Scattering correction method, device and equipment for X-ray imaging and medium

Abstract

The embodiment of the invention discloses a scattering correction method, device and equipment for X-ray imaging and a medium. The method comprises the following steps: acquiring a target scanning CT image of a target object, and performing Monte Carlo simulation on the target object by using the target scanning CT image to construct a target simulation model; for each first projection angle in a first preset number of first projection angles, Monte Carlo simulation is carried out on the target simulation model along the first projection angles, target scattering signals corresponding to the first projection angles are obtained, and the first preset number is smaller than or equal to a first preset number threshold value; cT image reconstruction is carried out on the target scattering signals corresponding to the first preset number of first projection angles, and a target scattering CT image of the target object is obtained; and obtaining a corrected CT image according to the target scanning CT image and the target scattering CT image. According to the technical scheme of the embodiment of the invention, rapid scattering correction of CT imaging can be realized.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of medical imaging technology, and in particular to a scatter correction method, device, equipment and medium for X-ray imaging. Background Art

[0002] In the process of X-ray cone beam computed tomography (CT) imaging, scattering is an important factor that limits its imaging quality. Therefore, in order to obtain high-quality cone beam CT images, scatter correction is an important part of the cone beam CT imaging process.

[0003] However, the correction speed of the currently used scatter correction scheme is slow, which makes it impossible to meet the needs of real-time scatter correction and the basic requirements of cone-beam CT imaging, and it is urgently needed to be improved. Summary of the invention

[0004] The embodiments of the present invention provide a scatter correction method, device, equipment and medium for X-ray imaging to achieve rapid scatter correction of CT imaging.

[0005] According to one aspect of the present invention, a scatter correction method for X-ray imaging is provided, which may include:

[0006] Acquire a target scanning CT image of the target object, and use the target scanning CT image to perform Monte Carlo simulation on the target object to construct a target simulation model;

[0007] For each first projection angle of a first preset number of first projection angles, a Monte Carlo simulation is performed on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold;

[0008] Performing CT image reconstruction on target scattering signals corresponding to a first preset number of first projection angles to obtain a target scattering CT image of the target object;

[0009] A corrected CT image is obtained according to the target scanning CT image and the target scattering CT image.

[0010] According to another aspect of the present invention, there is provided a scatter correction device for X-ray imaging, which may include:

[0011] A target simulation model building module is used to obtain a target scanning CT image of the target object, and use the target scanning CT image to perform Monte Carlo simulation on the target object to build a target simulation model;

[0012] a target scattering signal obtaining module, configured to perform a Monte Carlo simulation on a target simulation model along the first projection angle for each first projection angle in a first preset number of first projection angles, to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold;

[0013] a target scattering CT image obtaining module, configured to perform CT image reconstruction on target scattering signals corresponding to a first preset number of first projection angles, respectively, to obtain a target scattering CT image of the target object;

[0014] The corrected CT image obtaining module is used to obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

[0015] According to another aspect of the present invention, there is provided an electronic device, which may include:

[0016] at least one processor; and

[0017] a memory communicatively connected to at least one processor; wherein,

[0018] The memory stores a computer program that can be executed by at least one processor. The computer program is executed by at least one processor so that the at least one processor implements the scatter correction method for X-ray imaging provided by any embodiment of the present invention when executing the computer program.

[0019] According to another aspect of the present invention, a computer-readable storage medium is provided, on which computer instructions are stored, and the computer instructions are used to enable a processor to implement the scatter correction method for X-ray imaging provided by any embodiment of the present invention when executed.

[0020] The technical solution in the embodiment of the present invention obtains a target scanning CT image of the target object, and uses the target scanning CT image to perform Monte Carlo simulation on the target object to construct a target simulation model; then, along a first preset number of first projection angles that can ensure the scatter correction speed, the target simulation model is subjected to Monte Carlo simulation to obtain target scatter signals corresponding to each first projection angle; then, CT image reconstruction is performed for all the obtained target scatter signals to obtain a target scatter CT image; finally, a corrected CT image is obtained based on the target scanning CT image and the target scatter CT image. The above technical solution can significantly reduce the total time required for Monte Carlo simulation by reducing the number of first projection angles that need to be simulated during the Monte Carlo simulation, thereby achieving the effect of rapid scatter correction.

[0021] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is a diagram of a CT scanning process of a CT scanner used as an exemplary embodiment of the present invention;

[0024] Figure 2 is a flow chart of a scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of a first projection angle in a scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0026] Figure 4 is a flow chart of another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of an example of target scattering CT image reconstruction in another scattering correction method for X-ray imaging provided according to an embodiment of the present invention;

[0028] Figure 6 is a flow chart of another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0029] Figure 7 is a schematic diagram of a voxelization example in another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0030] Figure 8a is a flowchart of an optional example of another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0031] Figure 8b is a correction effect comparison diagram of another optional example in a scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0032] Fig. 9 is a structural block diagram of a scatter correction device for X-ray imaging provided according to an embodiment of the present invention;

[0033] Fig.10 It is a schematic diagram of the structure of an electronic device for implementing the scatter correction method for X-ray imaging according to an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. The situations of "target", "original", etc. are similar and will not be repeated here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] Before introducing the embodiment of the present invention, an application scenario of the embodiment of the present invention is first exemplarily described to more vividly understand the scatter correction method described in the embodiment of the present invention.

