X-ray detector and CT equipment that perform imaging by mixing energy integration and photon counting

Abstract

The present invention discloses an X-ray detector that performs imaging by mixing energy integration and photon counting, and a corresponding CT device. This X-ray detector includes a counting detector having at least one row of pixelated electronic elements, and an integration detector that is stacked and installed on one side of the counting detector along a first direction and has at least one row of pixelated photoelectric elements. At any one pixel position, the electronic element and the photoelectric element correspond one-to-one in the first direction. The counting detector and the integration detector share a radiation conversion unit, and the radiation conversion unit can receive X-rays, convert them into electron-hole pairs, and transmit them to the electronic elements. The radiation conversion unit can also receive X-rays, convert them into visible light photons, and transmit them to the photoelectric elements. The counting detector and the integration detector in this X-ray detector share a radiation conversion unit, and by processing two types of detection signals at the same pixel position at the same timing, a high-quality reconstructed image can be obtained.

Description

Technical Field

[0001] The present invention relates to an X-ray detector that performs imaging by mixing energy integration and photon counting, and at the same time, relates to a CT device using this X-ray detector, belonging to the technical field of computed tomography.

Background Art

[0002] CT (Computed Tomography) is an abbreviation for computed tomography. It uses accurately 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 characteristics 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 inspection.

[0003] Currently, the commonly used conventional CT detector is an energy integration detector (EID). Such an energy integration detector measures the energy integration signal of X-ray photons, and thus may lose energy-related information. As a result, noise increases and contrast decreases. The photon counting detector is a relatively new CT detector, which has higher conversion efficiency, lower quantum noise, and higher spatial resolution than the conventional energy integration detector, but has the problems that the intensity of its response signal is weak and pulse stacking occurs with a large X-ray photon beam.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The main technical problem to be solved by the present invention is to provide an X-ray detector that performs imaging by mixing energy integration and photon counting.

[0005] Another technical problem to be solved by the present invention is to provide a CT device using this X-ray detector.

[0006] To achieve the above object, the present invention adopts the following technical solutions.

[0007] According to a first aspect of an embodiment of the present invention, an X-ray detector that performs imaging by mixing energy integration and photon counting is provided. To obtain a photon counting image, a counting detector having at least one column of pixelated electronic elements, along a first direction, is stacked and installed on one side of the counting detector, and includes an integration detector having at least one column of pixelated photoelectric elements for obtaining an energy integration image. At any one pixel position, the electronic element corresponds one-to-one with the photoelectric element in the first direction. Here, the counting detector shares a radiation conversion unit with the integration detector. The radiation conversion unit can receive the X-ray, convert it into electron-hole pairs, and transmit it to the electronic element. The radiation conversion unit can receive the X-ray, convert it into visible light photons, and transmit it to the photoelectric element.

[0008] Preferably, the counting detector includes an electronic circuit board with a preset electronic readout circuit, and at least one column of pixelated electronic elements arranged along a second direction on the surface of the electronic circuit board close to the integration detector. Any one of the electronic elements is connected to the electronic readout circuit. The counting detector further includes at least one column of pixelated electronic elements. Here, the second direction is perpendicular to the first direction, and the first direction is perpendicular to the surface of the electronic circuit board.

[0009] Preferably, the integration detector includes a visible light circuit board with a preset visible light readout circuit, and further includes at least one column of pixelated photoelectric elements arranged along the second direction on the surface of the visible light circuit board close to the electronic circuit board. Any one of the photoelectric elements is connected to the visible light readout circuit.

[0010] Preferably, the radiation conversion unit has a one-piece structure and is made of a material having the characteristics of both a scintillator and a semiconductor.

[0011] Preferably, in the first direction, an electron blocking layer and a hole blocking layer are provided at both ends of the radiation conversion unit, respectively.

[0012] Preferably, the radiation conversion unit is installed between the electronic circuit board and the visible light circuit board, made of a semiconductor material, and is a first conversion unit that receives the X-rays and converts them into electron-hole pairs, and is attached to one side of the first conversion unit away from the electronic circuit board, made of a scintillator material having a hole blocking function, and is a second conversion unit that receives the X-rays and converts them into visible light photons.

[0013] Preferably, the counting detector and the integrating detector share the same common circuit board, and an electronic readout circuit and a visible light readout circuit are preset on the common circuit board. On the surface of the common circuit board, at least one row of pixelated optoelectronic devices is arranged along the second direction, and an electronic device is provided at each pixel position where each optoelectronic device is located. Any one of the optoelectronic devices is connected to the visible light readout circuit, and any one of the electronic devices is connected to the electronic readout circuit. The radiation conversion unit is installed on the common circuit board, receives the X-rays, and converts them into electron-hole pairs and visible light photons.

