WO2024041265A1

WO2024041265A1 - X-ray fluorescence imaging method and apparatus, electronic device, and storage medium

Info

Publication number: WO2024041265A1
Application number: PCT/CN2023/107540
Authority: WO
Inventors: 李亮; 陈志强; 张丽; 邢宇翔; 高河伟; 邓智; 王振天; 武传鹏
Original assignee: 清华大学
Priority date: 2022-08-22
Filing date: 2023-07-14
Publication date: 2024-02-29
Also published as: CN115356362A

Abstract

The present application relates to an X-ray fluorescence imaging method and apparatus, an electronic device, and a storage medium. The method comprises: enabling incidence of X-rays into a sample to be scanned, to excite X-ray fluorescence photons and scattered photons in said sample; enabling incidence of the fluorescence photons and/or the scattered photons into a Compton camera detector, and obtaining first spatial coordinates and first deposited energy during occurrence of a scattering event and second spatial coordinates and second deposited energy during occurrence of an absorption event when Compton scattering occurs to the fluorescence photons and the scattered photons in a moving process of the Compton camera detector; and performing Compton camera image reconstruction according to the first spatial coordinates, the first deposited energy, the second spatial coordinates, and the second deposited energy to obtain a three-dimensional image of said sample. Therefore, the present application solves the problems that it is difficult to implement recognition and imaging of fluorescence photons because a large amount of noise and a low signal-to-noise ratio are caused by scattered photons generated by X-ray excitation, and the Compton camera has a low resolution for incident photons below 100 keV.

Description

X-ray fluorescence imaging methods, devices, electronic equipment and storage media

Cross-references to related applications

This application is based on the Chinese patent application with application number 202211008806.6 and the filing date is August 22, 2022, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby incorporated into this application as a reference.

Technical field

The present application relates to the field of radiation imaging technology, and in particular to an X-ray fluorescence imaging method, device, electronic equipment and storage medium.

Background technique

X-ray fluorescence CT (Computed Tomograph) is an imaging mode that can obtain molecular and functional information of a target. Compared with general X-ray imaging modes, it has higher imaging contrast and sensitivity and has received a lot of attention in recent years. . For traditional XFCT (X-ray fluorescence Compton Tomograph, X-ray fluorescence electronic scanning) imaging system, in order to obtain the incident direction of fluorescence photons, it is usually necessary to use a very small aperture mechanical collimator, which will cause a large amount of photon loss. and reduce detection efficiency. The Compton camera is an imaging mode that uses electronic collimation to obtain incident direction information. It does not require a mechanical collimator and therefore has high detection efficiency. The earliest Compton cameras were used for astronomical observations. Later, due to their unique imaging capabilities, in recent years Compton cameras have been widely used in many fields such as environmental radiation detection, medical imaging, and proton therapy. In addition, the Compton camera can also achieve three-dimensional imaging under single-view or fewer-view scanning, thus saving scanning time.

In order to achieve three-dimensional X-ray fluorescence imaging with single-angle fast scanning, using Compton camera mode for X-ray fluorescence imaging is a brand-new idea worth exploring. In 2016, Vernekohl et al. used the Monte Carlo radiation transport method to simulate X-ray fluorescence imaging under the Compton camera, and simulated the current detection technology, especially the realistic energy resolution, to prove its feasibility. However, this work only considered simulation experiments under relatively ideal experimental conditions. The incident light was ideal 82keV monochromatic light. The energy resolution and spatial resolution of the detector were both good, and a large-area sector detection was used. The device can obtain projection data from all angles. These conditions are difficult to meet in a real medical experimental environment.

In fact, the X-ray fluorescence Compton camera imaging mode has still not been implemented in real experiments, mainly because this imaging mode faces many challenges. First, X-ray fluorescence imaging has inherent imaging challenges. That is, when X-ray excitation generates fluorescence photons, it is usually accompanied by a large number of scattered photons, which will bring a large amount of noise and a low signal-to-noise ratio. It brings difficulties to the identification and imaging of fluorescence photons. For traditional XFCT, since the detected projection signal is usually an integrated signal, the polynomial fitting method can be used to remove the scattering background and extract the fluorescence peak signal intensity from the integrated energy spectrum of the projection data. But for Compton camera imaging, the data required for reconstruction is usually independent information of each photon, and it is impossible to use the energy spectrum fitting method to remove scattering. Second, it is difficult for the Compton camera to reconstruct low-energy incident photons below 100keV. The negative impact of the Doppler broadening effect will become very significant, which will greatly reduce the accuracy of the Compton scattering angle. Third, traditional Compton cameras are usually used in low-flux radiation field environments and do not require high detector count rates. X-ray fluorescence photons are usually excited by X-ray machines, and the photon flux is very huge, so The detector is required to not only have good spatial resolution and energy resolution, but also have a high count rate, which is very challenging.

