Method, system and program product for controlling a breast cbct system

Abstract

This disclosure provides a control method for a breast CBCT system, a breast CBCT system, and a program product. The breast CBCT system includes a filter assembly located between a radiation source and a detector. The filter assembly is used to spatially selectively attenuate radiation passing through itself. The method of this disclosure firstly captures an image of the subject, wherein the subject is a human breast, by means of an imaging device before performing a CBCT scan. Then, the position of the filter assembly is moved by means of the spatial information of the subject in the imaging coordinate system represented by the image and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filter assembly, so that at least a portion of the radiation emitted by the radiation source that does not pass through the subject passes through the filter assembly and is attenuated before reaching the detector.

Description

Technical Field

[0001] This disclosure specifically relates to a control method for a breast CBCT system, a breast CBCT system, a readable storage medium, and a computer program product. Background Technology

[0002] When performing CBCT (Cone Beam Computed Tomography) scans on subjects such as the breast, the imaging field simultaneously includes both air and the subject. Since air and the subject absorb X-rays at significantly different rates, this can lead to substantial differences in the signal values ​​received by the detector. After receiving the signal, the detector needs to amplify it before further processing. If the signal values ​​differ too much, the amplified values ​​may exceed the detection range, resulting in image distortion. Summary of the Invention

[0003] This disclosure provides a control method for a breast CBCT system, a breast CBCT system, a readable storage medium, and a computer program product.

[0004] The first aspect of this disclosure discloses a control method for a breast CBCT system, the breast CBCT system including a filtering component located between a radiation source and a detector, the filtering component being used to spatially selectively attenuate radiation passing through itself; the control method includes: before performing a CBCT scan on a subject, capturing an image of the subject, the subject being a human breast, using an imaging device; and moving the position of the filtering component based on the spatial information of the subject in the imaging coordinate system of the imaging device represented by the image and an existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filtering component. This is to ensure that at least a portion of the rays emitted by the radiation source that do not pass through the subject pass through the filtering assembly and are attenuated before reaching the detector. The establishment of the existing mapping relationship includes: for each of a plurality of calibrators located in the imaging field of view, determining the pixel position of the calibrator in the image captured by the imaging device; and determining the target position of the filtering assembly when the feature points of the filtering assembly coincide with the feature points of the calibrators in the projection direction; and determining the mapping relationship between the imaging coordinate system and the physical coordinate system of the filtering assembly through the pixel positions corresponding to the plurality of calibrators and the target position.

[0005] According to some embodiments of this disclosure, the filter assembly satisfies at least one of the following: the structural thickness of the filter assembly is not uniformly distributed in the projection direction, and the different components of the filter assembly are made of different materials.

[0006] According to some embodiments of this disclosure, a groove structure is provided on one side of the filter assembly.

[0007] According to some embodiments of this disclosure, the groove structure is a recess and is located on top of the filter assembly, and at least a portion of the surface of the recess is curved.

[0008] According to some embodiments of this disclosure, the intersection lines between the groove and the top and side surfaces of the filter assembly are all arcs, and the side surface is the side facing or away from the radiation source.

[0009] According to some embodiments of this disclosure, moving the position of the filtering component by means of the spatial information of the subject in the imaging coordinate system of the imaging device represented by the image and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filtering component includes one or more of a first moving step and a second moving step; the first moving step includes: determining the spatial information of the subject in the imaging coordinate system of the imaging device by means of the image; and moving the filtering component by means of the spatial information and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filtering component; the second moving step includes: determining the target position of the real-time projection position of the filtering component in the imaging field of view in the physical coordinate system by means of the existing mapping relationship between the imaging coordinate system of the imaging device and the physical coordinate system of the filtering component, and representing the target position by means of an identifier in the displayed image, wherein the spatial information of the subject in the imaging coordinate system of the imaging device is provided by displaying the image; and moving the filtering component according to the control command in response to receiving a control command.

[0010] According to some embodiments of this disclosure, in the first moving step, the stopping condition for moving the filter component includes: the feature points of the filter component coincide with the feature points of the subject.

[0011] According to some embodiments of this disclosure, the movement range of the filtering component satisfies one or more of the following: if the filtering component moves to the lowest point allowed in the scanning rotation axis direction, the distance between the top edge of the groove structure of the filtering component and the top edge of the imaging field of view on the scanning rotation axis is less than a first distance threshold; if the filtering component moves to the highest point allowed in the scanning rotation axis direction, the bottom edge of the groove structure of the filtering component is lower than the top edge of the imaging field of view, and the distance between the bottom edge of the groove structure of the filtering component and the top edge of the imaging field of view on the scanning rotation axis is less than a second distance threshold.

[0012] According to some embodiments of this disclosure, determining the spatial information of the subject in the shooting coordinate system of the shooting device through the image includes: determining a mask region of the subject from the image, and determining the spatial information of the feature points of the subject in the mask region in the shooting coordinate system of the shooting device, wherein the spatial information includes height information.