[0037] Exemplarily, a CT scanner is used to perform a CT scan on a target object to obtain a target scanning signal, and the target scanning signal is reconstructed to obtain a target scanning CT image.

[0038] Here Figure 1 As an example of the CT scanning process shown in FIG. 1 , the CT scanner may include an X-ray source 1, a filter 2, and a device for fixing the target object (i.e. Figure 1 A rotating device ( Figure 1The specific CT scanning process is as follows: the target object is placed on a rotating device, which can be controlled by a mechanical axis to perform a uniform rotational motion; when performing a CT scan, the target object is fixed on the rotating device, so that it rotates at a uniform speed simultaneously with the rotating device. It can be understood that the CT scanning range should include the complete area of ​​the target object that needs to be scatter corrected, and the target scanning signal obtained includes Figure 1 There are two types of signals, namely, target direct signal 4 and target scattered signal 5 shown in FIG. 1 ; after the target object completes a 360-degree rotation, a complete CT scan is completed.

[0039] On this basis, the principle of CT imaging is that when using X-rays to perform CT scanning on a target object (hereinafter referred to as an object), some photons will be absorbed when the X-rays pass through the object, causing the intensity of the X-rays to decay exponentially, and this attenuation is related to the density of each part inside the object. The greater the density, the greater the attenuation of the X-rays. Therefore, by receiving the attenuated X-rays through the detector, the X-ray linear attenuation μ distribution map of the object (i.e., the target scanning CT image described above) can be obtained.

[0040] The attenuation formula of X-rays is as follows:

[0041] I=I0e -∫μ(l)dl

[0042] Among them, I0 is the X-ray before attenuation, specifically, the intensity of the X-ray before attenuation; I is the intensity of the X-ray after attenuation, that is, the target scanning signal finally received by the detector; μ(l) is a function with the ray path l as a variable, that is, the linear attenuation coefficient of the X-ray of the object; ∫μ(l)dl is the total attenuation of the X-ray along this direction.

[0043] In the CT scanning of an object, the I finally received by the detector is based on the target direct signal (or target attenuation signal) I′ and the target scattered signal I s composition:

[0044] I=I′+I s

[0045] Therefore, the target scanning CT image μ obtained above is based on the target attenuation CT image μ′ obtained according to I′ and the target attenuation CT image μ′ obtained according to I′. s The obtained target scattering CT image μ s Composition, where μ s It is also called a scattering artifact image:

[0046] μ=μ′+μ s

[0047] So far, we know that in order to obtain a high-quality CT image (i.e., μ′), we need to subtract μ from μ. s .

[0048] On this basis, the reasons why the scatter correction speed is slow as described in the background art are further exemplified here to better understand why the embodiments of the present invention can achieve fast scatter correction.

[0049] Exemplarily, Monte Carlo simulation is often used to estimate I s distribution, thus achieving high-precision scattering correction. However, Monte Carlo simulation needs to simulate the target scattering signals of dozens or even hundreds of projection angles, and the simulation of each projection angle takes a long time, which greatly prolongs the total time required for Monte Carlo simulation (about two orders of magnitude), thus affecting the scattering correction speed.

[0050] Figure 2 This is a flow chart of a scatter correction method for X-ray imaging provided by an embodiment of the present invention. This embodiment can be applied to the case where scatter correction is performed for CT imaging, and in particular, can be applied to the case where scatter correction is performed for cone beam CT imaging. The method can be executed by a scatter correction device for X-ray imaging provided by an embodiment of the present invention, and the device can be implemented by software and / or hardware, and the device can be integrated on an electronic device, and the electronic device can be various user terminals or servers.

[0051] See also Figure 2 The method of the embodiment of the present invention specifically includes the following steps:

[0052] S110. Obtain a target scanning CT image of the target object, perform Monte Carlo simulation on the target object using the target scanning CT image, and construct a target simulation model.

[0053] The target scanning CT image can be understood as a CT image obtained by performing a CT scan on a target object using a CT scanner to obtain a target scanning signal and then reconstructing the target scanning signal.

[0054] Obtaining a target scanning CT image. In practical applications, optionally, since the scatter correction method described in the embodiment of the present invention is performed in the image domain, the target scanning CT image can be obtained by real-time scanning and reconstruction, or directly obtained from any existing target scanning CT image library, which is not specifically limited here.