Contents of the invention

This application provides an X-ray fluorescence imaging method, device, electronic equipment and storage medium to solve the problem that scattered photons generated by X-ray excitation bring a large amount of noise and a low signal-to-noise ratio, resulting in difficulties in the identification and imaging of fluorescence photons. As well as the problem that the Compton camera has low resolution for incident photons below 100keV, an imaging system that can realize X-ray fluorescence imaging was constructed to achieve high-resolution reconstruction of the Compton camera under the condition of incident photons with energy below 100keV.

The first embodiment of the present application provides an X-ray fluorescence imaging method, which includes the following steps: injecting X-rays into a sample to be scanned, exciting X-ray fluorescence photons and scattered photons of fluorescent elements in the sample to be scanned; based on a preset At the incident angle, the fluorescence photons and/or the scattered photons are injected into the Compton camera detector, and the fluorescence photons and the scattered photons generated during the movement of the Compton camera detector are obtained. The first spatial coordinate and the first deposition energy at which the scattering event occurs during Dayton scattering, and the second spatial coordinate and the second deposition energy at which the absorption event occurs; according to the first spatial coordinate, the first deposition energy, the third The two spatial coordinates and the second deposition energy are used to reconstruct the image of the Compton camera to obtain a three-dimensional image of the sample to be scanned.

Optionally, the preset reconstruction algorithm is:

in, is the voxel j of the image after (l+1) rounds of iteration, l is an integer, is the voxel j of the image after l rounds of iteration, T _ij is the system matrix, S _j is the sensitivity matrix, i is the event number index, j is the voxel index, N is the total number of events, M is the total number of voxels, and k is Voxel index, T _ik is an element of the system matrix, is the voxel k of the image after l rounds of iteration.

Optionally, the system matrix is:

Among them, v _j is the imaging space volume of voxel j, P(y _i |x,E ₀ ) is the probability that event _yi is related to space point x, x is a point in space, y _i is the i-th event, E ₀ is the total energy of the incident photon, and P(x∈v _j ) is the probability that the spatial point x is within the volume v _j of voxel j.

Optionally, the above-mentioned X-ray fluorescence imaging method also includes: updating the system matrix based on a preset scattering correction algorithm, wherein the updated system matrix is:

in, is the rewritten system matrix, Indicates the probability that event _yi does not belong to the event set Y ^(Scattering) caused by scattered photons.

Optionally, the above-mentioned X-ray fluorescence imaging method also includes: determining the system matrix based on a preset Doppler broadening correction low-energy reconstruction algorithm and the scattering correction algorithm, wherein the system matrix is:

in, is the vector between event _yi and voxel v _j , is a vector The angle with the vertical direction, β is the true scattering angle, θ is the measured scattering angle, K(β,E ₀ ) is the Compton scattering cross section, σ _er is the energy resolution of the detector, and σ _sr is the spatial resolution of the detector rate, σ _db is the reconstruction angle uncertainty caused by the Doppler broadening effect, h(φ _i ) is the probability that event i comes from scattered photons.

A second embodiment of the present application provides an X-ray fluorescence imaging device, including: an excitation module for injecting X-rays into a sample to be scanned, and exciting X-ray fluorescence photons and scattered photons of fluorescent elements in the sample to be scanned; An acquisition module, configured to inject the fluorescence photons and/or the scattered photons into the Compton camera detector based on a preset incident angle, and acquire the fluorescence photons during the movement of the Compton camera detector. The first spatial coordinates and the first deposition energy of the scattering event when Compton scattering of the scattered photons occurs, and the second spatial coordinates and the second deposition energy of the absorption event; the imaging module is used to perform the imaging according to the first The spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy are used to reconstruct the image of the Compton camera to obtain a three-dimensional image of the sample to be scanned.