[0014] Preferably, a waterproof layer is integrally wrapped outside the counting detector and the integrating detector, and the waterproof layer includes at least one of a PI film, a PET film, a vapor-deposited parylene film, or a composite coating layer.

[0015] Preferably, the X-ray detector further comprises a power supply and a transparent electrode. The transparent electrode is disposed on one side of the radiation conversion unit away from the electronic element. One pole of the power supply is connected to the transparent electrode, and the other pole of the power supply is connected to the counting detector to form an electric field for driving electron-hole pairs.

[0016] Preferably, it further comprises an image processing unit connected to the counting detector for receiving a photon counting image at any one pixel position. The image processing unit is also connected to the integration detector for receiving an energy integration image at the same pixel position at the same timing, and for performing a fusion process on the photon counting image and the energy integration image at the same pixel position at the same timing.

[0017] A second aspect according to an embodiment of the present invention provides a CT apparatus using an X-ray detector that performs imaging by mixing the above energy integration and photon counting.

Advantages of the Invention

[0018] Compared with the prior art, the present invention has the following technical effects. 1) Since the radiation conversion unit has the characteristics of both a scintillator and a semiconductor, by simultaneously converting electron-hole pairs and visible light photons, the counting detector and the integration detector can share the radiation conversion unit. 2) At any one pixel position, since the electronic element and the optoelectronic element correspond one-to-one in the first direction, by performing image processing on two types of detection signals at the same pixel position at the same timing, a high-quality reconstructed image can be obtained.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

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

[0021] FIG. 1 shows an X-ray detector that performs imaging by mixing energy integration and photon counting provided by the first embodiment of the present invention, which includes at least a counting detector 1 and an integrating detector 2. Here, the counting detector 1 has at least one row of pixelated electronic elements 11 for acquiring a photon counting image. The integrating detector 2 is stacked and installed on one side of the counting detector 1 along the first direction (i.e., the X direction in FIG. 1), and has at least one row of pixelated photoelectric elements 21 for acquiring an energy integration image.

[0022] In this embodiment, it is preferable to select and use electrodes for the electronic element 11. In other embodiments, a complementary metal-oxide semiconductor (CMOS) thin-film transistor, an indium gallium zinc oxide thin-film transistor (IGZO-TFT), or the like can also be selected, and it is ensured that there are exposed electrodes on the surface of each material. For the optoelectronic element 21, it is preferable to select and use a photodiode. In other embodiments, a photodiode (PD), a complementary metal-oxide semiconductor (CMOS), a charge-coupled device (CCD), a photomultiplier tube (PMT), or the like can also be selected. At any one pixel position, the electronic element 11 and the optoelectronic element 21 correspond one-to-one in the first direction.

[0023] Also, the counting detector 1 and the integrating detector 2 share the radiation conversion unit 3. Here, this radiation conversion unit 3 has the characteristics of both a scintillator and a semiconductor. It can not only receive X-rays, convert them into electron-hole pairs, and transmit them to the electronic element 11, but also receive X-rays, convert them into visible light photons, and transmit them to the optoelectronic element 21. Therefore, by using the X-ray detector provided by this embodiment for hybrid imaging of energy integration and photon counting, high-quality reconstructed images can be obtained by performing image processing on two types of detection signals at the same pixel position at the same timing.

[0024] In one embodiment of the present invention, this radiation conversion unit 3 has at least one row of pixelated material units 31, and at any one pixel position, the electronic element 11, the pixelated material unit 31, and the optoelectronic element 21 correspond one-to-one in the first direction. Therefore, through the pixelated material unit 31, the correspondence relationship between the radiation conversion unit 3, the counting detector 1, and the integrating detector 2 can be improved, and mutual crosstalk can be avoided.

[0025] In the above embodiment, the counting detector 1 may further include an electronic circuit board 12. An electronic readout circuit is preset on this electronic circuit board 12. The at least one row of pixelated electronic elements 11 is arranged along the second direction (i.e., the Y direction in FIG. 1) on the surface of the electronic circuit board 12 close to the integration detector 2 (i.e., the A surface in FIG. 1), and any one of the electronic elements 11 is connected to the electronic readout circuit and thus used to acquire a photon counting image. In this embodiment, it can be understood that the electronic element 11, the electronic circuit board 12, and the radiation conversion unit 3 together constitute the counting detector 1. As shown in FIG. 1, when X-rays pass through the electronic circuit board 12 and irradiate the radiation conversion unit 3, the X-rays are converted into electron-hole pairs through the radiation conversion unit 3, and the electron-hole pairs are transmitted to the electronic element 11, so that a photon counting image can be acquired through the electronic readout circuit on the electronic circuit board 12.

