Medical image reconstruction method and device, computer device and storage medium

Abstract

The application discloses a medical image reconstruction method and device, computer equipment and a storage medium. The method comprises the following steps: acquiring first medical data and second medical data of a target object, calculating scatter data according to the first medical data and the second medical data, and performing image reconstruction according to the scatter data, the first medical data and the second medical data to obtain a medical image after scatter correction. In the application, the inherent characteristics of double-layer flat plates are considered, high and low energy medical data of an object can be obtained in one scan, the medical data under low energy contains primary projection and scatter data of the object, the scatter data under low energy is eliminated by solving the scatter data under low energy, the medical data without scatter data is obtained, the scatter artifacts are eliminated during subsequent image reconstruction, and the image quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the medical technology field, in particular to a medical image reconstruction method and device, computer equipment and storage medium. BACKGROUND

[0002] Computed Tomography (CT) has been widely used in human tissue imaging, industrial non-destructive testing and other fields. CT reconstruction algorithms can be divided into two categories: iterative reconstruction algorithm and analytical reconstruction algorithm. The advantages of analytical reconstruction algorithm are simple algorithm and fast reconstruction speed, and the disadvantages are higher requirement for data completeness and great influence of noise in projection data on the quality of reconstructed image. Compared with analytical reconstruction algorithm, the advantages of iterative reconstruction algorithm are high image quality and applicability to various forms of acquisition data. Even in the case of limited angle projection data, a better image can be reconstructed. Typical iterative algorithms include Simultaneous Algebraic Reconstruction Technique (SART), Weighted Least Squares (WLS) and Maximum Likehood-Expectation Maximization (EM-ML). However, due to the large amount of calculation, slow convergence speed and long reconstruction time of iterative reconstruction algorithm, it has become the biggest bottleneck restricting its wide application.

[0003] Before medical image reconstruction, a double-layer flat panel detector can obtain medical data of a scanned object under high and low energy in one X-ray exposure, so as to realize dual-energy medical imaging. The basic principle is that the first layer detector can obtain low-energy X-ray projection data, and the second layer detector obtains high-energy X-ray projection data after energy separation filter. In a medical imaging system, due to the wide Z-axis direction of the flat panel detector (Z-axis refers to the length direction of the bed, that is, corresponding to the Y direction of the panel), and the beam is not perpendicular to each detector unit, often the scattered photons from each direction are detected by the detector, resulting in that the obtained dual-energy image contains scattered data, so that the subsequent reconstructed image has serious scattering artifacts, affecting the quality of the reconstructed image. SUMMARY

[0004] The embodiments of the present application provide a medical image reconstruction method, device, computer equipment and storage medium. By solving the scattered data under low energy, the scattered data under low energy is eliminated, so as to obtain medical data eliminating scattered data, so that the scattering artifacts are eliminated in subsequent image reconstruction, and the quality of the reconstructed image is improved.

[0005] In one aspect, the present application provides a medical image reconstruction method, which comprises:

[0006] obtaining first medical data and second medical data of a target object, the first medical data and the second medical data being obtained by an upper layer panel and a lower layer panel respectively when scanning the target object by using a double-layer panel, the first medical data being obtained based on first energy rays, and the second medical data being obtained based on second energy rays, an energy value of the first energy rays being higher than an energy value of the second energy rays;

[0007] calculating scatter data according to the first medical data and the second medical data;

[0008] performing image reconstruction according to the scatter data, the first medical data and the second medical data, to obtain a medical image after scatter correction.

[0009] In some embodiments of the present application, the calculating of the scatter data according to the first medical data and the second medical data comprises:

[0010] calculating theoretical low-energy data according to the first medical data;

[0011] determining the scatter data according to the second medical data and the theoretical low-energy data.

[0012] In some embodiments of the present application, the calculating of the theoretical low-energy data according to the first medical data comprises:

[0013] obtaining a proportional coefficient of low-energy data and high-energy data under an empty field condition;

[0014] determining the theoretical low-energy data according to the first medical data and the proportional coefficient.

[0015] In some embodiments of the present application, the calculating of the theoretical low-energy data according to the first medical data comprises:

[0016] establishing a target object model according to the first medical data;

[0017] performing simulation scanning on the target object model by using low-energy rays of a preset energy, to obtain the theoretical low-energy data.

[0018] In some embodiments of the present application, the establishing of the target object model according to the first medical data comprises:

[0019] determining material information of the target object according to the first medical data;

[0020] establishing the target object model according to the material information.

[0021] In some embodiments of the present application, the method further comprises:

[0022] repeating the calculating of the scatter data for multiple times;

[0023] averaging the scatter data calculated for multiple times to obtain final scatter data.

[0024] In some embodiments of the present application, the reconstructing of the image according to the scatter data, the first medical data and the second medical data to obtain the medical image corrected for scatter includes:

[0025] obtaining second medical data corrected for scatter according to the second medical data and the scatter data;

[0026] reconstructing the image according to the first medical data and the second medical data corrected for scatter to obtain a high-energy medical image and a low-energy medical image.

[0027] In another aspect, the present application provides a medical image reconstruction device, which includes:

[0028] an acquisition module configured to acquire first medical data and second medical data of a target object, the first medical data and the second medical data being medical data acquired by an upper layer panel and a lower layer panel respectively when scanning the target object by using a double-layer panel, the first medical data being acquired based on first energy rays, and the second medical data being acquired based on second energy rays, the energy value of the first energy rays being higher than that of the second energy rays;

[0029] a calculation module configured to calculate scatter data according to the first medical data and the second medical data;

[0030] a reconstruction module configured to reconstruct the image according to the scatter data, the first medical data and the second medical data to obtain a medical image corrected for scatter.