[0013] According to some embodiments of this disclosure, the feature point of the filter component is the lowest point of the groove structure of the filter component.

[0014] A second aspect of this disclosure provides a breast CBCT system, comprising: a radiation source; a detector; a filter assembly located between the radiation source and the detector; a drive mechanism for controlling the movement of the filter assembly; a memory storing execution instructions; and a processor that executes the execution instructions stored in the memory, causing the processor to perform a control method for the breast CBCT system according to any of the above embodiments.

[0015] A third aspect of this disclosure provides a readable storage medium storing a computer program, which, when executed by a processor, is used to implement the control method of the breast CBCT system described in any of the above embodiments.

[0016] The fourth aspect of this disclosure provides a computer program product comprising a computer program that, when executed by a processor, is used to implement the control method of the breast CBCT system described in any of the above embodiments. Attached Figure Description

[0017] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description thereof, serve to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification.

[0018] Figure 1 A top view schematic diagram illustrating an application scenario of the control method of a breast CBCT system according to some embodiments of the present disclosure.

[0019] Figure 2 A schematic diagram of the overall flow of the control method M100 for a breast CBCT system according to some embodiments of the present disclosure is shown.

[0020] Figure 3 A three-dimensional structural schematic diagram of a filter assembly employing two materials according to some embodiments of the present disclosure is shown.

[0021] Figure 4 A three-dimensional structural schematic diagram of a filter assembly with through-slots according to some embodiments of the present disclosure is shown.

[0022] Figure 5 A three-dimensional structural schematic diagram of a filter assembly with grooves according to some embodiments of the present disclosure is shown.

[0023] Figure 6 A flowchart illustrating a control method for a breast CBCT system according to other embodiments of the present disclosure is shown.

[0024] Figure 7 A 3D schematic diagram of the filtering component in a moving scene is shown.

[0025] Figure 8 A 3D schematic diagram of the filtering component in another moving scenario is shown.

[0026] Figure 9 A flowchart illustrating a control method for a breast CBCT system according to other embodiments of the present disclosure is shown.

[0027] Figure 10 A partial flowchart illustrating a control method for a breast CBCT system according to other embodiments of this disclosure is shown.

[0028] Figures 11-12 This is a schematic block diagram of the structure of a breast CBCT system according to some embodiments of the present disclosure. Detailed Implementation

[0029] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0030] It should be noted that, where there is no conflict, the embodiments and features described in this disclosure can be combined with each other. The technical solutions of this disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] Unless otherwise stated, the exemplary implementations / embodiments shown are to be understood as providing exemplary features of various details that provide ways in which the technical concepts of this disclosure can be implemented in practice. Therefore, unless otherwise stated, the features of various implementations / embodiments may be additionally combined, separated, interchanged and / or rearranged without departing from the technical concepts of this disclosure.

[0032] The terminology used herein is for the purpose of describing particular embodiments and is not restrictive. As used herein, unless the context clearly indicates otherwise, the singular forms “a” and “the” are intended to include the plural forms as well. Furthermore, when the terms “comprising” and / or “including” and variations thereof are used in this specification, it indicates the presence of the stated features, integrals, steps, operations, parts, components, and / or groups thereof, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, parts, components, and / or groups thereof. It should also be noted that, as used herein, the terms “substantially,” “about,” and other similar terms are used as approximate terms rather than as terms of degree, thus explaining the inherent biases in measurements, calculated values, and / or provided values ​​that would be recognized by one of ordinary skill in the art.

[0033] During a breast examination using a CBCT system, the patient lies prone on the scanning table with their breast inserted through a keyhole and allowed to hang naturally. When scanning the breast using a CBCT system, the area outside the breast is primarily air. Some of the radiation emitted from the source passes through the air to reach the detector; these rays are hardly absorbed by the air, resulting in a high intensity detected by the detector, i.e., a high signal value. Other rays pass through the pectoral muscles and ribs and are largely absorbed, thus the intensity detected by the detector is lower. This leads to significant differences in radiation intensity received by different areas of the detector.

[0034] The detector converts the received X-ray photon signals into electrical signals, and then into digital values, such as 16-bit integers ranging from 0 to 65535. During the conversion, the signal is amplified; the selected gain level is the amplification factor.

[0035] If the intensity of X-rays received by different areas of the detector varies significantly, using a high gain setting may cause the amplified strong signals to exceed the upper limit (65536), resulting in truncation at the upper limit, or numerical saturation. In this case, details in that area will be lost, and the area will appear entirely white in the image. During CT reconstruction, this may cause ring artifacts in the reconstructed image. Conversely, using a lower gain setting will result in weak signals that remain small after amplification, easily confused with noise, leading to image distortion.

[0036] Therefore, this disclosure proposes a control method for a breast CBCT system.

