Multi-energy-spectrum X-ray detector and detection system

Abstract

The invention provides a multi-energy-spectrum X-ray detector and a multi-energy-spectrum X-ray detection system, and the multi-energy-spectrum X-ray detector comprises an upper-layer detector module, a filtering layer and a lower-layer detector module which are sequentially superposed from top to bottom in an X-ray incidence direction, the number of the filtering layers is N; the number of the lower layer detector modules is N, and N is an integer greater than or equal to 1; the filtering layers and the lower-layer detector modules are alternately stacked, and each lower-layer detector module comprises a CMOS sensor and a scintillator located above the CMOS sensor. The A-Si sensor on the lower layer is replaced by the CMOS sensor, and a high signal-to-noise ratio is obtained on the premise that the energy difference is large and the spatial resolution is not sacrificed; a plurality of lower-layer detector modules are arranged to obtain a multi-energy-spectrum image, so that the comprehensive performance of the detector is improved; the filtering layer is pixelated, and energy spectrum areas with different thicknesses are made on the filtering layer, so that the double-layer detector realizes a multi-energy spectrum effect, and the structure and electronic design complexity, the assembly complexity and the cost of the detector are remarkably reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of digital X-ray flat panel detectors, and in particular relates to a multi-energy spectrum X-ray detector and a detection system. Background Art

[0002] In the field of medical imaging, dual-energy X-ray systems have attracted much attention because they can distinguish the differences in X-ray absorption by substances of different atomic weights. The system can more significantly reflect the changes in the attenuation intensity of X-ray beams of different energies by utilizing the different characteristics of bone and soft tissue in X-ray absorption. Specifically, dual-energy silhouette technology obtains clear images of soft tissue, bone tissue or specific substances by subtracting two images obtained by exposing the same part with two different energies of X-rays.

[0003] At present, there are two main methods to achieve X-ray dual-energy silhouette: double exposure method and single exposure method. As the main subtraction technique used in clinical practice, the double exposure method quickly acquires low- and high-energy images through different tube voltage (kVp) switching techniques. However, this method has problems such as low radiation utilization, high dose, and easy generation of motion artifacts. In contrast, the single exposure method is based on a double-layer X-ray flat-panel detector design. Low-energy images are acquired through the upper flat-panel detector, while high-energy images are acquired through the lower flat-panel detector after the X-rays pass through the filter layer, effectively eliminating motion artifacts and reducing the radiation dose to patients and the requirements for X-ray systems.

[0004] However, the existing double-layer flat-panel detector technology has certain limitations. These detectors are mainly implemented by built-in double-layer amorphous silicon thin-film transistor (A-Si TFT) sensors, scintillators and filter layers, among which the filter layer usually uses a homogeneous Cu sheet to absorb low-energy X-rays. Increasing the thickness of the Cu sheet can improve the absorption capacity, thereby improving the effect of dual-energy silhouette, but it will also cause the energy of the rays received by the lower sensor to be weakened, the signal output to be reduced, and thus affect the image signal-to-noise ratio. In order to improve the signal output of the lower sensor, it is necessary to increase the thickness of the scintillator, but this will sacrifice spatial resolution. On the contrary, if the high spatial resolution is maintained, the signal value is small, resulting in a poor signal-to-noise ratio of the lower image.

[0005] For multi-energy spectrum detectors, the conventional solution uses a multi-layer flat-panel detector with at least three layers of A-SiTFT sensors, scintillators and filter layers built in. Each layer of sensor has a corresponding driving circuit. This solution is highly complex in structure, electronics and process, is costly, and has unsatisfactory performance.

[0006] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Summary of the invention

[0007] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a multi-energy spectrum X-ray detector and a detection system for solving at least one technical problem existing in the prior art.

[0008] To achieve the above-mentioned object and other related objects, the present invention provides a multi-energy spectrum X-ray detector, which includes an upper detector module, a filter layer and a lower detector module stacked in sequence from top to bottom along the X-ray incident direction;

[0009] The number of the filtering layers is N, where N ≥ 1 and is an integer;

[0010] The number of the lower layer detector modules is N, where N ≥ 1 and is an integer;

[0011] The filter layers are alternately stacked with the lower detector modules, and the lower detector modules include complementary metal oxide semiconductor sensors and scintillators located above the complementary metal oxide semiconductor sensors.

[0012] Preferably, the upper detector module comprises an upper detector and a scintillator layer located directly above the upper detector, wherein the upper detector comprises an amorphous silicon thin film transistor sensor or a complementary metal oxide semiconductor sensor.