[0031] In another aspect, the present application further provides a computer device, which includes:

[0032] one or more processors;

[0033] a memory; and

[0034] one or more application programs, wherein the one or more application programs are stored in the memory and configured to be executed by the processor to implement the medical image reconstruction method according to any one of the first aspect.

[0035] In another aspect, the present application further provides a computer readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to execute the medical image reconstruction method according to any one of the first aspect.

[0036] The application obtains first medical data and second medical data of a target object, calculates scatter data according to the first medical data and the second medical data, and performs image reconstruction according to the scatter data, the first medical data and the second medical data to obtain a medical image after scatter correction. In the application, the double-layer flat panel inherent characteristics are considered, high and low energy medical data of an object can be obtained in one scan, the medical data under low energy contains primary projection and scatter data of the object, the scatter data under low energy is solved to eliminate the scatter data under low energy, thereby obtaining medical data after elimination of scatter data, so that the scatter artifact is eliminated in subsequent image reconstruction, and the quality of the reconstructed image is improved. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0038] Figure 1 is a scene schematic diagram of a medical image reconstruction system provided by the embodiments of the present application;

[0039] Figure 2 is a flowchart of one embodiment of a medical image reconstruction method provided in the embodiments of the present application;

[0040] Figure 3 is a structure schematic diagram of one embodiment of a medical image reconstruction device provided in the embodiments of the present application;

[0041] Figure 4 is a structure schematic diagram of one embodiment of a computer device provided in the embodiments of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0043] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only 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 with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise explicitly specified.

[0044] In the present application, the word "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation described as "exemplary" in the present application is not necessarily to be construed as preferred or advantageous over other implementations. The following description is presented to enable any person skilled in the art to make and use the present application. In the following description, for the purposes of explanation, details are set forth in order to provide a thorough understanding of the present application. It should be appreciated that one of ordinary skill in the art will realize that the present application can be practiced without the use of these specific details. In other instances, well-known structures and processes are not elaborated in order not to obscure the description of the present application with unnecessary details. Thus, the present application is not intended to be limited by the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

[0045] It should be noted that the method of the embodiments of the present application is executed in a computer device, and the processing objects of each computer device exist in the form of data or information, such as time, which is essentially time information. It can be understood that if the size, quantity, position and the like are mentioned in subsequent embodiments, they all exist in the form of corresponding data for processing by the computer device, and specific details are not repeated here.

[0046] First, some basic concepts involved in the embodiments of the present application will be introduced as follows:

[0047] Computed Tomography (CT): is a kind of imaging technology that uses X-ray beams and detectors to scan a certain cross-section (tomography) of an object, obtains a set of projection data reflecting the physical or chemical characteristics of the cross-section by using the different characteristics of the absorption coefficient of human organs or tissues to X-rays, obtains the parameter value of any position on the cross-section by computer operation, and obtains the tomographic image. The main components of the existing CT system include: X-ray source, detector, and rotating device. In the CT imaging process, the X-ray source and the detector rotate relative to the object to obtain CT data at different rotation angles, also known as CT projection values. In CT imaging, the attenuation of X-rays follows an exponential law, and CT projection values are indirectly obtained, usually requiring "negative logarithm" preprocessing.

[0048] CBCT: CBCT is the abbreviation of Cone beam CT, that is, cone beam CT. As the name implies, it is a cone beam projection computer reconstruction tomography device. Its principle is that the X-ray generator makes a ring-shaped DR (digital projection) around the projection body at a relatively low radiation dose (usually the tube current is about 10 milliamps). Then the data obtained in the "intersection" after multiple (180-360 times, depending on the product) digital projections around the projection body are reconstructed in the computer to obtain a three-dimensional image.

[0049] CBCT based on flat panel detector has high radiation utilization, high resolution, isotropy, simple structure and easy miniaturization, and has become an important development direction of modern CT equipment. It has been widely used in image-guided radiotherapy (IGRT), oral / head disease diagnosis, small animal three-dimensional imaging, and image-guided interventional surgery, and plays an indispensable important role. CBCT has a larger irradiation field of view, and the probability of receiving scattered radiation by the detector is higher. Scattered radiation will cause cup-shaped, high-attenuation material strip-shaped or band-shaped artifacts in the reconstructed image, reduce the image contrast, and make the CT value inaccurate, which has become a key factor restricting its development and application.

[0050] The research on the theory and application of cone beam CT (CBCT) related imaging is also deepening. The CBCT experimental machine based on double-layer flat panel detector (double-layer flat panel for short) has appeared in the market. The CBCT based on double-layer flat panel detector is a digital X-ray detector with complex structure and spectral separation function. The double-layer flat panel detector has upper and lower flat panel detectors which are equal in space. The upper flat panel detector (upper flat panel for short) only absorbs and identifies low-energy photons and allows high-energy photons to pass through, and the low-energy photons are transmitted from the side data channel. The lower flat panel detector (lower flat panel for short) absorbs and identifies high-energy photons and is also transmitted from the side channel to avoid crosstalk between the upper and lower layers. The high-energy and low-energy data collected by the double-layer detector are analyzed under the premise that they are completely matched in time and space in the projection data domain, so that the reconstruction of multi-parameter spectral images can be realized, and they can be used for retrospective analysis. The advantage of the double-layer detector technology is that it does not need to pre-judge whether dual-energy scanning is needed before scanning, and there is no restriction on organs and scanning field of view. Moreover, the two sets of high-energy and low-energy data sets are completely registered in space and time, which helps to greatly reduce the noise of spectral images.