[0055] Further, using the target scanning CT image, the target object is subjected to Monte Carlo simulation to construct a target simulation model for characterizing the target object. In practical applications, optionally, in the Monte Carlo simulation model, scanning parameters consistent with the scanning parameters applied when performing CT scanning on the target object can be set. For example, the first is the scanning geometry, which may specifically include the distance from the light source to the target object (SOD), the distance from the light source to the detector (SDD), the actual size of the target object, and the field of view (FOV) of the scan, etc.; then the scanning voltage and the material and thickness of the filter. This part can actually be generated by simulating the corresponding scanning voltage and filter in advance to generate a scanning energy spectrum, and then the scanning energy spectrum is input into the Monte Carlo simulation model, so that the same scanning voltage and filter as the actual scan can be used in the Monte Carlo simulation.

[0056] S120. For each first projection angle in a first preset number of first projection angles, perform a Monte Carlo simulation on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold.

[0057] Among them, the first preset number threshold value can be understood as a preset upper limit of the number of first projection angles used under the premise that fast scatter correction can be achieved. The first preset number can be understood as a preset number of first projection angles used in the scatter correction process. It should be noted that, in an embodiment of the present invention, the first preset number is less than or equal to the first preset number threshold value. It can be seen that when the Monte Carlo simulation is performed using the first preset number of first projection angles to perform scatter correction, the scatter correction speed can be effectively guaranteed, thereby achieving fast scatter correction.

[0058] Specifically, for each first projection angle in the first preset number of first projection angles, a Monte Carlo simulation is performed on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, thereby obtaining a target scattering signal corresponding to each first projection angle, and then in combination with subsequent steps, these target scattering signals can be used to perform scattering correction.

[0059] On this basis, optionally, when the first preset number is 1, the first projection angles of the first preset number are any single projection angle; and further optionally, when the first preset number is 2, the first projection angles of the first preset number are any two projection angles that are perpendicular to each other.

[0060] For example, see Figure 3, dense projection angles, dual projection angles and single projection angles are shown from left to right, wherein the dense projection angle is an example of the first projection angle currently conventionally used; the dual projection angle and the single projection angle are examples of the first projection angle used in the embodiment of the present invention, specifically, the single projection angle is to apply any single projection angle in the 360-degree CT scanning process as the first preset number of first projection angles, and the dual projection angle is to apply any two mutually perpendicular projection angles in the 360-degree CT scanning process as the first preset number of first projection angles.

[0061] Understandably, Figure 3 The samples in the table are the items in the above examples.

[0062] S130. Perform CT image reconstruction on target scattering signals corresponding to a first preset number of first projection angles to obtain a target scattering CT image of the target object.

[0063] After obtaining the target scattering signals corresponding to all the first projection angles, CT image reconstruction may be performed on these target scattering signals to obtain a target scattering CT image.

[0064] S140. Obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

[0065] Among them, according to the above description, it can be known that the target scattering CT image is the scattering artifact in the originally acquired target scanning CT image. Therefore, scattering correction can be performed based on the target scanning CT image and the target scattering CT image to obtain a corrected CT image, that is, a high-quality CT image.

[0066] The technical solution in the embodiment of the present invention obtains a target scanning CT image of the target object, and uses the target scanning CT image to perform Monte Carlo simulation on the target object to construct a target simulation model; then, along a first preset number of first projection angles that can ensure the scatter correction speed, the target simulation model is subjected to Monte Carlo simulation to obtain target scatter signals corresponding to each first projection angle; then, CT image reconstruction is performed for all the obtained target scatter signals to obtain a target scatter CT image; finally, a corrected CT image is obtained based on the target scanning CT image and the target scatter CT image. The above technical solution can significantly reduce the total time required for Monte Carlo simulation by reducing the number of first projection angles that need to be simulated during the Monte Carlo simulation, thereby achieving the effect of rapid scatter correction.

[0067] An optional technical solution, obtaining a corrected CT image according to a target scanning CT image and a target scattering CT image, includes:

[0068] In the target scanning CT image, the target scattered CT image is sequentially subtracted according to each object tomographic plane of the target object to obtain a corrected CT image.

[0069] In other words, based on the object tomographic plane, the target scattered CT image is sequentially subtracted from the target scanned CT image to obtain the corrected CT image, i.e., μ ′ =μ-μ s ,The application of object tomography improves the accuracy of scatter correction.

[0070] It should be noted that the above technical solution reconstructs a target scattering CT image based on the simulated target scattering signal, and then subtracts the target scattering CT image from the target scanning CT image to obtain a corrected CT image. Compared with directly subtracting the target scattering signal from the target scanning signal obtained from the original scan, the advantage of this setting is that there is no need to perform scattering correction for each first projection angle separately, but scattering correction is performed for the target scanning CT image as a whole, thereby avoiding the situation where the image quality of the corrected CT image finally obtained is affected by inadequate scattering correction for a certain first projection angle, thereby solving the problem of incomplete scattering correction.

