Photon counting multi-spectral CT imaging device and method

Abstract

The present application provides a photon counting multi-spectrum CT imaging device and method, wherein the imaging device includes: a ray generating device; a surface array detector, the surface array detector includes: a sheet scintillation crystal, which is configured to convert the ray into visible light; a sheet microchannel plate, which is one-to-one coupled with the sheet scintillation crystal, which is configured to selectively pass the visible light converted by the sheet scintillation crystal; a photomultiplier element, which is coupled with the sheet microchannel plate to convert the selectively passed visible light into a scintillation pulse signal; a data transmission industrial control computer, which is configured to communicate with the ray generating device and the surface array detector to control the ray generating device and receive the detection data of the surface array detector; an image reconstruction industrial control computer, which is configured to communicate with the data transmission industrial control computer to receive the detection data of the surface array detector and perform image reconstruction. The present application can reduce optical crosstalk and improve spatial resolution.

Description

Technical Field

[0001] The present application relates to the field of CT imaging technology, and in particular to a photon counting multi-energy spectrum CT imaging device and method. Background Art

[0002] Existing CT detectors include semiconductor detectors and solid-state scintillation detectors (i.e., integrating detectors). Currently, mainstream international CT manufacturers have begun to make layouts in the field of photon counting based on semiconductor detectors. Existing photon counting X-ray detectors are mainly based on semiconductor silicon, cadmium telluride, cadmium zinc telluride, etc. Although these photon counting detectors have excellent X-ray detection performance, the intolerance and polarization effect of cadmium telluride and cadmium zinc telluride detectors for high-flux X-rays, complex readout circuits, high prices, and cadmium metals that cause environmental risks have greatly limited their applications. The solid-state scintillation detector used in the CT system includes scintillation crystals and photoelectric conversion devices. High-energy rays will be converted into visible light signals by scintillation crystals, and the visible light signals will be further converted into scintillation pulse signals by photoelectric conversion devices. In this process, the imaging spatial resolution has an important influence on the final imaging quality, and the current imaging spatial resolution needs to be improved. Taking small animal photon counting multi-spectral CT imaging as an example, small animal CT requires that the size of a single photoelectric conversion device be as small as possible to improve the spatial resolution of imaging. The existing detector scintillation crystal is coupled one-to-one with the photoelectric conversion device, and a single scintillation crystal requires light shielding, that is, a layer of anti-reflection material is wrapped around the outside of the single crystal to prevent light crosstalk. A single scintillation crystal cannot be cut to a sufficiently small size, and the overall size of a single pixel is further increased after being wrapped with anti-reflection material. Therefore, the size of a single pixel of the detector cannot be very small, which affects the spatial resolution of imaging and cannot be used for small animal micro-CT imaging. Summary of the invention

[0003] The present application aims to provide a photon counting multi-spectral CT imaging device and method to solve at least one of the above problems.

[0004] The photon counting multi-spectral CT imaging device provided by the present application comprises: a ray generating device; a surface array detector, wherein the surface array detector comprises: a sheet-like scintillation crystal, which is configured to convert the ray into visible light; a sheet-like microchannel plate, which is one-to-one coupled with the sheet-like scintillation crystal and is configured to selectively pass the visible light converted by the sheet-like scintillation crystal; a photomultiplier element, which is coupled with the sheet-like microchannel plate to convert the selectively passed visible light into a scintillation pulse signal; a data transmission industrial computer, which is configured to be communicatively connected with the ray generating device and the surface array detector to control the ray generating device and receive detection data of the surface array detector; and an image reconstruction industrial computer, which is configured to be communicatively connected with the data transmission industrial computer to receive detection data of the surface array detector and perform image reconstruction.

[0005] According to an embodiment of the present application, a thickness ratio of the sheet-like scintillator crystal to the sheet-like microchannel plate collimator is between 1:3 and 1:5.

[0006] According to an embodiment of the present application, silicone grease is provided between the sheet-like scintillator crystal and the sheet-like microchannel plate collimator, and silicone grease is provided between the sheet-like microchannel plate collimator and the photomultiplier element.

[0007] According to an embodiment of the present application, the ratio of the thickness of the sheet-like microchannel plate collimator to the diameter of the microchannel is between 8:1 and 10:1.

[0008] According to one embodiment of the present application, the photon counting multi-energy spectrum CT imaging device further includes a multi-voltage threshold digital readout acquisition card, which is configured to digitally acquire the scintillation pulse signal.

[0009] According to one embodiment of the present application, the multi-voltage threshold digital readout acquisition card is configured to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal, and classify and count the scintillation pulse signal according to the energy interval corresponding to the amplitude information of the scintillation pulse signal.

[0010] According to one embodiment of the present application, the multi-voltage threshold digital readout acquisition card is equipped with a multi-voltage threshold digital readout circuit, in which the energy interval is preset according to the energy of the photon, and the multi-voltage threshold digital readout circuit includes multiple digital readout channels, each readout channel includes: multiple comparators, which are configured to preset multiple thresholds corresponding to the amplitude of the scintillation pulse signal, and a threshold interval is formed between two adjacent thresholds, and the threshold interval corresponds to different energy intervals; the amplitude information of the scintillation pulse signal is the threshold interval corresponding to the amplitude of the pulse signal; multiple counting elements, which correspond one-to-one to the multiple comparators, and are configured to classify and count the scintillation pulse signal according to the energy interval corresponding to the amplitude information of the scintillation pulse signal.

[0011] According to an embodiment of the present application, the comparator is a plurality of low voltage differential signal input ports LVDS of a multi-voltage threshold digital readout acquisition card.

[0012] According to one embodiment of the present application, the photon counting multi-spectral CT imaging device further includes an image reconstruction module, which is configured to perform image reconstruction on the digital information acquired by the multi-voltage threshold digital readout acquisition card.

