Variable incident ray angle ray attenuation system on-axis collimation arrangement and ct apparatus

Abstract

This application relates to the field of CT imaging technology. A collimation device on a variable incident light angle X-ray attenuation system includes: a X-ray filter; an A-level collimator disposed at the incident end of the X-ray filter; and a B-level collimator disposed at the exit end of the X-ray filter. The opening centers of the A-level and B-level collimators are symmetrically arranged along the perpendicular bisector of the imaging field range perpendicular to the light plane, based on the X-ray source focal spot, to compensate for X-ray divergence deviation caused by the X-ray source focal spot and limit the X-ray incident width. While ensuring CT scan imaging quality, this application achieves the dual technical effects of improved X-ray utilization efficiency and reduced patient dose, effectively solving a series of scattering-related technical problems associated with traditional X-ray filtering devices alone.

Description

Technical Field

[0001] This application relates to the field of CT imaging technology, and more specifically, to a collimation device and CT equipment on a radiation attenuation system with a variable incident light angle. Background Technology

[0002] X-ray computed tomography (CT) imaging is based on the conversion of X-rays into readable signals after they pass through the human body (the object being scanned) and reach the detector. From the perspective of X-ray optical path design, the industry usually uses X-ray filtering devices with special distribution shapes (before passing through the human body). While this device solves its specific problems, it also introduces certain X-ray scattering problems. This scattering problem affects the X-ray distribution, making the effective focal spot size larger, which leads to a decrease in spatial resolution (X-rays are emitted from the focal spot, and the scattering caused by shape filtering is equivalent to increasing the radiation range of the focal spot. The size (width) of the focal spot directly determines the resolution of the system). At the same time, the increased width of the scattered lines also results in a higher dose to the scanned person.

[0003] In view of this, there is an urgent need for a collimation device on a ray attenuation system with a variable incident ray angle to solve the above problems. Summary of the Invention

[0004] The main objective of this application is to provide a collimation device and CT equipment for a radiation attenuation system with a variable incident light angle, in order to solve the technical problems in the prior art.

[0005] To achieve the above objectives, in a first aspect, this application proposes a collimation device for a ray attenuation system with a variable incident ray angle, comprising: X-ray filtration device; A Class A collimator is installed at the incident end of the radiation filtering device; A Class B collimator is installed at the exit end of the radiation filtering device; wherein... The opening centers of the Class A and Class B collimators are located along the X-ray source focal spot and within the defined imaging field perpendicular to the light plane. The perpendicular bisectors are symmetrically arranged to compensate for the X-ray divergence caused by the X-ray source focal spot and to limit the X-ray incident width.

[0006] In some feasible implementation methods, the formula for calculating the opening width of the Class A collimator is as follows: ; in, This refers to the aperture width of a Class A collimator. The distance from the focal point to the plane of the Class A collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

[0007] In some feasible implementation methods, the formula for calculating the opening width of the Class B collimator is as follows: ; in, This refers to the aperture width of a Class B collimator. The distance from the focal point to the plane of the B-class collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

[0008] In some possible implementations, the perpendicular bisector is the imaging field area that passes through the center of the X-ray source focal spot and is perpendicular to the light plane. A straight line in the width direction, the opening width of the Class A collimator and Class B collimator is based on the... and stated The calculation formula is linked to the symmetrical setting position.

[0009] In some feasible implementations, the radiation filtering device is a Bowtie filter, the A-level collimator is the front-end adjustable collimation structure of the radiation attenuation system, and the B-level collimator is the secondary adjustable collimation structure of the radiation attenuation system. The X-rays pass through the A-level collimator, the radiation filtering device, and the B-level collimator in sequence to form a target radiation beam.

[0010] In some possible implementations, SAD, SBD, and SID are all geometric parameters of the X-ray attenuation system of the X-ray computed tomography system, and SAD, SBD, and SID are fixed parameters inherent to the X-ray computed tomography system or configurable adjustable parameters, wherein the geometric parameters satisfy the distance relationship that SAD < SBD < SID.

[0011] In some feasible ways, the aforementioned and stated The aperture adjustment range is the same as the imaging field range perpendicular to the light plane. The width setting range matches, and the and stated The adjustment range is adapted to each other, and the adaptation relationship is determined by the geometric ratio of the SAD, the SBD and the SID.