[0071] Figure 4 It is a flow chart of another scatter correction method for X-ray imaging provided by an embodiment of the present invention. This embodiment is optimized based on the above-mentioned technical solutions. In this embodiment, optionally, the above-mentioned scatter correction method for X-ray imaging also includes: obtaining a pre-trained scatter CT image reconstruction model; performing CT image reconstruction on the target scatter signals corresponding to the first projection angles of the first preset number, to obtain a target scatter CT image of the target object, including: inputting the target scatter signals corresponding to the first projection angles of the first preset number into the scatter CT image reconstruction model, and obtaining the target scatter CT image of the target object according to the output result of the scatter CT image reconstruction model. Among them, the explanations of the terms that are the same or corresponding to the above-mentioned embodiments are not repeated here.

[0072] See also Figure 4 The method of this embodiment may specifically include the following steps:

[0073] S210. Obtain a target scanning CT image of the target object, perform Monte Carlo simulation on the target object using the target scanning CT image, and construct a target simulation model.

[0074] S220. For each first projection angle in a first preset number of first projection angles, perform a Monte Carlo simulation on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold.

[0075] S230. Obtain a pre-trained scatter CT image reconstruction model.

[0076] The scattered CT image reconstruction model can be understood as a pre-trained deep learning model that can be used to reconstruct a scattered CT image based on a scattered signal. In practical applications, the scattered CT image reconstruction model can be a convolutional neural network, such as U-Net.

[0077] Obtain scatter CT images and reconstruct the model.

[0078] S240. Input the target scattering signals corresponding to the first preset number of first projection angles into the scattering CT image reconstruction model, and obtain a target scattering CT image of the target object according to the output result of the scattering CT image reconstruction model.

[0079] Among them, for all the simulated target scattering signals of the target object, all the target scattering signals are input into the scattering CT image reconstruction model, so that the scattering CT image reconstruction model is used to perform feature processing on all the target scattering signals and reconstruct the corresponding target scattering CT image.

[0080] For example, see Figure 5 , the first row shows the target scattering CT image reconstructed after the target scattering signal simulated at a single projection angle is input into the scattering CT image reconstruction model, and the second row shows the target scattering CT image reconstructed after the target scattering signals simulated at two projection angles are input into the scattering CT image reconstruction model.

[0081] S250. Obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

[0082] It should be noted that, in the Monte Carlo simulation of the target object in S210, the target simulation model is constructed. The geometric shapes of different types of target objects may be different. For example, the geometric shapes of the head, abdomen and feet are different. In the conventional Monte Carlo simulation process, it is necessary to set corresponding scatter correction parameters in the Monte Carlo simulation model according to the geometric shape of the target object. The scatter correction parameters are, for example, the tube voltage of CT imaging, the number of first projection angles and the total number of photons, so as to construct a target simulation model that is more similar to the target object, thereby ensuring the accuracy of the target scatter CT image obtained by subsequent reconstruction. In other words, the conventional Monte Carlo simulation process has a strong object dependence.

[0083] However, in the embodiment of the present invention, a scattering CT image reconstruction model is used to reconstruct a target scattering CT image. Since the scattering CT image reconstruction model has learned the characteristics of multiple types of sample objects during the training process, in the previous Monte Carlo simulation process, even if the corresponding scattering correction parameters are not set according to the geometric shape of the target object to construct a target simulation model that is relatively similar to the target object, the scattering CT image reconstruction model can still automatically identify the type of the target object according to the input target scattering signal, and then reconstruct a target scattering CT image that matches the target object, thereby reducing the object dependence.

[0084] Of course, it is understandable that in order to allow the scattering CT image reconstruction model to accurately learn the characteristics of different types of sample objects, when performing Monte Carlo simulation, corresponding scattering correction parameters can be set according to the geometric shape of each type of sample object, so as to construct sample simulation models that are similar to each type of sample object, and then use these sample simulation models to simulate training samples for model training.

[0085] In addition, compared with the Monte Carlo simulation to reconstruct the target scattering CT image, the application of the scattering CT image reconstruction model can effectively shorten the reconstruction time of the target scattering CT image and improve the reconstruction accuracy.

[0086] The technical solution of the embodiment of the present invention processes the target scattering signal by using the scattering CT image reconstruction model to reconstruct the target scattering CT image, thereby solving the problem of excessive object dependence in the Monte Carlo simulation process, and greatly shortening the reconstruction time of the target scattering CT image and improving the reconstruction accuracy.

[0087] An optional technical solution, the above scatter correction method for X-ray imaging further includes:

[0088] Acquire a sample scanning CT image of the sample object, and use the sample scanning CT image to perform Monte Carlo simulation on the sample object to construct a sample simulation model;

[0089] For each second projection angle in a second preset number of second projection angles, along the second projection angle, a Monte Carlo simulation is performed on the sample simulation model to obtain a sample scattering signal corresponding to the second projection angle, wherein the second preset number is greater than or equal to a second preset number threshold, and the second preset number threshold is greater than the first preset number threshold;

[0090] Performing CT image reconstruction on sample scattering signals corresponding to a second preset number of second projection angles, respectively, to obtain a sample scattering CT image of the sample object;

[0091] Determine a first preset number of third projection angles from a second preset number of second projection angles, and use the first preset number of third projection angles and the sample scatter CT image as a group of training samples;

[0092] Based on multiple groups of training samples, the original CT image reconstruction model is trained to obtain a scattered CT image reconstruction model.