[0013] According to one embodiment of the present application, the photon counting multi-spectral CT imaging device also includes a replaceable power supply, which supplies power to the ray generating device, the planar array detector, the data transmission industrial computer and the image reconstruction industrial computer.

[0014] According to one embodiment of the present application, the replaceable power source is a modular combined battery.

[0015] According to one embodiment of the present application, the photon counting multi-spectral CT imaging device also includes a rotating element, and the ray generating device, the surface array detector, the replaceable power supply, the data transmission industrial computer, and the image reconstruction industrial computer are evenly arranged on the rotating element.

[0016] According to one embodiment of the present application, the rotating element is provided with an opening, and the motion-controlled bed can move through the opening.

[0017] According to one embodiment of the present application, the photon counting multi-spectral CT imaging device further includes a grating element, which is configured to monitor the rotation angle signal of the rotating element and feed it back to the data transmission industrial computer.

[0018] The photon counting multi-spectral CT imaging method provided in the present application comprises the following steps: using an image reconstruction industrial computer to perform a rapid pre-scan to adjust a motion control bed to a scanning position matching a ray generating device; the image reconstruction industrial computer controls the ray generating device to start via a data transmission industrial computer; using a surface array detector to count the energy intervals of the rays after attenuation by a measured object to generate projection data; the data transmission industrial computer receives the projection data and transmits it to the image reconstruction industrial computer for image reconstruction.

[0019] According to one embodiment of the present application, a planar array detector is used to count the energy intervals of rays after attenuation by the object to be measured to generate projection data, including: using the planar array detector to detect the rays to obtain a scintillation pulse signal; using a multi-voltage threshold digital readout acquisition card to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal, determining the corresponding energy interval according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal to generate projection data.

[0020] According to one embodiment of the present application, a multi-voltage threshold digital readout acquisition card is used to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal. The corresponding energy interval is determined based on the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal, and this is implemented using a multi-voltage threshold digital readout circuit.

[0021] According to one embodiment of the present application, the energy interval is preset in a multi-voltage threshold digital readout circuit according to the energy of the photon, and the energy interval corresponds to the threshold interval; the multi-voltage threshold digital readout circuit includes multiple digital readout channels, each readout channel includes multiple comparators and counting elements corresponding to the multiple comparators one by one; multiple comparators are used to preset multiple thresholds, and the amplitude of the scintillation pulse signal is compared with the preset multiple thresholds to obtain the highest threshold reached by the scintillation pulse signal to determine the threshold interval corresponding to the amplitude of the scintillation pulse signal; the energy interval corresponding to the scintillation pulse signal is determined according to the threshold interval corresponding to the amplitude of the scintillation pulse signal, and the multiple counting elements are used to classify and count the scintillation pulse signal according to the energy interval.

[0022] According to an embodiment of the present application, multiple thresholds are preset in a multi-voltage threshold digital readout acquisition card, and the comparison of the amplitude of the scintillation pulse signal with the preset multiple thresholds is implemented using a comparator of the multi-voltage threshold digital readout acquisition card.

[0023] According to one embodiment of the present application, the multi-voltage threshold digital readout circuit includes a plurality of digital readout channels, and each readout channel includes a plurality of the comparators.

[0024] According to one embodiment of the present application, a replaceable power supply is used to power the image reconstruction industrial computer, the motion control bed, the ray generating device, the data transmission industrial computer, and the photon counting detection device.

[0025] The photon counting multi-spectral CT imaging device and method provided in the present application adopt a surface array detector including a sheet-like scintillation crystal, a sheet-like microchannel plate, and a photomultiplier element array, so that the detector pixel is determined by the minimum size of the photomultiplier element. At this time, a single photomultiplier element can be made into a required small size, thereby improving the resolution. The sheet-like microchannel plate selects the visible light converted by the scintillation crystal, and visible light at a certain angle is incident on the photomultiplier element through its microchannel to reduce light crosstalk, so that the outside of the scintillation crystal does not need to be wrapped with anti-reflection material, and the detection area of ​​the scintillation crystal can be effectively utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following is a detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings. Here, the drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation of the present disclosure. In the drawings:

[0027] Figure 1 A schematic diagram showing the structure of a detector of a photon counting multi-energy spectrum CT imaging device according to an exemplary embodiment of the present application;

[0028] Figure 2 Another structural schematic diagram of a photon counting multi-energy spectrum CT imaging device according to an exemplary embodiment of the present application is shown;

[0029] Figure 3 A front view of a photon counting multi-energy spectrum CT imaging device according to an exemplary embodiment of the present application is shown;

[0030] Figure 4 A left side view of a photon counting multi-energy spectrum CT imaging device according to an exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0036] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present application.

[0037] like Figure 1 As shown, according to an exemplary embodiment of the present application, the photon counting multi-spectral CT imaging device disclosed in the present application has a surface array detector 100, which includes: a sheet-like scintillation crystal 110, which is configured to convert rays into visible light, and the rays include X-rays, gamma rays, and high-energy rays such as neutron rays, proton rays, and beta rays; a sheet-like microchannel plate 120, which is one-to-one coupled with the sheet-like scintillation crystal 110, and is configured to selectively pass the visible light converted by the sheet-like scintillation crystal 110; a photomultiplier element 130, and an array of the photomultiplier elements 130 is coupled to the sheet-like microchannel plate 120 to convert the visible light selected to pass into a scintillation pulse signal; wherein the sheet-like microchannel plate 120 selects visible light at a certain angle to be incident on the photomultiplier element 130 through its microchannel to reduce optical crosstalk.