[0051] In image-guided radiation therapy (IGRT) and adaptive radiotherapy (ART), CBCT is often used as a positioning device for a radiotherapy system. Therefore, the double-layer flat panel CBCT can also be used as a positioning device for a radiotherapy system.

[0052] Scatter correction: CBCT based on double-layer flat panel detector can obtain data of a scanned object under high and low energy in one X-ray exposure, so as to realize dual-energy CBCT imaging. The basic principle is that the first layer detector can obtain low-energy X-ray projection data, and the second layer detector obtains high-energy X-ray projection data after passing through an energy separation filter. In the CBCT imaging system, the Z-axis direction of the flat panel detector is relatively wide (the Z-axis refers to the length direction of the bed, that is, the Y direction of the flat panel), and the beam is not perpendicular to each detector unit. Therefore, scattered photons from various directions are detected by the detector, resulting in serious scattering artifacts in the reconstructed image and affecting the quality of the reconstructed image. One of the most core problems of improving the performance of CBCT imaging is to remove or reduce the scattering of rays, that is, scatter correction.

[0053] Iterative reconstruction technique: an image is obtained in a gradually approximating manner by using a series of approximate calculations. Before the image reconstruction starts, it is assumed that the image is of uniform density, and each step of the reconstructed image is to compare the calculated projection of the last step of the reconstructed image with the actually measured projection, and to correct the image by using the difference between the actual projection and the calculated projection. Each step makes the image closer to the original object, and after several corrections, a satisfactory image can be obtained.

[0054] The embodiment of the present application provides a medical image reconstruction method and device, computer equipment and a storage medium. The following will be described in detail.

[0055] Please refer to Figure 1 , Figure 1 The scene schematic diagram of the medical image reconstruction system provided by the embodiment of the present application can include computer equipment 100 and medical equipment 200, the computer equipment 100 is in communication connection with the medical equipment 200, the medical equipment 200 includes a double-layer flat panel detector, and medical data (such as actual projection data) collected by the medical equipment 200 can be transmitted to the computer equipment 100. The computer equipment 100 is integrated with a medical image reconstruction device, wherein the medical equipment 200 can be an imaging device, the imaging device can be a mega-volt CBCT (MV-CBCT) or a kilo-volt CBCT (KV-CBCT), and the medical equipment 200 can also be an imaging device configured on a radiotherapy device, which is not limited here.

[0056] In the embodiment of the present application, the computer equipment 100 is mainly used to obtain first medical data and second medical data for a target object, the first medical data and the second medical data are medical data obtained by an upper flat panel and a lower flat panel respectively when the double-layer flat panel scans the target object; the first medical data is obtained based on first energy rays, and the second medical data is obtained based on second energy rays, and the energy value of the first energy rays is higher than that of the second energy rays; according to the first medical data and the second medical data, the scattering data is calculated; according to the scattering data, the first medical data and the second medical data, the image reconstruction is performed, and the medical image after scattering correction is obtained.

[0057] In the embodiment of the present application, the computer equipment 100 can be an independent server, or a server network or a server cluster composed of servers, for example, the computer equipment 100 described in the embodiment of the present application includes but is not limited to a computer, a network host, a single network server, a plurality of network server sets or a cloud server composed of a plurality of servers. The cloud server is composed of a large number of computers or network servers based on cloud computing.

[0058] It can be understood that the computer device 100 in the embodiments of the present application can also be a terminal. The terminal can be a device that includes receiving and transmitting hardware, i.e., a device that has receiving and transmitting hardware capable of performing bidirectional communication on a bidirectional communication link. Such a device can include a cellular or other communication device with a single-line display or a multi-line display or a cellular or other communication device without a multi-line display. The terminal can specifically be a desktop terminal, such as a desktop computer, etc.

[0059] Those skilled in the art can understand that, Figure 1 The application environment shown in the above Figure 1 The application environment shown in the above Figure 1 Only one computer device is shown in the above It can be understood that the medical image reconstruction system can also include one or more other computer devices, without limitation.

[0060] In addition, as shown in the above Figure 1 The medical image reconstruction system can also include a memory 300 for storing medical data, such as image data or data directly acquired by a double-layer flat panel detector, etc.

[0061] In the embodiments of the present application, the medical device 200 can be a CT device, a CBCT device, or other medical devices, such as a Positron Emission Tomography-Computed Tomography (PET-CT) device, etc., without limitation. Correspondingly, in the embodiments of the present application, the medical image described can refer to a CT image, and further, in the embodiments of the present application, the medical device is an image device arranged on a radiotherapy device.

[0062] It should be noted that, Figure 1 The scenario diagram of the medical image reconstruction system shown in the above is only one example. The medical image reconstruction system and the scenario described in the embodiments of the present application are for more clearly illustrating the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art can know that, as the medical image reconstruction system evolves and new business scenarios appear, the technical solutions provided by the embodiments of the present application are also applicable to similar technical problems.

[0063] As shown in the above Figure 2 The medical image reconstruction method includes the following steps 201-203:

[0064] 201、acquire first medical data and second medical data of a target object.