[0093] The sample scanning CT image can be understood as a CT image obtained by performing a CT scan on a sample object using a CT scanner, obtaining a sample scanning signal, and then reconstructing the sample scanning signal. The sample scanning CT image is obtained, and then the sample scanning CT image is used to perform a Monte Carlo simulation on the sample object to construct a sample simulation model. In practical applications, optionally, as described above, in order to solve the problem of excessive object dependence in the Monte Carlo simulation process, in the Monte Carlo simulation process, corresponding scattering correction parameters can be set according to the geometric shape of the sample object, so as to construct a sample simulation model that is more similar to the sample object.

[0094] The second preset number threshold can be understood as a preset lower limit of the number of second projection angles used under the premise that an accurate sample scattering signal can be simulated. It can be known that the second preset number threshold is greater than the first preset number threshold. The second preset number can be understood as a preset number of second projection angles used in the Monte Carlo simulation. It should be noted that in the embodiment of the present invention, the second preset number is greater than or equal to the second preset number threshold. It can be known that when the second preset number of second projection angles (such as the dense projection angles exemplified above) are used for Monte Carlo simulation, the accuracy of the sample scattering signal simulated thereby can be effectively guaranteed.

[0095] Specifically, for each second projection angle in the second preset number of second projection angles, a Monte Carlo simulation is performed on the sample simulation model along the second projection angle to obtain a sample scattering signal corresponding to the second projection angle, thereby obtaining a sample scattering signal corresponding to each second projection angle; then, based on these sample scattering signals, a Monte Carlo simulation is used to reconstruct a sample scattering CT image.

[0096] On this basis, further, a first preset number of third projection angles (i.e., sparse projection angles) are determined from all the second projection angles, and then these third projection angles and the sample scatter CT images are used as a group of training samples. From then on, model training can be performed based on multiple groups of training samples, especially multiple groups of training samples corresponding to multiple categories of sample objects, to obtain a scatter CT image reconstruction model.

[0097] The above technical solution realizes the effective training of the scattered CT image reconstruction model.

[0098] Figure 6 It is a flowchart of another scatter correction method for X-ray imaging provided in an embodiment of the present invention. This embodiment is optimized based on the above-mentioned technical solutions. In this embodiment, optionally, a target scanning CT image is used to perform Monte Carlo simulation on the target object to construct a target simulation model, including: voxelizing the target scanning CT image to obtain a voxelized three-dimensional image; using Monte Carlo simulation software to perform material setting according to each voxel value in the voxelized three-dimensional image to construct a target simulation model of the target object. Among them, the explanations of the terms that are the same or corresponding to the above-mentioned embodiments are not repeated here.

[0099] See also Figure 6 The method of this embodiment may specifically include the following steps:

[0100] S310. Obtain a target scan CT image of the target object, and perform voxelization processing on the target scan CT image to obtain a voxelized three-dimensional image.

[0101] The target object is composed of at least one substance, and combined with the application scenarios that may be involved in the embodiments of the present invention, it can be composed of three substances, for example, bone, water and air. According to relevant experience, the density of various substances in the at least one substance usually varies; and according to the above description, the attenuation value of X-rays when penetrating a substance is related to the density of the substance, that is, the voxel value of each voxel in the target scan CT image is related to the density of the substance corresponding to the voxel.

[0102] On this basis, further considering that the voxel values ​​of each voxel corresponding to the same substance in the target scan CT image may be slightly different, in order to simulate a target simulation model that is more corresponding to the target object, the target scan CT image can be voxelized to obtain a voxelized three-dimensional image, that is, the voxel values ​​of each voxel corresponding to the same substance in the voxelized three-dimensional image are the same.

[0103] S320. Using Monte Carlo simulation software, material settings are performed according to the values ​​of each voxel in the voxelized three-dimensional image to construct a target simulation model of the target object.

[0104] Among them, according to the above description, each voxel unit with the same voxel value in the voxelized three-dimensional image corresponds to the same substance in the target object. Therefore, Monte Carlo simulation software can be used to set the material according to each voxel value in the voxelized three-dimensional image, thereby constructing a target simulation model.

[0105] Exemplarily, the voxelized three-dimensional image is input into the Monte Carlo simulation software, so that the material setting can be performed according to each voxel value in the Monte Carlo simulation software, thereby realizing the construction of the target simulation model. In practical applications, the target simulation model can also be optionally called a three-dimensional digital phantom model.

[0106] S330. For each first projection angle in a first preset number of first projection angles, perform a Monte Carlo simulation on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold.

[0107] S340. Perform CT image reconstruction on the target scattering signals corresponding to the first preset number of first projection angles to obtain a target scattering CT image of the target object.

