CN217955860U

CN217955860U - Curved surface detector for CT system

Info

Publication number: CN217955860U
Application number: CN202220844834.0U
Authority: CN
Inventors: 肖迦一; 王玉明
Original assignee: Hunan Taoshang Medical Instrument Co ltd
Current assignee: Hunan Taoshang Medical Instrument Co ltd
Priority date: 2022-04-12
Filing date: 2022-04-12
Publication date: 2022-12-02
Anticipated expiration: 2032-04-12

Abstract

The utility model relates to the technical field of medical equipment, in particular to curved surface detector for CT system. The structure of the CMOS imaging sensor comprises an external cover plate, wherein the external cover plate is in a curved surface shape, a plurality of CMOS imaging sensor modules which are electrically connected with each other are arranged in the external cover plate, and the CMOS imaging sensor modules are electrically connected with each other through a flexible circuit board. The utility model discloses a curved surface detector for CT system, it makes X ray source unanimous basically to detector upper surface distance everywhere, and it is more even to receive ray intensity, thoroughly solves the restraint of edge effect to the detector size, enlarges the detector imaging area, adapts to big formation of image object, shortens the imaging time, and keeps high-quality image for COMS curved surface screen detector is used for high-efficient CT image acquisition to become possible.

Description

Curved surface detector for CT system

Technical Field

The utility model relates to the technical field of medical equipment, in particular to curved surface detector for CT system.

Background

In Computed Tomography (CT), a detector is used to receive X-rays transmitted through an object, and the X-ray signals after passing through the object are converted into electrical signals, which are finally processed by a computer for imaging. The existing Detector is mainly divided into a linear array Detector and a Flat Panel Detector, and an indirect Flat Panel Detector (FPD) is mainly composed of a scintillator, a sensor, a readout circuit, a peripheral control circuit, and the like.

Currently, indirect flat panel detectors are mainly based on Thin Film Transistor (TFT) technology, and Complementary Metal Oxide Semiconductor (CMOS) technology. Based on amorphous silicon conductive material adopted by TFT technology, the conductive material is deposited on a glass substrate or a flexible substrate, and TFT or oxide with higher conductivity is adopted for driving display pixels. There is no signal amplifying circuit beside the photodiode array made by Thin Film Transistor (TFT) technology, and the signal is amplified after being transmitted to the outside of the detector. Different from a glass substrate adopted by a TFT technology, the substrate adopted based on the CMOS technology is monocrystalline silicon, the electron mobility of the substrate is thousands of times higher than that of amorphous silicon, the conductivity is greatly improved, and the size of a single transistor can be small. In CMOS technology, each pixel of the detector is integrated with a photodiode, an addressing circuit and an amplifier, and the signal is amplified and then transmitted to the outside.

The single crystal silicon substrate adopted by the CMOS flat panel detector amplifies signals and transmits the amplified signals to the outside, and the CMOS flat panel detector has great advantages compared with a TFT flat panel detector. The CMOS flat panel detector has high detection quantum efficiency and resolution ratio under the condition of low dose, has high reading speed, can realize full-frame-rate and full-resolution images, and has smaller tailing. From the current technical development trend, the detector is developed towards more sensitivity, lower noise and higher frame rate. With the progress of semiconductor technology, compared with a TFT flat panel detector, the COMS flat panel detector technology with better performance becomes a key research and development field at home and abroad, and has huge market potential.

Because the edge artifact of the flat panel detector imaging exists and the imaging surface is difficult to flexibly adjust according to the shape of an object, the image quality is greatly influenced, and therefore, the development of a large-area curved surface detector has great significance. At present, curved screen detectors are based on TFT technology, and form curved surfaces by adopting flexible substrates or splicing narrow planes. The flexible substrate curved screen and the narrow plane splicing curved screen based on the TFT technology have the common defects of low acquisition and reading speed and low dose definition. It is very unfavorable for low dose, high frame rate, fast dynamic imaging in mobile CT, and seriously affects the efficiency of use and image effect.