[0037] Figure 1A top view schematic diagram illustrating an application scenario of the control method for a breast CBCT system according to some embodiments of the present disclosure is shown. In this application scenario, a scanning bed Sc, a camera C, a scanning device, and a filter assembly Md may be included. The scanning device includes a detector De and a radiation source Rs. The filter assembly Md is mounted on the projection path of the radiation source Rs, and its height and horizontal position can be moved by controlling the action of a drive mechanism. A groove with a curved bottom is formed at the top of the filter assembly Md.

[0038] Camera C, detector De, and radiation source Rs all face the circular aperture. First, using two steel balls as calibration objects, these objects are installed in the imaging field of view below the circular aperture. The position of the filter component Md is adjusted so that in the projected image obtained after a single-angle scan by the scanning device, the lowest point of the groove surface in the vertical direction coincides with the center of one of the steel balls. The physical position w1 of the filter component Md is recorded, and camera C is controlled to take a picture to obtain the coordinates w2 of that steel ball. The above steps are repeated until the lowest point of the groove surface in the newly captured projected image coincides with the center of the other steel ball. The physical position w3 of the filter component Md is recorded, and camera C is controlled to take a picture to obtain the coordinates w4 of that steel ball. The mapping relationship between the camera coordinate system and the filter component coordinate system is determined using w1, w2, w3, and w4.

[0039] During a breast scan, the patient lies prone on the scanning bed Sc, with the breast hanging naturally through two circular openings on the Sc. A camera C takes an image, and based on the aforementioned mapping relationship, the position of the current filter component Md in the captured image is determined, represented by a red dot. The filter component Md is moved manually or automatically until the red dot coincides with the lowest point of the breast. At this position, the filter component Md's position ensures that the spatial modulation pattern formed by the groove best matches the cross-section of the breast in the projection direction. The scanning device then begins scanning, ensuring that most rays that only travel through air to reach the detector pass through the area outside the groove of the filter component Md and are attenuated. Rays that pass through the breast to reach the detector also pass through the groove and are attenuated, thereby reducing the intensity of the strongest signal received by the detector and minimizing the difference in ray intensity received by different areas of the detector.

[0040] exist Figure 1 The shape and structure of the scanning bed Sc, camera C, detector De, radiation source Rs, and filter assembly Md shown should not be construed as limiting the scope of this disclosure.

[0041] Figure 2 A schematic flowchart of the control method M100 for a breast CBCT system according to some embodiments of this disclosure is shown. Figure 2The method shown includes steps S110 and S120. This method can be performed by a breast CBCT system.

[0042] A breast CBCT system may include a filter assembly located between the radiation source and the detector. The filter assembly is a solid structure through which the radiation emitted from the source passes. The filter assembly may be mounted at the radiation source end and rotate with the radiation source during CBCT scanning.

[0043] Filtering components are used to spatially selectively attenuate rays passing through them. The degree of ray attenuation is related to the shape, structure, and materials of the filtering component. By making the spatial structure of the filtering component non-uniform, irregular, or containing multiple materials, the attenuation of multiple rays passing through it is non-uniform, with a higher attenuation rate for some rays in space than for others. For example, rays passing through the breast region may be attenuated less or not at all, while most rays passing only through the air region may be attenuated more significantly, thus making the intensity distribution of X-rays reaching the detector more uniform.

[0044] S110, before performing a CBCT scan on the subject, an image containing the subject is obtained by capturing images of the subject using an imaging device. In this article, the subject is a human breast.

[0045] S120, the position of the filter component is moved by using the spatial information of the subject in the imaging coordinate system of the imaging device represented by the image and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filter component, so that at least part of the rays emitted by the radiation source that do not pass through the subject pass through the filter component and are attenuated before reaching the detector.

[0046] Before scanning the subject, the position of the filter components is adjusted based on the image of the subject to attenuate as much high-intensity radiation as possible. The imaging device includes non-X-ray optical imaging equipment, such as a visible light camera.

[0047] The imaging coordinate system refers to a two-dimensional or three-dimensional spatial coordinate system defined by the imaging device. The position of the subject in this coordinate system can be represented by pixel coordinates. The physical coordinate system refers to the real physical world coordinate system in which the filtering component is located on the drive mechanism that drives its movement. The position in this system is usually measured in physical units such as millimeters.

[0048] The existing mapping relationship is a pre-established coordinate transformation relationship between the two coordinate systems mentioned above, which can be represented by a linear equation. The existing mapping relationship is used to transform coordinates in one of the two coordinate systems into coordinates in the other, thereby enabling the conversion of positional information in the visual image into control commands for moving the filtering component.