[0012] In some feasible implementations, both the A-level collimator and the B-level collimator are adjustable mechanical collimation structures. Each set of adjustable mechanical collimation structures includes symmetrically arranged adjusting blades, blade drive components, and position detection modules; the blade drive components are based on the... and stated The formula calculation value drives the movement of the corresponding adjusting blade, and the position detection module provides real-time feedback on the opening position of the adjusting blade.

[0013] In some feasible implementation methods, the A-level collimator and the B-level collimator are synchronously linked for adjustment; the linkage adjustment mechanism means that when the width of the imaging field perpendicular to the light plane set by the scanning is adjusted in real time, the blade drive assembly synchronously adjusts according to the... and stated The formula calculation value synchronously drives the two sets of adjustable mechanical collimation structures to adjust the adjusting blades to the target opening width, and the opening adjustment of the two sets of adjusting blades is completed synchronously.

[0014] Secondly, this application provides a CT device including the collimation device on the aforementioned variable incident light angle radiation attenuation system.

[0015] The technical solutions provided by the embodiments of this application may include the following beneficial effects: This application discloses a collimation device for a variable incident light angle X-ray attenuation system. This is achieved by setting an A-stage collimator and a B-stage collimator at the incident and exit ends of the X-ray filter, respectively. The centers of the openings of the two collimators are aligned along the X-ray source focal spot and within a predetermined imaging field perpendicular to the light plane. The symmetrical arrangement of the vertical axis creates a structural layout for precise bidirectional collimation before and after the X-ray filtering device. This structure allows for precise beam confinement of the incident X-rays using a Class A collimator before the X-rays are shaped by the filtering device, suppressing X-ray divergence at the source. After the filtering device shapes the X-rays, a Class B collimator provides secondary precise confinement, effectively eliminating X-ray scattering caused by the filtering device and preventing an increase in the effective focal spot radiation range due to scattering. This precisely controls the effective focal spot size to ensure the spatial resolution of the X-ray computed tomography system. Simultaneously, the symmetrical collimation structure limits the width of scattered rays, reducing the difference between the actual radiation width and the preset radiation width, significantly reducing the dose to the scanned patient. While ensuring CT imaging quality, this achieves the dual technical effects of improved X-ray utilization efficiency and reduced patient dose, effectively solving a series of scattering-related technical problems associated with traditional X-ray filtering devices alone. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 A schematic diagram illustrating the working principle of a collimating device on a ray attenuation system with a variable incident light angle, provided in this application. Figure 2 A schematic diagram illustrating the working principle of the collimation device on a variable incident light angle ray attenuation system provided in this application, showing the preset radiation width and the actual radiation width; Figure 3 The schematic diagrams of the Class A and Class B collimators of the collimation device on the ray attenuation system with a variable incident light angle provided in this application; Figure 4 The schematic diagram of a Class B collimator for a collimation device in a ray attenuation system with a variable incident ray angle provided in this application.

[0017] Figure label: 1. X-ray filtering device; 2. Class A collimator; 3. Class B collimator. Detailed Implementation

[0018] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0020] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0021] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0022] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] like Figures 1 to 4 As shown, this application provides a collimation device on a radiation attenuation system with a variable incident light angle, including a radiation filter 1, an A-class collimator 2, and a B-class collimator 3.

[0024] Among them, the Class A collimator 2 is installed at the incident end of the X-ray filtering device 1; the Class B collimator 3 is installed at the exit end of the X-ray filtering device 1.

[0025] The opening centers of the Class A collimator 2 and Class B collimator 3 are located along the X-ray source focal spot and within the set imaging field area perpendicular to the light plane. The perpendicular bisectors are symmetrically arranged to compensate for the X-ray divergence caused by the X-ray source focal spot and to limit the X-ray incident width.

[0026] Specifically, the calculation formula for the opening width setting of the Class A collimator 2 is as follows: ; in, The aperture width of the Class A collimator 2 is... The distance from the focal point to the plane of the Class A collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

[0027] The formula for calculating the opening width of the B-level collimator 3 is as follows: ; in, This refers to the aperture width of a Class B collimator. The distance from the focal point to the plane of the B-class collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

[0028] It should be noted that the opening widths of the Class A collimator 2 and Class B collimator 3 are both adapted to the core geometric parameters of the X-ray computed tomography system and the imaging field range perpendicular to the light plane preset by the scan. By combining the geometric ratio matching principle with the deviation compensation of the X-ray source focal spot size, the opening widths of the two collimators are accurately calculated and set, ensuring that the collimator openings match the scanning requirements and the optical path geometry of the equipment, thus constraining the X-ray incident width from the source and suppressing scattering problems.

