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

Abstract

The embodiment of the invention discloses a scattering correction method, device and system for X-ray imaging and a medium. The method comprises the steps that for a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system for a scanned object is obtained, an anti-scattering grid in the CT imaging system is placed between a low-energy detector and a high-energy detector, and the high-energy detector is arranged between the low-energy detector and the high-energy detector; the object signals comprise low-energy object signals received by the low-energy detector and high-energy object signals received by the high-energy detector, and the high-energy object signals are filtered by the anti-scattering grid; estimating a low-energy direct signal in the low-energy object signal according to the high-energy object signal; and performing CT image reconstruction according to the low-energy direct signal to obtain a low-energy image, and performing CT image reconstruction according to the high-energy object signal to obtain a high-energy 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, system 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, system 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] For a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system is obtained for a scanned object, wherein an anti-scatter grid in the CT imaging system is placed between a low-energy detector and a high-energy detector, and the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector, and the high-energy object signal has been filtered by the anti-scatter grid;

[0007] estimating a low-energy direct signal in a low-energy object signal according to a high-energy object signal;

[0008] The CT image is reconstructed based on the low-energy direct signal to obtain a low-energy image, and the CT image is reconstructed based on the high-energy object signal to obtain a high-energy image.

[0009] According to another aspect of the present invention, a scatter correction device for X-ray imaging is provided, which may include:

[0010] an object signal acquisition module, for acquiring, for a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system for a scanned object, wherein an anti-scatter grid in the CT imaging system is placed between the low-energy detector and the high-energy detector, and the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector, and the high-energy object signal has been filtered by the anti-scatter grid;

[0011] A low-energy direct signal estimation module, used for estimating a low-energy direct signal in a low-energy object signal according to a high-energy object signal;

[0012] The image reconstruction module is used to reconstruct the CT image according to the low-energy direct signal to obtain a low-energy image, and to reconstruct the CT image according to the high-energy object signal to obtain a high-energy image.

[0013] According to another aspect of the present invention, a CT imaging system based on a double-layer detector is provided, which may include:

[0014] Low energy detectors;

[0015] High energy detectors;

[0016] Anti-scatter grid placed between low-energy detector and high-energy detector;

[0017] at least one processor; and

[0018] a memory communicatively connected to at least one processor; wherein,

[0019] The memory stores a computer program executable by at least one processor, and 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.

[0020] 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.

[0021] According to the technical solution of the embodiment of the present invention, in a CT imaging system based on a double-layer detector, an anti-scatter grid is placed between a low-energy detector and a high-energy detector, thereby obtaining an object signal scanned by the CT imaging system for a scanned object, the object signal comprising a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector and filtered by the anti-scatter grid; since the high-energy object signal is mainly composed of a high-energy direct signal, the high-energy scattered signal therein can be basically ignored, and therefore the low-energy direct signal in the low-energy object signal can be directly estimated according to the high-energy object signal, that is, the low-energy scattered signal can be directly corrected without applying other scatter correction algorithms; further, CT image reconstruction is performed according to the low-energy direct signal to obtain a low-energy image, and CT image reconstruction is performed according to the high-energy object signal to obtain a high-energy image. The above technical solution, by placing the anti-scatter grid between the low-energy detector and the high-energy detector, realizes scatter correction of the front and rear layers of detectors at the same time, and uses the high-energy object signal to quickly estimate the low-energy direct signal, thereby realizing rapid scatter correction of CT imaging, meeting the needs of real-time scatter correction and the basic requirements of CT imaging.

[0022] 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

[0023] 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.