Optionally, the preset reconstruction algorithm is:

in, is the voxel j of the image after (l+1) rounds of iteration, l is an integer, is the graph after l rounds of iterations For image voxel j, T _ij is the system matrix, S _j is the sensitivity matrix, i is the event number index, j is the voxel index, N is the total number of events, M is the total number of voxels, k is the voxel index, and T _ik is elements of the system matrix, is the voxel k of the image after l rounds of iteration.

Optionally, the system matrix is:

Optionally, the above-mentioned X-ray fluorescence imaging device further includes: updating the system matrix based on a preset scattering correction algorithm, wherein the updated system matrix is:

Optionally, the above-mentioned X-ray fluorescence imaging device further includes: a low-energy reconstruction algorithm based on preset Doppler broadening correction and the scattering correction algorithm to determine the system matrix, wherein the system matrix is:

A third embodiment of the present application provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. The processor executes the program to implement X-ray fluorescence imaging method as described in the above embodiment.

A fourth embodiment of the present application provides a computer-readable storage medium on which a computer program is stored, and the program is executed by a processor to implement the X-ray fluorescence imaging method as described in the above embodiment.

Thus, by injecting X-rays into the sample to be scanned, the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned are excited, and based on the preset incident angle, the fluorescence photons and/or scattered photons are injected into the Compton camera. detector, and obtain the first spatial coordinate and the first deposition energy of the scattering event when the fluorescence photon and scattered photon are Compton scattered during the movement of the Compton camera detector, as well as the second spatial coordinate and the first deposition energy of the absorption event. 2. Deposition energy: perform image reconstruction of the Compton camera based on the first spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy to obtain a three-dimensional image of the sample to be scanned. It solves the problems that scattered photons generated by X-ray excitation bring a lot of noise and a low signal-to-noise ratio, making it difficult to identify and image fluorescence photons, and the Compton camera has low resolution for incident photons below 100keV. It builds a system that can An imaging system that realizes X-ray fluorescence imaging and achieves high-resolution reconstruction of Compton cameras under the incident conditions of photons with energy below 100keV.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

Figure 1 is a flow chart of an X-ray fluorescence imaging method provided according to an embodiment of the present application;

Figure 2 is a schematic diagram of data collection and physical processes of the XFCC system according to an embodiment of the present application;

Figure 3 is a schematic diagram of the data collection process of the Compton camera according to an embodiment of the present application;

Figure 4 is a schematic diagram of incident photons and scattered photons and their respective polarization vectors according to an embodiment of the present application;

Figure 5 is a schematic diagram of the theoretical change curve of Compton scattering KN (Klein-Nishina) cross section with azimuth angle φ according to an embodiment of the present application;

Figure 6 is a schematic diagram of the distribution of azimuth angle φ in data collected from real experiments according to an embodiment of the present application, and a schematic diagram of a trigonometric function fitting curve;

Figure 7 is a block diagram of an X-ray fluorescence imaging device according to an embodiment of the present application;

FIG. 8 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

Detailed ways

The embodiments of the present application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, but should not be construed as limiting the present application.

The following describes the X-ray fluorescence imaging method, device, electronic equipment and storage medium according to the embodiments of the present application with reference to the accompanying drawings. quality. Regarding the above-mentioned background technology center, the scattered photons generated by X-ray excitation bring a lot of noise and a low signal-to-noise ratio, which makes the identification and imaging of fluorescence photons difficult, and the Compton camera has low resolution for incident photons below 100keV. To solve the problem, this application provides an X-ray fluorescence imaging method. In this method, X-rays are incident on the sample to be scanned, and the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned are excited, based on the preset At the incident angle, the fluorescence photons and/or scattered photons are injected into the Compton camera detector, and the first spatial coordinates of the scattering event that occurs when the fluorescence photons and scattered photons undergo Compton scattering during the movement of the Compton camera detector are obtained. and the first deposition energy, as well as the second spatial coordinate and the second deposition energy where the absorption event occurs, and perform image reconstruction of the Compton camera based on the first spatial coordinate, the first deposition energy, the second spatial coordinate and the second deposition energy, Obtain a three-dimensional image of the sample to be scanned. This solves the problem that scattered photons generated by X-ray excitation bring a lot of noise and a low signal-to-noise ratio, making it difficult to identify and image fluorescence photons, and the Compton camera has low resolution for incident photons below 100keV. An imaging system that can realize X-ray fluorescence imaging was constructed to achieve high-resolution reconstruction of the Compton camera under the incident energy photons below 100keV.