[0026] Similarly, in the above embodiment, the integration detector 2 may further include a visible light circuit board 22. A visible light readout circuit is preset on this visible light circuit board 22. The at least one row of pixelated photoelectric elements 21 is arranged along the second direction on the surface of the visible light circuit board 22 close to the electronic circuit board 12 (i.e., the B surface in FIG. 1), and any one of the photoelectric elements 21 is connected to the visible light readout circuit and thus used to acquire an energy integration image. In this embodiment, it can be understood that the photoelectric element 21, the visible light circuit board 22, and the radiation conversion unit 3 together constitute the integration detector 2. As shown in FIG. 1, when X-rays pass through the electronic circuit board 12 and irradiate the radiation conversion unit 3, the X-rays are converted into visible light photons through the radiation conversion unit 3, and the visible light photons are transmitted to the photoelectric element 21, so that an energy integration image can be acquired through the visible light readout circuit on the visible light circuit board 22.

[0027] In the above embodiment, the radiation conversion unit 3 has an integral structure and is made of a material having the characteristics of both a scintillator and a semiconductor, such as a perovskite material of a lead-based metal halide. Thus, the radiation conversion unit 3 can simultaneously convert electron-hole pairs and photons of visible light and respectively correspond to the counting detector 1 and the integrating detector 2.

[0028] In one embodiment of the present invention, as shown in FIG. 2, in the first direction (i.e., the X direction in FIG. 2), it is preferable that an electron blocking layer 301 and a hole blocking layer 302 are respectively provided at both ends of the radiation conversion unit 3. Here, the electron blocking layer 301 is used to block electrons so that holes can pass smoothly, and N-diphenyl-N, N-bis(3-methylphenyl)benzidine (Poly-TPD) can be selected and used. Similarly, the hole blocking layer 302 is used to block holes so that electrons can pass smoothly, and PCBM, C60, a perovskite, a composite coating layer of an organic substance, etc. can be selected and used, and the thickness is 0.1 to 10 μm. Therefore, the flow efficiency of electron-hole pairs can be improved, the collection effect of the photon counting image can be further improved, and it is useful for the subsequent image reconstruction.

[0029] In the above embodiment, outside the counting detector 1 and the integrating detector 2, a waterproof layer (not shown) is integrally wrapped. The waterproof layer includes, but is not limited to, one or more of 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 precise inorganic waterproof film such as the above PI film, PET film, vapor-deposited parylene film blended with SiO2, TiO2, Al2O3, etc. By using this waterproof layer, the waterproof and moisture-proof performance of the entire X-ray detector for mixed energy integration and photon counting imaging is improved, and the use safety is improved.

[0030] In the above embodiment, this X-ray detector further includes a power supply 4 and a transparent electrode 5. Here, the transparent electrode 5 is installed on one side of the radiation conversion unit 3 away from the electronic element 11. One pole of the power supply 4 is connected to the transparent electrode 5, and the other pole of the power supply 4 is connected to the counting detector 1, forming an electric field used to drive electron-hole pairs. By utilizing this electric field, a driving force can be provided for the movement of electron-hole pairs, thereby improving the movement efficiency of electron-hole pairs.

[0031] As shown in FIG. 1, in the above embodiment, this X-ray detector further includes an image processing unit 6. The image processing unit 6 is connected to the counting detector 1 and receives a photon counting image at any one pixel position. The image processing unit 6 is also connected to the integration detector 2 and receives an energy integration image at the same pixel position at the same timing. Therefore, by using this image processing unit to perform a fusion process on the photon counting image and the energy integration image at the same pixel position at the same timing, a high-quality reconstructed image corresponding to this pixel position can be obtained.