[0049] Since different subjects have different shapes and sizes, the camera can be controlled to take pictures to obtain optical images containing the subjects. These optical images represent the spatial position information of the subjects in the imaging coordinate system. Since the position of the filter component is known, its spatial position information in the physical coordinate system is also known. By performing coordinate transformation through mapping relationships, the relative positional relationship between the filter component and the subjects in the same coordinate system (imaging coordinate system or physical coordinate system) can be obtained. By controlling the drive mechanism to move the filter component, some or all of the rays passing through the air area are significantly attenuated by the filter component, while some or all of the rays passing through parts of the human body other than the subjects (such as the pectoral muscles and ribs) are not attenuated by the filter component.

[0050] After adjusting the position of the filter component, keeping its position relative to the radiation source unchanged, the breast is scanned using the radiation source and detector to obtain a projected image. The difference between the maximum and minimum signal intensity in the projected image is reduced due to the presence of the filter component.

[0051] According to the control method of the breast CBCT system proposed in the embodiments of this disclosure, by introducing a visually guided filter component control mechanism, the position of the filter component is adjusted so that the spatial modulation pattern formed by the filter component on the detector matches the shape of the subject as closely as possible. This allows the filter component to adaptively match different subjects, attenuate most or even all of the high-intensity signals, avoid signal saturation in high-intensity areas (such as air), and compress the dynamic range of the signal received by the detector to a range more suitable for processing. Therefore, a higher gain level can be used to improve the signal resolution of low-dose areas (such as glandular tissue), so that the image can represent more details and improve the quality of the reconstructed CBCT image.

[0052] In some implementations, the filter assembly may satisfy at least one of the following: the structural thickness of the filter assembly is not uniformly distributed in the projection direction, and the different components of the filter assembly are made of different materials.

[0053] The projection direction refers to the direction from the X-ray source to the detector, i.e., the direction of X-ray propagation. The physical thickness of the filter assembly along the projection direction may not be uniform, but varies depending on its planar position. For example, the filter assembly may have through-slots, making the thickness of the through-slot portion zero, while the thickness of the non-through-slot portions is positive. Another example is that the central region of the filter assembly is thinner than the edge regions. By adjusting the thickness, selective attenuation can be achieved based on the contour of the object being inspected.

[0054] Different materials have different transmittances of radiation, meaning they attenuate radiation to varying degrees. Filter components can be composed of structural parts made of multiple different materials. By combining materials, different attenuation effects can be achieved at the same thickness, or more precise control of the attenuation gradient can be achieved in different regions.

[0055] Figure 3 A three-dimensional structural schematic diagram of a filter assembly employing two materials according to some embodiments of this disclosure is shown. (See also...) Figure 3 The filter assembly is a flat plate structure with uniform thickness throughout. The U-shaped block k1 covered by the dotted line can be made of a high-transmittance material (low attenuation), while other areas can be made of a low-transmittance material (high attenuation). This results in low attenuation in the breast area and high attenuation in the air area.

[0056] This embodiment enhances the ability of the filter assembly to adjust the radiation intensity distribution by designing non-uniform thickness or using composite materials. This allows the attenuation characteristics of the filter assembly to complement the attenuation characteristics of the subject to be compensated, thereby compressing the dynamic range of the signal.

[0057] In other embodiments, a groove structure may be formed on one side of the filter assembly. The groove structure is a recessed area formed on the surface of the filter assembly. The shape and size of the recessed area can be designed to accommodate or correspond to a specific protrusion of the subject.

[0058] When lying prone, the breast appears as a hemispherical or conical structure protruding outward from the chest wall. The projection contour of the groove structure on the filter assembly on the projection plane is similar to the projection contour of the breast on the projection plane, so that the thick-walled part of the filter assembly is located exactly in the air area around the breast, while the groove structure corresponds to the breast itself.

[0059] Figure 4 A three-dimensional structural schematic diagram of a filter assembly with through-slots according to some embodiments of this disclosure is shown. (See also...) Figure 4 The U-shaped channel k2 is a channel structure. The channel is opened on the top surface of the filter component, so that it only performs high attenuation in the air area, while not performing any attenuation in most or even all of the breast area.

[0060] In other embodiments, the groove structure can be a recess and located on top of the filter assembly, with at least a portion of the groove's surface being curved. The curved surface can be a sphere, a parabola, or other type of curved surface.

[0061] Figure 5 A three-dimensional structural schematic diagram of a filter assembly with grooves according to some embodiments of the present disclosure is shown. Figure 5The concave area k3 in the left image is the groove. The curvature of the arc-shaped contour line l2 formed by the groove on the top surface and the arc-shaped contour line l1 formed on the side surface can be the same or similar. It can be understood that the arc-shaped contour line l2 can also be a square contour line or other shapes. The groove can be located at the center of the top of the filter component. Figure 5 The image on the right shows a cross-section of the filter component on the YZ plane at the central axis. The YZ plane is either a sagittal plane or a plane parallel to the sagittal plane.