[0013] Preferably, the pixels of the complementary metal oxide semiconductor sensor are smaller than the pixels of the amorphous silicon thin film transistor sensor.

[0014] Preferably, the filter layer is one or a combination of a homogeneous filter layer and a pixelated filter layer.

[0015] Preferably, the material of the homogeneous filter layer includes copper, and the homogeneous filter layer corresponds to energy spectrum regions of the same thickness.

[0016] Preferably, the pixelated filter layer comprises at least two pixel units arranged in an array, each of the pixel units corresponds to an energy spectrum region of a different thickness, and each of the energy spectrum regions has a different absorption energy for X-rays.

[0017] Preferably, the material of the pixelated filter layer includes copper, and the thickness of each of the energy spectrum regions ranges from 0 to 3 mm.

[0018] The present invention also provides a detection system, which includes the above-mentioned multi-energy spectrum X-ray detector.

[0019] As described above, the multi-energy spectrum X-ray detector and detection system of the present invention have the following beneficial effects:

[0020] In order to improve the image effect of dual-energy silhouette, when the average energy difference is large, the energy of rays passing through the filter layer is weak. Under the premise of ensuring a certain spatial resolution, in order to collect an image with a high signal-to-noise ratio, the amorphous silicon thin film transistor sensor in the lower layer is replaced by a complementary metal oxide semiconductor sensor. Since the complementary metal oxide semiconductor sensor has high sensitivity and low noise, the dual-energy spectrum X-ray detector can obtain a higher signal-to-noise ratio under the premise of a large energy difference without sacrificing spatial resolution. In addition, the upper layer is set as an amorphous silicon thin film transistor sensor, and the lower layer adopts a complementary metal oxide semiconductor sensor to reduce the overall cost and the difficulty of complex process.

[0021] In the present invention, multiple lower detector modules are arranged to obtain multi-energy spectrum images, so as to improve the comprehensive performance of the multi-energy spectrum X-ray detector; the filter layer is pixelated, and since the complementary metal oxide semiconductor sensor of the lower layer has much smaller pixels than the amorphous silicon thin film transistor sensor of the upper layer, energy spectrum areas of different thicknesses are made on the filter layer corresponding to multiple pixels of the lower layer corresponding to a single pixel of the upper layer, and energy spectrum areas of different thicknesses correspond to different energy spectrum information, so that the double-layer detector can achieve the effect of multi-energy spectrum. Compared with multi-layer sensors and multi-layer filter layers, the design complexity, assembly complexity and cost of the structure and electronics of the multi-energy spectrum X-ray detector can be significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Shown is a schematic structural diagram of a multi-energy spectrum X-ray detector in a specific embodiment of the present invention.

[0023] Figure 2 Shown is a schematic structural diagram of another multi-energy spectrum X-ray detector in a specific embodiment of the present invention.

[0024] Figure 3 Shown is a schematic structural diagram of another multi-energy spectrum X-ray detector in a specific embodiment of the present invention.

[0025] Figure 4 Shown is a schematic structural diagram of another multi-energy spectrum X-ray detector in a specific embodiment of the present invention.

[0026] Figure 5 It is a schematic diagram showing the structure of a filter layer having two energy spectrum regions in a specific embodiment of the present invention.

[0027] Figure 6 It is a schematic diagram showing the structure of a filter layer having three energy spectrum regions in a specific embodiment of the present invention.

[0028] Figure 7 It is a schematic diagram showing the structure of a filter layer having four energy spectrum regions in a specific embodiment of the present invention.

[0029] Component number description

[0030] 10 Multi-spectrum X-ray detector

[0031] 100, 400 Scintillator layer

[0032] 200 Amorphous silicon thin film transistor sensor or A-Si sensor

[0034] 300 Filter Layer

[0035] 301 pixel unit

[0036] 3011 The first energy spectrum area

[0037] 3012 The second energy spectrum area

[0038] 3013 The third spectral region

[0039] 3014 The fourth energy spectrum area

[0040] 500 Complementary Metal Oxide Semiconductor Sensor or CMOS Sensor DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0043] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0044] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0045] See also Figures 1 to 7 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0046] See also Figures 1 to 7 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0047] The present invention provides a multi-energy spectrum X-ray detector 10. Along the X-ray incident direction, the multi-energy spectrum X-ray detector 10 includes an upper detector module, a filter layer 300 and a lower detector module stacked in sequence from top to bottom;

[0048] The number of the filtering layers 300 is N, where N ≥ 1 and is an integer;

[0049] The number of lower layer detector modules is N, where N ≥ 1 and is an integer;

[0050] The filter layers 300 are alternately stacked with the lower detector modules, which include complementary metal oxide semiconductor (CMOS) sensors and scintillators located above the complementary metal oxide semiconductor sensors 500 .

