A semiconductor detector, an imaging device and a medical imaging method thereof

Abstract

Embodiments of the present specification provide a semiconductor detector, an imaging device and a medical imaging method thereof. The semiconductor detector comprises at least one group of detector modules, each of the detector modules comprising: a photosensitive substrate, a back electrode located at a first main surface of the photosensitive substrate, a plurality of groups of electrode strips located at a second main surface of the photosensitive substrate, at least one group of electrode strips of the plurality of groups of electrode strips comprising a signal collection electrode and a non-collection electrode; and a readout circuit configured to read out an electrical signal output by the plurality of groups of electrode strips and convert the electrical signal into digitized data, the electrical signal comprising an electrical signal collected by the signal collection electrode or an electrical signal collected by the signal collection electrode and the non-collection electrode.

Description

Technical Field

[0001] This specification relates to the field of medical technology, and in particular to a semiconductor detector, imaging device and medical imaging method thereof. Background Technology

[0002] A semiconductor detector is a radiation detector that uses semiconductor materials as its detection medium. Semiconductor detectors rely on charged particles generating electron-hole pairs within their sensitive volume. These electron-hole pairs drift under the influence of an external electric field, thus outputting a signal. With the continuous development of science and technology, semiconductor detectors have undergone significant improvements in structure and materials, and are widely used in high-energy physics, astrophysics, industry, security monitoring, nuclear medicine, X-ray imaging, and military fields. For example, in CT (Computed Tomography) imaging equipment, semiconductor detectors are used to convert photon signals from the X-rays emitted by the CT scanner into electrical signals. These electrical signals are then transmitted or stored in a computer via electronic devices to generate medical images. The performance of the detector can significantly affect the image quality of the medical images.

[0003] Therefore, it is desirable to propose a semiconductor detector. Summary of the Invention

[0004] This specification provides a semiconductor detector in one aspect. The semiconductor detector includes at least one set of detector modules, each detector module comprising: a photosensitive substrate; a back electrode located on a first main surface of the photosensitive substrate; multiple sets of electrode strips located on a second main surface of the photosensitive substrate, at least one set of the multiple sets of electrode strips including a signal collecting electrode and a non-collecting electrode; and a readout circuit for reading electrical signals output by the multiple sets of electrode strips and converting the electrical signals into digital data, the electrical signals including electrical signals collected by the signal collecting electrode, or electrical signals collected by the signal collecting electrode and the non-collecting electrode.

[0005] In some embodiments, each group of electrode strips includes at least two groups of sub-electrodes arranged longitudinally, and the difference between the photon count rates output by each group of sub-electrodes of the at least two groups of sub-electrodes is within a preset range.

[0006] In some embodiments, each group of electrode strips comprises three groups of sub-electrodes arranged longitudinally.

[0007] In some embodiments, the length of each of the at least two sets of sub-electrodes increases exponentially along the incident direction of the ray.

[0008] In some embodiments, the length of each of the at least two sets of sub-electrodes increases or decreases exponentially along the longitudinal direction.

[0009] In some embodiments, one of the at least two sets of sub-electrodes near the edge of the detector module includes a signal collection electrode and a non-collection electrode.

[0010] In some embodiments, the longer sub-electrode in the at least two sets of sub-electrodes includes a signal collection electrode and a non-collection electrode.

[0011] In some embodiments, the sub-electrode closest to the incident direction of the ray in the at least two sets of sub-electrodes includes a signal collecting electrode and a non-collecting electrode.

[0012] In some embodiments, one or more of the at least two sets of sub-electrodes that are away from the incident direction of the ray include signal collecting electrodes and non-collecting electrodes.

[0013] In some embodiments, the signal collecting electrode of the at least one set of electrode strips is surrounded by the non-collecting electrode, and / or the signal collecting electrode and the non-collecting electrode are connected by interlocking fingers.

[0014] In some embodiments, the semiconductor detector is an energy integrating detector; the readout circuit includes at least a charge integrator, and the number of readout circuits is the same as the number of sub-electrodes included in each group of electrode strips.

[0015] Another aspect of this specification provides a medical imaging method. The method includes: acquiring digital data related to photons passing through a target object based on a semiconductor detector as described above; and generating a medical image of the target object based on the digital data.

[0016] Another aspect of this specification provides an imaging apparatus. The apparatus includes a radiation source, a semiconductor detector as described above, and an image processing device; the radiation source is used to emit X-rays toward a target object; the semiconductor detector system is used to convert the X-rays passing through the target object into digital data; and the image processing device is used to generate a medical image of the target object based on the digital data.

[0017] In some embodiments, the X-rays are incident along the sub-electrode arrangement direction of one set of electrode strips of the semiconductor detector. Attached Figure Description

[0018] This specification will be further described by way of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting; in these embodiments, the same reference numerals denote the same structures, wherein:

[0019] Figure 1 These are schematic diagrams illustrating application scenarios of semiconductor detectors according to some embodiments of this specification;

[0020] Figure 2 These are exemplary schematic diagrams of detector modules according to some embodiments of this specification;

[0021] Figure 3A and 3B These are exemplary schematic diagrams of detector modules according to other embodiments of this specification;

[0022] Figure 4 This is an exemplary structural diagram of a detector module according to some embodiments of this specification;

[0023] Figures 5A-5C This is an exemplary structural diagram of a detector module according to other embodiments of this specification;

[0024] Figures 6A-6B This is an exemplary structural diagram of a detector module according to other embodiments of this specification;

[0025] Figure 7 These are exemplary schematic diagrams of semiconductor detectors according to some embodiments of this specification;

[0026] Figure 8 This is an exemplary flowchart of a medical imaging method according to some embodiments of this specification;

[0027] Figure 9 This is an exemplary block diagram of a medical imaging system according to some embodiments of this specification. Detailed Implementation

[0028] To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0029] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0030] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0031] Flowcharts are used in this specification to illustrate the operations performed by the system according to embodiments of this specification. The related descriptions are provided to aid in a better understanding of the medical imaging methods and / or systems. It should be understood that preceding or subsequent operations are not necessarily performed precisely in sequence. Instead, steps can be processed in reverse order or simultaneously. Furthermore, other operations can be added to these processes, or one or more steps can be removed from them.