[0038] The detector 100 in the present application adopts a surface array detector coupled with an array of a sheet (or surface) scintillation crystal 110, a sheet microchannel plate 120 and a photomultiplier element 130, so that the detector pixel is determined by the minimum size of the photomultiplier element 130, and at this time, a single photomultiplier element 130 can be processed to a required small size, thereby improving the resolution; and the visible light converted from the X-ray photon is incident on the photomultiplier element 130 through its microchannel by selecting a certain angle of visible light through the sheet microchannel plate 120 to reduce the light crosstalk, so that the outside of the scintillation crystal does not need to be wrapped with anti-reflection material, and the detection area of ​​the scintillation crystal can be effectively utilized. The present application adds a sheet microchannel plate 120 between the sheet (or surface) scintillation crystal 110 and the photomultiplier element 130 to filter out the visible light photons incident on the photomultiplier element at a large tilt angle, that is, selects the visible light photons in a certain angle direction to enter the photomultiplier element through the microchannel, thereby reducing the light crosstalk.

[0039] In one embodiment, the photomultiplier element 130 of the area array detector is a silicon photomultiplier tube (i.e., SiPM). The sheet (surface) scintillation crystal 110 is coupled one-to-one with the sheet (surface) microchannel plate 120, and coupled with the SiPM array to form a scintillation crystal / microchannel plate / SiPM area array detector. The pixel of the area array detector is determined by the minimum size of the SiPM. The size of a single SiPM can be reduced to 200μm or even smaller. The use of a detector with a smaller pixel size combined with adjustable magnification ratios can achieve higher resolution CT imaging of small animal CT. At the same time, due to the use of SiPM photonic chips, it has certain advantages in sensitivity, gain and dynamic range, can detect lower light intensities, and can even count single photons, which is particularly suitable for low-dose and ultra-low-dose CT imaging.

[0040] In a preferred embodiment, the scintillation crystal 110 of the surface array detector of the present application adopts lutetium yttrium silicate crystal with low background radiation, but is not limited thereto. The use of scintillation crystal 110 instead of semiconductor overcomes the problem that the photosensitive element of the semiconductor-based photon counting detector is intolerant to high-flux X-rays.

[0041] In one embodiment, the thickness ratio of the sheet-like scintillating crystal 110 to the sheet-like microchannel plate 120 along the radiation direction is between 1:3-1:5, so as to improve the effect of reducing light crosstalk. In a preferred embodiment, the ratio of the thickness of the sheet-like microchannel plate 120 to the diameter of the microchannel is between 8:1-10:1, so as to further improve the effect of reducing light crosstalk. Further, the visible light is selected to be incident on the photomultiplier element through the microchannel of the sheet-like microchannel plate at an angle of 0-30 degrees to reduce light crosstalk.

[0042] In one embodiment, silicone grease is disposed between the sheet-like scintillating crystal 110 and the sheet-like microchannel plate 120 , and silicone grease is disposed between the sheet-like microchannel plate 120 and the photomultiplier element 130 , so that visible light can be better incident on the silicon photomultiplier tube.

[0043] In one embodiment, the detector 100 may also include a multi-voltage threshold (MVT) digital readout acquisition card, which is configured to digitally acquire the scintillation pulse signal. By using a multi-voltage threshold digital readout acquisition card to realize digital readout, the position, energy, and time information of a single event can be accurately extracted, and the signal can be restored with high precision, so as to realize accurate acquisition of multi-energy spectrum CT data.

[0044] In one embodiment, the photon counting multi-spectral CT imaging device of the present application may further include an image reconstruction module, which is configured to reconstruct the digital information collected by the multi-voltage threshold digital readout acquisition card. The structural design of the image reconstruction module can adopt the existing technology and will not be described in detail here.

[0045] In one embodiment, the photon counting multi-energy spectrum CT imaging device of the present application may also include a ray generating device, which is configured to emit rays to the detection device, and the rays may include X-rays, gamma rays, neutron rays, proton rays, beta rays, etc.

[0046] like Figure 2 As shown, a photon counting multi-energy spectrum CT imaging device of another embodiment of the present application has a detector 200, which has at least one energy interval divided according to the photon energy. The multi-voltage threshold digital readout acquisition card 210 in the detector 200 is configured to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal, and classify and count the scintillation pulse signal according to the energy interval corresponding to the amplitude information of the scintillation pulse signal.

[0047] In one embodiment, the multi-voltage threshold digital readout acquisition card 210 is equipped with a multi-voltage threshold (MVT) digital readout circuit, in which the energy interval is preset according to the energy of the photon, and the multi-voltage threshold digital readout circuit includes multiple digital readout channels, each readout channel includes: multiple comparators, which are configured to preset multiple thresholds corresponding to the amplitude of the scintillation pulse signal, and a threshold interval is formed between two adjacent thresholds, and the threshold interval corresponds to different energy intervals; the amplitude information of the scintillation pulse signal is the threshold interval corresponding to the amplitude of the pulse signal; multiple counting elements, which correspond one-to-one to the multiple comparators, and are configured to classify and count the scintillation pulse signal according to the energy interval corresponding to the amplitude information of the scintillation pulse signal.

[0048] Through the dedicated digital readout circuit MVT equipped with the multi-voltage threshold digital readout acquisition card 210, the ray photons reaching the photon counting detection device are recorded in the form of pulses, the amplitude of the recorded pulses is related to the photon energy, and the photon counts of different energies are added to the corresponding energy segment. The amplitude of the pulse corresponds to the energy of the ray photons, and the number of pulses corresponds to the number of photons. By setting a plurality of electronic system thresholds corresponding to the amplitude of the scintillation pulse signal, pulses with lower energy can be filtered out, eliminating the influence of low-energy noise on the imaging results. At the same time, pulse signals with different amplitude heights are identified, their energy information is identified and accumulated corresponding to different energy zones, and the wider energy spectrum distribution is counted according to the set energy interval to obtain imaging information of different energy intervals. At the same time, the use of a dedicated multi-voltage threshold digital readout acquisition card 120 can realize multi-channel measurement, avoid the use of a large number of ADCs, and greatly reduce the cost of the photon counting detection device.