[0062] In other embodiments, the intersection of the groove with the top and side surfaces of the filter assembly is an arc, with the side surface facing or away from the radiation source. Figure 5 In the diagram, l2 is the intersection line between the groove k3 and the top surface of the filter assembly. l3 is the intersection line between the groove k3 and the side surface of the filter assembly. This side surface can be either the side facing the radiation source or the side facing away from the radiation source. In other words, the groove can be formed in... Figure 5 Another aspect of the filter components.

[0063] The groove can be disc-shaped. The axis of symmetry of the groove can be parallel to the rotation axis of the CBCT. Figure 5 Taking point p1 on the boundary line between the top and side surfaces of the filter assembly as the target position, starting from p1 downwards, the thickness of the groove in the Z-axis direction gradually decreases, while the thickness of the filter assembly body in the Z-axis direction gradually increases. This continues until it reaches its maximum, marking the lowest point of the groove. Starting from p1 and moving towards both the positive and negative X-axis directions, the thickness of the groove in the Z-axis direction gradually decreases, while the thickness of the filter assembly body in the Z-axis direction gradually increases. This continues until it reaches its maximum, marking the edges of the groove.

[0064] This embodiment uses a curved surface to fit the surface of the breast as closely as possible. The continuous curved surface can provide a smooth attenuation gradient, making the ray attenuation continuous and avoiding image artifacts caused by abrupt attenuation changes, thus achieving better imaging results.

[0065] Figure 6 A schematic flowchart illustrating the overall control method of a breast CBCT system according to other embodiments of this disclosure is shown. (See also...) Figure 6 In which step S610 and Figure 2 Step S110 in the implementation method is the same. Step S620 corresponds to Figure 2 Step S120 of the implementation method, which moves the position of the filter component by using the spatial information of the subject represented by the image in the shooting coordinate system of the shooting device and the existing mapping relationship between the shooting coordinate system and the physical coordinate system of the filter component, may include one or more of a first moving step S621 and a second moving step S622. The first moving step S621 is used for automatic movement of the filter component, and the second moving step S622 is used for manual movement of the filter component.

[0066] The first moving step S621 includes steps S621a and S621b.

[0067] S621a, determines the spatial information of the subject in the imaging coordinate system of the imaging device through the image.

[0068] S621b moves the filter assembly by means of spatial information and an existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filter assembly, so that at least a portion of the rays emitted by the source that do not pass through the subject pass through the filter assembly and are attenuated before reaching the detector.

[0069] Spatial information can include the height information of the subject, such as the height coordinates of the lowest point of the breast, i.e., the value along the scanning rotation axis. A mapping relationship is used to map the height coordinates of the lowest point of the breast from the imaging coordinate system to the physical coordinate system, obtaining the height value of the lowest point of the breast in the physical coordinate system. The current height value of the filtering component in the physical coordinate system is known. The filtering component can be moved by calculating the distance in height and through automatic control.

[0070] In the first moving step, the stopping condition for the moving filter component may include: the feature point of the filter component coincides with the feature point of the subject. The feature point of the filter component can be the lowest point of the groove. The feature point of the subject can also be the lowest point of the subject. That is, when the lowest point of the groove of the filter component coincides with the lowest point of the breast, the height value of the lowest point of the groove in the filter component will be the same as the height value of the lowest point of the breast, so that the groove is as complementary to the breast as possible in the projection direction.

[0071] It is understandable that the above spatial information may only include height information, because the position of the circular hole of the scanning bed is known and fixed. Therefore, the center of the filter assembly can be pre-aligned with the center of the circular hole, so that the lateral position of the filter assembly does not need to be adjusted, and only the longitudinal position needs to be adjusted each time.

[0072] The second moving step S622 includes steps S622a and S622b.

[0073] S622a, by using the existing mapping relationship between the shooting coordinate system of the shooting device and the physical coordinate system of the filtering component, the real-time projection position of the filtering component in the imaging field of view is determined as the target position in the physical coordinate system, and the target position is represented by an identifier in the displayed image, wherein the spatial information of the subject in the shooting coordinate system of the shooting device is provided by displaying the image.

[0074] S622b, in response to receiving a control command, moves the filter assembly according to the control command so that at least a portion of the rays emitted by the source that have not passed through the subject pass through the filter assembly and are attenuated before reaching the detector.

[0075] The physical location of the filter component is known. Using the same known mapping relationship, the projected position of the filter component in the imaging field of view can be calculated in the physical coordinate system, for example, calculating the position of the filter component in the physical coordinate system. When displaying the image captured by the camera, the image includes not only the breast but also the position marker of the filter component. The marker refers to a graphic element superimposed on the displayed image. For example, a red dot might represent the height of the lowest point of the groove in the filter component.

[0076] The aforementioned image is provided to the operator, who then views the displayed image and manually controls the drive mechanism to move the filter component. The red dot in the image will then move accordingly. The operator can manipulate the red dot to align it with the lowest point of the breast in the image, thus making the groove as complementary to the breast as possible in the projection direction.