Specifically, FIG. 1 is a schematic flow chart of an X-ray fluorescence imaging method provided by an embodiment of the present application.

As shown in Figure 1, the X-ray fluorescence imaging method includes the following steps:

In step S101, X-rays are incident on the sample to be scanned, and X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned are excited.

Specifically, as shown in Figure 2, X-rays are incident on the sample to be scanned, and X-ray fluorescence photons and scattered photons of fluorescent elements in the sample are excited.

In step S102, based on the preset incident angle, the fluorescence photons and/or scattered photons are injected into the Compton camera detector, and the Compton scattering of the fluorescence photons and scattered photons during the movement of the Compton camera detector is obtained. The first spatial coordinate and the first deposition energy at which the scattering event occurs, and the second spatial coordinate and the second deposition energy at which the absorption event occurs.

It should be understood that, as shown in Figure 3, fluorescence photons and scattered photons enter the Compton camera detector in the direction of 90° of the incident direction together, or the fluorescence photons or scattered photons enter the Compton camera detector in the direction of 90° of the incident direction together. In the Compton camera detector, the incident photon detected by the Compton camera detector undergoes Compton scattering inside the detector. Through the response of the area array detector, the first spatial coordinates and the first deposition energy of the scattering event can be obtained, and Obtain the second spatial coordinate and the second deposition energy where the absorption event occurs.

In step S103, image reconstruction of the Compton camera is performed based on the first spatial coordinates, the first deposition energy, the second spatial coordinates, and the second deposition energy to obtain a three-dimensional image of the sample to be scanned.

Specifically, according to the first spatial coordinate, the first deposition energy, the second spatial coordinate and the second deposition energy, different tomographic switching of the fan beam scanning can be realized by moving the translation stage, and finally a three-dimensional image can be formed.

Optionally, in some embodiments, the preset reconstruction algorithm is:

Specifically, according to the list mode data required for Compton camera reconstruction, they are used for iterative reconstruction of the list mode maximum likelihood expectation maximization algorithm, where the voxel index value can be selected arbitrarily, such as a random initial value, The reconstruction result of the filtered back-projection algorithm can be used as the initial value, etc.

Optionally, in some embodiments, the system matrix is:

It should be understood that since the fluorescence photon energy of some elements is lower than 100keV, the Compton camera reconstruction for this energy range will be affected by the Doppler broadening effect, so the Doppler broadening correction is introduced. Compton camera reconstruction algorithm for low-energy reconstruction, using a probabilistic model representation of the system matrix.

Optionally, in some embodiments, the above-mentioned X-ray fluorescence imaging method further includes: updating the system matrix based on a preset scattering correction algorithm, where the updated system matrix is:

It can be understood that since among the incident photons, there are both effective signals, namely X-ray fluorescence photons, and scattered photons, so in order to correct the noise of scattered photons, a scattering correction algorithm based on photon polarization information is used for correction processing.

Among them, in order to solve It needs to be discussed that when linearly polarized scattered photons are incident on the detector, health will occur again. The Klein-Nishina (KN) differential cross section in Puton scattering is as follows:

Among them, r ₀ is the classical electron radius, E ₂ and E ₀ are the scattered photon energy and the incident photon total energy respectively, θ is the Compton scattering angle, φ is the polarization azimuth angle, which is the scattering photon vector on the incident photon polarization plane. The angle between the projection and the polarization direction of the incident photon, the incident photon and the scattered photon and their respective polarization vectors are shown in Figure 4. Figure 5 shows the change of the Klein-Nishina differential cross section with the polarization azimuth angle φ.

Furthermore, when only scattered photons are incident, the distribution of the azimuth angle φ (the angle window is 10°), and the trigonometric function nonlinear curve fitting of the distribution is performed as follows: Among them, the azimuth angle in the data collected from the real experiment is The distribution of angles and the schematic diagram of the trigonometric function fitting curve are shown in Figure 6.