[0029] For Class A collimator 2, using the isocenter plane of the equipment as a reference, the geometric ratio of the distance from the source to the isocenter to the distance from the source to the imaging plane is used to convert the preset imaging field range perpendicular to the light plane into the theoretical optical path width of the Class A collimator 2 installation position. At the same time, based on the ratio of the difference between the distance from the source to the isocenter and the distance from the source to the imaging plane, the focal spot size of the X-ray tube is proportionally compensated to make up for the problem of the expansion of the radiation range caused by the natural divergence of the focal spot. This ensures that the actual opening width of Class A collimator 2 matches the effective irradiation requirements of the scan and can also offset the divergence deviation caused by the focal spot, thus achieving precise beam confinement at the X-ray incident end.

[0030] The principle of setting the opening width of the Class B collimator 3 is the same as that of the Class A collimator 2. The core difference is that the distance from the source to the Class B collimator 3 is used instead of the distance from the source to the center for geometric proportional conversion. This adapts the Class B collimator 3 to the installation position at the exit end of the X-ray filtering device 1. It also combines focal spot size compensation to achieve precise opening setting and complete the secondary collimation constraint of X-rays.

[0031] Based on the actual installation position of the Class B collimator 3, the imaging field range perpendicular to the light plane is converted into the theoretical optical path width of the installation position of the Class B collimator 3 by utilizing the geometric ratio of the distance from the source to the Class B collimator 3 and the distance from the source to the imaging plane. At the same time, the focal spot size of the X-ray tube is proportionally compensated according to the ratio of the difference between the distance from the source to the Class B collimator 3 and the distance from the source to the imaging plane. This compensates for the natural divergence of the focal spot and the scattering deviation caused by the shaping of the X-ray filter device 1, so that the actual opening width of the Class B collimator 3 matches the optical path characteristics of the X-ray emitted from the filter device, and achieves precise secondary beam confinement at the X-ray emission end.

[0032] In one embodiment, the perpendicular bisector is the imaging field that passes through the center of the X-ray source focal spot and is perpendicular to the light plane. The straight line in the width direction, the opening width of the A-level collimator 2 and the B-level collimator 3 is based on the... and stated The calculation formula is linked to the symmetrical setting position.

[0033] Specifically, in this embodiment, the vertical alignment positioning structure of the collimation device and the opening width matching linkage structure of the A-level collimator 2 and the B-level collimator 3 are all designed based on the optical path geometric reference of the X-ray computed tomography equipment. By combining the spatial positioning principle of vertical alignment with the optical path geometric ratio adaptation principle, the position and opening of the two-stage collimators are precisely linked, ensuring that the X-ray beam is transmitted along the preset optical path throughout the entire process and effectively suppressing scattering problems.

[0034] The perpendicular bisector is the core symmetrical reference line of the X-ray optical path. Its positioning structure uses the center of the X-ray source focal spot and the center of the width of the imaging field perpendicular to the optical plane as dual reference points. Specifically, it passes through the geometric center of the X-ray source focal spot and is aligned with the imaging field range perpendicular to the optical plane set for scanning. A straight line perpendicular to each other in the width direction serves as the positioning reference for the opening center of collimator 2 (Class A) and collimator 3 (Class B), and is also the ideal central transmission optical path for the X-ray beam.

[0035] Imaging field range perpendicular to the light plane Width direction: refers to the lateral extension direction of the effective irradiation area formed by the X-ray beam in the central plane of CT equipment, etc., which is the preset optical path width reference direction for scanning; Spatial properties of the perpendicular bisector: The perpendicular bisector is a three-dimensional straight line that runs through the X-ray emitting end, collimation device, X-ray filtering device 1 of the CT equipment to the detector imaging plane. It is the central axis of symmetry of the entire X-ray transmission optical path. Uniqueness of the reference point: The geometric center of the X-ray source focal spot is a fixed reference point for ray emission, and the imaging field range is perpendicular to the light plane. The width center is the optical path illumination reference point set by the scan, and the vertical line determined by the two is unique and certain, avoiding positioning deviation of the two-stage collimator.