[0077] This implementation provides two different control modes: the fully automatic mode, represented by the first movement step, is more efficient, while the manual interactive mode, represented by the second movement step, offers greater flexibility and allows for manual fine-tuning. These two control modes enhance the flexibility and practicality of equipment control.

[0078] In some implementations, the range of motion of the filtering component can satisfy one or more of the following conditions one and two.

[0079] In case one, if the filter assembly moves to the lowest point allowed in the direction of the scanning rotation axis, the distance between the top edge of the groove structure of the filter assembly and the top edge of the imaging field of view on the scanning rotation axis is less than a first distance threshold.

[0080] Figure 7 A 3D schematic diagram of the filtering component in a moving scene is shown. (See also...) Figure 7 The radiation source Rs (not shown in the figure) is mounted on the support structure B. When the filter assembly is driven by the drive mechanism to reach the lowest position achievable by the hardware, the top of the groove k3 is approximately flush with the top of the imaging field of view, or there is a small gap between the top of the imaging field of view and the top of the imaging field of view in terms of height. The first distance threshold can be a small distance value. At this time, the position of the groove k3 is the lowest position that can be reached. This situation is suitable for scanning larger breasts, as the groove at a low position can accommodate as much of the breast area as possible, avoiding high-intensity attenuation of the breast area.

[0081] In the second scenario, if the filter assembly moves to the highest point allowed in the scanning rotation axis direction, the bottom edge of the groove structure of the filter assembly is lower than the top edge of the imaging field of view, and the distance between the filter assembly and the top edge of the imaging field of view on the scanning rotation axis is less than the second distance threshold.

[0082] Figure 8 A 3D schematic diagram of the filtering component in another moving scene is shown. See also... Figure 8 The radiation source Rs (not shown in the figure) is mounted on the support structure B. When the filter assembly is driven by the drive mechanism to reach the highest position achievable by the hardware, the bottom of the groove k3 is approximately flush with the top of the imaging field of view, or slightly lower in height. The second distance threshold can also be a small distance value. At this time, the position of the groove k3 is the highest position that can be achieved. This situation is suitable for scanning smaller breasts, as the groove at a high position can fit the contour of the small breast as closely as possible, avoiding excessive gaps between the groove and the breast that would cause many rays to pass through the air without being sufficiently attenuated by the filter assembly.

[0083] This embodiment enables the breast CBCT system to be universally applicable to breasts of various sizes, and allows for appropriate attenuation by adjusting the filter components for different breast sizes.

[0084] Figure 9 A flowchart illustrating a control method for a breast CBCT system according to other embodiments of this disclosure is shown. For example... Figure 9 As shown, the control method may include steps S910, S921a, S921b, S922a, and S922b, wherein steps S910, S921b, S922a, and S922b are respectively related to... Figure 6 Steps S610, S621b, S622a, and S622b of the illustrated embodiment are the same and will not be described again for the sake of brevity. In step S921a, the method for determining the spatial information of the subject in the imaging coordinate system of the imaging device through the image can specifically be: determining the mask region of the subject from the image, and determining the spatial information of the feature points of the subject in the mask region in the imaging coordinate system of the imaging device. The spatial information includes height information.

[0085] The masked region can be obtained using segmentation algorithms (such as thresholding, edge detection, deep learning models, etc.) and can be represented as a binary image. In the binary image, pixels belonging to the masked region are marked as 1, and pixels not belonging to the masked region are marked as 0. The masked region can represent the outline of the breast. The spatial information of the breast includes height values, i.e., values ​​along the scanning rotation axis.

[0086] This implementation simplifies the image information of the subject to be examined into a geometric shape by generating a mask region, thereby enabling the subject to be located quickly and accurately.

[0087] Figure 10 A partial flowchart illustrating a control method for a breast CBCT system according to other embodiments of this disclosure is shown. Figure 10 The control method of the illustrated embodiment may include steps S101 and S102. Steps S101 and S102 are used to establish a mapping relationship between coordinate systems, and can be executed after step S102. Figure 2 Step S110 in the control method of the implementation method.

[0088] S101, for each of the multiple calibration objects located in the imaging field of view, determine the pixel position of the calibration object in the image captured by the imaging device, and determine the target position of the filtering component when the feature points of the filtering component coincide with the feature points of the calibration object in the projection direction.

[0089] S102 determines the mapping relationship between the shooting coordinate system and the physical coordinate system of the filtering component by using the pixel positions and target positions corresponding to multiple calibration objects.

[0090] The camera of the imaging device can be a binocular camera. The calibration object is used for parameter calibration. In a CT scenario, the calibration object can specifically be a steel ball that is easily identifiable in both the projected and visible light images. The feature point of the calibration object can be its geometric center. Coincidence in the projection direction means that the lowest point of the filter component in the projected image coincides with the center point of the steel ball. At this point, the physical position of the filter component is the first target position Yf1. The position of the first steel ball in the visible light image captured by the camera is the first pixel position Yc1.