[0032] Figure 1 This is a schematic diagram illustrating the application scenarios of semiconductor detectors according to some embodiments of this specification.

[0033] like Figure 1 As shown, the medical imaging system 100 may include an imaging device 110, a processor 120, a display device 130, and a storage device 140.

[0034] Imaging device 110 can be used to scan a target object within a detection area to obtain scan data of the target object. For illustrative purposes, in the embodiments of this specification, image data of the target object acquired using imaging device 110 is referred to as a medical image, while image data acquired using its image acquisition device is referred to as an image. In some embodiments, the target object may include biological and / or non-biological objects. For example, the target object may include specific parts of the body, such as the head, chest, abdomen, etc., or combinations thereof. As another example, the target object may be a human-made component of living or non-living organic and / or inorganic matter. In some embodiments, medical image data related to the target object may include projection data of the target object, one or more scanned images, etc.

[0035] In some embodiments, the imaging device 110 may be a non-invasive biomedical imaging device for disease diagnosis or research purposes. For example, the imaging device 110 may include a single-modal scanner and / or a multimodal scanner. A single-modal scanner may include, for example, an ultrasound scanner, an X-ray scanner, a computed tomography (CT) scanner, a magnetic resonance imaging (MRI) scanner, an ultrasound examination device, a positron emission tomography (PET) scanner, an optical coherence tomography (OCT) scanner, an ultrasound (US) scanner, an intravascular ultrasound (IVUS) scanner, a near-infrared spectroscopy (NIRS) scanner, a far-infrared (FIR) scanner, or any combination thereof. A multimodal scanner may include, for example, an X-ray imaging-magnetic resonance imaging (X-MRI) scanner, a positron emission tomography-X-ray imaging (PET-X-ray) scanner, a single-photon emission computed tomography-magnetic resonance imaging (SPECT-MRI) scanner, a positron emission tomography-computed tomography (PET-CT) scanner, a digital subtraction angiography-magnetic resonance imaging (DSA-MRI) scanner, etc. The scanners described above are for illustrative purposes only and are not intended to limit the scope of this application. As used herein, the term "imaging modality" or "modality" broadly refers to imaging methods or techniques for collecting, generating, processing, and / or analyzing imaging information of a target object.

[0036] In some embodiments, the imaging device 110 may include modules and / or components for performing imaging and / or related analyses. In some embodiments, the imaging device 110 may include a radiation generating device, auxiliary devices, and an imaging device. A radiation generating device refers to a device that generates and controls radiation (e.g., X-rays). Radiation auxiliary devices refer to various facilities designed to complement the radiation generating device to meet the needs of clinical diagnosis and treatment. These may include mechanical equipment such as examination beds, diagnostic beds, catheterization beds, radiography beds, etc., various support and suspension devices, braking devices, holding devices, grids, filter plates, and shielding devices. In some embodiments, the radiation imaging device may take many forms. For example, a digital imaging device may include a detector, a computer system, and image processing software; other imaging devices may include a fluorescent screen, a film cassette, an image intensifier, or a video conferencing system.

[0037] This specification describes embodiments primarily using an imaging device including a digital imaging apparatus as an example. The detector can be used to convert the acquired optical signals into electrical signals. In some embodiments, the detector may include one or more detector modules, for example, Figure 7 As shown, each bar can represent a group of detector modules, and the detector can consist of multiple detector modules corresponding to multiple bars. In some embodiments, each group of detector modules may include a photosensitive module and a readout circuit, for example, Figure 2The detector module shown herein includes a photosensitive module for acquiring photon signals from rays passing over a target object and converting these photon signals into electrical signals. A readout circuit reads the electrical signals collected by the photosensitive module and converts them into digital data for generating medical images. In some embodiments, the detector may include semiconductor detectors, photovoltaic detectors, etc., and this specification does not limit this. More information about detectors can be found elsewhere in this specification, for example... Figures 2-7 The details and related descriptions will not be repeated here.

[0038] In some embodiments, data acquired by imaging device 110 (e.g., medical images of the target object) may be transmitted to processor 120 for further analysis. Additionally or alternatively, data acquired by imaging device 110 may be sent to a terminal device (e.g., display device 130) for display and / or to a storage device (e.g., storage device 140) for storage.

[0039] Processor 120 can process data and / or information obtained from imaging device 110, storage device 140, or other components of medical imaging system 100 (e.g., user terminal). For example, processor 120 can acquire medical image data of a target object from imaging device 110. Alternatively, processor 120 can acquire and analyze images of a target object captured by an image acquisition device. In some embodiments, processor 120 can be a single server or a group of servers. The server group can be centralized or distributed. In some embodiments, processor 120 can be local or remote. For example, processor 120 can access information and / or data from imaging device 110 and / or storage device 140 via a network. Alternatively, processor 120 can be directly connected to imaging device 110 and / or storage device 140 to access information and / or data. In some embodiments, processor 120 can be implemented on a cloud platform. For example, the cloud platform can include private cloud, public cloud, hybrid cloud, community cloud, distributed cloud, inter-cloud cloud, multi-cloud, etc., or any combination thereof.

[0040] In some embodiments, processor 120 may include one or more processors (e.g., a single-chip processor or a multi-chip processor). By way of example only, processor 120 may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), an application-specific instruction set processor (ASIP), an image processing unit (GPU), a physical processing unit (PPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), a programmable logic device (PLD), a controller, a microcontroller unit, a reduced instruction set computer (RISC), a microprocessor, or any combination thereof. In some embodiments, processor 120 may be part of imaging device 110. For example, processor 120 may be integrated within imaging device 110 to process digitized data output from a detector system to generate medical images of the target object.