[0024] Figure 1a is an imaging process diagram of a double-layer detector-based CT imaging system applied in an embodiment of the present invention;

[0025] Figure 1b is a schematic structural diagram of an anti-scatter grid applied in an embodiment of the present invention;

[0026] Figure 2 is a flow chart of a scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0027] Figure 3a is a flowchart of an optional example of another scatter correction method for X-ray imaging provided by an embodiment of the present invention;

[0028] Figure 3bis a rendering of an optional example of another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0029] Figure 4 is a flow chart of another scatter correction method for X-ray imaging provided according to an embodiment of the present invention;

[0030] Figure 5 is a structural block diagram of a scatter correction device for X-ray imaging provided according to an embodiment of the present invention;

[0031] Figure 6 It is a schematic structural diagram of a CT imaging system based on a double-layer detector provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] Before introducing the embodiment of the present invention, a CT imaging system based on a double-layer detector used therein is first exemplarily described to better understand the scatter correction method described in the embodiment of the present invention.

[0035] For example, see Figure 1a The above-mentioned CT imaging system may include an X-ray source 1, a filter 2, and a device for fixing the scanned object (i.e. Figure 1a A rotating device ( Figure 1a), a double-layer detector 3 and an anti-scatter grid 4.

[0036] Among them, the double-layer detector 3 can be a double-layer flat-panel detector, which may include a low-energy detector mainly used to detect low-energy X-rays and a high-energy detector mainly used to detect high-energy X-rays. On this basis, compared with the high-energy detector, the low-energy detector is closer to the scanned object, so the low-energy detector can also be called a front-layer detector, and the high-energy detector can also be called a rear-layer detector.

[0037] The anti-scatter grid 4 is placed between the low-energy detector and the high-energy detector. In other words, the X-ray source 1, the filter 2, the rotating device, the low-energy detector, the anti-scatter grid 4 and the high-energy detector are placed in sequence in the CT imaging system. On this basis, for example, see Figure 1b , the left side thereof shows a side schematic diagram of the anti-scatter grid 4, and the right side thereof shows a front schematic diagram of the anti-scatter grid 4, wherein the anti-scatter grid 4 is made of lead, the side thickness is 0.5 mm, the front is a 300 mm*300 mm square, and the imaging focal length is 1200 mm.

[0038] Using the above CT imaging system, an X-ray scan is performed on the scanned object. The specific process is as follows: the scanned object is placed on a rotating device, which can be controlled by a mechanical axis to perform a uniform rotational motion. When performing an X-ray scan, the scanned object is fixed on the rotating device to rotate at a uniform speed while following the rotating device. After the scanned object completes a 360-degree rotational motion, a complete X-ray scan is completed. On this basis, it can be understood that when performing an X-ray scan on the scanned object, there is Figure 1a There are two types of signals shown in the figure: direct signal 5 and scattered signal 6.

[0039] Figure 2 It is a flow chart of a scatter correction method for X-ray imaging provided in an embodiment of the present invention. This embodiment is applicable to the case of performing scatter correction for CT imaging, and is particularly applicable to the case of performing scatter correction for cone beam CT imaging. The method can be executed by a scatter correction device for X-ray imaging provided in an embodiment of the present invention, the device can be implemented by software and / or hardware, the device can be integrated on an electronic device, the electronic device can be deployed in a CT imaging system based on a double-layer detector, and the electronic device can be various user terminals or servers.

[0040] See also Figure 2 The method of the embodiment of the present invention specifically includes the following steps:

[0041] S110, for a CT imaging system based on a double-layer detector, obtaining an object signal scanned by the CT imaging system for a scanned object;

[0042] The anti-scatter grid in the CT imaging system is placed between the low-energy detector and the high-energy detector. The object signal includes the low-energy object signal received by the low-energy detector and the high-energy object signal received by the high-energy detector. The high-energy object signal has been filtered by the anti-scatter grid.

[0043] Among them, for the low-energy detector and the high-energy detector in the CT imaging system, the low-energy detector is mainly used to detect low-energy X-rays, while the high-energy detector is mainly used to detect high-energy X-rays. In practical applications, optionally, in order to achieve the above-mentioned detection effect, the thickness of the conversion material used to convert X-rays into visible light in the low-energy detector is less than the thickness of the conversion material used to convert X-rays into visible light in the high-energy detector. In practical applications, optionally, the above-mentioned conversion material can be a scintillator material.