The CMOS flat panel detector is processed based on the wafer, is limited by the current production process and technology of the wafer, and has a smaller imaging area in the conventional CMOS flat panel detector. The CMOS flat panel detector is widely used for 8-inch wafers, and the flat panel size is generally 13 × 13cm and 15 × 12cm. In addition, because of the fragile physical characteristics of the monocrystalline silicon wafer material, and the printed circuit boards for arranging the control circuit and the readout circuit are distributed on two sides of the photosensitive pixel plane, the detector cannot have a curved surface structure, and the detector can be bent. These factors have resulted in the inability of the prior art to fabricate large area CMOS detectors with a curvature. This greatly limits the application scenarios of CMOS detectors, especially for fast whole-body imaging in mobile CT.

SUMMERY OF THE UTILITY MODEL

In order to solve the problem of the prior art, the utility model provides a curved surface detector for CT system, it makes X ray source to detector upper surface distance everywhere unanimous basically, and it is more even to receive ray intensity, thoroughly solves the restraint of marginal effect to the detector size, enlarges the detector imaging area, adapts to big formation of image object, shortens the imaging time, and keeps high quality image for COMS curved surface screen detector is used for high-efficient CT image acquisition to become possible.

The utility model discloses the technical scheme who adopts as follows:

a curved surface detector for a CT system comprises an external cover plate, wherein the external cover plate is in a curved surface shape, and a plurality of CMOS imaging sensor modules arranged along the inside of the external cover plate are arranged inside the external cover plate.

The CMOS imaging sensor modules are preferably electrically connected through a flexible circuit board.

Namely, the CMOS imaging sensor modules can be mutually independent and can also be electrically connected with each other through a flexible circuit board.

Preferably, the CMOS imaging sensor modules are in parallel or series relation.

Preferably, the CMOS imaging sensor module comprises a supporting plate, a CMOS photosensitive array is arranged on the supporting plate, the outer side of the CMOS photosensitive array is connected with the external cover plate through a scintillation crystal, the CMOS photosensitive arrays of the adjacent CMOS imaging sensor modules are electrically connected through a flexible circuit board, and a circuit board is further arranged on the supporting plate.

Preferably, the CMOS imaging sensor module is in a parallel mode, equipped with separate row scan driving circuitry, readout circuitry, and timing gating circuitry and analog front end signal processing circuitry.

Preferably, the CMOS photosensitive array includes at least one photosensitive pixel unit, a line scanning driving circuit, and an analog front end signal processing circuit, where the line scanning driving circuit is configured to turn on and off pixels, and each photosensitive pixel unit corresponds to one analog front end signal processing circuit.

Preferably, a circuit pad area is manufactured in the peripheral area of the CMOS photosensitive array and used for being connected with the flexible circuit board, the CMOS photosensitive array is electrically led out to be connected in parallel or in series, and then signal control is achieved through the circuit board.

The utility model provides a beneficial effect that technical scheme brought is:

the invention is realized by adopting a CMOS process, has high detection quantum efficiency under low dosage, high image resolution, fast acquisition frame number and small smear.

The large-area CMOS curved-surface screen detector can be realized by bamboo slip type splicing of a single flat CMOS detector, is suitable for fast scanning of large parts of the whole body, improves the scanning efficiency and obtains high-quality images.

The problem that an existing CMOS flat panel detector cannot be bent is solved, the curved-surface-screen CMOS detector can be realized, X rays received by the detector are more uniform, and image artifacts caused by edge effects are solved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic top cross-sectional view of a curved detector structure for a CT system in embodiment 1 of the present invention.

Fig. 2 is a rear view of a curved detector for a CT system in embodiment 1 of the present invention.

Fig. 3 is a schematic top cross-sectional view of a curved detector for a CT system in embodiment 2 of the present invention.

Fig. 4 is a rear view of a curved detector for a CT system in embodiment 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

Example 1

As shown in fig. 1-2, the present embodiment provides a curved detector for a CT system, which includes an external cover 100, a scintillation crystal 101, a CMOS photosensitive array 102, a support plate 103, a circuit board 104, and a flexible circuit board 105.

