Flexible CT detector and its static CT system

Abstract

The present invention discloses a flexible CT detector and its static CT system. This flexible CT detector is used to be attached inside a CT frame and includes a flexible circuit board having a signal reading part, and a flexible conversion part attached inside the flexible circuit board for absorbing X-rays and converting them into set signals. The signal reading part receives the set signals and is used to output continuous projection images without interruption. This flexible CT detector uses a large-area flexible circuit as the detector substrate and realizes a dense arrangement of pixels throughout the detector ring, thereby significantly reducing the problems of splice seams caused by the assembly of conventional rigid detectors and the problem of losing projection information. Under ideal circumstances, there is only one splice seam where the head and tail of the detector ring are connected, greatly reducing the difficulty of algorithm correction.

Description

Technical Field

[0001] The present invention relates to a flexible CT detector and also to a static CT system using this flexible CT detector, belonging to the technical field of computed tomography.

Background Art

[0002] CT (Computed Tomography) is an abbreviation for computed tomography. This uses precisely linearized X-rays, etc., and performs cross-sectional imaging centered on a specific part of the human body together with a highly sensitive CT detector. It has features such as a short imaging time and clear images, and can be utilized in a wide range of fields such as medical treatment and safety inspections. A static CT system composed of a plurality of radiation sources and the entire ring of detectors breaks through the physical rotation speed limit in the conventional mechanical rotation imaging method and can obtain a higher imaging speed, and has become a hot spot in current academic research and industrial transformation.

[0003] As shown in FIG. 1, in order to achieve a wide coverage range that satisfies clinically relevant diagnoses, a typical static CT system generally consists of a plurality of photon counting detectors or integrating detectors 100, and each detector module is also composed of a plurality of detector units spliced together. In the case of a static CT system, there may be dozens or even hundreds of detector splicing seams in the entire detector ring, and the size of each splicing seam is affected by the size accuracy and assembly accuracy of the detector itself.

[0004] However, in a silicon-based photodiode or a complementary metal-oxide-semiconductor (CMOS)-based electronic readout system, the problem of loss of projection information at the splice seam site cannot be avoided. When the radiation source 200 irradiates the object 300 to be detected with X-rays, the presented exposure projection 400 takes a discontinuous intermittent form. At the same time, in order to obtain a higher spatial resolution and a larger imaging range, the CT detector always aims for a smaller pixel size and a larger number of rows. The smaller the pixel size of the detector, the more loss information that needs to be compensated by the algorithm for the splice seam of the same physical size, which seriously affects the further improvement of the spatial resolution of the CT image.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The main technical problem to be solved by the present invention is to provide a flexible CT detector that reduces the problems of loss of splice seams and projection information caused by the assembly of the detector.

[0006] Another technical problem to be solved by the present invention is to provide a static CT system using the above flexible CT detector.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions.

[0008] According to a first aspect of an embodiment of the present invention, a flexible CT detector is provided, a flexible circuit board used for pasting inside the CT frame and having a signal reading part, and a flexible conversion part pasted inside the flexible circuit board, which absorbs X-rays and converts them into set signals. The signal reading part receives the set signals and is used to output a continuous projection image without interruption.

[0009] Preferably, the signal reading unit includes an electronic reading circuit and pixelated electrodes in a plurality of columns. The electronic reading circuit is printed in the flexible circuit board, and the pixelated electrodes in the plurality of columns are arranged on the surface of the flexible circuit board along the length direction of the flexible circuit board, and the pixelated electrodes in the plurality of columns are connected to the electronic reading circuit. The flexible conversion unit includes an X-ray absorption conversion layer that absorbs X-rays and converts them into electrical signals.

[0010] Preferably, the flexible conversion unit further includes an electron transport layer and a hole transport layer. The electron transport layer is attached between the outside of the X-ray absorption conversion layer and the inside of the flexible circuit board to transmit electrons and block holes. The hole transport layer is attached inside the X-ray absorption conversion layer to transmit holes and block electrons. Here, the positions of the electron transport layer and the hole transport layer are interchangeable.

[0011] Preferably, the flexible conversion unit further includes a common electrode layer and a power source. The common electrode layer is attached inside the hole transport layer, and the common electrode layer is connected to one electrode of the power source. The other electrode of the power source is connected to the flexible circuit board to form an electric field for driving the movement of electron-hole pairs.