[0044] For the anti-scatter grid in the CT imaging system, the anti-scatter grid is placed between the low-energy detector and the high-energy detector. Compared with the conventional anti-scatter grid placed in front of the low-energy detector, the advantages of this arrangement are:

[0045] 1) By utilizing a low-energy detector to receive a large amount of low-energy signals (i.e., low-energy object signals after penetrating the scanned object), specifically, low-energy direct signals and low-energy scattered signals, the problem that when the anti-scatter grid is placed in front of the low-energy detector, a large amount of low-energy direct signals are filtered out by the anti-scatter grid, resulting in obvious noise and poor image quality in the subsequently reconstructed CT image is solved. On this basis, the signals reaching the anti-scatter grid are mostly high-energy signals with strong penetrating ability, thereby ensuring that more high-energy direct signals penetrate the anti-scatter grid, thereby further ensuring image quality.

[0046] 2) Since a large amount of low-energy scattered signals have been received by the low-energy detector, the anti-scatter grid can focus on filtering high-energy scattered signals, that is, filtering out more high-energy scattered signals, so that the high-energy scattered signals reaching the high-energy detector can be almost ignored.

[0047] 3) It can improve the degree of X-ray energy spectrum differentiation, which is conducive to the realization of multi-spectrum cone-beam CT imaging.

[0048] An object signal scanned by a CT imaging system is acquired for the scanned object. The object signal may include a low-energy object signal received by a low-energy detector and a high-energy object signal received by a high-energy detector, and the high-energy object signal has been filtered by an anti-scatter grid.

[0049] S120 . Estimate a low-energy direct signal in the low-energy object signal according to the high-energy object signal.

[0050] Among them, according to existing experience, when both the high-energy object signal and the low-energy object signal contain a large amount of scattered signals, it is necessary to correct the scattered signals based on other scatter correction algorithms, and the conventionally used scatter correction algorithms usually have the problem of long calculation time.

[0051] In addition, according to the above description, the low-energy object signal can be composed of the low-energy direct signal and the low-energy scattered signal, while the high-energy object signal is mainly composed of the high-energy direct signal, in which the high-energy scattered signal is almost negligible. Therefore, in the embodiment of the present invention, the low-energy direct signal in the low-energy object signal can be directly estimated according to the high-energy object signal, that is, the low-energy scattered signal can be directly corrected without applying other scatter correction algorithms, thereby improving the correction efficiency of the scattered signal.

[0052] S130, reconstructing the CT image according to the low-energy direct signal to obtain a low-energy image, and reconstructing the CT image according to the high-energy object signal to obtain a high-energy image.

[0053] Among them, by reconstructing the CT image based on the low-energy direct signal, a low-energy image with low-energy scattered signals removed can be obtained, and by reconstructing the CT image based on the high-energy object signal, a high-energy image with high-energy scattered signals removed can be obtained, thereby ensuring the image quality of the dual-energy CT image.

[0054] According to the technical solution of the embodiment of the present invention, in a CT imaging system based on a double-layer detector, an anti-scatter grid is placed between a low-energy detector and a high-energy detector, thereby obtaining an object signal scanned by the CT imaging system for a scanned object, the object signal comprising a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector and filtered by the anti-scatter grid; since the high-energy object signal is mainly composed of a high-energy direct signal, the high-energy scattered signal therein can be basically ignored, and therefore the low-energy direct signal in the low-energy object signal can be directly estimated according to the high-energy object signal, that is, the low-energy scattered signal can be directly corrected without applying other scatter correction algorithms; further, CT image reconstruction is performed according to the low-energy direct signal to obtain a low-energy image, and CT image reconstruction is performed according to the high-energy object signal to obtain a high-energy image. The above technical solution, by placing the anti-scatter grid between the low-energy detector and the high-energy detector, realizes scatter correction of the front and rear layers of detectors at the same time, and uses the high-energy object signal to quickly estimate the low-energy direct signal, thereby realizing rapid scatter correction of CT imaging, meeting the needs of real-time scatter correction and the basic requirements of CT imaging.