[0051] Specifically, when N=1, the multi-spectrum X-ray detector 10 is a dual-spectrum X-ray detector. In order to improve the image effect of dual-energy subtraction, when the average energy difference is large, the energy of the rays passing through the filter layer 300 is weak. Under the premise of ensuring a certain spatial resolution, in order to collect an image with a high signal-to-noise ratio, the sensor in the lower detector module is replaced with a CMOS sensor 500. Due to the high sensitivity and low noise of the CMOS sensor 500, a higher signal-to-noise ratio is obtained under the premise of a large energy difference without sacrificing spatial resolution. Of course, in other embodiments, N can also be 2, 3, 4, etc., that is, in order to obtain more energy levels and obtain images with more energy spectra, multiple sensors are stacked.

[0052] As an example, the upper detector module includes an upper detector and a scintillator layer 100 located directly above the upper detector, wherein the upper detector includes an amorphous silicon thin film transistor sensor 200 or a complementary metal oxide semiconductor sensor 500 .

[0053] Specifically, the scintillator layers 100 and 400 are responsible for absorbing X-rays and converting them into visible light. When X-rays enter the scintillator layers 100 and 400, the scintillator atoms are ionized or excited, and the excited atoms emit fluorescence with a wavelength in the visible light band when de-excited. In a specific embodiment of the present invention, both the upper detector module and the lower detector module include scintillator layers 100 and 400. The specific thickness and material of the scintillator layers 100 and 400 are not overly restricted herein, and can meet actual usage requirements.

[0054] In one embodiment of the present invention, referring to Figure 1 , the sensor in the upper detector module is an amorphous silicon thin film transistor (A-Si) sensor, N=1, and there is one lower detector module, that is, along the incident direction of the X-ray, the structure of the multi-spectrum X-ray detector 10 includes a scintillator layer 100, an A-Si sensor, a filter layer 300, a scintillator layer 400, and a CMOS sensor 500. Since the large-area CMOS sensor 500 has a relatively high cost and a complex process, the overall cost and implementation difficulty can be reduced by using an A-Si sensor in the upper layer and a CMOS sensor 500 in the lower layer, and at the same time, a higher signal-to-noise ratio can be obtained without sacrificing spatial resolution.

[0055] In another specific embodiment of the present invention, refer to Figure 2 The sensor in the upper detector module is a CMOS sensor 500, N=1, and there is one lower detector module, that is, along the incident direction of X-rays. The structure of the multi-energy spectrum X-ray detector 10 includes a scintillator layer 100, a CMOS sensor 500, a filter layer 300, a scintillator layer 400, and a CMOS sensor 500.

[0056] In another specific embodiment of the present invention, in order to obtain more energy levels and acquire images with more energy spectra, multiple scintillator layers 100, 400 and sensors may also be stacked. Figure 3 , the sensor in the upper detector module is an A-Si sensor, the sensor in the lower detector module is a CMOS sensor 500, and N=2; that is, along the X-ray incident direction, the structure of the multi-energy spectrum X-ray detector 10 includes a scintillator layer 100, an A-Si sensor, a filter layer 300, a scintillator layer 400, a CMOS sensor 500, a filter layer 300, a scintillator layer 400, and a CMOS sensor 500.

[0057] In another specific embodiment of the present invention, refer to Figure 4, the sensor in the upper detector module is a CMOS sensor 500, the sensor in the lower detector module is a CMOS sensor 500, and N=2; that is, along the incident direction of X-rays, the structure of the multi-spectrum X-ray detector 10 includes a scintillator layer 100, a CMOS sensor 500, a filter layer 300, a scintillator layer 400, a CMOS sensor 500, a filter layer 300, a scintillator layer 400, and a CMOS sensor 500. Of course, when N=3, it includes three filter layers 300 and three lower sensor modules; N can also be other integers, which will not be described in detail here.

[0058] As an example, the pixels of the complementary metal oxide semiconductor sensor 500 are smaller than the pixels of the amorphous silicon thin film transistor sensor 200 .

[0059] Specifically, the pixel size of the amorphous silicon thin film transistor sensor 200 is usually in the hundreds of micrometers level. The pixel size of the amorphous silicon thin film transistor sensor 200 commonly seen on the market is 100 μm to 200 μm. However, the pixel size of the complementary metal oxide semiconductor sensor 500 can be in the nanometer level, which can be adjusted according to the design requirements, and no excessive restrictions are made here.