[0032] To summarize the above, in the X-ray detector for hybrid energy integration and photon counting imaging provided by the first embodiment of the present invention, the radiation conversion unit 3 has the characteristics of both a scintillator and a semiconductor, so that it can simultaneously convert electron-hole pairs and visible light photons, and the counting detector 1 and the integration detector 2 can share the radiation conversion unit. Furthermore, at any one pixel position, since the electronic element 11, the material unit 31, and the photoelectric element 21 correspond one-to-one in the first direction, two types of detection signals at the same pixel position at the same timing can be image-processed, thereby obtaining a high-quality reconstructed image. Second Embodiment

[0033] FIG. 3 shows an X-ray detector for hybrid energy integration and photon counting imaging provided by the second embodiment of the present invention, which includes at least a counting detector 1 and an integration detector 2. Different from the first embodiment, in this embodiment, the radiation conversion unit 3 has a two-layer structure.

[0034] Specifically, in this embodiment, the radiation conversion unit 3 includes a first conversion unit 310 and a second conversion unit 320. Here, the first conversion unit 310 is made of a semiconductor material, installed between the electronic circuit board 12 and the visible light circuit board 22, and receives X-rays and converts them into electron-hole pairs. In this embodiment, it can be understood that the electronic element 11, the electronic circuit board 12, and the first conversion unit 310 together form the counting detector.

[0035] Similarly, the second conversion unit 320 is made of a scintillator material, attached to one side of the first conversion unit 310 away from the electronic circuit board 12, and receives X-rays and converts them into visible light photons. In this embodiment, it can be understood that the photoelectric element 21, the visible light circuit board 22, and the second conversion unit 320 together form the integration detector.

[0036] In an embodiment of the present invention, when selecting the manufacturing material of the second conversion unit 320, it is preferable to select a material having a hole blocking function in addition to the scintillator characteristics in order to allow electrons to pass through. In order to block the passage of electrons, it is more preferable that an electron blocking layer is provided on one side of the first conversion unit 310 away from the second conversion unit 320. Therefore, the flow efficiency of electron-hole pairs can be improved.

[0037] The structure of this embodiment is the same as that of the first embodiment in all respects except for the above differences, and will not be described repeatedly here. The Third Embodiment

[0038] FIG. 4 shows an X-ray detector that performs imaging by mixing energy integration and photon counting provided by the third embodiment of the present invention, which includes at least a counting detector 1 and an integration detector 2. The difference between this embodiment and the first embodiment is that in this embodiment, the counting detector and the integration detector share the same common circuit board 10.

[0039] Specifically, in this embodiment, an electronic readout circuit and a visible light readout circuit are preset on this common circuit board 10. Also, on the surface of the common circuit board 10, at least one row of pixelated optoelectronic elements 21 is arranged along the second direction (i.e., the Y direction in FIG. 4), and an electronic element 11 is provided at each pixel position where each optoelectronic element 21 is located. Any one of the optoelectronic elements 21 is connected to the visible light readout circuit, and any one of the electronic elements 11 is connected to the electronic readout circuit. Correspondingly, by being installed on the common circuit board 10, the radiation conversion unit 3 is configured such that at least one row of pixelated material units 31 corresponds one-to-one to at least one row of pixelated optoelectronic elements 21. In an embodiment of the present invention, instead of installing the pixelated material units 31 in the radiation conversion unit 3, the overall structure may be directly formed of a material having the characteristics of a scintillator and a semiconductor.

[0040] In this embodiment, it can be understood that the electronic element 11, the common circuit board 10, and the radiation conversion unit 3 together constitute the counting detector 1, and the optoelectronic element 21, the common circuit board 10, and the radiation conversion unit 3 together constitute the integration detector 2.

[0041] Also, since the counting detector 1 and the integration detector 2 share the same common circuit board 10, it can be understood that the transparent electrode 5 in this embodiment is installed on one side of the radiation conversion unit 3 away from the electronic element 11 (i.e., the C side in FIG. 4).

[0042] The structure of this embodiment is the same as that of the first embodiment in all respects except for the above differences, and thus will not be repeatedly described here.

[0043] Various embodiments or variations in the present invention are all described in a mutually related manner. It should be noted that for the same parts and similar parts among various embodiments or variations, they can be referred to each other. Various embodiments or variations focus on the differences from other embodiments, but since they are all realized based on the operating principle of an X-ray detector that combines energy integration and photon counting for imaging, they will not be described in detail here.

[0044] Based on the X-ray detector that combines energy integration and photon counting for imaging provided by the above various embodiments, the present invention further provides a CT device. As shown in FIG. 5, the CT detector in this CT device can be realized by using the X-ray detector that combines energy integration and photon counting for imaging provided by the present invention. Other components such as tubes and frames can be implemented using general designs in the prior art and will not be specifically described here.

[0045] As described above in detail, the X-ray detector that combines energy integration and photon counting for imaging and the corresponding CT device provided by the present invention have been described. 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 the corresponding legal liability.