[0091] For example, the calibration object is first scanned by CBCT to obtain a projection image. The position of the filter component is adjusted based on the projection image, and then the scan is performed again until the lowest point of the filter component coincides with the center of the first steel ball. If the color of the steel ball changes from white to, for example, gray in the projection image, it indicates that the two coincide.

[0092] Then, the position of the filter component is readjusted and the scan is performed again until the lowest point of the filter component coincides with the center of the second steel ball. At this point, the physical position of the filter component is the second target position Yf2. The position of the second steel ball in the visible light image captured by the camera is the second pixel position Yc2.

[0093] Yf1 and Yc1 form one set of points, and Yf2 and Yc2 form another set of points. Substituting these two sets of points into the linear equation Yc = a×Yf + b, we can determine the coefficients a and b, thereby obtaining the coordinate transformation relationship between the shooting coordinate system and the physical coordinate system.

[0094] This embodiment establishes a transformation relationship between the shooting coordinate system and the physical coordinate system by using a calibration object that can appear simultaneously in the projected image and the visible light image. The position of the filter component is bound to the calibration object by ray imaging, and the position of the calibration object is bound to the pixel coordinates by camera imaging, thereby indirectly establishing a mapping relationship between the physical position of the filter component and the pixel coordinates of the camera.

[0095] Based on any of the above embodiments, this disclosure also provides a breast CBCT system. Figure 11 This is a schematic block diagram of a breast CBCT system according to one embodiment of this disclosure. Figure 11 As shown, the breast CBCT system includes a filter assembly Md located between the radiation source and the detector, an imaging device 110, and a drive module 120.

[0096] The filter component Md is used to spatially selectively attenuate rays passing through it; The imaging device 110 is used to capture images of the subject before performing a CBCT scan on the subject to obtain an image containing the subject.

[0097] The drive module 120 is used to move the position of the filter component by using the spatial information of the subject in the imaging coordinate system of the imaging device represented by the image and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filter component, so that at least part of the rays emitted by the source that do not pass through the subject pass through the filter component and are attenuated before reaching the detector.

[0098] The specific implementation process of the functions and roles of each module in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0099] This disclosure also provides a breast CBCT system. See [link / reference] Figure 1 The breast CBCT system includes a radiation source Rs, a detector De, a filter assembly Md located between the radiation source Rs and the detector De, a drive mechanism for controlling the movement of the filter assembly Md, a memory, and a processor. Figure 1 (Not shown in the image). The memory stores execution instructions, and the processor executes the execution instructions stored in the memory, causing the processor to perform the control method of the breast CBCT system according to any of the above embodiments.

[0100] This disclosure also provides a breast CBCT system that can perform the control method of a breast CBCT system according to any of the embodiments described above.

[0101] Figure 12 This is a schematic block diagram of a breast CBCT system 1000 according to one embodiment of the present disclosure.

[0102] The hardware architecture of the breast CBCT system 1000 can be implemented using a bus architecture. The bus architecture can include any number of interconnect buses and bridges, depending on the specific application and overall design constraints of the hardware. Bus 1100 connects various circuits, including one or more processors 1200, memory 1300, and / or hardware modules. Bus 1100 can also connect various other circuits 1400, such as peripheral devices, voltage regulators, power management circuits, external antennas, etc.

[0103] Bus 1100 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of representation, this diagram uses only one connection line, but this does not imply that there is only one bus or one type of bus.

[0104] The processor 1200 can be a central processing unit (CPU). The processor 1200 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations of the above types of chips.

[0105] The memory 1300 can serve as a non-transitory computer-readable storage medium, used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as program instructions of the computer program in the embodiments of this disclosure. The processor 1200 implements the control method of the breast CBCT system by running the non-transitory software programs, instructions, and modules stored in the memory 1300.

[0106] The memory 1300 may include a program storage area and a data storage area, wherein the program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created by the processor 1200. Furthermore, the memory 1300 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 1300 may optionally include memory remotely located relative to the processor 1200, and these remote memories may be connected to the processor 1200 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0107] This disclosure also provides a readable storage medium storing a computer program that, when executed by a processor, is used to implement the methods described above. A "readable storage medium" can be any means capable of containing, storing, communicating, propagating, or transmitting a program for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples of a readable storage medium include: an electrical connection with one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable read-only memory (CDROM), etc.

[0108] This disclosure also provides a computer program product, the methods of which can be implemented wholly or partially through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented wholly or partially as a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed, the processes or functions of this disclosure are performed wholly or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, network equipment, user equipment, core network equipment, OAM, or other programmable device.

[0109] Computer programs or instructions can be stored in a readable storage medium or transferred from one readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The readable storage medium can be any available medium capable of access, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; an optical medium, such as a digital video optical disc; or a semiconductor medium, such as a solid-state drive. The computer-readable storage medium can be a volatile or non-volatile storage medium, or it can include both volatile and non-volatile types of storage media.