[0036] Both the A-level collimator 2 and the B-level collimator 3 are symmetrically arranged with their opening centers coaxially aligned, using the vertical line as their center of symmetry. Specifically, the geometrical centers of the openings of both the A-level and B-level collimators coincide with this vertical line, and the opening width adjustment directions of both collimators are perpendicular to the imaging field area of ​​the light plane. The width direction remains consistent and is perpendicular to the vertical line.

[0037] The unique reference positioning of the perpendicular bisector, the symmetrical arrangement of the two-stage collimators, and the matching linkage of their opening widths form a coordinated overall structure: with the perpendicular bisector as the core axis of symmetry, the spatial positioning of the two-stage collimators is ensured; with the imaging field range perpendicular to the light plane as a unified reference, combined with the optical path geometry ratio and focal spot deviation compensation, the precise linkage of the openings of the two-stage collimators is achieved; ultimately, the X-ray beam is always transmitted along the preset optical path during its entire transmission through the A-stage collimator 2 incident beam limiting, the X-ray filter device 1 shaping, and the B-stage collimator 3 secondary beam limiting, effectively suppressing the scattering problem caused by the X-ray filter device 1, avoiding an increase in the effective focal spot size, and controlling the width of the scattered rays to reduce the dose to the scanned subject.

[0038] In one embodiment, the X-ray filtering device 1 is a Bowtie filter, the A-level collimator 2 is the front-end adjustable collimation structure of the X-ray attenuation system, and the B-level collimator 3 is the secondary adjustable collimation structure of the X-ray attenuation system. The X-rays pass through the A-level collimator 2, the X-ray filtering device 1, and the B-level collimator 3 in sequence to form a target X-ray beam.

[0039] Specifically, the Bowtie filter is a fixed radiation shaping and intensity attenuation component of the radiation attenuation system. It is made of radiation attenuation filter material specifically for CT equipment and has an overall irregular structure adapted to the radiation attenuation characteristics of the human body. Its filter thickness varies in gradient along the width of the imaging field perpendicular to the light plane. The filter thickness is thinnest in the central region near the vertical line of the light path and gradually increases in thickness in the regions extending to both sides of the light path. This can achieve non-uniform gradient attenuation of X-ray intensity, optimize the X-ray spectrum distribution, and reduce CT imaging artifacts caused by excessive radiation hardness.

[0040] The transmission and modulation of X-rays in the radiation attenuation system follows the logic of "front-end beam limiting, shaping attenuation, and secondary beam limiting," with the three working together to form the target beam: After the original X-rays are emitted from the X-ray source focal spot, they first enter the Class A collimator 2, where they are source-limited to form a primary beam with regular size and propagation along a preset optical path; the primary beam enters the Bowtie filter perpendicularly, where the gradient thickness attenuation of the filter completes the beam spectrum shaping and intensity optimization to meet the radiation requirements of human CT scans; the beam shaped by the filter then enters the Class B collimator 3, which completes the elimination of scattered rays and the final constraint on the beam exit width, ultimately forming a target beam with precise irradiation range, no extra scattered rays, and suitable intensity distribution.

[0041] In one embodiment, SAD, SBD, and SID are all geometric parameters of the X-ray attenuation system of the X-ray computed tomography system, and SAD, SBD, and SID are fixed parameters or configurable adjustable parameters inherent to the X-ray computed tomography system. The geometric parameters satisfy the distance relationship that SAD < SBD < SID.

[0042] Specifically, SAD (source to isocenter distance), SBD (source to Class B collimator 3 distance), and SID (source to imaging plane distance) are all core optical path geometric parameters of the X-ray attenuation system in X-ray computed tomography (CT) systems. All three are measured with the center of the X-ray source focal spot as the unified measurement origin, and the measured values ​​are all straight-line distances along the main X-ray transmission direction. They are the core geometric references for achieving accurate adaptation of the opening of Class A and Class B collimators 3. Moreover, the three can be adapted as inherent fixed or configurable adjustable parameters according to the design type of the CT system, while always maintaining the distance relationship of SAD < SBD < SID. This relationship is determined by the spatial arrangement of the optical path reference positions corresponding to each parameter, and is highly matched with the overall optical path layout of the X-ray attenuation system and the CT system.