[0108] S350. Obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

[0109] The technical solution of the embodiment of the present invention performs voxelization processing on the target scanned CT image to obtain a voxelized three-dimensional image that can accurately reflect various substances in the target object, and then uses Monte Carlo simulation software to set the material according to each voxel value in the voxelized three-dimensional image, thereby achieving the effect of constructing a target simulation model that is more closely aligned with the target object.

[0110] An optional technical solution is to voxelize the target scanned CT image to obtain a voxelized three-dimensional image, including:

[0111] Acquire a material attenuation range corresponding to at least one material contained in the target object;

[0112] For each reconstruction unit in the target scan CT image, determine a target substance corresponding to the reconstruction unit in at least one substance according to an attenuation value corresponding to the reconstruction unit and the acquired attenuation ranges of all substances;

[0113] Based on the voxel value pre-set for the target substance, the voxel value of each voxel unit in the reconstruction unit is set to obtain a voxelized three-dimensional image.

[0114] For each substance in the at least one substance, a corresponding material attenuation range may be set for the substance according to various attenuation values ​​that may appear when the X-ray penetrates the substance. In other words, for various attenuation values ​​that may appear in CT scanning, these attenuation values ​​are divided into ranges, so as to obtain at least one material attenuation range, and then the at least one material attenuation range is respectively mapped to the corresponding substance, so as to obtain the material attenuation ranges corresponding to various substances.

[0115] On this basis, further, the target scan CT image can be threshold segmented according to the material attenuation range corresponding to at least one substance, so as to obtain the substances corresponding to each reconstruction unit in the target scan CT image, and then the voxel value of each voxel unit in the corresponding reconstruction unit is set in combination with the voxel values ​​set in advance for various substances, thereby obtaining a voxelized three-dimensional image.

[0116] For example, see Figure 7 , assuming that at least one substance includes bone, water and air, wherein the material attenuation range corresponding to bone is called bone attenuation range, and 1 is used as the new voxel value of bone; the material attenuation range corresponding to water is called water attenuation range, and 0.5 is used as the new voxel value of water; the material attenuation range corresponding to air is called air attenuation range, and 0 is used as the new voxel value of air.

[0117] On this basis, for each reconstruction unit in the target scan CT image, if the attenuation value corresponding to the reconstruction unit is within the bone attenuation range, 1 is used as the new voxel value of each voxel unit in the reconstruction unit; if the attenuation value corresponding to the reconstruction unit is within the water attenuation range, 0.5 is used as the new voxel value of each voxel unit in the reconstruction unit; if the attenuation value corresponding to the reconstruction unit is within the air attenuation range, 0 is used as the new voxel value of each voxel unit in the reconstruction unit.

[0118] After each reconstruction unit is processed based on the above steps, a voxelized three-dimensional image can be obtained.

[0119] The above technical solution realizes rapid and accurate voxelization processing for target scanned CT images.

[0120] On this basis, in order to better understand the above-mentioned various technical solutions as a whole, the following is an exemplary description of them in combination with specific examples. Figure 8a , specifically:

[0121] 1. Set the cone beam CT scanning parameters, perform a complete scan of the object, obtain the complete target scanning signal of the object, and then use the filtered back projection method to reconstruct the CT image to obtain the target scanning CT image;

[0122] 2. Perform threshold segmentation on the target scanned CT image and perform voxel modeling in Monte Carlo simulation software to obtain the target simulation model;

[0123] 3. Set the scanning parameters corresponding to step 1, and obtain the target scattering signal of the object at a single projection angle or dual-angle projection through Monte Carlo simulation;

[0124] 4. Input the collected target scattering signal into the trained scattering CT image reconstruction model to directly obtain the corresponding target scattering CT image;

[0125] 5. Subtract the target scattered CT image from the target scanned CT image to obtain a high-quality corrected CT image, thereby completing the scatter correction.

[0126] In order to prove the effectiveness of the above example scheme, an experiment was conducted. The specific process and results are as follows: For an object with a diameter of 20 cm, a CT scanner was used to scan it, and the target scanning signal obtained by scanning was reconstructed to obtain the target scanning CT image of the object. Furthermore, the scatter correction was performed using this example scheme. The entire scatter correction process took less than 1 minute, achieving the purpose of fast scatter correction. Moreover, the scatter correction effect is as follows: Figure 8b As shown, the left side shows the target scan CT image and the right side shows the corrected CT image, which shows that the purpose of effective scatter correction is achieved.

[0127] Fig. 9 This is a structural block diagram of a scatter correction device for X-ray imaging provided in an embodiment of the present invention. The device is used to execute the scatter correction method for X-ray imaging provided in any of the above embodiments. The device and the scatter correction method for X-ray imaging in the above embodiments belong to the same inventive concept. For details not described in detail in the embodiment of the scatter correction device for X-ray imaging, please refer to the embodiment of the scatter correction method for X-ray imaging. Fig. 9 The device may specifically include: a target simulation model building module 410, a target scattering signal obtaining module 420, a target scattering CT image obtaining module 430 and a corrected CT image obtaining module 440.

