the detector modules which are arranged in an L shape and the center of the scanning channel is larger than 180 degrees.

5. The gantry-less CT apparatus of claim 1, wherein

The ray beams emitted by a plurality of ray emission points of the X-ray source are perpendicular to the advancing direction of the object to be detected along the scanning channel or perpendicular to the scanning channel, or inclined relative to the advancing direction of the object or the scanning channel.

6. The gantry-less CT apparatus of claim 1, wherein

Ray beams emitted by a plurality of ray emission points of the X-ray source are in the same plane with the ray receiving surface of the detector module.

7. The gantry-less CT apparatus of claim 1, wherein

The radiation receiving faces of the detector modules are adjacent end to end such that radiation emanating from the plurality of radiation emitting points cannot pass between the radiation receiving faces.

8. The gantry-less CT apparatus of claim 1, wherein

When the detector is viewed in a plane intersecting with the scanning channel, a midpoint connecting line of ray receiving surfaces of the detector receiving module can form two straight lines, and the two straight lines intersect at one point.

9. The gantry-less CT apparatus of claim 1, wherein

The X-ray source comprises a plurality of X-ray emitting points and a plurality of detector modules, wherein the X-ray emitting points and the receiving surfaces of the detector modules are arranged in the same plane, and the directions of ray beams are approximately vertical to the receiving surfaces of the corresponding detector modules.

10. The gantry-less CT apparatus of claim 1, wherein

Each detector module is capable of receiving radiation emitted by at least one of the plurality of radiation emission points from the X-ray source.

11. The gantry-less CT apparatus of claim 1, wherein

The plurality of ray emission points of the X-ray source and the corresponding ray emission points and the corresponding detector modules in the plurality of detector modules are arranged in the same plane.

12. The gantry-less CT apparatus of claim 1, wherein

The plurality of radiation emission points are arranged in at least one row in the direction of the scan path.

13. The gantry-less CT apparatus of claim 1, further comprising: and the front collimating device is arranged between the plurality of ray emission points and the detector module.

14. The gantry-less CT device of claim 1, wherein the pre-alignment device is a correction grid.

15. The gantry-less CT apparatus of claim 13 or 14, wherein

The distance from the front collimating device to the receiving surface of the detector module is greater than the distance from the correction grid to the ray emitting point.

16. The gantry-less CT apparatus of claim 13 or 14, wherein

The distance of the pre-alignment device from the receiving surface of the detector module is at least 5 times the distance of the correction grid from the ray emission point.

17. The gantry-less CT apparatus of claim 14, wherein

The correction grid shape is a fitted curve shape.

18. The gantry-less CT apparatus of claim 1, wherein

The X-ray source is a carbon nanotube X-ray source.

19. The gantry-less CT apparatus of claim 1, wherein

The X-ray source includes a plurality of ray emitting points to emit X-rays in an interval sequence or continuously.

20. The gantry-less CT apparatus of claim 1, wherein

The ray emission points of the X-ray source are arranged in an L shape, a U shape, a semicircular shape, an arc shape, a parabola shape or a curve shape.