[0065] The target object can be any living body, such as a human or an animal, and can also be a model of a human or an animal, etc. In this embodiment, the target object is taken as a human body as an example. When the target object is a human body, it can be a part of the human body or the whole human body, such as a tissue or an organ of the human body, specifically, a head, a lung, a liver, or the like.

[0066] In this embodiment, a double-layer flat panel detector (referred to as a double-layer flat panel) is arranged in the medical device. The double-layer flat panel detector has upper and lower flat panel detectors that are spatially equivalent. The upper flat panel detector (referred to as the upper flat panel) only absorbs and identifies low-energy photons and allows high-energy photons to pass through, and the low-energy photons are transmitted from a side data channel. The lower flat panel detector (referred to as the lower flat panel) absorbs and identifies high-energy photons, and is also transmitted from a side channel to avoid upper and lower layer crosstalk. The high-energy and low-energy data collected by the double-layer detector are analyzed under the premise that they are completely matched in time and space in the projection data domain, which can realize the reconstruction of the energy spectrum multi-parameter image and can be used for retrospective analysis.

[0067] The first medical data and the second medical data are medical data acquired by the upper flat panel and the lower flat panel of the double-layer flat panel in the medical device when scanning the target object. The first medical data and the second medical data can be medical projection data of the target object collected by the medical device, such as medical projection data formed by the medical device penetrating the target object.

[0068] In the medical device, a fixed X-ray tube is arranged, and a fixed tube voltage and tube current are arranged through the X-ray tube to generate rays of different energies. In this embodiment, the first medical data is acquired based on first energy rays, and the second medical data is acquired based on second energy rays. The energy value of the first energy rays is higher than that of the second energy rays.

[0069] In this embodiment, the energy values of the first energy rays and the second energy rays can be predefined. Further, the first energy rays can be high-energy rays, and the second energy rays can be low-energy rays. The energy value range of the low-energy rays and the high-energy rays can refer to the conventional definition of the low-energy ray range and the high-energy ray range in the CT field. Of course, based on the actual application scenario, the range can be further narrowed within the conventional definition of the low-energy ray range and the high-energy ray range in the CT field. The specific range is not limited here, as long as the energy value of the first energy rays is higher than that of the second energy rays.

[0070] 202、According to the first medical data and the second medical data, calculate the scatter data.

[0071] In this embodiment, the double-layer flat panel detector can obtain the data of the scanning target object under high and low energy, i.e., the first medical data and the second medical data in step 201, when scanning the target object once, so as to realize the dual-energy CBCT imaging. In this step, the scatter data is the scatter data of the double-layer flat panel detector when scanning the target object once.

[0072] Since the Z-axis direction of the double-layer flat panel detector is relatively wide, and the beam is not perpendicular to each detector unit, the scattered photons from each direction are often detected by the detector, thereby causing serious scatter artifacts in the reconstructed image. Specifically, the projection data under low energy contains the primary projection and scatter data of the object. In this step, the scatter data is estimated by the first medical data and the second medical data, so as to eliminate the scatter data under low energy in the subsequent step, thereby achieving the purpose of scatter correction.

[0073] 203. Image reconstruction is performed according to the scatter data, the first medical data and the second medical data, to obtain a scatter-corrected medical image.

[0074] According to the obtained scatter data, the corresponding scatter data is eliminated in the first medical data, or in the second medical data, or in both the first medical data and the second medical data. According to the first medical data and the second medical data after eliminating the scatter data, image reconstruction is performed, and the reconstructed medical image does not exist scatter artifacts, thereby improving the quality of the reconstructed image. In the image reconstruction, the first medical image corresponding to the energy level can be reconstructed according to the first medical data, and the second medical image corresponding to the energy level can be reconstructed according to the second medical data.

[0075] In the embodiments of the present application, the first medical data and the second medical data of the target object are obtained, the scatter data is calculated according to the first medical data and the second medical data, and image reconstruction is performed according to the scatter data, the first medical data and the second medical data, to obtain a scatter-corrected medical image. In the present application, the double-layer flat panel inherent characteristics are considered, which can obtain the high and low energy medical data of the object under one-time scanning. The low-energy medical data contains the primary projection and scatter data of the object. The scatter data under low energy is solved to eliminate the scatter data under low energy, so as to obtain the medical data without scatter data, so that the scatter artifacts are eliminated in the subsequent image reconstruction, and the quality of the reconstructed image is improved.

[0076] In the traditional CT scatter correction method, an arc filter is usually added at the X-ray source beam exit port, which functions to pre-harden the X-rays, reduce the low-energy part of the energy spectrum, and allow as much high-energy radiation as possible to pass through to reduce scattering. The imaging characteristics of the double-layer flat panel naturally meet the above-mentioned scatter correction principle. The upper flat panel detector and the lower flat panel detector of the double-layer flat panel detector will filter scattered data, and therefore, theoretically, no arc filter is needed at the X-ray source beam exit port opposite to the double-layer flat panel detector.

[0077] In the embodiments of the present application, it is assumed that the low-energy data part of the medical data formed by the double-layer flat panel detector is composed of theoretical low-energy data and scattered data, and the high-energy data part only contains theoretical high-energy data. For the double-layer flat panel detector, the medical data of the target object under high energy (first energy ray) is obtained by one scan The medical data of the target object under low energy (second energy ray) The medical data under low energy is composed of theoretical low-energy data and scattered data, as shown in equation (1).

[0078]

[0079] In the formula, and The theoretical low-energy data and scattered data under low energy.