The outer cover 100 may be made of, but not limited to, one of carbon fiber composite, rubber, and film, and the curvature may be designed according to different imaging requirements. The curved outer cover plate 100 is an arc-shaped integral surface, so that the distances from the X-ray source to the upper surface of the detector in the same cross section are the same, and the received X-ray intensity is more uniform.

The inner side of the outer cover 100 is coupled with the scintillation crystal 101 in an adhesive manner, and serves as a protective layer of the scintillation crystal 101 to prevent physical damage to the scintillation crystal.

The scintillator crystal 101 is a material capable of emitting light after absorbing radiation, and gadolinium oxysulfide (GdOS) or cesium iodide (CsI) can be used, but is not limited thereto. The scintillation crystal 101 can be coupled with the CMOS photosensitive array 102 by direct growth or by bonding. The scintillation crystal of each CMOS imaging sensor module 106 is grown or bonded separately and corresponds to the CMOS photosensitive array 102.

In the CMOS photosensitive array 102, each pixel unit at least includes a photodiode and corresponding circuits, including a row scan driving circuit, a readout circuit, and a timing gating circuit. Meanwhile, the CMOS photosensitive array 102 is further equipped with an analog front-end signal processing circuit to achieve amplification of signals, improve the anti-noise interference capability of output signals, and increase the signal-to-noise ratio, thereby obtaining high-quality scanned images.

The CMOS photosensitive array 102 is connected with the supporting plate 103 in a bonding mode, and a circuit corresponding to the CMOS photosensitive array 102 is led out from a circuit pad area arranged on the periphery and is connected with the circuit board 104 through a flexible circuit board 105. Here, it is to be noted that the drawing direction of the circuit corresponding to the CMOS photosensitive array 102 may be a combination of one side or a plurality of sides around the CMOS photosensitive array 102.

The X-ray generates visible light through the action with the scintillation crystal 101, is converted into an electric signal through the CMOS photosensitive array 102, and then reaches the chip of the circuit board 104 through the transmission of the flexible circuit board 105 for signal processing. The above scintillator crystal 101, CMOS photosensitive array 102, flexible wiring board 105, circuit board 104, and support plate 103 constitute a CMOS imaging sensor module 106 (106A).

Each CMOS imaging sensor module 106 is in a parallel mode, equipped with a separate row scan drive circuit, readout circuit, and timing gating circuit, and analog front end signal processing circuitry. The exposure and readout stages can work independently and are not affected by each other. Meanwhile, the output signal generated by each CMOS imaging sensor module 106 is processed by the main chip to output an image.

As shown in fig. 1 and fig. 2, the CMOS imaging sensor module 106 in the form of bamboo slip is formed into a large-area CMOS curved panel detector by means of an angular splicing. It should be noted that, in the present invention, the size and the number of the CMOS imaging sensor modules 106 are not limited. The size and number of the CMOS imaging sensor modules 106 may be optimized based on the wafer size according to different imaging requirements and applicable scenarios.

Example 2

As shown in fig. 3-4, the present embodiment provides a curved surface detector, which includes an outer cover 200, a scintillation crystal 201, a CMOS photosensitive array 202, a supporting plate 203, a circuit board 204, and a flexible circuit board 205.

The outer cover 200 may be made of, but not limited to, one of carbon fiber composite, rubber, and film, and the curvature may be designed according to different imaging requirements. The curved outer cover plate 200 is an arc-shaped integral surface, so that the distances from the X-ray source to the upper surface of the detector in the same cross section are the same, and the received X-ray intensity is more uniform.

The inner side of the outer cover plate 200 is coupled with the scintillation crystal 201 in an adhesion mode and serves as a protective layer of the scintillation crystal 201 to prevent physical damage of the scintillation crystal.

Scintillation crystal 201 is a material capable of emitting light upon absorption of radiation, and gadolinium oxysulfide (GdOS) or cesium iodide (CsI) may be used, but is not limited thereto. The scintillation crystal 201 is coupled with the CMOS photosensitive array 202 in a direct growth or bonding manner. The scintillation crystal of each CMOS imaging sensor module 206 is grown separately or bonded to correspond to the CMOS photosensitive array 202.