[0049] In one embodiment, the comparator is a plurality of low voltage differential signal input ports LVDS of a chip of the multi-voltage threshold digital readout acquisition card 210 .

[0050] In view of the fact that the more commonly used solid-state scintillation detectors, i.e., integrating detectors, are currently used in CT systems, the total deposited energy of X-rays is obtained by integrating the charge for a certain period of time. The result reflects the average attenuation characteristics of X-rays, and the energy information of X-rays is lost. The biggest problem of energy integrating detectors is the existence of dark current, which leads to the deterioration of the image signal-to-noise ratio under low-dose conditions. Therefore, the present application adopts a photon counting detector, which can be divided into one or more energy intervals according to the energy of the photons, and the photons detected in each energy interval are counted to achieve multi-spectrum CT imaging. By setting a suitable threshold, the electronic noise caused by the dark current can be eliminated, which helps to reduce the radiation dose, obtain a higher signal-to-noise ratio, and achieve low-dose CT imaging; at the same time, a dedicated multi-voltage threshold digital readout acquisition card can be used to achieve simultaneous measurement of multiple energy channels.

[0051] An embodiment of the present application provides a photon counting detection system, including: a photon counting detection device; a data transmission industrial computer, which is configured to communicate with the photon counting detection device to receive the detection data of the detector; an image reconstruction industrial computer, which is configured to communicate with the data transmission industrial computer to receive the detection data and perform image reconstruction. The data transmission industrial computer can be a computer, a single-chip microcomputer, an ARM (Acorn RISCMachine, processor) or an FPGA (Field-Programmable Gate Array, field programmable gate array), etc. The data transmission industrial computer is connected to the photon counting detection device through the CameraLink method to receive the projection data detected by the photon counting detection device; the image reconstruction industrial computer is used as a host computer, and is wirelessly interconnected with the data transmission industrial computer, and can control the entire system and store data, as well as perform image processing. In one embodiment, the image reconstruction industrial computer is a computer, preferably an industrial computer with superior performance.

[0052] like Figure 3 As shown, an embodiment of the present application provides a small photon counting multi-spectrum CT imaging device, comprising:

[0053] A ray generating device 400; a detector 200 as described in the embodiment of the present application; a data transmission industrial computer 600, which is configured to communicate with the ray generating device 400 and the detector 200 to control the ray generating device 400 and receive the detection data of the detector 200; an image reconstruction industrial computer 700, which is configured to communicate with the data transmission industrial computer 600 to receive the detection data of the detector 200 for image reconstruction. The specific design of the data transmission industrial computer 600 and the image reconstruction industrial computer 700 can refer to the photon counting detection system, and will not be described in detail here.

[0054] like Figure 3 As shown, the animal photon counting multi-spectrum CT imaging system 10000 provided by the present application also includes: a motion control bed 500; a ray generating device 400; a detector 200; a data transmission industrial computer 600, which is configured to communicate with the ray generating device 400 and the detector 200 to control the ray generating device 400 and receive the projection data of the detector 200; an image reconstruction industrial computer 700, which is configured to communicate with the data transmission industrial computer 600 to receive the projection data of the detector 200 and perform image reconstruction. Among them, the ray generating device 400 generates rays, such as X-rays or gamma rays; the multi-row surface array photon counting detection device composed of the scintillation crystal / microchannel plate / SiPM detector unit of the detector 200 and the multi-voltage threshold digital readout acquisition card detects the rays that pass through the object to be tested (small animal), counts the rays of different energies, and realizes small animal photon counting multi-spectrum CT imaging.

[0055] In the embodiment of the present application, the ray generating device 400 is used to emit rays to the detector 200. In the preferred embodiment, an X-ray tube is used as the ray generating device, which is heavy and requires a large power. The rays are attenuated by the object to be measured (small animal) and then reach the photon counting detection device. After being detected by the detector 200, projection data is generated.

[0056] In one embodiment, the data transmission industrial computer 600 and the image reconstruction industrial computer 700 are both industrial computers with wireless transmission. The weight of the data transmission industrial computer 600 and the image reconstruction industrial computer 700 is lighter than that of the X-ray tube.

[0057] The data transmission industrial computer 600 sends a corresponding control signal to the ray generating device 400 to control the ray to be turned on. After the ray is attenuated by the object to be measured (small animal), the projection data generated by the detector 200 is transmitted to the data transmission industrial computer.

[0058] The image reconstruction industrial computer 700 is installed on the CT bracket, has a CT imaging system operation interface, and has a preset scanning protocol. By adjusting the software in the CT imaging system operation interface, the rapid pre-scanning of the object to be tested, such as a small animal, can be controlled. The image reconstruction industrial computer installed on the CT bracket serves as a host computer and is wirelessly connected to the data transmission industrial computer. It can control the entire system, store data, and perform image processing. The data transmission industrial computer transmits data to the image reconstruction industrial computer installed on the CT bracket. After the scan is completed, the image reconstruction industrial computer will reconstruct, post-process, and visualize the received projection data.

[0059] In one embodiment, the animal photon counting multi-spectral CT imaging system 10000 further includes a replaceable power supply 1200, which is used to provide power for the system.