Claims

1. An X-ray detector that performs imaging by mixing energy integration and photon counting, comprising: a counting detector having at least one column of pixelated electronic elements for acquiring a photon counting image; an integration detector that is stacked and installed on one side of the counting detector along a first direction and has at least one column of pixelated photoelectric elements for acquiring an energy integration image, wherein at any one pixel position, the electronic element corresponds one-to-one with the photoelectric element in the first direction; wherein the counting detector shares a radiation conversion unit with the integration detector, the radiation conversion unit can receive the X-ray, convert it into electron-hole pairs, and transmit it to the electronic element, and the radiation conversion unit can receive the X-ray, convert it into visible light photons, and transmit it to the photoelectric element. An X-ray detector that performs imaging by mixing energy integration and photon counting.

2. The counting detector includes: an electronic circuit board with an electronic readout circuit preset; at least one column of pixelated electronic elements arranged on the surface of the electronic circuit board close to the integration detector along a second direction, wherein any one of the electronic elements is connected to the electronic readout circuit. The X-ray detector for imaging by mixing energy integration and photon counting according to Claim 1, wherein the second direction is perpendicular to the first direction, and the first direction is perpendicular to the surface of the electronic circuit board. wherein the second direction is perpendicular to the first direction, and the first direction is perpendicular to the surface of the electronic circuit board. An X-ray detector for imaging by mixing energy integration and photon counting according to Claim 1.

3. The integration detector includes: a visible light circuit board with a visible light readout circuit preset; at least one column of pixelated photoelectric elements arranged on the surface of the visible light circuit board close to the electronic circuit board along the second direction, and any one of the photoelectric elements is connected to the visible light readout circuit. The X-ray detector for imaging by mixing energy integration and photon counting according to Claim 2.

4. The radiation conversion unit has an integrated structure and is made of a material having the characteristics of both a scintillator and a semiconductor. An X-ray detector for imaging by mixing energy integration and photon counting according to Claim 3.

5. In the first direction, an electron blocking layer and a hole blocking layer are provided at both ends of the radiation conversion unit, respectively. The X-ray detector for imaging by mixing energy integration and photon counting according to claim 4, characterized in that.

6. The radiation conversion unit is Installed between the electronic circuit board and the visible light circuit board, manufactured of a semiconductor material, a first conversion unit that receives the X-ray and converts it into electron-hole pairs, and A second conversion unit that is attached to one side of the first conversion unit away from the electronic circuit board and is manufactured of a scintillator material having a hole blocking function, and receives the X-ray and converts it into visible light photons. The X-ray detector for imaging by mixing energy integration and photon counting according to claim 3, characterized in that it comprises.

7. The counting detector and the integrating detector share the same common circuit board, and an electronic readout circuit and a visible light readout circuit are preset on the common circuit board. On the surface of the common circuit board, at least one row of pixelated photoelectric elements is arranged along a second direction, and an electronic element is provided at each pixel position where each photoelectric element is located. Any one of the photoelectric elements is connected to the visible light readout circuit, and any one of the electronic elements is connected to the electronic readout circuit. The radiation conversion unit is installed on the common circuit board, receives the X-ray, and converts it into electron-hole pairs and visible light photons. The X-ray detector for imaging by mixing energy integration and photon counting according to claim 1, characterized in that.

8. Outside the counting detector and the integrating detector, a waterproof layer is integrally wrapped, and the waterproof layer includes at least one or more of a PI film, a PET film, a vapor-deposited parylene film, or a composite coating layer. The X-ray detector for imaging by mixing energy integration and photon counting according to claim 1, characterized in that.

9. Further comprising a power supply and a transparent electrode, the transparent electrode is installed on one side of the radiation conversion unit away from the electronic element, one pole of the power supply is connected to the transparent electrode, and the other pole of the power supply is connected to the counting detector to form an electric field for driving electron-hole pairs. The X-ray detector for imaging by mixing energy integration and photon counting according to claim 1, characterized in that.

10. Further comprising an image processing unit connected to the counting detector for receiving a photon counting image at any one pixel position, the image processing unit being also connected to the integration detector for receiving an energy integration image at the same pixel position at the same timing, and fusing the photon counting image and the energy integration image at the same pixel position at the same timing. An X-ray detector for hybrid imaging of energy integration and photon counting according to claim 1.

11. A CT apparatus comprising an X-ray detector for hybrid imaging of energy integration and photon counting according to any one of claims 1 to 10.

Images