[0041] Display device 130 can be connected to imaging device 110 and / or processor 120 for inputting / outputting information and / or data. For example, a user can interact with imaging device 110 through display device 130 to control one or more components of imaging device 110. As another example, imaging device 110 can output generated medical images to display device 130 for display to the user. In some embodiments, display device 130 may include an input device. The input device may be a keyboard input, a touchscreen (e.g., with haptic or haptic feedback) input, voice input, eye-tracking input, gesture tracking input, brain monitoring system input, image input, video input, or any other similar input mechanism. Input information received through the input device can be transmitted to processor 120 via, for example, a bus, for further processing. Other types of input devices may include cursor control devices, such as a mouse, trackball, or cursor arrow keys. In some embodiments, an operator (e.g., a healthcare professional) can input instructions reflecting the category of a medical image of a target object through the input device. In some embodiments, display device 130 may be part of imaging device 110.

[0042] Storage device 140 can store data, instructions, and / or any other information. For example, storage device 140 can store medical image data of a target object acquired by imaging device 110, images captured by image acquisition device, etc. In some embodiments, storage device 140 can store data obtained from imaging device 110 and / or processor 120. In some embodiments, storage device 140 can store data and / or instructions used by processor 120 to perform or use in order to complete the exemplary methods described in this application. In some embodiments, storage device 140 may include mass storage, removable storage, volatile read-write storage, read-only storage (ROM), etc., or any combination thereof. In some embodiments, storage device 140 can be implemented on a cloud platform.

[0043] In some embodiments, storage device 140 may be connected to a network to communicate with at least one other component of medical imaging system 100 (e.g., imaging device 110, processor 120). At least one component of medical imaging system 100 may access data stored in storage device 140 (e.g., medical image data of a target object, etc.) via the network. In some embodiments, storage device 140 may be part of imaging device 110 and / or processor 120.

[0044] It should be noted that the above description is provided for illustrative purposes only and is not intended to limit the scope of this application. Various changes and modifications can be made by those skilled in the art based on the guidance of this application. Features, structures, methods, and other features of the exemplary embodiments described in this application can be combined in various ways to obtain other and / or alternative exemplary embodiments. For example, storage device 140 may be a data storage device including a cloud computing platform (e.g., public cloud, private cloud, community cloud, and hybrid cloud). However, these changes and modifications will not depart from the scope of this application.

[0045] Figure 2 This is an exemplary schematic diagram of a detector module according to some embodiments of this specification.

[0046] The basic principle of a semiconductor detector is that charged particles generate electron-hole pairs within the sensitive volume of the detector. These electron-hole pairs drift under the influence of an external electric field, thus outputting a signal. In some embodiments, the electron-hole pairs in the semiconductor detector can also be referred to as the information carriers of the detector. In some embodiments, the semiconductor detector may include a PN junction semiconductor detector, a lithium drift semiconductor detector, a high-purity germanium semiconductor detector, a compound semiconductor detector, or other special types of semiconductor detectors.

[0047] Semiconductor detectors, with their advantages of good energy linearity, high resolution, fast time response, adjustable sensitive area thickness, simple structure, small size, and light weight, are widely used in the field of medical imaging. For example, when X-rays emitted by imaging device 110 pass through the target object and irradiate the semiconductor detector, if the energy of the photons is equal to or greater than the band gap of the semiconductor, electrons in the valence band absorb the photons and enter the conduction band, generating electron-hole pairs (this type of charge carrier can also be called photogenerated charge carriers). Under high voltage, the electron-hole pairs separate and drift to the corresponding electrodes, generating induced charges on the electrodes. The semiconductor detector can output the induced charges to a processor (e.g., processor 120) for processing or to a storage device (e.g., storage device 140) for storage. In some embodiments, the semiconductor detector can collect the generated induced charges and convert them into digital data, for example, obtain photon counts in different energy ranges based on the induced charges, and output them to a processor (e.g., processor 120) for processing or to a storage device (e.g., storage device 140) for storage.

[0048] Because of the effect of the electric field on electrons, their velocity and energy change. From the perspective of the band structure, this energy change represents an electron transitioning from one energy level to another. In the valence band, the energy levels are already occupied by electrons; generally, under the influence of an external electric field, these electrons do not form a current and contribute nothing to conductivity. In the conduction band, the energy levels are partially occupied by electrons. Under the influence of an external electric field, electrons absorb energy from the field and transition to unoccupied energy levels, forming a current and contributing to conductivity. The forbidden zone between the valence and conduction bands is called the forbidden band.

[0049] In some embodiments, the detector module may include a photosensitive module and a readout circuit. The photosensitive module can be used to convert photons into electrical signals (e.g., electron-hole pairs), and the readout circuit can be used to read the electrical signals from the photosensitive module and convert them into digital data. In some embodiments, the photosensitive module and the readout circuit can be integrated on a data acquisition board to form a thin-film detector module.

[0050] In some embodiments, such as Figure 2 As shown, the photosensitive module may include a photosensitive substrate, a back electrode located on a first main surface of the photosensitive substrate, and multiple sets of electrode strips located on a second main surface of the photosensitive substrate. In some embodiments, each set of electrode strips may include a set of sub-electrodes, and at least one set of the multiple sets of electrode strips may include signal collection electrodes and non-collection electrodes, for example... Figure 4 As shown in the illustration. In some embodiments, each group of electrode strips may comprise at least two groups of sub-electrodes whose length increases or decreases exponentially along the longitudinal direction. For example... Figure 2As shown, the direction indicated by the black arrow can represent the incident direction of the ray, and the black rectangle can represent the sub-electrode. Each set of electrode strips can include a first sub-electrode 201, a second sub-electrode 203, etc., whose length increases exponentially in the Z direction. In some embodiments, at least one set of multiple sets of sub-electrodes can be composed of signal collecting electrodes and non-collecting electrodes, for example... Figures 5A-6B As shown.