[0055] On this basis, in order to prove the effectiveness of the scatter correction method described above, the following is a demonstration combined with specific experiments. Figure 3a :

[0056] 1. Place the anti-scatter grid between the double-layer detectors to perform a complete X-ray scan of the scanned object to obtain low-energy object signals and high-energy object signals;

[0057] 2. Based on the high-energy object signal, the algorithm is used to estimate the low-energy direct signal in the low-energy object signal;

[0058] 3. Reconstruct CT images of high-energy object signals and low-energy direct signals respectively, so as to obtain high-quality (i.e. corrected) high-energy images and low-energy images. For specific effects, see Figure 3b .

[0059] Figure 3b In the figure, the left side shows the high-energy image directly acquired, the middle shows the low-energy image directly acquired, and the right side shows the corrected low-energy image. It can be seen that the high-energy image directly acquired contains almost no scattering artifacts, and the low-energy image obtained by the above scattering correction method, on the basis of the original low-energy image, effectively eliminates the influence of the low-energy scattering signal on the imaging result, thereby proving the effectiveness and feasibility of the above scattering correction method.

[0060] 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 background signal obtained when performing an empty scan using a CT imaging system, wherein the background signal includes a low-energy background signal received by a low-energy detector and a high-energy background signal received by a high-energy detector; based on the high-energy object signal, estimating the low-energy direct signal in the low-energy object signal, including: estimating the low-energy direct signal in the low-energy object signal based on the high-energy object signal, the low-energy background signal and the high-energy background signal. Among them, the explanations of the terms that are the same or corresponding to the above-mentioned embodiments are not repeated here.

[0061] See also Figure 4 The method of this embodiment may specifically include the following steps:

[0062] S210, for a CT imaging system based on a double-layer detector, obtaining an object signal scanned by the CT imaging system for the scanned object;

[0063] The anti-scatter grid in the CT imaging system is placed between the low-energy detector and the high-energy detector. The object signal includes the low-energy object signal received by the low-energy detector and the high-energy object signal received by the high-energy detector. The high-energy object signal has been filtered by the anti-scatter grid.

[0064] S220, obtaining a background signal obtained when performing an empty scan using the CT imaging system;

[0065] The background signal includes a low-energy background signal received by a low-energy detector and a high-energy background signal received by a high-energy detector.

[0066] Among them, the air scan can be understood as an X-ray scan of the air, that is, an X-ray scan performed without placing the scanned object on a rotating device. The background signal obtained when the CT imaging system is used for air scan is obtained. The background signal can be composed of a low-energy background signal and a high-energy background signal. It can be understood that the low-energy background signal is a signal received by a low-energy detector, and the high-energy background signal is a signal received by a high-energy detector after being filtered by an anti-scattering grid.

[0067] S230 , estimating a low-energy direct signal in the low-energy object signal according to the high-energy object signal, the low-energy background signal and the high-energy background signal.

[0068] Among them, since the low-energy background signal and the high-energy background signal can reflect the background characteristics, the low-energy direct signal can be estimated based on the high-energy object signal, the low-energy background signal and the high-energy background signal.

[0069] S240, reconstructing the CT image according to the low-energy direct signal to obtain a low-energy image, and reconstructing the CT image according to the high-energy object signal to obtain a high-energy image.

[0070] The technical solution of the embodiment of the present invention uses a CT imaging system to perform an empty scan to obtain low-energy background signals and high-energy background signals, and then combines high-energy object signals, low-energy background signals and high-energy background signals to jointly estimate low-energy direct signals, thereby improving the estimation accuracy of low-energy direct signals.