Among them, y ₀ , A, ω, φ ₀ are the parameters to be fitted. The fitting results show that the azimuth angle distribution of the real experiment is consistent with the theoretical analysis. Therefore, f(φ) is normalized so that its value range is between [0, 1], and the function h(φ) is obtained. , and use this function to construct the probability as follows:

Optionally, in some embodiments, the above-mentioned X-ray fluorescence imaging method also includes: determining a system matrix based on a preset Doppler broadening correction low-energy reconstruction algorithm and a scattering correction algorithm, where the system matrix is:

in, is the vector between event _yi and voxel v _j , is a vector The angle with the vertical direction, β is the true scattering angle, θ is the measured scattering angle, K(β,E ₀ ) is the Compton scattering cross section, σ _er is the energy resolution of the detector, and σ _sr is the spatial resolution of the detector rate, σ _db is the reconstruction angle uncertainty caused by the Doppler broadening effect, h(φ _i ) is the probability that event i comes from scattered photons. Among them, σ _er , σ _sr and σ _db can be obtained by any reasonable method, such as numerical calculation method, Monte Carlo simulation method, experimental measurement method, etc.

Specifically, by combining the low-energy reconstruction algorithm with Doppler broadening correction and the scattering correction algorithm based on polarization information, CCFIRM (Compton camera-based X-ray fluorescence imaging reconstruction method, Compton camera-based X-ray fluorescence spectrometer imaging reconstruction method) can be obtained Method) method to solve the system matrix obtained.

Among them, in addition to fitting and constructing the probability model with data from real experiments, it can also be realized by fitting and constructing simulation data, constructing theoretical calculation data, etc., which are not specifically limited here.

According to the X-ray fluorescence imaging method proposed in the embodiment of the present application, X-rays are incident on the sample to be scanned, and the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned are excited. Based on the preset incident angle, the fluorescence photons and /or scattered photons are injected into the Compton camera detector, and the first spatial coordinates and the first deposition energy of the scattering event when the fluorescence photons and scattered photons undergo Compton scattering during the movement of the Compton camera detector are obtained, and The second spatial coordinates and the second deposition energy of the absorption event occur, and the image reconstruction of the Compton camera is performed according to the first spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy, and a three-dimensional image of the sample to be scanned is obtained. . This solves the problem that scattered photons generated by X-ray excitation bring a lot of noise and a low signal-to-noise ratio, making it difficult to identify and image fluorescence photons, and the Compton camera has low resolution for incident photons below 100keV. An imaging system that can realize X-ray fluorescence imaging was constructed to achieve high-resolution reconstruction of the Compton camera under the incident energy photons below 100keV.

Next, the X-ray fluorescence imaging device proposed according to the embodiment of the present application will be described with reference to the accompanying drawings.

Figure 7 is a block diagram of an X-ray fluorescence imaging device according to an embodiment of the present application.

As shown in FIG. 7 , the X-ray fluorescence imaging device 10 includes: an excitation module 100 , an acquisition module 200 and an imaging module 300 .

Among them, the excitation module 100 is used to inject X-rays into the sample to be scanned, and excite the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned; the acquisition module 200 is used to combine the fluorescence photons and scattered photons based on the preset incident angle. /or scattered photons are injected into the Compton camera detector, and the first spatial coordinates and the first deposition energy of the scattering event when the fluorescence photons and scattered photons undergo Compton scattering during the movement of the Compton camera detector are obtained, and The second spatial coordinates and the second deposition energy at which the absorption event occurs; the imaging module 300 is configured to perform image reconstruction of the Compton camera according to the first spatial coordinates, the first deposition energy, the second spatial coordinates, and the second deposition energy, to obtain A three-dimensional image of the sample to be scanned.

Optionally, in some embodiments, the preset reconstruction algorithm is:

Optionally, in some embodiments, the system matrix is:

Optionally, in some embodiments, the above-mentioned X-ray fluorescence imaging device 10 also includes: updating the system matrix based on a preset scattering correction algorithm, where the updated system matrix is:

Optionally, in some embodiments, the above-mentioned X-ray fluorescence imaging device 10 also includes: a low-energy reconstruction algorithm and a scattering correction algorithm based on preset Doppler broadening correction to determine a system matrix, where the system matrix is:

It should be noted that the foregoing explanation of the embodiment of the X-ray fluorescence imaging method also applies to the X-ray fluorescence imaging device of this embodiment, and will not be described again here.