[0051] In some embodiments, the photosensitive substrate may employ compounds as photosensitive materials, such as crystalline Si (silicon), CdTe, GaAs, HgI2, and CdZnTe (CZT). By way of example only, the semiconductor detector may employ an N-type Si substrate as the photosensitive material. In some embodiments, the photosensitive substrate may include PN-type, PIN-type, or other structures.

[0052] In some embodiments, the readout circuit may include an integrated circuit, such as an application-specific integrated circuit (ASIC). In some embodiments, the detector module may include one or more readout circuits. In some embodiments, the number of readout circuits in the detector module may be the same as the number of electrode strip groups, or the total number of sub-electrodes, or the number of sub-electrodes in each electrode strip group. For example, each electrode strip group may correspond to one ASIC circuit, or each sub-electrode group may correspond to one ASIC circuit, or sub-electrodes of the same length in all electrode strip groups may correspond to one ASIC circuit, etc. In some embodiments, the readout circuit may be located at any position on the semiconductor detector. Preferably, the readout circuit may be located on any side of the detector module parallel to the incident direction of the radiation, for example... Figure 2 The positions shown are to prevent photons from affecting the readout circuit when they enter the semiconductor detector. In some embodiments, the readout circuit can be used to read the electrical signals output by the electrode strips, for example, to read the electrical signals collected by the signal collection electrodes of at least one set of electrode strips, or the electrical signals collected by the signal collection electrodes and non-collection electrodes of at least one set of electrode strips.

[0053] It is important to clarify that the term "Application-Specific Integrated Circuit (ASIC)" should be interpreted broadly as any general integrated circuit used and configured for a specific application. For example, in a photon counting detector, an ASIC may include preamplifier circuits, shaping and filtering circuits, pulse comparator circuits, and digital signal output circuits. As another example, in a photon energy integrating detector, an ASIC may include shaping filters and charge integrators.

[0054] In some embodiments, the readout circuit and the photosensitive module can be integrated on a single chip, meaning that the photosensitive module and the readout circuit can be fabricated on the same wafer.

[0055] In some embodiments, the length, width, and thickness (e.g., the length, width, and thickness of the photosensitive substrate) of the detector module 200 can be any reasonable value, and are not limited here. As an example only, the length (Z direction) of the detector module 200 can be greater than 30 mm, the width (Y direction) can be greater than 40 mm, and the thickness (X direction) can be in the range of 0.5 mm to 1 mm. By setting the detector module to have a length greater than 30 mm, a width greater than 40 mm, and a thickness in the range of 0.5 mm to 1 mm, the X-ray absorption efficiency of the semiconductor detector can be improved.

[0056] In some embodiments, the rays can enter from the edge or surface of the detector. For example, X-rays can enter from... Figure 2 The radiation enters the semiconductor detector in the direction of the black arrow or perpendicular to the depth direction of the electrode strip. Preferably, the radiation can enter the semiconductor detector along the depth direction of the electrode strip.

[0057] Figure 3A and 3B These are exemplary schematic diagrams of detector modules according to other embodiments of this specification. Figure 3A To show the diagram from the front, Figure 3B This is a side view diagram.

[0058] like Figure 3A As shown in 3B, in some embodiments, the detector module 300 can be a strip detector, i.e., the electrode strips are strip electrodes, wherein a group of strip electrodes (each column corresponds to a group of strip electrodes) can constitute a pixel. In some embodiments, the pixel size of the detector can be determined based on the spacing between the strip electrodes and the thickness of the photosensitive substrate. For example, when the thickness h of the photosensitive substrate and the spacing s between the horizontally arranged strip electrodes are both 0.5 mm, the pixel size of the detector module is 0.5 mm * 0.5 mm. In some embodiments, the spacing between each group of strip electrodes and the thickness of the photosensitive substrate can be set according to actual conditions. For example, when the width of the detector module is 40 mm, if it is divided into 80 groups of strip electrodes, the spacing between each group of strip electrodes can be 0.5 mm, i.e., the detector contains 80 pixels. For example, the thickness of the photosensitive substrate can be in the range of 0.5 mm to 1 mm.

[0059] In some embodiments, each set of electrode strips may include at least two sets of sub-electrodes. For example, Figure 3AAs shown in 3B, each electrode strip may include three sets of sub-electrodes arranged longitudinally: a first sub-electrode 201, a second sub-electrode 203, and a third sub-electrode 205. In some embodiments, the difference between the photon count rates output by each sub-electrode in at least two sets of sub-electrodes of the electrode strip may be within a preset range. In some embodiments, the preset range may include any reasonable range such as 0-1, 0-10, 1-10, etc. For example, the difference between the photon count rates output by each sub-electrode in at least two sets of sub-electrodes may be 0, that is, the photon count rates output by each sub-electrode are the same. In some embodiments, the length of each sub-electrode in at least two sets of sub-electrodes may increase or decrease exponentially along the longitudinal direction. In some embodiments, during application, the length of each sub-electrode in at least two sets of sub-electrodes may increase exponentially along the incident direction of the ray; for example, the lengths of the first sub-electrode 201, the second sub-electrode 203, and the third sub-electrode 205 may increase exponentially along the incident direction of the ray. In some embodiments, the length ratio of at least two sub-electrodes (e.g., first sub-electrode 201, second sub-electrode 203, and third sub-electrode 205) of each set of electrode strips can be any value that makes the photon count rate output by each set of sub-electrodes similar or the same. For example, the ratio along the incident direction of the ray (i.e., the Z direction) can be 1:2:4, and this specification does not limit this.