[0012] Preferably, the signal reading unit includes a visible light reading circuit and pixelated photosensitive units in a plurality of columns. The visible light reading circuit is printed in the flexible circuit board, and the pixelated photosensitive units in the plurality of columns are arranged on the surface of the flexible circuit board along the length direction of the flexible circuit board, and the pixelated photosensitive units in the plurality of columns are connected to the visible light reading circuit. The flexible conversion unit is a flexible scintillator thin film that absorbs X-rays and converts them into optical signals.

[0013] Preferably, the flexible circuit board includes a plurality of sub-flexible circuit boards, and the head and tail of the plurality of sub-flexible circuit boards are sequentially spliced in order to be attached inside the CT frame.

[0014] Preferably, the lengths of the plurality of sub-flexible circuit boards are all the same, all different, or partially the same.

[0015] Preferably, the flexible CT detector further includes a waterproof layer that covers the outside of the flexible circuit board and the flexible conversion unit.

[0016] According to a second aspect of an embodiment of the present invention, a static CT system is provided. A CT frame, The above flexible CT detector attached inside the CT frame, And at least one X-ray source that is evenly distributed inside the flexible CT detector and irradiates X-rays toward the object to be photographed.

[0017] Preferably, the CT frame is provided with a control circuit that is connected to the flexible circuit board and controls the signal reading unit to execute signal reading.

Advantages of the Invention

[0018] Compared with the prior art, the flexible CT detector and its static CT system provided by the present invention use a large-area flexible circuit as the detector substrate and realize the dense arrangement of pixels throughout the detector ring, thereby significantly reducing the problems of splice seams caused by the assembly of conventional rigid detectors and the problem of losing projection information. Under ideal circumstances, there is only one splice seam where the head and tail of the detector ring are connected, greatly reducing the difficulty of algorithm correction.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0020] Regarding the technical content of the present invention, it will be described in detail and specifically below in combination with the accompanying drawings and specific embodiments. The First Embodiment

[0021] FIG. 2 shows a flexible CT detector provided by the first embodiment of the present invention, which includes at least a flexible circuit board 1 and a flexible conversion unit 2.

[0022] Here, the flexible circuit board 1 is used to be attached inside the CT frame 10 and has a signal reading section. The flexible conversion section 2 is attached inside the flexible circuit board 1 (i.e., the A side in FIG. 2), is used to absorb X-rays and convert them into set signals, and the signal reading section receives the set signals and is used to output continuous projection images without interruption.

[0023] In this embodiment, since the flexible circuit board 1 can be integrally attached inside the CT frame 10, by adjusting the size of the flexible circuit board 1 to match the CT frame 10, the splice gap between different modules can be significantly reduced. Under ideal circumstances, there is only one docking gap for connecting the head and the tail, and this docking gap is smaller than the splice gap between different modules. Therefore, the loss of projection information and the image discontinuity problem caused by the splice seam between different modules in the detector of the static CT system can be avoided or reduced, and the imaging quality of the static CT system can be improved.

[0024] In the above embodiment, for the flexible circuit board 1, a sensor panel such as a TFT or IGZO may be selected. Also, in order to match the size of the flexible circuit board 1 to the CT frame 10, the width of this flexible circuit board 1 needs to be equal to or less than the width of the CT frame 10, and the length needs to be the same as the perimeter (inner perimeter) of the CT frame 10. Thus, the flexible circuit board 1 can be closely attached inside the CT frame 10.

[0025] Also, after closely attaching the flexible circuit board 1 inside the CT frame 10, it is necessary to closely attach and relatively fix the head and the tail of the flexible circuit board 1. Here, as a method for relative fixation, methods such as bolts, carbon fiber cover plates, and adhesive tapes can be used to ensure the attachment stability of the flexible circuit board 1.

[0026] In the above embodiment, the signal reading unit includes an electronic reading circuit and pixelated electrodes in a plurality of columns. The electronic reading circuit is printed inside the flexible circuit board 1, and the pixelated electrodes in a plurality of columns are arranged on the surface of the flexible circuit board 1 along the length direction of the flexible circuit board 1, and the pixelated electrodes in a plurality of columns are connected to the electronic reading circuit and used to receive an electronic signal.