According to the X-ray fluorescence imaging device proposed in the embodiment of the present application, X-rays are incident on the sample to be scanned, and the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned are excited. Based on the preset incident angle, the fluorescence photons and /or scattered photons are injected into the Compton camera detector, and the first spatial coordinates and the first deposition energy of the scattering event when the fluorescence photons and scattered photons undergo Compton scattering during the movement of the Compton camera detector are obtained, and The second spatial coordinates and the second deposition energy of the absorption event occur, and the image reconstruction of the Compton camera is performed according to the first spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy, and a three-dimensional image of the sample to be scanned is obtained. . This solves the problem that scattered photons generated by X-ray excitation bring a lot of noise and a low signal-to-noise ratio, making it difficult to identify and image fluorescence photons, and the Compton camera has low resolution for incident photons below 100keV. An imaging system that can realize X-ray fluorescence imaging was constructed to achieve high-resolution reconstruction of the Compton camera under the incident energy photons below 100keV.

FIG. 8 is a schematic structural diagram of an electronic device provided by an embodiment of the present application. The electronic device may include:

Memory 801, processor 802, and a computer program stored on memory 801 and executable on processor 802.

When the processor 802 executes the program, it implements the X-ray fluorescence imaging method provided in the above embodiment.

Furthermore, electronic equipment also includes:

Communication interface 803 is used for communication between the memory 801 and the processor 802.

Memory 801 is used to store computer programs that can run on the processor 802.

The memory 801 may include high-speed RAM memory, and may also include non-volatile memory (non-volatile memory), such as at least one disk memory.

If the memory 801, the processor 802 and the communication interface 803 are implemented independently, the communication interface 803, the memory 801 and the processor 802 can be connected to each other through a bus and complete communication with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of presentation, only one thick line is used in Figure 8, but it does not mean that there is only one bus or one type of bus.

Optionally, in terms of specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated on one chip, the memory 801, the processor 802 and the communication interface 803 can communicate with each other through the internal interface.

The processor 802 may be a central processing unit (Central Processing Unit, CPU for short), or an Application Specific Integrated Circuit (ASIC for short), or one or more processors configured to implement the embodiments of the present application. integrated circuit.

Embodiments of the present application also provide a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the above X-ray fluorescence imaging method is implemented.

In the description of this specification, reference to the terms "one embodiment,""someembodiments,""anexample,""specificexamples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or N embodiments or examples. Furthermore, those skilled in the art may combine and combine different embodiments or examples and features of different embodiments or examples described in this specification unless they are inconsistent with each other.

In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically limited. Any process or method descriptions in flowcharts or otherwise described herein may be understood to represent modules, segments, or portions of code that include one or more executable instructions for implementing customized logical functions or steps of the process. , and the scope of the preferred embodiments of the present application includes additional implementations in which functions may be performed out of the order shown or discussed, including in a substantially simultaneous manner or in the reverse order, depending on the functionality involved, which shall It should be understood by those skilled in the technical field to which the embodiments of this application belong.

The logic and/or steps represented in the flowcharts or otherwise described herein, for example, may be considered a sequenced list of executable instructions for implementing the logical functions, and may be embodied in any computer-readable medium, For use by, or in combination with, instruction execution systems, devices or devices (such as computer-based systems, systems including processors or other systems that can fetch instructions from and execute instructions from the instruction execution system, device or device) or equipment. For the purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections with one or N wires (electronic device), portable computer disk cartridge (magnetic device), random access memory (RAM), Read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium may even be paper or other suitable medium on which the program may be printed, as the paper or other medium may be optically scanned, for example, and subsequently edited, interpreted, or otherwise suitable as necessary. process to obtain the program electronically and then store it in computer memory.

It should be understood that various parts of the present application can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if it is implemented in hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: discrete logic gate circuits with logic functions for implementing data signals; Logic circuits, application specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

Those of ordinary skill in the art can understand that all or part of the steps involved in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. The program can be stored in a computer-readable storage medium. When executed, one of the steps of the method embodiment or a combination thereof is included.

In addition, each functional unit in each embodiment of the present application can be integrated into one processing module, or each functional unit can be integrated into one processing module. Each unit physically exists alone, or two or more units can be integrated into one module. The above integrated modules can be implemented in the form of hardware or software function modules. If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

The storage media mentioned above can be read-only memory, magnetic disks or optical disks, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are illustrative and cannot be understood as limitations of the present application. Those of ordinary skill in the art can make modifications to the above-mentioned embodiments within the scope of the present application. The embodiments are subject to changes, modifications, substitutions and variations.