[0071] An optional technical solution, the above-mentioned scatter correction method for X-ray imaging further includes:

[0072] Obtaining a target proportional relationship, wherein the target proportional relationship is a proportional relationship between a material attenuation coefficient under high-energy X-rays and a material attenuation coefficient under low-energy X-rays;

[0073] According to the high-energy object signal, the low-energy background signal and the high-energy background signal, the low-energy direct signal in the low-energy object signal is estimated, including:

[0074] According to the high-energy object signal, the low-energy background signal, the high-energy background signal and the target ratio, the low-energy direct signal in the low-energy object signal is estimated.

[0075] In practical applications, optionally, the material attenuation coefficient under high-energy X-rays and the material attenuation coefficient under low-energy X-rays are both obtained by pre-calibration using a standard body film that matches the scanned object.

[0076] The above technical scheme, based on the high-energy object signal, the low-energy background signal and the high-energy background signal, further considers the target proportional relationship that can be used to characterize the material attenuation coefficient under high-energy X-rays and the material attenuation coefficient under low-energy X-rays, thereby further improving the estimation accuracy of the low-energy direct signal.

[0077] On this basis, optionally, the high-energy object signal is a high-energy direct signal, and the low-energy direct signal in the low-energy object signal is estimated according to the high-energy object signal, the low-energy background signal, the high-energy background signal and the target ratio relationship, including:

[0078] The low-energy direct signal in the low-energy object signal is estimated by the following formula:

[0079]

[0080] in, Indicates low energy direct signal, Indicates a high-energy direct signal. Indicates low-energy background signal, represents the high-energy background signal, and β represents the target ratio relationship.

[0081] On this basis, in order to better understand the above technical solution, the following is an exemplary explanation of it in combination with specific examples. For example, the principle of CT imaging is that when the scanned object (hereinafter referred to as the object) is scanned by X-rays, some photons will be absorbed in the process of X-rays passing 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 X-ray detector, the X-ray linear attenuation μ distribution map (i.e., CT image) of the object can be obtained.

[0082] The attenuation formula of X-rays is as follows:

[0083] I=I0e -∫μ(l)dl

[0084] 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 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.

[0085] In the X-ray scanning of an object, the I finally received by the detector is based on the direct signal I p and the object scattered signal I s composition:

[0086] I=I p +I s

[0087] On this basis, further, for the double-layer detector, there are two different measurement signals, corresponding to X-rays at different energies: the low-energy object signal received by the front layer detector (i.e., the low-energy object signal mentioned above) I LE , and the high-energy object signal received by the rear detector (i.e. the high-energy object signal mentioned above) I HE According to the above description, I LE Based on low energy direct signal and low energy scattered signals Composition, and I HE Based on high energy direct signal The specific formula is as follows:

[0088]

[0089]

[0090] Based on the above X-ray attenuation formula and the X-ray material attenuation law, this example uses the following approximate estimation method to achieve The solution:

[0091]

[0092] in, is the low-energy background signal (i.e., the background count under low-energy X-rays), are the high-energy background signals (i.e., background counts under high-energy X-rays), which are the signals received by the detector when there is no object (i.e., during an empty scan); β is the target proportional coefficient, i.e., the proportional relationship between the material attenuation coefficients of high energy and low energy, which can be obtained by pre-calibration of the standard body film.

[0093] It can be seen that the low-energy direct signal can be quickly calculated through the above formula, thereby realizing the rapid correction of the low-energy scattered signal.

[0094] Figure 5 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. Figure 5 The device may specifically include: an object signal acquisition module 310, a low-energy direct signal estimation module 320 and an image reconstruction module 330.

[0095] The object signal acquisition module 310 is used for acquiring, for a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system for a scanned object, wherein the anti-scatter grid in the CT imaging system is placed between the low-energy detector and the high-energy detector, and the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector, and the high-energy object signal has been filtered by the anti-scatter grid;

[0096] A low-energy direct signal estimation module 320, configured to estimate a low-energy direct signal in a low-energy object signal according to a high-energy object signal;

[0097] The image reconstruction module 330 may be used to reconstruct a CT image according to a low-energy direct signal to obtain a low-energy image, and to reconstruct a CT image according to a high-energy object signal to obtain a high-energy image.