[0027] Correspondingly, the flexible conversion unit 2 includes an X-ray absorption conversion layer 21, an electron transmission layer 22, a hole transmission layer 23, a common electrode layer 24, and a power source. Here, the X-ray absorption conversion layer 21 is located inside the flexible circuit board 1 and is used to absorb X-rays and convert them into electrical signals. The electron transmission layer 22 is attached between the outside of the X-ray absorption conversion layer 21 and the inside of the flexible circuit board 1 and is used to transmit electrons and block holes. The hole transmission layer 23 is attached inside the X-ray absorption conversion layer and is used to transmit holes and block electrons. The common electrode layer 24 is attached inside the hole transmission layer 23, and the common electrode layer 24 is connected to one electrode of the power source, and the other electrode of the power source is connected to the flexible circuit board 1 to form an electric field for driving the movement of electron-hole pairs.

[0028] In the above embodiment, the positions of the electron transmission layer 22 and the hole transmission layer 23 are interchangeable. Correspondingly, it is also necessary to reverse the direction of the electric field for driving the movement of electron-hole pairs, and specifically, it can be adaptively selected according to actual needs.

[0029] In the above embodiment, it can be understood that the flexible circuit board 1 and the flexible conversion unit 2 cooperate to form a photon counting detector together. When specifically used, when the radiation source emits X-rays, the X-rays are absorbed through the X-ray absorption conversion layer 21 and converted into electrical signals (i.e., electron-hole pairs). Then, the common electrode layer 24 utilizes the electric field formed in cooperation with the power supply and the flexible circuit board 1 to drive the electron-hole pairs to move. Here, when the electron-hole pairs move, by providing the electron transmission layer 22 and the hole transmission layer 23, the movement efficiency of the electron-hole pairs can be effectively improved. Finally, using the plurality of rows of pixelated electrodes on the flexible circuit board 1, this electrical signal is received, and through the electronic readout circuit, this electrical signal is read out to output a photon counting image.

[0030] In the above embodiment, the flexible CT detector further includes a waterproof layer covering the outside of the flexible circuit board 1 and the flexible conversion unit 2. This waterproof layer includes, but is not limited to, a PI film, a PET film, a vapor-deposited parylene film, or a composite coating layer. Here, the composite coating layer is composed of a vapor-deposited parylene film mixed with the above PI film, PET film, SiO 2 TiO 2 , Al 2 O 3 and other precise inorganic waterproof films. By using this waterproof layer, the waterproof and moisture-proof performance of the entire flexible CT detector can be improved, and the safety of use can be improved.

[0031] To summarize the above, the flexible CT detector provided by the first embodiment of the present invention uses a large-area flexible circuit as the detector's substrate, and by realizing the close arrangement of pixels throughout the detector ring, it significantly reduces the problems of splice seams caused by the assembly of conventional rigid detectors and the problem of loss of projection information. Under ideal circumstances, there is only one splice seam where the head and tail of the detector ring are connected, greatly reducing the difficulty of algorithm correction. In addition, the flexible conversion unit 2 used for photoelectric conversion adopts a composite film structure, which helps to improve the photoelectric conversion efficiency and the sharpness of the photon counting image. Second Embodiment

[0032] FIG. 3 shows a flexible CT detector provided by the second embodiment of the present invention, which includes at least a flexible circuit board 1 and a flexible conversion unit 2. The difference between this embodiment and the first embodiment is that in this embodiment, the type of the flexible CT detector is different from that of the first embodiment.

[0033] Specifically, in this embodiment, the signal reading unit includes a visible light reading circuit and a plurality of columns of pixelated photosensitive units. The visible light reading circuit is engraved inside the flexible circuit board 1, and the plurality of columns of pixelated photosensitive units are arranged on the surface of the flexible circuit board 1 along the length direction of the flexible circuit board 1, and the plurality of columns of pixelated photosensitive units are connected to the visible light reading circuit and are used to receive optical signals. Correspondingly, the flexible conversion unit 2 is a flexible scintillator thin film and is used to absorb X-rays and convert them into optical signals.