[0060] In some embodiments, the three sub-electrodes of the detector module 300 can each correspond to three different readout circuits. For example, Figure 3A The three dashed boxes in the diagram correspond to three sub-electrodes. All first sub-electrodes 201 in the first dashed box can correspond to the same readout circuit 1; all second sub-electrodes 203 in the second dashed box can correspond to the same readout circuit 2; and all third sub-electrodes 205 in the third dashed box can correspond to the same readout circuit 3. This effectively distributes the count of a pixel evenly across the three sub-electrodes, which are then read out separately.

[0061] In some embodiments, the detector module 300 may include a photon counting detector, an energy integrating detector, etc. The number of readout circuits is the same as the number of sub-electrodes in each group of strip electrodes (i.e., electrode strips). When photons enter the semiconductor detector and are deposited in a pixel, electron-hole pairs are generated. These pairs separate under high voltage (e.g., a bias voltage of 100-150V) and drift to the corresponding electrode, generating induced charges. The readout circuits can collect the induced charges on the electrodes and output photon counts or charge integrations for different energy ranges. For example, the readout circuit of a photon counting detector may correspond to a counting integrated circuit composed of a preamplifier circuit, a shaping filter circuit, a pulse comparator, and a digital signal output circuit. In this case, the semiconductor detector can output photon counts for three different energy ranges by pulse comparison of the shaped and filtered signal. As another example, the readout circuit of a photon energy integrating detector may correspond to an integrating integrated circuit composed of a shaping filter circuit and a charge integrating circuit. In this case, the semiconductor detector can perform current integration on the shaped and filtered photocurrent (i.e., the current signal generated by photon conversion) to achieve charge integration of the number of photogenerated charges. Furthermore, the processor can calculate the light intensity information of the corresponding segmented energy spectrum based on the charge integration collected by each electrode and the linear relationship between light intensity and photogenerated charge.

[0062] Generally, when rays enter a semiconductor detector from the edge, lower-energy photons are more likely to deposit in the upper layer along the incident direction, while higher-energy photons are more likely to deposit in the lower layer. Therefore, the upper layer reads out mostly low-energy photons, the middle layer mostly reads out mostly medium-energy photons, and the bottom layer mostly reads out mostly high-energy photons. In the embodiments of this specification, by dividing each group of electrode strips into multiple segments of exponentially increasing length (e.g., first sub-electrode 201, second sub-electrode 203, and third sub-electrode 205), low, medium, and high-energy photons can be collected separately. This improves the efficiency of photon counting / integration calculation while satisfying multi-spectral image reconstruction, thereby reducing patient radiation dose, improving the accuracy of quantitative imaging analysis, and achieving ultra-high spatial resolution.

[0063] Figure 3B To and Figure 3A A side view of the corresponding detector module. (For example...) Figure 3BAs shown, in some embodiments, the other side of the detector module 300 opposite the electrode strip (i.e., the first main surface) may include a back electrode 213 covering the entire sensitive area of ​​the detector. The distance h between the electrode strip and the back electrode 213 corresponds to the thickness of the photosensitive substrate. It should be noted that the thicknesses of the electrode strip and the back electrode 213 in the figure are for illustrative purposes only; in actual applications, the electrode strip and the back electrode 213 are relatively thin. In some embodiments, the back electrode 213 may be a cathode or an anode. More information about the photosensitive substrate and electrodes can be found in other parts of this specification (e.g., Figure 2 (and related descriptions), which will not be elaborated here.

[0064] In some alternative embodiments, the number of sub-electrodes in each group of electrode strips in the detector module 300 can be adjusted to other numbers as needed, for example, dividing each group of electrode strips into 5-6 groups of sub-electrodes. For photon counting detectors, this design can reduce the data readout time and bandwidth requirements of the readout circuit; for energy integrating detectors, this design can obtain information in more energy ranges, thereby making the energy spectrum image more accurate.

[0065] It should be noted that the above descriptions of detector modules 200 and 300 are for illustrative purposes only and do not limit the scope of this specification. Those skilled in the art can make various modifications and changes to the structure of detector modules 200 or 300 under the guidance of this specification. For example, the structure of detector module 300 can be applied to a photovoltaic detector. However, these modifications and changes are still within the scope of this specification.

[0066] Figure 4 This is a schematic diagram of the detector module according to some embodiments of this specification.

[0067] like Figure 4 As shown, in some embodiments, at least one set of multiple electrode strips in the detector module may consist of signal collecting electrodes and non-collecting electrodes. In some embodiments, the signal collecting electrodes of at least one set of electrode strips may be surrounded by one or more non-collecting electrodes, for example, Figure 4 As shown in the dashed box below, the central black circle represents the signal collection electrode, and the multiple rectangular frames surrounding the signal collection electrode represent non-collection electrodes. In some embodiments, the shape of the non-collection electrodes may include circles, rectangles, hexagons, ellipses, etc., or any combination thereof. In some embodiments, the signal collection electrode may be located at any reasonable position such as the center, top, or bottom of the electrode strip, without limitation. In some embodiments, the signal collection electrodes and non-collection electrodes of at least one set of electrode strips can be connected by interlocking fingers, for example... Figures 6A-6BAs shown in the figure. In some embodiments, multiple sets of electrode strips may include electrode strips in which signal collection electrodes and non-collection electrodes are connected by interlocking fingers, and electrode strips in which signal collection electrodes are surrounded by multiple non-collection electrodes.

[0068] By setting at least one set of multiple electrode strips in the detector module to a special geometric structure consisting of signal collection electrodes and non-collection electrodes, the area of ​​the signal readout electrode (i.e., signal collection electrode) can be reduced, thereby reducing the detector readout capacitance, improving electrode performance uniformity, and reducing the impact of incomplete collection on the detector's sensitive area, thus improving the detector's energy resolution and count rate.