Claims

An X-ray fluorescence imaging method, characterized by including the following steps:

Incident X-rays into the sample to be scanned, and excite X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned;

Based on the preset incident angle, the fluorescence photons and/or the scattered photons are injected into the Compton camera detector, and the fluorescence photons and the scattered photons are acquired during the movement of the Compton camera detector. When Compton scattering occurs, a first spatial coordinate and a first deposition energy at which a scattering event occurs, and a second spatial coordinate and a second deposition energy at which an absorption event occurs; and

Image reconstruction of the Compton camera is performed according to the first spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy to obtain a three-dimensional image of the sample to be scanned.
The method according to claim 1, characterized in that the preset reconstruction algorithm is:

in, is the voxel j of the image after (l+1) rounds of iteration, l is an integer, is the voxel j of the image after l rounds of iteration, T ij is the system matrix, S j is the sensitivity matrix, i is the event number index, j is the voxel index, N is the total number of events, M is the total number of voxels, and k is Voxel index, T ik is an element of the system matrix, is the voxel k of the image after l rounds of iteration.
The method according to claim 2, characterized in that the system matrix is:

Among them, v j is the imaging space volume of voxel j, P(y i |x,E 0 ) is the probability that event yi is related to space point x, x is a point in space, y i is the i-th event, E 0 is the total energy of the incident photon, and P(x∈v j ) is the probability that the spatial point x is within the volume v j of voxel j.
The method according to claim 3, further comprising:

Based on the preset scattering correction algorithm, the system matrix is updated, where the updated system matrix is:

Among them, is the rewritten system matrix, Expressed as the probability that event yi does not belong to the event set Y (Scattering) caused by scattered photons.
The method according to claim 3, further comprising:

Based on the preset Doppler broadening correction low-energy reconstruction algorithm and the scattering correction algorithm, the system matrix is determined, wherein the system matrix is:

in, is the vector between event yi and voxel v j , is a vector The angle with the vertical direction, β is the true scattering angle, θ is the measured scattering angle, K(β,E 0 ) is the Compton scattering cross section, σ er is the energy resolution of the detector, and σ sr is the spatial resolution of the detector rate, σ db is the reconstruction angle uncertainty caused by the Doppler broadening effect, h(φ i ) is the probability that event i comes from scattered photons.
An X-ray fluorescence imaging device, characterized by including:

An excitation module, used to inject X-rays into the sample to be scanned and excite the X-ray fluorescence photons and scattered photons of the fluorescent elements in the sample to be scanned;

An acquisition module, configured to inject the fluorescence photons and/or the scattered photons into the Compton camera detector based on a preset incident angle, and acquire the fluorescence photons during the movement of the Compton camera detector. and the first spatial coordinate and the first deposition energy at which a scattering event occurs when Compton scattering of the scattered photon occurs, and the second spatial coordinate and the second deposition energy at which the absorption event occurs; and

An imaging module, configured to perform image reconstruction of the Compton camera according to the first spatial coordinates, the first deposition energy, the second spatial coordinates and the second deposition energy to obtain a three-dimensional image of the sample to be scanned image.
The device according to claim 6, wherein the preset reconstruction algorithm is:

in, is the voxel j of the image after (l+1) rounds of iteration, l is an integer, is the voxel j of the image after l rounds of iteration, T ij is the system matrix, S j is the sensitivity matrix, i is the event number index, j is the voxel index, N is the total number of events, M is the total number of voxels, and k is Voxel index, T ik is an element of the system matrix, is the voxel k of the image after l rounds of iteration.
The device according to claim 7, characterized in that the system matrix is:

Among them, v j is the imaging space volume of voxel j, P(y i |x,E 0 ) is the probability that event yi is related to space point x, x is a point in space, y i is the i-th event, E 0 is the total energy of the incident photon, P (x∈v j ) is the energy of the space point x in the volume v j of voxel j Probability.
An electronic device, characterized by including a memory and a processor;

Wherein, the processor reads the executable program code stored in the memory to run a program corresponding to the executable program code, so as to implement the X-ray method as claimed in any one of claims 1-5. Fluorescence imaging methods.
A computer-readable storage medium stores a computer program, characterized in that when the program is executed by a processor, the X-ray fluorescence imaging method according to any one of claims 1-5 is implemented.