[0034] Therefore, in this embodiment, the detector formed by the combination of the flexible circuit board 1 and the flexible conversion unit 2 is an integrating detector. When specifically used, when X-rays are emitted from the radiation source, the flexible conversion unit 2 formed by the flexible scintillator thin film converts the X-rays into optical signals. Then, a plurality of rows of pixelated photosensitive units on the flexible circuit board 1 are used to receive this electrical signal. Finally, this optical signal is read out through the visible light readout circuit, and an energy integration image is output.

[0035] Except for the above differences, the structures of this embodiment are all the same as those of the first embodiment, and will not be described repeatedly here. The Third Embodiment

[0036] As shown in FIG. 4, based on the first embodiment, the third embodiment of the present invention provides a flexible CT detector. The difference from the first embodiment is that the flexible circuit board 1 in this embodiment has a multi-stage splicing structure.

[0037] Specifically, in this embodiment, the flexible circuit board 1 includes a plurality of sub-flexible circuit boards 101. Since the plurality of sub-flexible circuit boards 101 are attached to the inside of the CT frame, the head and the tail are sequentially spliced. The flexible circuit board 1 preferably has 2 to 32 sub-flexible circuit boards 101 with the head and the tail connected to form the entire ring of the detector. However, the specific number of the sub-flexible circuit boards 101 is not limited and can be adaptively selected according to needs.

[0038] For the flexible circuit board 1 with a set length, the more the number of sub-flexible circuit boards 101, the lower the manufacturing difficulty. It can be understood that the number of corresponding splice seams increases as the number of sub-flexible circuit boards 101 increases. Conversely, the higher the manufacturing difficulty of the sub-flexible circuit board 101, the fewer the number of corresponding splice seams, which decreases as the number of sub-flexible circuit boards 101 decreases. However, compared with the conventional rigidity detectors, even when the flexible circuit board 1 of the present application adopts a form of splicing a plurality of sub-flexible circuit boards 101, the size of the splice seam itself is significantly reduced, and the loss of projection information and the problem of image discontinuity are reduced.

[0039] Also, in a modification of the present invention, the lengths of the plurality of sub-flexible circuit boards 101 are all the same. In another modification, the lengths of the plurality of sub-flexible circuit boards 101 are all different. In still another modification, the lengths of the plurality of sub-flexible circuit boards 101 are only partially the same. Specifically, by selecting according to the actual usage situation, it can be adapted to CT frames with different size structures.

[0040] Except for the above differences, the structure of this embodiment is the same as that of the first embodiment in all other aspects, and will not be described repeatedly here. The Fourth Embodiment

[0041] FIG. 5 shows a static CT system provided by the fourth embodiment of the present invention, which includes a CT frame 10, a flexible CT detector 20, and a plurality of X-ray sources 30.

[0042] Here, the CT frame is used to provide a mounting base for the flexible CT detector 20. This flexible CT detector 20 is attached to the inside of the CT frame 10, and a plurality of X-ray sources 30 are evenly distributed inside the flexible CT detector 20 and are used to irradiate X-rays toward the object 40 to be imaged. Using this flexible CT detector 20, a continuous projection image 50 without interruption is formed.

[0043] In this embodiment, the CT frame 10 is ring-shaped. In other embodiments, the CT frame 10 may be in a shape such as an ellipse or a rectangle. Also, the CT frame 10 can adopt a spiral shape. Thus, the entire flexible CT detector 20 is attached to the CT frame 10 in a spiral shape, there is no splice seam in the entire arc-shaped detector, and the complete continuity of the pixels is guaranteed.

[0044] In the above embodiment, a control circuit 60 is provided in the CT frame 10. This control circuit is connected to the flexible circuit board 1 and controls the signal reading unit to read signals. Therefore, CT detection can be automatically controlled using this control circuit 60, improving the convenience of CT detection.

[0045] Also, in another modification of the present invention, there may be only one radiation source 30, and it is not necessary to select and use the entire ring of the detector 20. This detector 20 may be arc-shaped (i.e., a part of the flexible detector in FIG. 4). Then, the detector 20 can rotate at high speed together with the radiation source 30 to form spiral CT, thereby reducing the influence of the splice seam inside the detector 20 as well.