[0080] The medical data under high energy only contains theoretical high-energy data, that is:

[0081]

[0082] In the formula, The theoretical high-energy data under high energy.

[0083] Based on equations (1) and (2), the embodiments of the present application can estimate the scatter in multiple ways and estimate the corresponding scatter data. Finally, after subtracting the estimated scatter data, the corresponding theoretical low-energy data is obtained and reconstructed, and the scatter-corrected reconstructed image can be obtained. The following will be illustrated respectively.

[0084] In some embodiments of the present application, the upper flat panel detector can be directly used for scatter estimation by using the medical data. Specifically, according to the first medical data and the second medical data, the scatter data is calculated, including: calculating the theoretical low-energy data according to the first medical data; determining the scatter data according to the second medical data and the theoretical low-energy data.

[0085] Further, in some embodiments of the present application, the calculating the theoretical low-energy data according to the first medical data can further include: obtaining a proportional coefficient of the low-energy data and the high-energy data under the empty field condition; and determining the theoretical low-energy data according to the first medical data and the proportional coefficient.

[0086] For example, in the present embodiment, it is assumed that the first medical data (high-energy data) does not contain scattering, and then the proportional coefficient under the empty field condition can be obtained by using the above formulas (1) and (2) assuming that there is a proportional coefficient under the empty field condition. Then, the corresponding scattering data can be obtained by using the proportional coefficient under the empty field condition to deduce back, and then the second medical data (low-energy data) does not contain the scattering data.

[0087] (1)-(2) are as follows:

[0088] In some other embodiments of the present application, the scanning object information can be reconstructed by using the high-energy medical data, the theoretical low-energy data can be obtained by considering the projection model, and the corresponding scattering data can be estimated.

[0089] Similarly, it is assumed that the first medical data (high-energy medical data) does not contain scattering data, and then the scanning object information can be obtained by directly reconstructing the first medical data. The theoretical low-energy data can be obtained by simulating the scanning of the object under the low-energy condition by using the projection model. Then, the scattering data can be obtained by subtracting the theoretical low-energy data from the second medical data.

[0090] For example, the calculating the theoretical low-energy data according to the first medical data includes: establishing a target object model according to the first medical data; and simulating the scanning of the target object model by using the low-energy rays of the preset energy to obtain the theoretical low-energy data.

[0091] Since the target object can be any living body or phantom, the target object model can also be a model corresponding to the living body or the phantom. For example, when the target object is a human body, the target object model is a model of the human body. For example, when the target object is a human phantom, the target object model is a model corresponding to the human phantom.

[0092] In the present embodiment, the low-energy rays of the preset energy can have the same energy value as the second energy rays in the above embodiment, or can have different energy values, which can be within the range of the low-energy rays defined in the CT field or conventionally defined in the CT field.

[0093] In addition, the simulation scanning described in the embodiments of the present application is similar to the way of obtaining low-energy medical data by the medical device in the above-described embodiments, except that the object of the scanning is the target object model instead of an actual person or object, thus becoming a simulation scanning. The specific scanning technical means is the prior art, which is not described here.

[0094] Further, the establishing the target object model according to the first medical data includes: determining material information of the target object according to the first medical data; and establishing the target object model according to the material information.

[0095] Specifically, the way of determining the material information of the target object according to the first medical data can be through an image reconstruction manner. The image reconstruction manner can be one of the above-described iterative reconstruction algorithm and analytical reconstruction algorithm, for example, a reconstruction manner such as Simultaneous Algebraic Reconstruction Technique (SART), Weighted Least Squares (WLS), and Maximum Likehood-Expectation Maximization (EM-ML), which is not limited here.

[0096] The establishing the object model according to the known material information of the object is the prior art, thus, in the embodiments of the present application, the establishing the target object model according to the material information is not described here.

[0097] Further, in the embodiments of the present application, the scattering data in the process of scanning the target object once can also be determined by calculating the scattering data multiple times and averaging. That is, the scattering data can be calculated multiple times repeatedly; and the average of the scattering data calculated multiple times is taken as the final scattering data.

[0098] For example, in some embodiments of the present application, the calculating the scattering data according to the first medical data and the second medical data includes: obtaining multiple scattering data in the process of scanning the target object multiple times under the same scanning condition; and obtaining the scattering data in the process of scanning the target object once by averaging the multiple scattering data.

[0099] The way of obtaining each of the multiple scattering data in the process of scanning the target object multiple times under the same scanning condition can refer to the specific process in the above-described embodiments, which is not described here.

[0100] Further, the way of acquiring the plurality of scatter data in the process of the double-layer panel scanning the target object multiple times under the same scanning condition can be the same way of acquiring the plurality of scatter data, for example, the calculating the scatter data according to the first medical data and the second medical data comprises: acquiring a plurality of scatter data in the process of the double-layer panel scanning the target object multiple times under the same scanning condition, each scatter data being determined according to the first medical data generated in the process of each time of scanning the target object and the proportion coefficient; and obtaining the scatter data in the process of the double-layer panel scanning the target object once by averaging the plurality of scatter data.