[0098] Optionally, the above-mentioned scatter correction device for X-ray imaging further includes:

[0099] A background signal acquisition module is used to acquire a background signal obtained when performing an empty scan using the CT imaging system, wherein the background signal includes a low-energy background signal received by a low-energy detector and a high-energy background signal received by a high-energy detector;

[0100] The low energy direct signal estimation module 320 includes:

[0101] The low-energy direct signal estimation unit is used to estimate the low-energy direct signal in the low-energy object signal according to the high-energy object signal, the low-energy background signal and the high-energy background signal.

[0102] On this basis, optionally, the above-mentioned scatter correction device for X-ray imaging further includes:

[0103] A target proportional relationship acquisition module is used to acquire a target proportional relationship, wherein the target proportional relationship is a proportional relationship between a material attenuation coefficient under high-energy X-rays and a material attenuation coefficient under low-energy X-rays;

[0104] Low energy direct signal estimation unit, including:

[0105] The low-energy direct signal estimation subunit is used to estimate the low-energy direct signal in the low-energy object signal according to the high-energy object signal, the low-energy background signal, the high-energy background signal and the target ratio relationship.

[0106] On this basis, an optional low-energy direct signal estimation subunit is specifically used to:

[0107] The low-energy direct signal in the low-energy object signal is estimated by the following formula:

[0108]

[0109] in, Indicates low energy direct signal, Indicates a high-energy direct signal. Indicates low-energy background signal, represents the high-energy background signal, and β represents the target ratio relationship.

[0110] Alternatively, the material attenuation coefficient under the high-energy X-ray and the material attenuation coefficient under the low-energy X-ray are both obtained by pre-calibration using a standard body film that matches the scanned object.

[0111] Based on any of the above devices, optionally, the thickness of the conversion material of the low-energy detector is less than the thickness of the conversion material of the high-energy detector, and the conversion material of the low-energy detector and the conversion material of the high-energy detector are both used to convert X-rays into visible light.

[0112] According to the scatter correction device for X-ray imaging provided by the embodiment of the present invention, in a CT imaging system based on a double-layer detector, an anti-scatter grid is placed between a low-energy detector and a high-energy detector, so that an object signal scanned by the CT imaging system for a scanned object can be obtained through an object signal acquisition module, wherein the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector and filtered by the anti-scatter grid; since the high-energy object signal is mainly composed of a high-energy direct signal, the high-energy scatter signal therein can be basically ignored, and therefore, the low-energy direct signal in the low-energy object signal can be directly estimated according to the high-energy object signal through the low-energy direct signal estimation module, so that the low-energy scatter signal can be directly corrected without applying other scatter correction algorithms; further, the CT image is reconstructed according to the low-energy direct signal to obtain a low-energy image through the image reconstruction module, and the CT image is reconstructed according to the high-energy object signal to obtain a high-energy image. The above device, by placing the anti-scatter grid between the low-energy detector and the high-energy detector, simultaneously realizes the scatter correction of the front and rear layers of detectors, and uses the high-energy object signal to quickly estimate the low-energy direct signal, thereby realizing rapid scatter correction of CT imaging, meeting the needs of real-time scatter correction and the basic requirements of CT imaging.

[0113] 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.

[0114] 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.

[0115] Figure 6A schematic diagram of the structure of a double-layer detector-based CT imaging system is shown, and the CT imaging system includes an electronic device 10, a low-energy detector 20, a high-energy detector 30, and an anti-scatter grid 40 placed between the low-energy detector 20 and the high-energy detector 30, which can be used to implement an embodiment of the present invention. 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 only examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0116] like Figure 6 As 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.

[0117] 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.

[0118] The processor 11 may be a variety of general and / or special 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 special 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 executes the various methods and processes described above, such as a scatter correction method for X-ray imaging.

[0119] 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).

[0120] 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.

[0121] 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.