[0043] After being emitted from the X-ray source focal spot, the X-rays first reach the isocenter plane of the CT system (corresponding to SAD) along the main transmission direction. This position is the core reference point where the X-ray beam will irradiate the scanned object and is located at the front of the entire optical path. The X-rays continue to propagate, passing through the front-end limiter of the Class A collimator 2 and the X-ray shaping of the Bowtie filter, before reaching the working plane of the Class B collimator 3 (corresponding to SBD). This position is located at the rear of the optical path of the X-ray attenuation system and at the incident front of the scanned object, spatially later than the isocenter plane. Finally, after passing through the scanned object, the X-rays continue along the main transmission direction to reach the detector imaging plane (corresponding to SID). This position is the end of the X-ray transmission and is spatially located at the rear of the entire optical path.

[0044] In one embodiment, the and stated The aperture adjustment range is the same as the imaging field range perpendicular to the light plane. The width setting range matches, and the and stated The adjustment range is adapted to each other, and the adaptation relationship is determined by the geometric ratio of the SAD, the SBD and the SID.

[0045] Imaging field range perpendicular to the light plane ( The width setting range is preset before scanning based on the size of the scanned object and imaging accuracy requirements. It represents the effective irradiation width range of the X-ray beam in the isocentric plane of the CT system and is the core target reference for adjusting the opening of the two-stage collimator; and stated The opening adjustment range is based on this benchmark, and geometric conversion is performed by combining the respective installation position characteristics in the optical path to achieve [the desired result]. Full-range precise matching within a specified width range, with specific matching features as follows: Coverage matching: the and stated The opening adjustment range can be fully covered. The entire width setting range, i.e. The minimum setpoint corresponds to the minimum adjustable opening of the two-stage collimator. The maximum setting value corresponds to the maximum adjustable opening of the two-stage collimator, ensuring that the two-stage collimator can be adjusted to a suitable opening size under any scanning preset requirements, without the problem of insufficient adjustment range causing preset requirements to be unmet. Correspondence matching: The opening adjustment range of the two-stage collimator is consistent with... The width setting range forms a one-to-one correspondence at the optical path geometry level, that is... Any width value within the set range can be converted to the corresponding optical path ratio to obtain the desired result. and stated The target aperture value, and all of these target aperture values, are within the adjustable range of the two-stage collimator, ensuring that the adjusted collimator aperture allows the X-ray beam to irradiate the actual area of ​​the isocentric plane, in accordance with the preset scanning parameters. The width is precisely consistent to avoid the radiation range being too large or too small due to deviations in opening.

[0046] This matching relationship ensures that the opening adjustment of the two-stage collimator always revolves around the actual scanning needs, thus avoiding problems such as excessive X-ray incident scattering caused by the filter device due to mismatch between the collimator adjustment range and the scanning preset, or insufficient X-ray irradiation range affecting imaging.

[0047] and The aperture adjustment range forms an adaptation relationship based on the optical path position. This adaptation relationship is directly determined by the geometric ratio of SAD, SBD, and SID. The core principle is that SAD, SBD, and SID are optical path core distance parameters with the X-ray source focal spot as the unified measurement origin. Their ratio reflects the relative position characteristics of the A-level collimator 2 and the B-level collimator 3 in the X-ray transmission optical path. The aperture adjustment range of the two collimators must be adapted to this position characteristic to ensure that the X-ray beam maintains a regular beam shape and has no divergence or obstruction problems throughout the entire transmission process, from the A-level collimator 2, through the X-ray filter device 1, and then through the B-level collimator 3 for secondary beam confinement.

[0048] The core function of geometric ratios: SID represents the total optical path distance of the X-ray from the source focal spot to the detector imaging plane, serving as a unified benchmark for optical path ratio conversion. SAD / SID represents the ratio of the installation position of Class A collimator 2 to the total optical path, and SBD / SID represents the ratio of the installation position of Class B collimator 3 to the total optical path. These two ratios directly determine... and The numerical ratio of the adjustment range; that is, the ratio of the opening adjustment range of the two-stage collimator, is consistent with the numerical ratio of SAD and SBD to ensure that the collimator opening at different optical path positions can form a continuous and matched beam-limiting effect on the ray beam. The specific manifestation of the adaptation relationship: During the scanning process, when When the width setting is adjusted, and The opening will be adjusted synchronously according to the above geometric proportions, and the adjustment range will always be adapted to the ratio of SAD and SBD; for example, if the ratio of SAD to SBD is 1:1.2, then... The opening adjustment range and The opening adjustment ratio is also close to 1:1.2, ensuring that after the X-ray beam passes through the Class A collimator 2, its beam shape size can be precisely matched with the opening of the Class B collimator 3. The scattered rays after being shaped by the filtering device can be completely intercepted by the Class B collimator 3, avoiding X-ray beam divergence caused by the mismatch of the opening of the front and rear collimators. Stability of the adaptation relationship: If SAD, SBD, and SID are inherent fixed parameters of the CT system, and their geometric ratios are constants, and The adjustment range adaptation ratio is also a fixed value, which can be calibrated during the system design phase; if SAD, SBD, and SID are configurable adjustable parameters, their geometric ratios will change synchronously with parameter adjustments. and The adjustment range and adaptation ratio will also be dynamically adjusted accordingly, always maintaining a high degree of adaptation with the optical path position characteristics, ensuring that the beam-limiting effect of the two-stage collimators can meet the scanning requirements under different optical path parameter settings.