[0069] Figures 5A-5C This is a schematic diagram of the detector module according to other embodiments of this specification.

[0070] In some embodiments, each set of sub-electrodes or each set of electrode strips in the detector module may consist of signal collecting electrodes and non-collecting electrodes. In some embodiments, the signal collecting electrodes may be surrounded by one or more non-collecting electrodes, i.e., the electrode strips or sub-electrodes have a drift-type structure. For example Figure 5A As shown, each group of sub-electrodes can be composed of multiple non-collecting electrodes surrounding the signal collecting electrode. By setting all the electrode strips of the detector to a structure in which non-collecting electrodes surround the signal collecting electrode, it helps to ensure that the signal collecting electrode area of ​​electrodes (i.e., sub-electrodes) at different depths is consistent, thereby improving the consistency of the detector's response across different channels.

[0071] In some embodiments, a portion of the sub-electrodes of the detector module may consist of signal collecting electrodes and non-collecting electrodes. In some embodiments, one of the sub-electrodes near the edge of the detector module in at least two sets of sub-electrodes of each set of electrode strips may include signal collecting electrodes and non-collecting electrodes, for example, Figure 5B or Figure 5C As shown in the diagram. In some embodiments, the shorter sub-electrode of at least two sub-electrodes in each group of electrode strips may include a signal collection electrode and a non-collection electrode. For example, Figure 5B As shown, in the detector module 500, among the sub-electrodes in which the length of each set of electrode strips increases exponentially along the incident direction of the rays, the first sub-electrode 201 near the incident direction of the rays can be composed of a signal collecting electrode and a non-collecting electrode.

[0072] In some embodiments, one or more sub-electrodes away from the incident direction of the radiation may include signal collecting electrodes and non-collecting electrodes; that is, the longer sub-electrodes in the multiple sets of sub-electrodes of the detector module may be composed of signal collecting electrodes and non-collecting electrodes. For example... Figure 5CAs shown, the longest third sub-electrode 205 in each group of electrode strips of the detector module 500 can be composed of a signal collecting electrode and a non-collecting electrode. Similarly, the longer second sub-electrode 203 and the longest third sub-electrode 205 in each group of electrode strips of the detector module 500 can both be composed of signal collecting electrodes and non-collecting electrodes. Furthermore, the longer second sub-electrode 203 in each group of electrode strips of the detector module 500 can be composed of both a signal collecting electrode and a non-collecting electrode.

[0073] The non-collecting electrodes surrounding the signal collecting electrode can create depletion regions on both sides of the detector module (i.e., on both sides corresponding to the incident direction of the ray). Under the influence of an external electric field, this helps the detector achieve a fully depleted state and forms a drift electric field pointing towards the signal collecting electrode. Electrons drift to the signal collecting electrode under the influence of this electric field. Since electrons drift for a long time in the depletion region before reaching the small-area signal collecting electrode, the capacitance between the electrodes is very small, resulting in low noise and improved energy resolution of the detector.

[0074] Figures 6A-6B This is a schematic diagram of the detector module according to other embodiments of this specification.

[0075] like Figure 6A As shown in Figure 6B, in some embodiments, all or part of the electrode strips or strip-shaped sub-electrodes of the detector module can be coplanar gate electrodes, that is, the signal collection electrode and the non-collection electrode are connected by interlocking fingers. For example, any 3, 6, or 8 groups of electrode strips can be selected to be configured as coplanar gate electrodes, or any 1 group (such as the first sub-electrode 201 or the third sub-electrode 205), 2 groups, or 3 groups of strip-shaped sub-electrodes can be selected to configure their signal collection electrodes and non-collection electrodes to be connected by interlocking fingers. In some embodiments, the opposite sides of the signal collection electrode and the non-collection electrode connected by interlocking fingers can be connected together, for example... Figure 6A As shown in the dashed box, the signal collecting electrode and the non-collecting electrode are connected by interlocking fingers, and the signal collecting electrode and the non-collecting electrode are connected to the opposite side of the interlocking side by wires or other conductive structures. In some embodiments, the number of branches of the signal collecting electrode and the number of branches of the non-collecting electrode can be any reasonable value, and they are all the same number.

[0076] The detector's electrode strips or strip-shaped sub-electrodes are designed as a coplanar grid structure in which the signal collection electrode and the non-collection electrode are connected by interpolation. The output signal of the photosensitive substrate is the difference between the signals of the signal collection electrode and the non-collection electrode. By adjusting the weighting factors of the signal collection electrode and the non-collection electrode, the influence of incomplete collection can be almost eliminated on the one hand, and the influence of the non-uniformity of the weighting potential on the collection of electrons in the non-sensitive region can be reduced on the other hand, thereby improving the energy resolution of the detector.

[0077] It should be noted that the above descriptions of detector modules 500 and 600 are for illustrative purposes only and do not limit the scope of this specification. Those skilled in the art can make various modifications and changes to the structure of detector modules 500 and 600 under the guidance of this specification. For example, multiple sets of electrode strips may contain only one set of coplanar grid structure electrodes or drift-type structure electrodes. As another example, drift-type structure electrodes, coplanar grid structure electrodes, and strip electrodes may be arranged alternately. Furthermore, the signal collection electrodes and non-collection electrodes of at least two sets of sub-electrodes in each set of electrode strips, with the shorter or longer sub-electrodes, can be connected by interlocking fingers. However, these modifications and changes are still within the scope of this specification.

[0078] Figure 7 This is an exemplary schematic diagram of a semiconductor detector according to some embodiments of this specification.