[0060] In one embodiment of the present application, the replaceable power supply 1200 used is a modular combination battery. The battery is a customized capacity battery with different voltage and current outputs to meet the different power supply requirements of the ray generating device, the photon counting detector, the industrial computer with wireless transmission, etc., and different specifications of batteries can be combined according to the power requirements of different devices, so that the overall weight of the device can be reasonably balanced, and it is also convenient to replenish power in time to improve the scanning efficiency. The modular combination battery can ensure a certain number of CT scanning power supply requirements. Specifically, the modular combination battery includes a battery for powering a ray generating device, a battery for powering a photon counting detection device, a battery for powering a data transmission industrial computer, a battery for powering an image reconstruction industrial computer, etc., and also includes backup batteries of different specifications. The power of each battery is related to the component it powers. In one example, the ray generating device requires the greatest power, followed by the industrial computer, and the photon counting detection device requires the least power. The corresponding batteries have different capacities. The battery for powering the ray generating device has the largest capacity and is the heaviest, the battery for powering the industrial computer has the second largest capacity and is of medium weight, and the battery for powering the photon counting detection device has the smallest capacity and is the lightest.

[0061] In one embodiment, the replaceable power supply 1200 is equipped with a battery power detection system. The battery power detection system is used to monitor the power in real time, and is connected to the data transmission industrial computer for communication, and transmits the real-time power information to the data transmission industrial computer. The battery power detection system is preset with the power required for CT scanning, and monitors the power in real time during the scanning process. When it is detected that the power of the battery currently supplying power is insufficient to support the completion of the scanning work during the ongoing scanning process, the current power shortage is automatically calculated, and an auxiliary battery with a suitable power matching the power shortage is automatically selected from the modular battery combination, and the power supply continues until the scan is completed. By timely selecting a suitable backup battery to replenish the power, the scanning efficiency is improved. In another embodiment, if the power is not enough for a CT scan, the battery can also be charged.

[0062] In one embodiment, the animal photon counting multi-spectral CT imaging system 10000 further includes a rotating element 300. The data transmission industrial computer 600 has a motion controller to control the rotating element 300. In a preferred embodiment, the rotating element 300 is a motion turntable, but is not limited thereto. In one embodiment, the motion turntable is driven to rotate by a direct-drive servo motor, and the rear end of the motion turntable is connected to the direct-drive servo motor 1000 through a hollow rotary bearing terminal. The motion turntable is used to fix devices such as a ray generating device, a photon counting detection device, a modular combination battery, and a data transmission industrial computer 600. The data transmission industrial computer 600 is installed on the motion turntable, and the motion controller in the data transmission industrial computer is used to control the motion turntable. The control of the components on the motion turntable is realized through the data transmission industrial computer 600, including the motion control of the motion control bed 500, the acquisition control of the detector 200, the storage and transmission of projection data, and the real-time monitoring of the battery power of the replaceable power supply 1200.

[0063] Based on the fact that the ray generating device 400 is the heaviest, the data transmission industrial computer 600 with wireless transmission is the second heaviest, and the detector 200 is the lightest, the ray generating device 400, the detector 200, the replaceable power supply 1200, and the data transmission industrial computer 600 are arranged in a polygon on the rotating element 300 to ensure the stability of the rotation center of gravity of the entire moving turntable. The moving turntable controls the ray generating device and the photon counting detection device to rotate as a whole relative to the object to be measured to collect projection data of the object to be measured at different angles.

[0064] In one embodiment, the animal photon counting multi-spectral CT imaging system 10000 also includes a grating element 1100, which is arranged on the rotating element and is configured to monitor the rotation angle signal of the rotating element 300 and feed it back to the data transmission industrial computer 600. In a specific embodiment, the grating element 1100 includes but is not limited to a grating ruler. The grating ruler is arranged on the moving turntable to obtain the accurate position of the moving turntable during CT imaging. The grating ruler, the ray generating device 400, the detector 200, the replaceable power supply 1200, the data transmission industrial computer 600, etc. are arranged in a polygonal shape. The rotation angle signal of the moving turntable is fed back to the data transmission industrial computer through the grating ruler, so that the detector 200 can record the projection of each angle. After completing the entire 360° scan, the image reconstruction industrial computer 700 will receive the projection data of all angles and reconstruct, post-process, and visualize. The replaceable power supply 1200 also includes a battery for powering the grating ruler.

[0065] According to an embodiment of the present invention, the battery is used to power all devices such as the ray generating device, photon counting detection device, replaceable power supply, data transmission industrial computer, grating element, etc. arranged in a polygonal shape on the moving turntable. The battery is rechargeable, removable and replaceable; the battery is a customized capacity battery with different voltage and current outputs to meet the different power supply requirements of the ray generating device, photon counting detector, and industrial computer with wireless transmission. The embodiment of the present application uses a battery to replace the slip ring power supply, and can guarantee a certain number of CT scan power supply requirements. It is equipped with a battery power detection system, which exchanges information with the industrial computer with wireless transmission, and can monitor the power supply in real time. If the power is not enough for a CT scan, replace it with another set of fully charged matching batteries or wait for charging.

[0066] In one embodiment, the rotating element 300 is provided with an opening 310. Preferably, the opening 310 is provided at the center of the rotating element 300. When a moving turntable is used as the rotating element, the opening 310 is provided at the center of the moving turntable. The aperture of the opening 310 is larger than the object to be measured (small animal) and the maximum effective detection field of view, and is equipped with a position calibration tool for laser calibration. The rear end of the moving turntable is connected to the direct drive servo motor 1000 through a hollow rotary bearing terminal.

[0067] In one embodiment, the motion control bed 500 realizes positioning and precession of the object to be measured (small animal) during measurement. The motion control bed 500 is driven by a forward and backward motion servo motor 900 and an upward and downward motion servo motor 800 to realize forward and backward and upward and downward motion.