[0049] In one embodiment, both the A-level collimator 2 and the B-level collimator 3 are adjustable mechanical collimation structures. Each set of adjustable mechanical collimation structures includes symmetrically arranged adjusting blades, a blade drive assembly, and a position detection module; the blade drive assembly is based on the... and stated The formula calculation value drives the movement of the corresponding adjusting blade, and the position detection module provides real-time feedback on the opening position of the adjusting blade.

[0050] Furthermore, the Class A collimator 2 and Class B collimator 3 are synchronously linked for adjustment; the linked adjustment mechanism indicates that when scanning the set imaging field range perpendicular to the light plane... When the width is adjusted in real time, the blade drive assembly synchronously adjusts according to the... and stated The formula calculation value synchronously drives the two sets of adjustable mechanical collimation structures to adjust the adjusting blades to the target opening width, and the opening adjustment of the two sets of adjusting blades is completed synchronously.

[0051] Specifically, in this embodiment, the A-level collimator 2 and the B-level collimator 3 can adopt an adjustable mechanical collimation structure with uniform structural specifications. Both are composed of symmetrically arranged adjustment blades, blade drive components, and position detection modules. The three sets of components form a closed-loop adjustment unit of "power drive - mechanical movement - position feedback" to achieve precise adjustment of the opening of a single-stage collimator. At the same time, the A-level collimator 2 and the B-level collimator 3 are equipped with a synchronous linkage adjustment mechanism. Based on the unified control logic of the X-ray attenuation system, the action and positioning of the opening adjustment of the two-stage collimators are synchronized, ensuring that the two-stage collimators always maintain an appropriate opening relationship when the scanning requirements change, so as to form a continuous and precise beam confinement effect for X-rays.

[0052] Furthermore, in the symmetrically arranged adjusting blades, the adjusting blades are the core X-ray beam-limiting components of the adjustable mechanical collimation structure, made of a material with high X-ray shielding performance to meet the X-ray attenuation requirements of CT. The adjusting blades are arranged in pairs symmetrically with the vertical line of the optical path as the center of symmetry. Each collimator has at least one pair of adjusting blades in combination. The effective working surface of the blades is a flat surface and is perpendicular to the main transmission direction of X-rays to ensure the flatness and beam limiting of the X-ray beam. The movement of the adjusting blades is along the imaging field range perpendicular to the optical plane (…). The blades move in a straight line with equal intervals in the width direction, that is, the blades extend or contract synchronously and equally to both sides from the position of the vertical line of the optical path, always keeping the center of the opening coincide with the vertical line of the optical path, ensuring that the center of the collimator opening will not shift due to the opening adjustment, and ensuring that the X-ray beam is always transmitted along the preset optical path.

[0053] The blade drive assembly is the power actuator of an adjustable mechanical collimation structure, and is the core component for realizing the opening and closing motion of the adjustable blades. It consists of two parts: a drive source and a transmission mechanism. The drive source uses a servo motor or stepper motor to meet the high precision and low hysteresis requirements of CT system collimation adjustment, and can achieve precise control of speed and angle according to control signals. The transmission mechanism uses a lead screw or synchronous belt drive structure, which can convert the rotational power of the drive source into the linear opening and closing motion of the adjustable blades, ensuring the smoothness and accuracy of the blade movement and avoiding opening adjustment deviations caused by movement jamming. The core function of the blade drive assembly is to receive the opening adjustment signal from the X-ray attenuation system control terminal, accurately output power according to the target opening value, and drive the adjustable blades to perform the corresponding opening and closing motion through the transmission mechanism, driving the blades to the target opening position, thus realizing active opening adjustment.