[0110] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0111] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, systems, and computer program products according to this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0112] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0113] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0114] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., refer to specific features, structures, or characteristics described in connection with that embodiment / mode or example, which are included in at least one embodiment / mode or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0115] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0116] Those skilled in the art should understand that the above embodiments are merely for illustrating the present disclosure and are not intended to limit the scope of the disclosure. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present disclosure.

Claims

1. A control method of a breast CBCT system, characterized by, The breast CBCT system includes a filtering assembly located between the radiation source and the detector, the filtering assembly being used for spatially selective attenuation of radiation passing through itself; the control method includes: Before performing a CBCT scan on the subject, an image containing the subject (a human breast) is captured using an imaging device; and The position of the filter assembly is moved by using the spatial information of the subject in the imaging coordinate system of the imaging device, as represented by the image, and the existing mapping relationship between the imaging coordinate system and the physical coordinate system of the filter assembly, so that at least a portion of the rays emitted by the radiation source that do not pass through the subject pass through the filter assembly and are attenuated before reaching the detector. The establishment of the existing mapping relationship includes: for each of the multiple calibration objects located in the imaging field of view, determining the pixel position of the calibration object in the image captured by the imaging device, and determining the target position of the filtering component when the feature point of the filtering component coincides with the feature point of the calibration object in the projection direction; and determining the mapping relationship between the imaging coordinate system and the physical coordinate system of the filtering component through the pixel positions and the target positions corresponding to the multiple calibration objects.

2. The control method of a breast CBCT system according to claim 1, characterized in that, The filter assembly satisfies at least one of the following: the structural thickness of the filter assembly is not uniformly distributed in the projection direction, and the different components of the filter assembly are made of different materials.

3. The control method of a breast CBCT system according to claim 1 or 2, characterized in that, The filter assembly has a groove structure on one side.

4. The control method of a breast CBCT system according to claim 3, characterized in that, The groove structure is a recess and is located on top of the filter assembly, and at least a portion of the surface of the recess is curved.

5. The control method for the breast CBCT system according to claim 4, characterized in that, The intersection lines between the groove and the top and side surfaces of the filter assembly are all arcs, and the side surface is the side facing or away from the radiation source.

6. The control method for the breast CBCT system according to claim 1, characterized in that, The position of the filter component is moved by using the spatial information of the subject in the shooting coordinate system of the shooting device represented by the image and the existing mapping relationship between the shooting coordinate system and the physical coordinate system of the filter component, including one or more of a first moving step and a second moving step; The first moving step includes: The spatial information of the subject within the imaging coordinate system of the imaging device is determined using the image; and The filtering component is moved using the spatial information and the existing mapping relationship between the shooting coordinate system and the physical coordinate system of the filtering component; The second moving step includes: By utilizing the existing mapping relationship between the imaging coordinate system of the imaging device and the physical coordinate system of the filtering component, the real-time projection position of the filtering component in the imaging field of view is determined to be the target position in the physical coordinate system. This target position is then represented by an identifier in the displayed image, thereby providing spatial information of the subject within the imaging coordinate system of the imaging device. In response to receiving a control command, the filter component is moved according to the control command.

7. The control method for the breast CBCT system according to claim 6, characterized in that, In the first moving step, the stopping condition for moving the filter component includes: the feature points of the filter component coincide with the feature points of the subject.

8. The control method for the breast CBCT system according to any one of claims 4-7, characterized in that, The movement range of the filter component satisfies one or more of the following: If the filter assembly moves to the lowest point allowed in the direction of the scanning rotation axis, the distance between the top edge of the groove structure of the filter assembly and the top edge of the imaging field of view on the scanning rotation axis is less than a first distance threshold. If the filter assembly moves to the highest point allowed in the scanning rotation axis direction, the bottom edge of the groove structure of the filter assembly is lower than the top edge of the imaging field of view, and the distance between the filter assembly and the top edge of the imaging field of view on the scanning rotation axis is less than a second distance threshold.

9. The control method according to claim 6, characterized in that, Determining the spatial information of the subject in the imaging coordinate system of the imaging device through the image includes: The mask region of the subject is determined from the image, and the spatial information of the feature points of the subject in the mask region in the shooting coordinate system of the shooting device is determined, wherein the spatial information includes height information.

10. The control method for the breast CBCT system according to claim 1, characterized in that, The characteristic point of the filter component is the lowest point of the groove structure of the filter component.

11. A breast CBCT system, characterized in that, include: Source of radiation; detector; A filtering assembly located between the radiation source and the detector; A drive mechanism for controlling the movement of the filter assembly; The memory stores execution instructions; as well as A processor that executes the execution instructions stored in the memory, causing the processor to perform the control method of the breast CBCT system according to any one of claims 1 to 10.

12. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, is used to implement the control method of the breast CBCT system according to any one of claims 1 to 10.

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