[0079] like Figure 7 As shown, in some embodiments, the semiconductor detector 700 may include multiple detector modules (such as detector modules 200, 400, 500, or 600), for example, 500, 1000, 3000, etc. In some embodiments, the multiple detector modules of the semiconductor detector 700 can be combined in any reasonable manner. For example, multiple detector modules can be divided into two groups, interlocked, or stacked together to form the semiconductor detector 700. In some embodiments, the semiconductor detector can be made of materials such as silicon, cadmium telluride, or cadmium zinc telluride. In some embodiments, when the semiconductor detector is made of silicon, since silicon has a low blocking ability for X-rays, its thickness in the depth direction (Z direction) can be set to be greater than 30 mm to achieve a quantum efficiency of 80%.

[0080] In some embodiments, to reduce crosstalk between each detector module of the semiconductor detector and improve the quantum efficiency of the semiconductor detector, a reflective material, such as tungsten, can be coated on one side of the back electrode of each detector module. In some embodiments, the thickness of the reflective material can be in the range of 0.2 micrometers to 0.5 micrometers.

[0081] It should be noted that the above description of the semiconductor detector 700 is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to the structure of the semiconductor detector 700 under the guidance of this specification. However, these modifications and changes are still within the scope of this specification.

[0082] In some embodiments, the imaging device may include a radiation source, a semiconductor detector 700, and an image processing device. The radiation source may be used to emit radiation with multiple energy ranges toward a target object, such as X-rays with a certain energy range. The semiconductor detector may be used to convert the radiation passing through the target object into digital data. The image processing device may be used to generate a medical image of the target object based on the digital data of the target object.

[0083] Figure 8 This is an exemplary flowchart of a medical imaging method according to some embodiments of this specification.

[0084] The medical imaging method 800 can be executed by the medical imaging device 110. For example, the medical imaging method 800 can be stored in a storage device (such as storage device 140) in the form of a program or instructions, and the medical imaging method 800 can be implemented when the imaging device 110 executes the program or instructions. In some embodiments, the medical imaging method 800 can be executed by the medical imaging system 900.

[0085] Step 810 involves acquiring digital data related to photons passing through the target object using a semiconductor detector. In some embodiments, step 810 may be performed by the detection module 910.

[0086] In some embodiments, the digitized data may include projection data of the target object. In some embodiments, the digitized data may include photon counts in different energy ranges. In some embodiments, the digitized data may include energy integrals in different energy ranges. In some embodiments, digitized data related to photons passing through the target object may be acquired from a semiconductor detector. In some embodiments, digitized data related to photons passing through the target object may be acquired from a storage device.

[0087] In some embodiments, the imaging device emits rays from a ray source toward a target object. The rays pass through the target object and enter a semiconductor detector, where they are converted into electron-hole pairs. These electron-hole pairs drift to their corresponding electrodes under the influence of an external electric field, generating induced charges. The readout circuit of the semiconductor detector can calculate photon counts or energy integrals for different energy ranges based on the readout induced charges, thereby obtaining projection data—i.e., digitized data—of rays with different energy ranges after passing through the target object.

[0088] Step 820: Based on the digitized data, generate a medical image of the target object. In some embodiments, step 820 may be performed by the medical image generation module 920.

[0089] In some embodiments, the processor may perform image processing based on the digitized data of the target object to generate a medical image of the target object. For example, image processing may include image normalization, image reconstruction, image smoothing, image compression, image enhancement, image matching, image registration, image geometric correction, image fusion, image restoration, or removal of image distortion, noise, etc., or any combination thereof.

[0090] In some embodiments, the processing device can post-process the medical images generated by the imaging device to obtain a target medical image. For example, the medical image generation module 920 can perform image quality evaluation on the medical images reconstructed by the imaging device 110 to obtain better quality medical images, helping medical staff to clearly understand the user's lesion information, etc.

[0091] It should be noted that the above description of method 800 is for illustrative purposes only and does not limit the scope of this specification. Those skilled in the art can make various modifications and changes to method 800 under the guidance of this specification. However, these modifications and changes remain within the scope of this specification.

[0092] Figure 9 This is an exemplary block diagram of a medical imaging system according to some embodiments of this specification.

[0093] like Figure 9 As shown, the medical imaging system 900 may include a detection module 910, a medical image generation module 920, and an output module 930. In some embodiments, the medical imaging system 900 may be composed of... Figure 1 The imaging device 110 shown is implemented.

[0094] The detection module 910 can be used to convert photons passing through a target object into digital data.

[0095] The medical image generation module 920 can be used to generate a medical image of a target object based on digitized data. In some embodiments, the medical image generation module 920 may further include a data processing unit 923 and an image generation unit 925. In some embodiments, the data processing unit 923 can be used to process the digitized data of the target object. In some embodiments, the image generation unit 925 can be used to generate a medical image of the target object based on projection data. In some embodiments, the image generation unit 925 can be used to perform image processing on the reconstructed image. In some embodiments, the image generation unit 925 can be used to perform post-processing on the medical image to obtain the target medical image.

[0096] The output module 930 can be used to output medical images. In some embodiments, the output module 930 can output medical images to a user. For example, the output module 930 can output the generated medical images to a display device 130 for display to the user.

[0097] It should be noted that the above description of system 900 and its modules is for convenience only and should not be construed as limiting this specification to the scope of the embodiments described. It is understood that those skilled in the art, after understanding the principles of this system, may arbitrarily combine the various modules or construct subsystems connected to other modules without departing from these principles. In some embodiments, the detection module 910, the medical image generation module 920, and the output module 930 may be different modules within the same system, or a single module may implement the functions of two or more of the aforementioned modules. In some embodiments, the detection module 910, the medical image generation module 920, and the output module 930 may share a single storage module, or each module may have its own separate storage module. Such modifications are all within the scope of this specification.