[0060] As an example, the filter layer 300 is one or a combination of a homogeneous filter layer 300 and a pixelated filter layer 300 .

[0061] As an example, the material of the homogenous filter layer 300 includes copper, and the homogenous filter layer 300 corresponds to energy spectrum regions of the same thickness.

[0062] Specifically, when N=1, if the filter layer 300 is a homogeneous filter layer 300, the multi-spectrum X-ray detector 10 includes an upper detector module, a filter layer 300 and a lower detector module, that is, the multi-spectrum X-ray detector 10 is a dual-spectrum X-ray detector. When N=1, if the filter layer 300 is a pixelated filter layer 300, the dual-spectrum X-ray detector 10 is essentially at least a tri-spectrum X-ray detector. When N≥2, the filter layer 300 can be a homogeneous filter layer 300, or a pixelated filter layer 300, and of course, it can also be a combination of the two filter layers 300, which will not be described one by one here.

[0063] As an example, the pixelated filter layer 300 includes at least two pixel units 301 arranged in an array, each pixel unit 301 corresponds to an energy spectrum region of different thickness, and each energy spectrum region has a different absorption energy for X-rays.

[0064] Specifically, the pixelated filter layer 300 includes at least two pixel units 301 arranged in an array, that is, the original homogeneous filter layer 300 is pixelated. The pixelated filter layer 300 changes the traditional continuous and uniform filter layer 300 into a structure composed of many pixel units 301. Each pixel unit 301 can independently filter the passing X-rays, thereby performing more precise control over the filtering of the X-rays, thereby improving the performance and imaging quality of the detector.

[0065] See also Figure 1 When N=1, the structure of the multi-energy spectrum X-ray detector 10 includes a scintillator layer 100, an A-Si sensor, a filter layer 300, a scintillator layer 400, and a CMOS sensor 500. The filter layer 300 is set as an array of pixel units 301, and each pixel unit 301 corresponds to an energy spectrum area of ​​different thickness, that is, different filter layer 300 thicknesses, and different filter thickness areas correspond to different energy spectrum areas. Different energy spectrum areas have different absorption energies for X-rays, which will make the X-rays passing through the filter layer 300 thick be divided into X-rays with different energy spectra, thereby realizing a multi-energy spectrum design; compared with a multi-layer sensor and a multi-layer filter layer 300, the dual-energy spectrum X-ray detector significantly reduces the complexity of the structure and electronic design, the complexity of assembly, and the cost.

[0066] Specifically, when N ≥ 2 and is an integer, the multi-spectrum X-ray detector 10 includes an upper detector module, at least two filter layers 300 and at least two lower detector modules, that is, the multi-spectrum X-ray detector 10 is at least a three-spectrum X-ray detector, which can obtain a multi-spectrum image. Figure 3 and Figure 4 Of course, a combination of a homogeneous filter layer 300 and a pixelated filter layer 300 may also be used, which will not be described in detail here.

[0067] As an example, the material of the pixelated filter layer 300 includes copper, and the thickness of each energy spectrum region ranges from 0 to 3 mm.

[0068] Specifically, the materials of each energy spectrum region are the same but the thicknesses are different. Different thicknesses have different absorption capacities for X-rays (the thickness is proportional to the absorption capacity for X-rays), so that each energy spectrum region has different absorption energies for X-rays. The thickness of each energy spectrum region may include values ​​within any range such as 0, 0.1mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, etc., and may be adjusted according to actual application conditions.

[0069] In the first example of the present invention, refer to Figure 5It is a structural schematic diagram of a filtering layer 300 having two energy spectrum regions, wherein the filtering layer 300 includes two pixel units 301 arranged in an array, and the two pixel units 301 correspond to energy spectrum regions of different thicknesses, namely a first energy spectrum region 3011 domain and a second energy spectrum region 3012 domain; if the first energy spectrum region 3011 domain is defined as having low absorption energy for X-rays, and the second energy spectrum region 3012 domain is defined as having high absorption energy for X-rays, then the X-rays passing through the filtering layer 300 will be divided into two X-rays having different low energy spectra and high energy spectra; wherein the pixel unit 301 is in the shape of a rectangle, and the shape of each energy spectrum region is in the shape of a rectangle, and each energy spectrum region can be equally divided left and right or up and down, and of course, each energy spectrum region can also be of different sizes.