[0128] The target simulation model building module 410 is used to obtain a target scanning CT image of the target object, and use the target scanning CT image to perform Monte Carlo simulation on the target object to build a target simulation model;

[0129] A target scattered signal obtaining module 420 is used to perform a Monte Carlo simulation on the target simulation model along the first projection angle for each first projection angle in a first preset number of first projection angles to obtain a target scattered signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold;

[0130] A target scattering CT image obtaining module 430 is used to perform CT image reconstruction on target scattering signals corresponding to a first preset number of first projection angles to obtain a target scattering CT image of the target object;

[0131] The corrected CT image obtaining module 440 is used to obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

[0132] Optionally, the above-mentioned scatter correction device for X-ray imaging further includes:

[0133] A scattering CT image reconstruction model acquisition module is used to acquire a pre-trained scattering CT image reconstruction model;

[0134] The target scattered CT image acquisition module 430 includes:

[0135] The target scattered CT image obtaining unit is used to input the target scattered signals corresponding to the first preset number of first projection angles into the scattered CT image reconstruction model, and obtain the target scattered CT image of the target object according to the output result of the scattered CT image reconstruction model.

[0136] On this basis, optionally, the above-mentioned scatter correction device for X-ray imaging further includes:

[0137] A sample simulation model building module is used to obtain a sample scanning CT image of a sample object, and use the sample scanning CT image to perform Monte Carlo simulation on the sample object to build a sample simulation model;

[0138] a sample scattering signal obtaining module, configured to perform a Monte Carlo simulation on the sample simulation model for each second projection angle in a second preset number of second projection angles along the second projection angle to obtain a sample scattering signal corresponding to the second projection angle, wherein the second preset number is greater than or equal to a second preset number threshold, and the second preset number threshold is greater than the first preset number threshold;

[0139] a sample scattering CT image obtaining module, configured to perform CT image reconstruction on sample scattering signals corresponding to a second preset number of second projection angles, to obtain a sample scattering CT image of the sample object;

[0140] A training sample obtaining module, used to determine a first preset number of third projection angles from a second preset number of second projection angles, and use the first preset number of third projection angles and the sample scatter CT image as a group of training samples;

[0141] The scattered CT image reconstruction model obtaining module is used to train the original CT image reconstruction model based on multiple groups of training samples to obtain the scattered CT image reconstruction model.

[0142] Optionally, the target simulation model construction module 410 includes:

[0143] A voxelized three-dimensional image obtaining submodule is used to perform voxelization processing on the target scanned CT image to obtain a voxelized three-dimensional image;

[0144] The target simulation model construction submodule is used to use Monte Carlo simulation software to perform material settings according to the values ​​of each voxel in the voxelized three-dimensional image to construct a target simulation model of the target object.

[0145] On this basis, optionally, a submodule for obtaining a voxelized three-dimensional image includes:

[0146] A material attenuation range acquisition unit, used to acquire a material attenuation range corresponding to at least one material contained in the target object;

[0147] A target substance determination unit, for determining, for each reconstruction unit in the target scan CT image, a target substance corresponding to the reconstruction unit in at least one substance according to an attenuation value corresponding to the reconstruction unit and an attenuation range of all substances that have been acquired;

[0148] The voxelized three-dimensional image obtaining unit is used to set the voxel value of each voxel unit in the reconstruction unit based on the voxel value pre-set for the target substance to obtain the voxelized three-dimensional image.

[0149] Optionally, the corrected CT image obtaining module 440 includes:

[0150] The corrected CT image obtaining unit is used to sequentially subtract the target scattered CT image from each object tomographic plane of the target object in the target scanning CT image to obtain the corrected CT image.

[0151] Based on any of the above devices, optionally, when the first preset number is 1, the first projection angles of the first preset number are any single projection angle; and / or,

[0152] When the first preset number is 2, the first preset number of first projection angles are any two projection angles that are perpendicular to each other.

[0153] The scatter correction device for X-ray imaging provided by the embodiment of the present invention obtains the target scanning CT image of the target object through the target simulation model construction module, and then uses the target scanning CT image to perform Monte Carlo simulation on the target object to construct a target simulation model; then, through the target scattering signal acquisition module, Monte Carlo simulation is performed on the target simulation model along the first preset number of first projection angles that can ensure the scattering correction speed, to obtain the target scattering signals corresponding to each first projection angle; then, through the target scattering CT image acquisition module, CT image reconstruction is performed for all the obtained target scattering signals to obtain the target scattering CT image; finally, through the corrected CT image acquisition module, a corrected CT image is obtained according to the target scanning CT image and the target scattering CT image. The above device can significantly reduce the total time required for Monte Carlo simulation by reducing the number of first projection angles that need to be simulated during the Monte Carlo simulation, thereby achieving the effect of fast scattering correction.