[0098] The beneficial effects that the embodiments of this specification may bring include, but are not limited to: (1) By dividing the electrode strip into multiple groups of sub-electrodes, the collection efficiency of photon charges in the high, medium and low energy ranges can be improved, thereby improving the imaging efficiency; (2) By designing the electrode strip as a drift electrode or a coplanar gate electrode, the area of ​​the signal collection electrode can be reduced, noise can be reduced, and resolution can be improved; (3) By setting the sub-electrode of the detector module that mainly absorbs low-energy rays near the incident direction of the rays to a structure in which multiple non-collection electrodes surround the signal collection electrode, the count rate and energy resolution of the layer where the sub-electrode is located are improved, thereby helping to improve the performance of the detector; (4) By setting the long sub-electrode of the semiconductor detector to a structure in which multiple non-collection electrodes surround the signal collection electrode, the area increase caused by the long electrode strip is avoided, the performance of the deep electrode is improved, and the uniformity of electrodes at different depths of the detector is beneficial; (5) By setting the number of readout circuits to be the same as the number of sub-electrodes contained in each group of electrode strips, the interference between readout circuits can be reduced, the readout efficiency can be improved, thereby improving the detection efficiency of the detector. It should be noted that different embodiments may produce different beneficial effects. In different embodiments, the beneficial effects may be any one or a combination of the above, or any other possible beneficial effects.

[0099] The basic concepts have been described above. Obviously, for those skilled in the art, the detailed disclosure above is merely illustrative and does not constitute a limitation of this specification. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this specification. Such modifications, improvements, and corrections are suggested in this specification and therefore remain within the spirit and scope of the exemplary embodiments described herein.

[0100] Furthermore, this specification uses specific terms to describe embodiments thereof. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "an embodiment," "one embodiment," or "an alternative embodiment" in different locations throughout this specification do not necessarily refer to the same embodiment. Moreover, certain features, structures, or characteristics in one or more embodiments of this specification can be appropriately combined.

[0101] Furthermore, unless expressly stated in the claims, the order of processing elements and sequences, the use of numbers and letters, or other names described in this specification are not intended to limit the order of the processes and methods described herein. Although various examples have been discussed in the foregoing disclosure of some embodiments of the invention that are currently considered useful, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments; rather, the claims are intended to cover all modifications and equivalent combinations that conform to the spirit and scope of the embodiments described herein. For example, while the system components described above can be implemented using hardware devices, they can also be implemented solely using software solutions, such as installing the described system on existing servers or mobile devices.

[0102] Similarly, it should be noted that, in order to simplify the description disclosed herein and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of embodiments in this specification may sometimes combine multiple features into a single embodiment, drawing, or description thereof. However, this method of disclosure does not imply that the subject matter of this specification requires more features than those mentioned in the claims. In fact, the embodiments contain fewer features than all the features of a single embodiment disclosed above.

[0103] In some embodiments, numbers describing the quantity of components and attributes are used. It should be understood that such numbers used in the description of embodiments are modified in some examples with the terms "approximately," "approximately," or "generally." Unless otherwise stated, "approximately," "approximately," or "generally" indicates that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed depending on the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this specification are approximate values, in specific embodiments, such values ​​are set as precisely as feasible.

[0104] For each patent, patent application, patent application publication, and other material, such as articles, books, specifications, publications, and documents, referenced in this specification, the entire contents of which are incorporated herein by reference. This excludes historical application documents that are inconsistent with or conflict with the content of this specification, as well as documents that limit the broadest scope of the claims in this specification (currently or subsequently appended to this specification). It should be noted that in the event of any inconsistency or conflict between the descriptions, definitions, and / or terminology used in the supplementary materials to this specification and the content of this specification, the descriptions, definitions, and / or terminology used in this specification shall prevail.

[0105] Finally, it should be understood that the embodiments described in this specification are merely illustrative of the principles of the embodiments described herein. Other variations may also fall within the scope of this specification. Therefore, alternative configurations of the embodiments described herein are intended to be illustrative rather than limiting, and should be considered consistent with the teachings of this specification. Accordingly, the embodiments described herein are not limited to those explicitly introduced and described herein.

Claims

1. An energy integrating semiconductor detector comprising at least one set of detector modules, characterized in that, The detector module includes: A photosensitive substrate, a back electrode located on a first main surface of the photosensitive substrate, and multiple sets of electrode strips located on a second main surface of the photosensitive substrate. Each set of electrode strips includes 5-6 sets of sub-electrodes arranged along the depth direction of the detector module. The length of each set of sub-electrodes increases exponentially along the depth direction, and the longest sub-electrode along the depth direction and closest to the edge of the detector module in each set of electrode strips includes a signal collecting electrode and a non-collecting electrode. The signal collecting electrode is surrounded by the non-collecting electrode or the signal collecting electrode and the non-collecting electrode are connected by interlocking fingers. The readout circuit is used to read the electrical signals output by the multiple sets of electrode strips and convert the electrical signals into digital data. The electrical signals include the electrical signals collected by the signal collection electrode, or the electrical signals collected by the signal collection electrode and the non-collection electrode.

2. The semiconductor detector of claim 1, wherein, The difference in photon count rate between adjacent sub-electrodes in each group of electrode strips is within a preset range.

3. The semiconductor detector according to claim 1, characterized in that, The readout circuit includes at least a charge integrator, and the number of readout circuits is the same as the number of sub-electrodes contained in each group of electrode strips.

4. A medical imaging method, characterized by, include: The semiconductor detector according to any one of claims 1-3 acquires digital data related to photons passing through the target object; Based on the digitized data, a medical image of the target object is generated.

5. An imaging device, characterized in that, include: X-ray source, used to emit X-rays to a target object; A semiconductor detector as described in any one of claims 1-3, for converting X-rays passing through the target object into digital data; and An image processing device for generating a medical image of the target object based on the digitized data.

6. The imaging device according to claim 5, characterized in that, The X-rays are incident along the sub-electrode arrangement direction of one set of electrode strips of the semiconductor detector.

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