[0070] See also Figure 5 , if Figure 1 The filter layer 300 of the dual-energy spectrum X-ray detector is designed to have a first energy spectrum region 3011 and a second energy spectrum region 3012 , and the detector is equivalent to a three-energy spectrum X-ray detector.

[0071] In another example of the present invention, see Figure 6 It is a structural schematic diagram of a filtering layer 300 with three energy spectrum regions. The filtering layer 300 includes three pixel units 301 arranged in an array. The three pixel units 301 correspond to energy spectrum regions with different thicknesses, namely a first energy spectrum region 3011, a second energy spectrum region 3012 and a third energy spectrum region 3013. The X-rays passing through the filtering layer 300 are divided into three X-rays with different energy spectra.

[0072] In another example of the present invention, see Figure 7 It is a structural schematic diagram of a filtering layer 300 having four energy spectrum regions. The filtering layer 300 includes four pixel units 301 arranged in an array. The four pixel units 301 correspond to energy spectrum regions of different thicknesses, namely a first energy spectrum region 3011, a second energy spectrum region 3012, a third energy spectrum region 3013 and a fourth energy spectrum region 3014. The X-rays passing through the filtering layer 300 are divided into four X-rays with different energy spectra.

[0073] Of course, the filter layer 300 may also include 5 or more than 5 energy spectrum regions with different absorption energies for X-rays, which will not be elaborated herein.

[0074] The present invention also provides a detection system, which includes the multi-energy spectrum X-ray detector 10 mentioned above.

[0075] Specifically, the detection system includes an X-ray source; the above-mentioned multi-energy spectrum X-ray detector 10, which is arranged opposite to the X-ray source and is used to receive X-rays and convert them into electrical signals; a driving circuit and a readout circuit, which are connected to the multi-energy spectrum X-ray detector 10.

[0076] In summary, in order to improve the image effect of dual-energy silhouette, when the average energy difference is large, the energy of the rays passing through the filter layer is weak. Under the premise of ensuring a certain spatial resolution, in order to collect an image with a high signal-to-noise ratio, the amorphous silicon thin film transistor sensor in the lower layer is replaced by a complementary metal oxide semiconductor sensor. Since the complementary metal oxide semiconductor sensor has high sensitivity and low noise, the dual-energy spectrum X-ray detector can obtain a higher signal-to-noise ratio under the premise of a large energy difference without sacrificing spatial resolution. In addition, the upper layer is set as an amorphous silicon thin film transistor sensor, and the lower layer adopts a complementary metal oxide semiconductor sensor to reduce the overall cost and labor. The invention has the advantages of high precision, high reliability, high reliability and high cost performance. The invention has the advantages of high precision ...

[0077] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A multi-energy spectrum X-ray detector, characterized in that: Along the X-ray incident direction, the multi-energy spectrum X-ray detector includes an upper detector module, a filter layer and a lower detector module stacked in sequence from top to bottom; The number of the filtering layers is N, where N ≥ 1 and is an integer; The number of the lower layer detector modules is N, where N ≥ 1 and is an integer; The filter layers are alternately stacked with the lower detector modules, and the lower detector modules include complementary metal oxide semiconductor sensors and scintillators located above the complementary metal oxide semiconductor sensors.

2. The multi-spectrum X-ray detector according to claim 1, characterized in that: The upper detector module includes an upper detector and a scintillator layer located directly above the upper detector, wherein the upper detector includes an amorphous silicon thin film transistor sensor or a complementary metal oxide semiconductor sensor.

3. The multi-energy spectrum X-ray detector according to claim 2, characterized in that: The pixels of the complementary metal oxide semiconductor sensor are smaller than the pixels of the amorphous silicon thin film transistor sensor.

4. The multi-energy spectrum X-ray detector according to claim 1, characterized in that: The filtering layer is one or a combination of a homogeneous filtering layer and a pixelated filtering layer.

5. The multi-energy spectrum X-ray detector according to claim 4, characterized in that: The material of the homogeneous filter layer includes copper, and the homogeneous filter layer corresponds to energy spectrum regions with the same thickness.

6. The multi-energy spectrum X-ray detector according to claim 4, characterized in that: The pixelated filter layer includes at least two pixel units arranged in an array, each of the pixel units corresponds to an energy spectrum region of different thickness, and each of the energy spectrum regions has a different absorption energy for X-rays.

7. The multi-spectrum X-ray detector according to claim 6, characterized in that: The material of the pixelated filter layer includes copper, and the thickness of each of the energy spectrum regions ranges from 0 to 3 mm.

8. A detection system, characterized in that: The detection system comprises the multi-energy spectrum X-ray detector according to any one of claims 1 to 7.

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