[0068] The motion control bed 500 can move through the opening 310 in the center of the motion turntable. The aperture of the opening 310 of the motion turntable is larger than the object to be measured (small animal) and the diameter of the maximum effective detection field of view. The motion turntable is equipped with a position calibration tool to perform laser calibration on the motion control bed. According to one embodiment of the present invention, the motion control bed determines the coordinate origin of the correction coordinates based on laser collimation. A laser beam is set in the center of the ray generating device and irradiates the center of the detector, and another laser beam is collimated to irradiate the center of the motion turntable. The initial position of the motion control bed is adjusted according to the pre-scanned image to determine the one-time irradiation range of the cone beam CT and the starting position of the spiral CT.

[0069] According to one embodiment of the present invention, the CT system uses lead plates as a shielding shell, and the door for replacing the object to be measured also uses lead plates as a shielding shell. When the door to be measured is not closed, the ray generating device cannot be started. In addition, the CT system is designed with a dual-channel emergency stop switch, which is used to control the servo motor controllers of the ray generating device and the direct drive servo motor, the forward and backward motion servo motor, and the up and down motion servo motor to stop working at the same time.

[0070] The workflow of the small animal photon counting multi-spectral CT imaging system of the present application embodiment is as follows:

[0071] The operation control process of cone-beam small animal photon counting multi-spectral CT imaging for high-resolution local scanning of key tissues of small animals is as follows: the small animal to be tested is anesthetized and fixed on the motion control bed 500, and the lead shielding door of the object to be tested is closed; the CT imaging system operation interface in the image reconstruction industrial computer 700 with wireless transmission installed on the CT bracket is opened to perform a quick pre-scan to determine whether the position of the object to be tested (small animal) is appropriate. If not, it is adjusted through the software in the CT imaging system operation interface until it reaches the appropriate position; the scanning protocol is selected, and the scanning instruction is sent to the data transmission industrial computer 600 installed on the motion turntable through wireless transmission; the motion controller in the data transmission industrial computer 600 controls the motion turntable, and the data transmission industrial computer 600 sends the corresponding control signal to the ray generating device 400. After the ray is turned on, it reaches the detector 200 after being attenuated by the object to be tested, and the projection data is generated after being detected by the detector 200; the rotation angle signal of the motion turntable is fed back to the data transmission industrial computer 600 through the grating ruler, and the detector 200 records the projection of each angle. The data transmission industrial computer 600 installed on the moving turntable transmits data to the image reconstruction industrial computer 700 installed on the CT bracket. After completing the entire 360° scan, the image reconstruction industrial computer installed on the CT bracket will receive the projection data from all angles and reconstruct, post-process, and visualize it, and finally display it in the image reconstruction industrial computer interface.

[0072] In the embodiment of the present application, a spiral CT scan is required for a whole-body scan of a small animal, which is achieved by switching to a spiral scanning mode. Operation control flow:

[0073] After anesthetizing the small animal to be tested, fix it on the motion control bed, and close the lead shielding door of the object to be tested; open the CT imaging system operation interface in the image reconstruction industrial computer 700 with wireless transmission installed on the CT bracket, perform a quick pre-scan, and determine whether the initial measurement position of the object to be tested (small animal) is appropriate. If not, adjust it through the software in the CT imaging system operation interface until it reaches the appropriate position; select a scanning protocol, and the scanning command controls the motion control bed 500, and at the same time sends it to the data transmission industrial computer 600 installed on the motion turntable through wireless transmission, and the motion controller in the data transmission industrial computer 600 controls the motion turntable; the data transmission industrial computer 600 sends the corresponding control signal to the ray generating device 400, and after the ray is turned on, it reaches the detector 200 after being attenuated by the object to be tested, and generates projection data after being detected by the detector 200; the rotation angle signal of the motion turntable is fed back to the data transmission industrial computer 600 through the grating ruler, and the detector 200 records the projection of each angle. The data transmission industrial computer 600 installed on the moving turntable transmits data to the image reconstruction industrial computer 700 installed on the CT bracket. After completing the entire 360° scan, the image reconstruction industrial computer 700 installed on the CT bracket will receive the projection data from all angles and reconstruct, post-process, and visualize it, and finally display it in the image reconstruction industrial computer 700 interface.

[0074] At present, cone beam CT is widely used in small animals, and cone beam CT generally uses flat-panel detectors. However, the surface array of the detector used in the existing detection device of the photon counting multi-spectral CT imaging system for small animals cannot be very large (only one or several rows), which limits the application of cone beam CT to a certain extent. The present application adopts a multi-row surface array detector, which can meet the needs of cone beam CT imaging and achieve local high-resolution scanning of some key tissues of small animals. The whole body scan of small animals is completed by switching the spiral scanning method. Therefore, the present application adopts a multi-row surface array detector, which can switch between cone beam and spiral scanning schemes, and can meet various needs and usage environments of multi-spectral CT imaging.

[0075] The present application also provides a small photon counting multi-energy spectrum CT imaging method, comprising:

[0076] Use image reconstruction industrial computer to perform quick pre-scanning to adjust the motion control bed to the scanning position matching the ray generating device;

[0077] The image reconstruction industrial computer controls the ray generating device to start through data transmission;

[0078] The detector described in the above embodiment of the present application is used to count the energy intervals of the rays after attenuation by the object to be measured, so as to generate projection data;

[0079] The data transmission industrial computer receives the projection data and transmits it to the image reconstruction industrial computer for image reconstruction.

[0080] In one embodiment, a replaceable power source is used to power the image reconstruction industrial computer, the motion control bed, the ray generating device, the data transmission industrial computer, and the photon counting detection device. In a preferred embodiment, the replaceable power source is a modular combination battery.

[0081] In one embodiment, a photon counting detector is used to count the energy intervals of the rays attenuated by the object to be measured to generate projection data, including:

[0082] The detector of the embodiment of the present application is used to detect the rays to obtain a scintillation pulse signal;

[0083] The scintillation pulse signal is digitally acquired using a multi-voltage threshold digital readout acquisition card to obtain the amplitude information of the scintillation pulse signal, and the corresponding energy interval is determined according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal to generate projection data.