[0122] On this basis, optionally, the CT imaging system described above may also include:

[0123] X-ray source; and

[0124] A rotating device used to fix the scanned object to drive the scanned object to rotate; wherein,

[0125] The X-ray source, rotating equipment, low-energy detector, anti-scatter grid and high-energy detector are placed in sequence.

[0126] 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.

[0127] 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).

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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: For a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system is obtained for a scanned object, wherein an anti-scatter grid in the CT imaging system is placed between a low-energy detector and a high-energy detector, and the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector, and the high-energy object signal has been filtered by the anti-scatter grid; estimating a low-energy direct signal in the low-energy object signal according to the high-energy object signal; A CT image is reconstructed according to the low-energy direct signal to obtain a low-energy image, and a CT image is reconstructed according to the high-energy object signal to obtain a high-energy image.

2. The method according to claim 1, characterized in that Also includes: Acquire a background signal obtained when performing an empty scan using the CT imaging system, wherein the background signal includes a low-energy background signal received by the low-energy detector and a high-energy background signal received by the high-energy detector; The estimating the low-energy direct signal in the low-energy object signal according to the high-energy object signal comprises: A low-energy direct signal in the low-energy object signal is estimated according to the high-energy object signal, the low-energy background signal and the high-energy background signal.

3. The method according to claim 2, characterized in that Also includes: Acquiring a target proportional relationship, wherein the target proportional relationship is a proportional relationship between a material attenuation coefficient under high-energy X-rays and a material attenuation coefficient under low-energy X-rays; The estimating the low-energy direct signal in the low-energy object signal according to the high-energy object signal, the low-energy background signal and the high-energy background signal comprises: A low-energy direct signal in the low-energy object signal is estimated according to the high-energy object signal, the low-energy background signal, the high-energy background signal and the target ratio relationship.

4. The method according to claim 3, characterized in that The high-energy object signal is a high-energy direct signal, and estimating the low-energy direct signal in the low-energy object signal according to the high-energy object signal, the low-energy background signal, the high-energy background signal and the target ratio relationship includes: The low-energy direct signal in the low-energy object signal is estimated by the following formula: in, represents the low energy direct signal, represents the high energy direct signal, represents the low energy background signal, represents the high-energy background signal, and β represents the target ratio relationship.

5. The method according to claim 3, characterized in that: The material attenuation coefficient under the high-energy X-ray and the material attenuation coefficient under the low-energy X-ray are both obtained by pre-calibration through a standard body film that matches the scanned object.

6. The method according to any one of claims 1 to 5, characterized in that The thickness of the conversion material of the low-energy detector is smaller than that of the conversion material of the high-energy detector. The conversion material of the low-energy detector and the conversion material of the high-energy detector are both used to convert X-rays into visible light.

7. A scatter correction device for X-ray imaging, characterized in that: include: an object signal acquisition module, configured to acquire, for a CT imaging system based on a double-layer detector, an object signal scanned by the CT imaging system for a scanned object, wherein an anti-scatter grid in the CT imaging system is placed between a low-energy detector and a high-energy detector, and the object signal includes a low-energy object signal received by the low-energy detector and a high-energy object signal received by the high-energy detector, and the high-energy object signal has been filtered by the anti-scatter grid; A low-energy direct signal estimation module, used for estimating a low-energy direct signal in the low-energy object signal according to the high-energy object signal; The image reconstruction module is used to reconstruct the CT image according to the low-energy direct signal to obtain a low-energy image, and to reconstruct the CT image according to the high-energy object signal to obtain a high-energy image.

8. A CT imaging system based on a double-layer detector, characterized in that: include: Low energy detectors; High energy detectors; an anti-scatter grid placed between the low-energy detector and the high-energy detector; 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 so that the at least one processor performs the scatter correction method for X-ray imaging according to any one of claims 1 to 6.

9. The system according to claim 8, characterized in that Also includes: X-ray source; as well as A rotating device for fixing the scanned object to drive the scanned object to rotate; wherein, The X-ray source, the rotating device, the low-energy detector, the anti-scatter grid and the high-energy detector are placed in sequence.

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 6 when executed.

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