[0154] The scatter correction device for X-ray imaging provided by the embodiment of the present invention can execute the scatter correction method for X-ray imaging provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0155] It is worth noting that in the above-mentioned embodiment of the scatter correction device for X-ray imaging, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of the present invention.

[0156] Fig.10 A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0157] like Fig.10As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0158] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0159] The processor 11 may be a variety of general and / or dedicated processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 performs the various methods and processes described above, such as a scatter correction method for X-ray imaging.

[0160] In some embodiments, the scatter correction method for X-ray imaging may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the scatter correction method for X-ray imaging described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform the scatter correction method for X-ray imaging in any other appropriate manner (e.g., by means of firmware).

[0161] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0162] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0163] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0164] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0165] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0166] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0167] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0168] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A scatter correction method for X-ray imaging, characterized in that: include: Acquire a target scan CT image of the target object, and use the target scan CT image to perform Monte Carlo simulation on the target object to construct a target simulation model; For each first projection angle of a first preset number of first projection angles, performing a Monte Carlo simulation on the target simulation model along the first projection angle to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold; Performing CT image reconstruction on target scattering signals corresponding to the first preset number of first projection angles respectively to obtain a target scattering CT image of the target object; A corrected CT image is obtained according to the target scanning CT image and the target scattered CT image.

2. The method according to claim 1, characterized in that Also includes: Obtain a pre-trained scattering CT image reconstruction model; The performing CT image reconstruction on the target scattering signals corresponding to the first preset number of first projection angles respectively to obtain a target scattering CT image of the target object includes: The target scattering signals corresponding to the first preset number of first projection angles are input into the scattering CT image reconstruction model, and a target scattering CT image of the target object is obtained according to an output result of the scattering CT image reconstruction model.

3. The method according to claim 2, characterized in that Also includes: Acquire a sample scan CT image of a sample object, and use the sample scan CT image to perform Monte Carlo simulation on the sample object to construct a sample simulation model; For each second projection angle of a second preset number of second projection angles, along the second projection angle, performing a Monte Carlo simulation on the sample simulation model to obtain a sample scattering signal corresponding to the second projection angle, wherein the second preset number is greater than or equal to a second preset number threshold, and the second preset number threshold is greater than the first preset number threshold; Reconstructing a CT image for the sample scattering signals corresponding to the second preset number of second projection angles, to obtain a sample scattering CT image of the sample object; Determine the first preset number of third projection angles from the second preset number of second projection angles, and use the first preset number of third projection angles and the sample scatter CT image as a group of training samples; Based on the multiple groups of training samples, the original CT image reconstruction model is trained to obtain the scattered CT image reconstruction model.

4. The method according to claim 1, characterized in that: The method of using the target scanned CT image to perform Monte Carlo simulation on the target object to construct a target simulation model includes: Performing voxel processing on the target scanned CT image to obtain a voxelized three-dimensional image; Monte Carlo simulation software is used to perform material settings according to the voxel values ​​in the voxelized three-dimensional image to construct a target simulation model of the target object.

5. The method according to claim 4, characterized in that The step of performing voxel processing on the target scanned CT image to obtain a voxelized three-dimensional image includes: Acquire a material attenuation range corresponding to at least one substance contained in the target object; For each reconstruction unit in the target scan CT image, determine a target substance corresponding to the reconstruction unit in the at least one substance according to an attenuation value corresponding to the reconstruction unit and the acquired attenuation ranges of all substances; Based on the voxel value preset for the target substance, the voxel value of each voxel unit in the reconstruction unit is set to obtain a voxelized three-dimensional image.

6. The method according to claim 1, characterized in that The step of obtaining a corrected CT image according to the target scanning CT image and the target scattered CT image comprises: In the target scanning CT image, the target scattered CT image is sequentially subtracted according to each object tomographic plane of the target object to obtain a corrected CT image.

7. The method according to any one of claims 1 to 6, characterized in that When the first preset number is 1, the first projection angles of the first preset number are any single projection angle; And / or, when the first preset number is 2, the first preset number of first projection angles are any two projection angles that are perpendicular to each other.

8. A scatter correction device for X-ray imaging, characterized in that: include: A target simulation model building module is used to obtain a target scanning CT image of a target object, and use the target scanning CT image to perform Monte Carlo simulation on the target object to build a target simulation model; a target scattering signal obtaining module, configured to perform a Monte Carlo simulation on the target simulation model along each first projection angle of a first preset number of first projection angles to obtain a target scattering signal corresponding to the first projection angle, wherein the first preset number is less than or equal to a first preset number threshold; a target scattering CT image obtaining module, configured to perform CT image reconstruction on target scattering signals corresponding to the first preset number of first projection angles, respectively, to obtain a target scattering CT image of the target object; The corrected CT image obtaining module is used to obtain a corrected CT image according to the target scanning CT image and the target scattering CT image.

9. An electronic device, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor to enable the at least one processor to perform the scatter correction method for X-ray imaging according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the scatter correction method for X-ray imaging as described in any one of claims 1 to 7 when executed.

Images