[0084] In one embodiment, a multi-voltage threshold digital readout acquisition card is used to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal. The corresponding energy interval is determined according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal, and this is achieved by a multi-voltage threshold digital readout circuit configured therein.

[0085] In an embodiment of the present application, the step of "using a multi-voltage threshold digital readout acquisition card to digitally acquire a scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal" includes: presetting multiple thresholds in the multi-voltage threshold digital readout acquisition card; comparing the amplitude of the scintillation pulse signal with the preset multiple thresholds, and obtaining the highest threshold reached by the scintillation pulse signal to determine the threshold interval corresponding to the amplitude of the scintillation pulse signal.

[0086] In one embodiment, multiple thresholds are preset in the multi-voltage threshold digital readout acquisition card and implemented by the comparator of the multi-voltage threshold digital readout acquisition card. Specifically, the multi-voltage threshold digital readout acquisition card is configured with a multi-voltage threshold digital readout circuit, and the multi-voltage threshold digital readout circuit includes multiple digital readout channels, and each readout channel includes multiple comparators. In a preferred embodiment, the comparator is a plurality of low voltage differential signal input ports LVDS of the chip of the multi-voltage threshold digital readout acquisition card.

[0087] In one embodiment, two adjacent thresholds constitute a threshold interval, and the amplitude information of the scintillation pulse signal is the threshold interval corresponding to the amplitude of the pulse signal.

[0088] In one embodiment, the comparison between the amplitude of the scintillation pulse signal and the preset multiple thresholds is implemented by using a comparator of a multi-voltage threshold digital readout acquisition card. The comparator is a plurality of low voltage differential signal input ports LVDS of a chip of the multi-voltage threshold digital readout acquisition card.

[0089] In one embodiment, an energy interval is preset in a multi-voltage threshold digital readout acquisition card according to the energy of the photons, and the energy interval corresponds to the threshold interval.

[0090] In one embodiment, the step of "determining the corresponding energy interval according to the amplitude information to classify and count the flicker pulse signal" includes: determining the energy interval corresponding to the flicker pulse signal according to the threshold interval corresponding to the amplitude of the flicker pulse signal, and classifying and counting the flicker pulse signal according to the energy interval.

[0091] In a preferred embodiment, counting of scintillation pulse signals by energy interval classification is implemented by using counting elements.

[0092] In one embodiment, each readout channel of the multi-voltage threshold digital readout circuit includes a plurality of counting elements.

[0093] In another embodiment of the present application, the step of "using a multi-voltage threshold digital readout acquisition card to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal, and determining the corresponding energy interval according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal" is implemented using a multi-voltage threshold digital readout circuit configured therein.

[0094] In a preferred embodiment, an energy interval is preset in a multi-voltage threshold digital readout acquisition card according to the energy of the photon, and the energy interval corresponds to the threshold interval; the multi-voltage threshold digital readout acquisition card includes multiple digital readout channels, each readout channel includes multiple comparators and counting elements corresponding to the multiple comparators one by one; multiple comparators are used to preset multiple thresholds, and the amplitude of the scintillation pulse signal is compared with the preset multiple thresholds to obtain the highest threshold reached by the scintillation pulse signal to determine the threshold interval corresponding to the amplitude of the scintillation pulse signal; the energy interval corresponding to the scintillation pulse signal is determined according to the threshold interval corresponding to the amplitude of the scintillation pulse signal, and multiple counting elements are used to classify and count the scintillation pulse signal according to the energy interval.

[0095] The apparatus described in the embodiments of the present application may be combined with the method features described in the embodiments of the present application, and vice versa.

[0096] In this article, multiple embodiments are described, but for the sake of simplicity, the description of each embodiment is not exhaustive, and the same or similar features or parts between the embodiments may be omitted. In this article, "one embodiment", "some embodiments", "example", "specific example", or "some examples" are meant to be applicable to at least one embodiment or example according to the present application, rather than all embodiments. The above terms do not necessarily mean to refer to the same embodiment or example. In the absence of contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples.

[0097] Finally, it should be noted that the above is only an example embodiment of the present disclosure and is not intended to limit the present disclosure. Although the present disclosure is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A photon counting multi-spectral CT imaging device, characterized in that: include: Radiation generating device; A surface array detector, the surface array detector comprising: a sheet-like scintillation crystal, which is configured to convert radiation into visible light; a sheet-like microchannel plate, which is coupled to the sheet-like scintillation crystal in a one-to-one manner and is configured to selectively pass the visible light converted by the sheet-like scintillation crystal; a photomultiplier element, which is coupled to the sheet-like microchannel plate to convert the visible light that has been selectively passed into a scintillation pulse signal; A data transmission industrial computer, which is configured to communicate with the ray generating device and the surface array detector to control the ray generating device and receive detection data of the surface array detector; The image reconstruction industrial computer is configured to be communicatively connected with the data transmission industrial computer to receive the detection data of the area array detector and perform image reconstruction.

2. The photon counting multi-spectral CT imaging device according to claim 1, characterized in that: The thickness ratio of the sheet-like scintillator crystal to the sheet-like microchannel plate collimator is between 1:3 and 1:

5.

3. The photon counting multi-spectral CT imaging device according to claim 1, characterized in that: The ratio of the thickness of the sheet-shaped microchannel plate collimator to the diameter of the microchannel is between 8:1 and 10:

1.

4. The photon counting multi-spectral CT imaging device according to claim 1, characterized in that: Silicone grease is provided between the sheet-like scintillating crystal and the sheet-like microchannel plate collimator, and silicone grease is provided between the sheet-like microchannel plate collimator and the photomultiplier element.