[0101] In addition, the way of acquiring the plurality of scatter data in the process of the double-layer panel scanning the target object multiple times under the same scanning condition can also be multiple different ways of acquiring the plurality of scatter data, for example, a part of the plurality of scatter data is acquired by way 1 and a part of the plurality of scatter data is acquired by way 2, wherein, way 1 can be one of the ways of calculating the scatter data in the above embodiments, for example, determining the theoretical low-energy data under the empty field condition, and then determining the scatter data according to the second medical data and the theoretical low-energy data; and way 2 can be another way of calculating the scatter data in the above embodiments, for example, establishing a target object model according to the first medical data, performing simulation scanning on the target object model by using low-energy rays of a preset energy to obtain theoretical low-energy data, and then determining the scatter data according to the second medical data and the theoretical low-energy data. After the plurality of scatter data is calculated, the scatter data in the process of the double-layer panel scanning the target object once is obtained by averaging the plurality of scatter data, and the final scatter data is determined.

[0102] In some other embodiments of the present application, when the plurality of scatter data is acquired by multiple different ways, the final scatter data can also be determined by weighted calculation in addition to averaging.

[0103] For example, a part of the plurality of scatter data is acquired by way 1 and a part of the plurality of scatter data is acquired by way 2, the scatter data acquired by way 1 is multiplied by a preset first weighting coefficient, the scatter data acquired by way 2 is multiplied by a preset second weighting coefficient, and the final scatter data is determined after weighted calculation.

[0104] In one embodiment, the calculating the scatter data according to the first medical data and the second medical data includes: obtaining a ratio coefficient of low-energy data and high-energy data under an empty field condition; determining first theoretical low-energy data according to the first medical data and the ratio coefficient; determining material information of the target object according to the first medical data; establishing a target object model according to the material information; performing simulation scanning on the target object model by using low-energy rays of a preset energy to obtain second theoretical low-energy data; obtaining first scatter data according to the second medical data and the first theoretical data, and obtaining second scatter data according to the second medical data and the second theoretical low-energy data; and performing weighted calculation on the first scatter data and the scatter data to obtain scatter data of the double-layer flat panel in the process of scanning the target object once.

[0105] In the weighted calculation, a preset weighting coefficient can be used for weighted operation, and the weighting coefficient can be determined according to an actual application scenario, and is not limited herein.

[0106] In some embodiments of the present application, the image reconstruction according to the scatter data, the first medical data and the second medical data to obtain the scatter-corrected medical image includes: obtaining scatter-corrected second medical data according to the second medical data and the scatter data; and performing image reconstruction according to the first medical data and the scatter-corrected second medical data to obtain high-energy medical images and low-energy medical images.

[0107] Specifically, the scatter-corrected second medical data obtained according to the second medical data and the scatter data can be obtained by subtracting the scatter data from the second medical data.

[0108] The method of performing image reconstruction according to the first medical data of the target object and the scatter-corrected second medical data can adopt the reconstruction method described above, for example, an iterative reconstruction method, and specifically, a joint iterative reconstruction method, a weighted least square method or the like can be adopted, and is not limited herein.

[0109] For the reconstruction process of image reconstruction according to the first medical data of the target object and the scatter-corrected second medical data, one possible way in the embodiment of the application can be: firstly, the original estimation of the X-ray photon distribution is performed, on the basis of which the possible count (i.e. forward projection data) obtained by the detector in each projection direction is estimated, then the forward projection data is compared with the actual forward projection data actually collected by the detector to obtain the projection data difference, the reconstruction image is obtained by back projection of the projection data difference, and the original estimation data is updated by forward projection of the current reconstruction image; the process is repeatedly performed to continuously check and correct the projection data corresponding to the image until the error (the minimum of the projection difference data) is minimized, the result of the next iteration is infinitely close, and finally the reconstructed high-energy medical image and low-energy medical image are obtained.

[0110] It should be noted that, in the embodiment of the application, the theoretical low-energy data can also be preprocessed before image reconstruction. The preprocessing method can be some methods of image enhancement, such as gray scale transformation in the spatial domain (such as direct gray scale transformation, histogram correction method, image algebra operation, etc.), spatial domain filtering (image smoothing processing and image sharpening processing), high-pass filtering, low-pass filtering, band-pass filtering, band-stop filtering, etc. in the frequency domain, and the specific method is not limited here.

[0111] For example, in order to reduce the noise in the projection data, the theoretical low-energy data can be subjected to nonlinear filtering and filtering based on the Bayesian statistical theory; in order to overcome the bar artifacts, ring artifacts, metal artifacts and cup-shaped artifacts in the reconstructed image, emerging image processing methods based on dictionary learning and morphological component analysis can be used to process the projection data, and the processed data and parameters related to reconstruction, specifically the phantom position and size, the position of the rotation center, the distance from the ray source to the rotation center, the detector size, the distance from the detector to the rotation center and the projection angle, are transmitted to the GPU of the computer device. Since these processed data and parameters are on the CPU of the computer device, these data also need to be transmitted to the computer device to use the GPU for acceleration.

[0112] In addition, the reconstruction of the medical image in the embodiment of the application can also use the pipeline technology. The working principle of the pipeline technology is that each processor module of the array machine independently performs its own task in turn, and the next step is performed immediately after the previous task is completed, so that the preprocessing, convolution and back projection can be performed at the same time in most of the time. The speed of image reconstruction is accelerated, so that the CT image can be reconstructed almost in real time after the scanning is completed, and the image can be displayed immediately.

[0113] It can be understood that in the embodiments of the present application, in addition to the medical data, other reconstruction-related parameters are also included in the image reconstruction, such as the specific phantom position and size when the medical data is acquired, the position of the rotation center, the distance from the ray source to the rotation center, the size of the detector, the distance from the detector to the rotation center, and the projection angle, etc. Since the improvement of the specific parameters is not involved, the specific process can refer to the prior art, and thus will not be described in detail here.