In the CMOS photosensitive array 202, each pixel unit at least includes a photodiode and corresponding circuits, including a row scan driving circuit, a readout circuit, and a timing gating circuit. Meanwhile, the CMOS photosensitive array 202 is further equipped with an analog front-end signal processing circuit to achieve amplification of signals, improve the anti-noise interference capability of output signals, and increase the signal-to-noise ratio, thereby obtaining high-quality scanned images.

The X-ray generates visible light by acting with the scintillation crystal 201, is converted into an electric signal by the CMOS photosensitive array 202, and then reaches the chip of the circuit board 204 through the transmission of the flexible circuit board 205 to perform signal processing. The scintillation crystal 201, the CMOS photosensitive array 202, the flexible circuit board 205, the circuit board 204 and the support plate 203 constitute a CMOS imaging sensor module 206.

The CMOS imaging sensor modules 206 are connected in series, and the circuits corresponding to the previous CMOS photosensitive array 202 are all led out from the circuit pad region disposed on the peripheral side, and are connected to the circuits corresponding to the CMOS photosensitive array 202 of the next adjacent CMOS imaging sensor module 206 through the flexible circuit board 205. Finally, the circuit board 204 performs unified signal transmission control of the CMOS imaging sensor modules 206.

The CMOS imaging sensor module 206 of the whole detector is provided with a line scanning driving circuit and a time sequence gate control circuit; while the individual pixels of each CMOS imaging sensor module 206 are provided with readout circuitry and analog front end signal processing circuitry.

As shown in fig. 3 and 4, the CMOS imaging sensor module 206 in the form of bamboo slip is formed into a large-area CMOS curved panel detector by an angular splicing. It should be noted that, in the present invention, the size and the number of the CMOS imaging sensor modules 206 are not limited. The size and number of CMOS imaging sensor modules 206 may be optimized based on wafer size according to different imaging requirements and applicable scenarios.

Based on the above examples 1 and 2, the present invention provides a large curved surface detector based on CMOS technology, which has the characteristics of high resolution, high frame count, high detection quantum efficiency at low dose, small smear, etc., and can realize large-area imaging. The method can be applied to the rapid imaging scanning scene of the large part of the human body, and is particularly suitable for the mobile CT medical treatment.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A curved surface detector for a CT system comprises an outer cover plate and is characterized in that the outer cover plate is in a curved surface shape, and a plurality of CMOS imaging sensor modules arranged along the inside of the outer cover plate are arranged inside the outer cover plate.

2. The curved detector according to claim 1, wherein the CMOS imaging sensor modules are electrically connected to each other via a flexible printed circuit.

3. The curved detector of claim 1, wherein said CMOS imaging sensor modules are connected in parallel or in series.

4. The curved detector according to claim 1, wherein the CMOS imaging sensor module comprises a supporting plate, the supporting plate is provided with a CMOS photosensitive array, the outer side of the CMOS photosensitive array is connected to the outer cover plate through a scintillation crystal, the CMOS photosensitive arrays of adjacent CMOS imaging sensor modules are electrically connected through a flexible circuit board, and the supporting plate is further provided with a circuit board.

5. A curved detector for CT system as claimed in claim 3 or 4, wherein the CMOS imaging sensor module is in parallel connection with separate line scan driving circuit, readout circuit, and timing gating circuit and analog front end signal processing circuit.

6. A curved detector as claimed in claim 4, wherein the CMOS photosensitive array comprises at least one photosensitive pixel unit, a line scan driving circuit, and an analog front end signal processing circuit, wherein the line scan driving circuit is used for turning on and off the pixel, and each photosensitive pixel unit corresponds to one analog front end signal processing circuit.

7. The curved detector according to claim 4, wherein a circuit pad region is formed in a peripheral region of the CMOS photosensitive array, and the circuit pad region is used to connect the flexible circuit board, electrically lead out the CMOS photosensitive array, and realize parallel connection or serial connection between the CMOS photosensitive array and the flexible circuit board, and then realize signal control through the flexible circuit board.