5. The photon counting multi-spectral CT imaging device according to claim 1, characterized in that: The photon counting multi-energy spectrum CT imaging device also includes a multi-voltage threshold digital readout acquisition card, which is configured to digitally acquire the scintillation pulse signal.

6. The photon counting multi-spectral CT imaging device according to claim 5, characterized in that: The multi-voltage threshold digital readout acquisition card is configured to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal, and classify and count the scintillation pulse signal according to the energy interval corresponding to the amplitude information of the scintillation pulse signal.

7. The photon counting multi-spectral CT imaging device according to claim 6, characterized in that: The multi-voltage threshold digital readout acquisition card is equipped with a multi-voltage threshold digital readout circuit, in which the energy interval is preset according to the energy of the photon, and the multi-voltage threshold digital readout circuit includes a plurality of digital readout channels, each of which includes: A plurality of comparators, which are configured to preset a plurality of threshold values ​​corresponding to the amplitude of the scintillation pulse signal, wherein a threshold interval is formed between two adjacent threshold values, and the threshold interval corresponds to different energy intervals; the amplitude information of the scintillation pulse signal is the threshold interval corresponding to the amplitude of the pulse signal; A plurality of counting elements correspond one-to-one to the plurality of comparators and are configured to classify and count the scintillation pulse signals according to energy intervals corresponding to the scintillation pulse signal amplitude information.

8. The photon counting multi-spectral CT imaging device according to claim 7, characterized in that: The comparator is a multiple low voltage differential signal input port LVDS of a multi-voltage threshold digital readout acquisition card.

9. The photon counting multi-spectral CT imaging device according to claim 5, characterized in that: The photon counting multi-energy spectrum CT imaging device also includes an image reconstruction module, which is configured to perform image reconstruction on the digital information collected by the multi-voltage threshold digital readout acquisition card.

10. The photon counting multi-spectral CT imaging device according to claim 1, characterized in that: The photon counting multi-energy spectrum CT imaging device also includes a replaceable power supply, which supplies power to the ray generating device, the planar array detector, the data transmission industrial computer and the image reconstruction industrial computer.

11. The photon counting multi-spectral CT imaging device according to claim 10, characterized in that: The replaceable power source is a modular combined battery.

12. The photon counting multi-spectral CT imaging device according to claim 10, characterized in that: The photon counting multi-energy spectrum CT imaging device also includes a rotating element, and the ray generating device, the surface array detector, the replaceable power supply, the data transmission industrial computer, and the image reconstruction industrial computer are evenly arranged on the rotating element.

13. The photon counting multi-spectral CT imaging device according to claim 12, characterized in that: The rotating element is provided with an opening through which the motion-controlled bed is movable.

14. The photon counting multi-spectral CT imaging device according to claim 12, characterized in that: It also includes a grating element, which is configured to monitor the rotation angle signal of the rotating element and feed it back to the data transmission industrial computer.

15. A photon counting multi-spectral CT imaging method for claim 1, characterized in that: The following steps are involved: Use image reconstruction industrial computer to perform quick pre-scanning to adjust the motion control bed to the scanning position matching the ray generating device; The image reconstruction industrial computer controls the ray generating device to start up by transmitting data to the industrial computer; A surface array detector is used to count the energy intervals of the rays after attenuation by the object to be measured to generate projection data; The data transmission industrial computer receives the projection data and transmits it to the image reconstruction industrial computer for image reconstruction.

16. The photon counting multi-spectral CT imaging method according to claim 15, characterized in that: The surface array detector is used to count the energy intervals of the rays after attenuation by the object to generate projection data, including: Using the surface array detector to detect the rays to obtain a scintillation pulse signal; The scintillation pulse signal is digitally acquired using a multi-voltage threshold digital readout acquisition card to obtain the amplitude information of the scintillation pulse signal, and the corresponding energy interval is determined according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal to generate projection data.

17. The photon counting multi-spectral CT imaging method according to claim 16, characterized in that: A multi-voltage threshold digital readout acquisition card is used to digitally acquire the scintillation pulse signal and obtain the amplitude information of the scintillation pulse signal. The corresponding energy interval is determined according to the amplitude information of the scintillation pulse signal to classify and count the scintillation pulse signal, and this is achieved using a multi-voltage threshold digital readout circuit.

18. The photon counting multi-spectral CT imaging method according to claim 17, characterized in that: The energy interval is preset in a multi-voltage threshold digital readout circuit according to the energy of the photon, and the energy interval corresponds to the threshold interval; the multi-voltage threshold digital readout circuit includes a plurality of digital readout channels, each readout channel includes a plurality of comparators and counting elements corresponding to the plurality of comparators one by one; Preset multiple thresholds using the multiple comparators, compare the amplitude of the scintillation pulse signal with the preset multiple thresholds, obtain the highest threshold reached by the scintillation pulse signal, and determine the threshold interval corresponding to the amplitude of the scintillation pulse signal; The energy interval corresponding to the scintillation pulse signal is determined according to the threshold interval corresponding to the amplitude of the scintillation pulse signal, and the scintillation pulse signal is classified and counted according to the energy interval using the multiple counting elements.

19. The photon counting multi-spectral CT imaging method according to claim 17, characterized in that: Presetting multiple thresholds in a multi-voltage threshold digital readout acquisition card, and comparing the amplitude of the scintillation pulse signal with the preset multiple thresholds are implemented using a comparator of the multi-voltage threshold digital readout acquisition card.

20. The photon counting multi-spectral CT imaging method according to claim 17, characterized in that: The multi-voltage threshold digital readout circuit includes a plurality of digital readout channels, and each readout channel includes a plurality of comparators.

21. The photon counting multi-spectral CT imaging method according to claim 15, characterized in that: A replaceable power supply is used to power the image reconstruction industrial computer, the motion control bed, the ray generating device, the data transmission industrial computer, and the photon counting detection device.

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