[0114] In order to better implement the medical image reconstruction method in the embodiments of the present application, on the basis of the medical image reconstruction method, a medical image reconstruction device is further provided in the embodiments of the present application, which is applied to a computer device, and the computer device is in communication connection with a medical device, as shown in the following figure: Figure 3 The medical image reconstruction device 300 includes an acquisition module 301, a calculation module 302, and a reconstruction module 303.

[0115] The acquisition module 301 is configured to acquire first medical data and second medical data for a target object, the first medical data and the second medical data being medical data acquired by an upper layer panel and a lower layer panel respectively when a double-layer panel scans the target object; the first medical data is acquired based on a first energy ray, and the second medical data is acquired based on a second energy ray; the energy value of the first energy ray is higher than the energy value of the second energy ray.

[0116] The calculation module 302 is configured to calculate scatter data according to the first medical data and the second medical data.

[0117] The reconstruction module 303 is configured to perform image reconstruction according to the scatter data, the first medical data, and the second medical data, to obtain a scatter-corrected medical image.

[0118] In the embodiments of the present application, the acquisition module 301 acquires first medical data and second medical data for a target object, the calculation module 302 calculates scatter data according to the first medical data and the second medical data, and the reconstruction module 303 performs image reconstruction according to the scatter data, the first medical data, and the second medical data, to obtain a scatter-corrected medical image. In the present application, the inherent characteristics of the double-layer panel are considered, which can obtain high and low energy medical data of an object in one scan. The medical data at low energy contains the original projection and scatter data of the object. By solving the scatter data at low energy, the scatter data at low energy is eliminated, so that the medical data without scatter data is obtained, which eliminates the scatter artifacts in subsequent image reconstruction and improves the quality of the reconstructed image.

[0119] In some embodiments of the present application, the calculation module 302 is specifically configured to:

[0120] According to the first medical data, theoretical low-energy data is calculated;

[0121] According to the second medical data and the theoretical low-energy data, scatter data is determined.

[0122] In some embodiments of the present application, the calculation module 302 is specifically configured to:

[0123] Obtain a proportionality coefficient of low-energy data and high-energy data under an empty field condition;

[0124] According to the first medical data and the proportionality coefficient, theoretical low-energy data is determined.

[0125] In some embodiments of the present application, the calculation module 302 is specifically configured to:

[0126] According to the first medical data, a target object model is established;

[0127] The target object model is simulated scanned by using low-energy rays of a preset energy, and theoretical low-energy data is obtained.

[0128] In some embodiments of the present application, the calculation module 302 is specifically configured to:

[0129] According to the first medical data, material information of a target object is determined;

[0130] According to the material information, a target object model is established.

[0131] In some embodiments of the present application, the calculation module 303 is specifically configured to:

[0132] The scatter data is calculated repeatedly for multiple times;

[0133] An average value of the scatter data calculated for multiple times is taken as final scatter data.

[0134] In some embodiments of the present application, the reconstruction module is specifically configured to:

[0135] According to the second medical data and the scatter data, second medical data after scatter correction is obtained;

[0136] According to the first medical data and the second medical data after scatter correction, image reconstruction is performed, and high-energy medical images and low-energy medical images are obtained.

[0137] Embodiments of the present application also provide a computer device integrated with any one of the medical image reconstruction devices provided by the embodiments of the present application, and the computer device comprises:

[0138] One or more processors;

[0139] Memory; and

[0140] one or more application programs, wherein the one or more application programs are stored in the memory and configured to perform the steps of the medical image reconstruction method in any of the above medical image reconstruction method embodiments by the processor.

[0141] The embodiments of the present application further provide a computer device integrating any of the medical image reconstruction apparatuses provided by the embodiments of the present application. As shown in Figure 4 the structure schematic diagram of the computer device related by the embodiments of the present application, specifically:

[0142] The computer device can include a processor 401 with one or more processing cores, a memory 402 with one or more computer readable storage media, a power supply 403, an input unit 404, and the like. Those skilled in the art can understand that the computer device structure shown in Figure 4 does not constitute a limitation to the computer device, which can include more or fewer components than those shown, or combine certain components, or have different arrangement of components. Among them:

[0143] The processor 401 is the control center of the computer device, which connects all parts of the computer device through various interfaces and lines, executes the software programs and / or modules stored in the memory 402 and calls the data stored in the memory 402, performs various functions and processes data of the computer device, and thus overall monitors the computer device. Optionally, the processor 401 can include one or more processing cores; preferably, the processor 401 can integrate an application processor and a modem processor, wherein the application processor mainly processes the operating system, user interface and application programs, etc., and the modem processor mainly processes wireless communication. It can be understood that the above-mentioned modem processor can also not be integrated into the processor 401.

[0144] The memory 402 can be used to store software programs and modules, and the processor 401 executes various functions and data processing by running the software programs and modules stored in the memory 402. The memory 402 can mainly include a program storage area and a data storage area, wherein the program storage area can store the operating system, at least one application program required by the function (such as sound playing function, image playing function, etc.), etc.; the data storage area can store the data created according to the use of the computer device, etc. In addition, the memory 402 can include a high-speed random access memory, and can also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state memory device. Accordingly, the memory 402 can also include a memory controller to provide the processor 401 with access to the memory 402.