[0046] Various embodiments or variations in the present invention are all described by adopting relevant methods. It should be noted that the same parts and similar parts among various embodiments or variations can refer to each other. Various embodiments or variations focus on the differences from other embodiments, but since they are all implemented based on the operating principles of the flexible CT detector and its static CT system, they will not be described in detail here.

[0047] Compared with the prior art, the flexible CT detector and its static CT system provided by the present invention use a large-area flexible circuit as the detector's substrate and realize the close arrangement of pixels throughout the detector ring, thereby greatly reducing the problems of the splice seam caused by the assembly of conventional rigid detectors and the problem of losing projection information. Under ideal circumstances, there is only one splice seam where the head and tail of the detector ring are connected, greatly reducing the difficulty of algorithm correction.

[0048] As described above, the flexible CT detector and its static CT system provided by the present invention have been described in detail. For those skilled in the art, any obvious modifications made to the present invention without departing from the substantial content of the present invention will all constitute an infringement of the patent right of the present invention and bear corresponding legal responsibilities.

Claims

1. A flexible CT detector, comprising: A flexible circuit board used for being attached to the inside of a CT frame and having a signal reading section; A flexible conversion section attached to the inside of the flexible circuit board, configured to absorb X-rays and convert them into set signals, wherein the signal reading section receives the set signals and is used for outputting continuous projection images without interruption. A flexible CT detector characterized by this.

2. The signal reading section includes an electronic reading circuit and pixelated electrodes in a plurality of columns, The electronic reading circuit is engraved in the flexible circuit board, and the pixelated electrodes in the plurality of columns are arranged on the surface of the flexible circuit board along the length direction of the flexible circuit board, and the pixelated electrodes in the plurality of columns are connected to the electronic reading circuit, The flexible conversion section includes an X-ray absorption conversion layer configured to absorb X-rays and convert them into electrical signals. The flexible CT detector according to Claim 1, characterized by this.

3. The flexible conversion section further includes an electron transmission layer and a hole transmission layer, The electron transmission layer is attached between the outside of the X-ray absorption conversion layer and the inside of the flexible circuit board for transmitting electrons and blocking holes, The hole transmission layer is attached to the inside of the X-ray absorption conversion layer for transmitting holes and blocking electrons. Here, the positions of the electron transmission layer and the hole transmission layer are exchangeable. The flexible CT detector according to Claim 2, characterized by this.

4. The flexible conversion section further includes a common electrode layer and a power supply, The common electrode layer is attached to the inside of the hole transmission layer, and the common electrode layer is connected to one electrode of the power supply. The other electrode of the power supply is connected to the flexible circuit board, and forms an electric field for driving the movement of electron-hole pairs. The flexible CT detector according to Claim 3, characterized by this.

5. The signal reading section includes a visible light reading circuit and pixelated photosensitive units in a plurality of columns, The visible light reading circuit is printed within the flexible circuit board, and the plurality of pixelated photosensitive units in the plurality of columns are arranged on the surface of the flexible circuit board along the length direction of the flexible circuit board, and the plurality of pixelated photosensitive units in the plurality of columns are connected to the visible light reading circuit. The flexible conversion unit is a flexible scintillator thin film that absorbs X-rays and converts them into optical signals, and the flexible CT detector according to claim 1 is characterized in that.

6. The flexible circuit board includes a plurality of sub-flexible circuit boards, and the plurality of sub-flexible circuit boards are characterized in that the head and the tail are sequentially spliced in order to be attached to the inside of the CT frame, and the flexible CT detector according to claim 1 is characterized in that.

7. The lengths of the plurality of sub-flexible circuit boards are all the same, all different, or partially the same, and the flexible CT detector according to claim 6 is characterized in that.

8. The flexible CT detector according to any one of claims 1 to 7 is further provided with a waterproof layer that covers the outside of the flexible circuit board and the flexible conversion unit.

9. A static CT system, a CT frame, the flexible CT detector according to any one of claims 1 to 8, which is attached to the inside of the CT frame, and at least one X-ray source that is distributed inside the flexible CT detector and irradiates X-rays toward an object to be photographed, and a static CT system is characterized in that.

10. The static CT system according to claim 9 is characterized in that a control circuit is provided on the CT frame, which is connected to the flexible circuit board and controls the signal reading unit to execute signal reading.

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