[0145] The computer device further includes a power supply 403 for supplying power to the various components. Preferably, the power supply 403 is logically connected to the processor 401 through a power management system, so that the power management system can be used to manage charging, discharging, power consumption management, and the like. The power supply 403 can also include one or more DC or AC power sources, a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator, and the like.

[0146] The computer device can also include an input unit 404 for receiving input digital or character information, and generating keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function controls.

[0147] Although not shown, the computer device can also include a display unit, and the like, which will not be described here. In particular, in the present embodiment, the processor 401 in the computer device loads one or more executable files corresponding to processes of one or more application programs into the memory 402, and runs the application programs stored in the memory 402, in accordance with the following instructions, so as to implement the medical image reconstruction method described in any of the above embodiments.

[0148] Those of ordinary skill in the art can understand that all or part of the steps of the various methods of the above embodiments can be completed by instructions, or by controlling relevant hardware by the instructions, which can be stored in a computer readable storage medium and loaded and executed by a processor.

[0149] To this end, the embodiments of the present application provide a computer readable storage medium, which can include a read only memory (ROM), a random access memory (RAM), a magnetic or optical disk, and the like. A computer program is stored on the storage medium, and the computer program is loaded by a processor to execute the steps of any of the medical image reconstruction methods provided by the embodiments of the present application. For example, the computer program loaded by the processor can execute the medical image reconstruction method described in any of the above embodiments.

[0150] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the detailed description of other embodiments above, which will not be described here.

[0151] In particular implementations, the above various units or structures can be implemented as independent entities, or can be combined as the same or several entities, and the specific implementation of the above various units or structures can be referred to the method embodiments above, which will not be described here.

[0152] The specific implementation of each operation can refer to the foregoing embodiments, which will not be described here again.

[0153] The foregoing describes in detail a medical image reconstruction method and device, computer equipment and a storage medium provided by an embodiment of the application. The principle and implementation manner of the application are described by applying specific examples in this paper. The foregoing embodiment description is only used to help understand the method and core idea of the application. Meanwhile, for those skilled in the art, the specific implementation manner and application range will be changed according to the idea of the application. In summary, the content of the specification should not be understood as a limitation of the application.

Claims

1. A method for medical image reconstruction, characterized in that, The medical image reconstruction method includes: First and second medical data for the target object are acquired. The first and second medical data are medical data acquired by the upper and lower plates respectively when scanning the target object using a double-layer plate. The first medical data is acquired based on a first energy ray, and the second medical data is acquired based on a second energy ray. The energy value of the first energy ray is higher than the energy value of the second energy ray. Calculate the scattering data based on the first medical data and the second medical data; Based on the scattering data, the first medical data, and the second medical data, image reconstruction is performed to obtain a scatter-corrected medical image; The step of calculating scattering data based on the first medical data and the second medical data includes: Based on primary medical data, calculate theoretical low-energy data; The scattering data were determined based on the second medical data and theoretical low-energy data; The calculation of theoretical low-energy data based on the first medical data includes: Obtain the ratio of low-energy data to high-energy data under empty field conditions; Based on the first medical data and the aforementioned proportionality coefficient, the theoretical low-energy data is determined; Alternatively, the calculation of theoretical low-energy data based on the first medical data includes: Based on the first medical data, establish a target object model; The target object model is simulated and scanned using low-energy rays of preset energy to obtain theoretical low-energy data.

2. The medical image reconstruction method according to claim 1, characterized in that, The step of establishing the target object model based on the first medical data includes: Based on the first medical data, determine the material information of the target object; Based on the material information, a target object model is established.

3. The medical image reconstruction method according to claim 1 or 2, characterized in that, The step of calculating scattering data based on the first medical data and the second medical data includes: Repeat the calculation of scattering data multiple times; The average value of the scattering data calculated multiple times is taken as the final scattering data.

4. The medical image reconstruction method according to claim 1, characterized in that, The step of reconstructing the image based on the scattering data, the first medical data, and the second medical data to obtain the scatter-corrected medical image includes: Based on the second medical data and the scattering data, the scattering-corrected second medical data is obtained; Image reconstruction is performed based on the first medical data and the second medical data after scattering correction to obtain high-energy medical images and low-energy medical images.

5. A medical image reconstruction device, characterized in that, The medical image reconstruction device includes: The acquisition module is used to acquire first medical data and second medical data for the target object. The first medical data and the second medical data are medical data acquired by the upper plate and the lower plate respectively when scanning the target object using a double-layer plate. The first medical data is acquired based on a first energy ray, and the second medical data is acquired based on a second energy ray. The energy value of the first energy ray is higher than the energy value of the second energy ray. The calculation module is used to calculate scattering data based on the first medical data and the second medical data; The reconstruction module is used to reconstruct the image based on the scattering data, the first medical data, and the second medical data to obtain a scatter-corrected medical image. The calculation module is further used for: Based on primary medical data, calculate theoretical low-energy data; The scattering data were determined based on the second medical data and theoretical low-energy data; The calculation module is further used for: Obtain the ratio of low-energy data to high-energy data under empty field conditions; Based on the first medical data and the aforementioned proportionality coefficient, the theoretical low-energy data is determined; Alternatively, the computing module may also be used for: Based on the first medical data, establish a target object model; The target object model is simulated and scanned using low-energy rays of preset energy to obtain theoretical low-energy data.

6. A computer device, characterized in that, The computer device includes: One or more processors; Memory; and One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the medical image reconstruction method of any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that, It contains a computer program that is loaded by a processor to execute the medical image reconstruction method according to any one of claims 1 to 4.

Images