[0054] The position detection module is a real-time feedback component of an adjustable mechanical collimation structure, consisting of a position detection sensor and a signal transmission unit. The sensor can be directly attached to the moving parts of the adjusting blade or transmission mechanism, enabling real-time, high-precision acquisition of the actual opening position data of the adjusting blade. The signal transmission unit converts the acquired physical position data into an electrical signal, which is fed back to the control terminal of the ray attenuation system in real time, forming real-time position feedback for the opening adjustment. This position detection module can use high-precision position detection sensors such as grating rulers and linear proximity switches. When the adjusting blade reaches the target opening position, the position detection module continuously feeds back the blade's position signal. If the blade's position shifts due to factors such as equipment vibration, the position detection module feeds back the deviation signal to the control terminal, triggering the blade drive assembly to perform fine adjustments, ensuring the stability of the collimator opening.

[0055] In other words, the position detection sensor is connected to the signal transmission unit, the signal transmission unit is connected to the drive source of the blade drive assembly, and the drive source is connected to the adjusting blade through the transmission mechanism.

[0056] The closed-loop adjustment principle of a single-stage collimator: The adjusting blades, blade drive assembly, and position detection module of each collimator stage form a closed-loop adjustment logic: the control terminal sends a target opening signal, the blade drive assembly receives the signal and drives the adjusting blades to move, the position detection module collects the actual blade opening in real time and feeds it back to the control terminal, the control terminal compares the actual opening with the target opening, and if there is a deviation, it triggers the drive assembly to fine-tune until the actual opening and the target opening are precisely matched. This closed-loop adjustment achieves precise and stable control of the single-stage collimator opening, avoiding beam limiting failure caused by opening adjustment deviation.

[0057] The core adaptation logic of the synchronous linkage mechanism is that "synchronization" is reflected in the full synchronization of the adjustment action. The target opening size of the two collimators is determined by the geometric ratio of SAD, SBD, and SID according to their respective installation positions in the optical path, and is not the same opening size. This logic of "synchronized action and matching opening size" ensures that the scattered rays generated after the X-ray beam is limited by the front end of the A-stage collimator 2 and shaped by the Bowtie filter can be accurately intercepted a second time by the B-stage collimator 3 with a matching opening size. This avoids problems such as missed interception of scattered rays and beam divergence caused by asynchronous adjustment or mismatch of opening size between the two-stage collimators.

[0058] The synergistic effect of collimator A2 and collimator B3 ensures that the X-ray attenuation system can continuously, accurately, and adaptively limit the X-rays throughout the scanning process via the two collimators: from the source X-ray limiting of collimator A2 to the secondary interception of scattered rays by collimator B3, the system can adapt in real time to the adjustment of the imaging field range perpendicular to the light plane during scanning. This effectively suppresses X-ray scattering problems caused by the Bowtie filter, avoids the increase in effective focal spot size due to scattering, ensures the spatial resolution of the X-ray computed tomography system, and precisely controls the radiation range of scattered rays, significantly reducing the dose to the scanned subject.

[0059] Secondly, this application provides a CT device including the collimation device on the aforementioned variable incident light angle radiation attenuation system.

[0060] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0061] Obviously, those skilled in the art should understand that the various units or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a storage device for execution by a computing device, or fabricating them separately as individual integrated circuit modules, or fabricating multiple modules or steps into a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A variable incident light ray angle system-on-a-ray collimation device, characterized by, include: X-ray filtration device; A Class A collimator is installed at the incident end of the radiation filtering device; A Class B collimator is installed at the exit end of the radiation filtering device; wherein... The opening centers of the Class A and Class B collimators are located along the X-ray source focal spot and within the defined imaging field perpendicular to the light plane. The perpendicular bisectors are symmetrically arranged to compensate for the X-ray divergence caused by the X-ray source focal spot and to limit the X-ray incident width.

2. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 1, characterized in that, The formula for calculating the opening width of the Class A collimator is as follows: ； in, This refers to the aperture width of a Class A collimator. The distance from the focal point to the plane of the Class A collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

3. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 2, characterized in that, The formula for calculating the opening width of the Class B collimator is as follows: ； in, This refers to the aperture width of a Class B collimator. The distance from the focal point to the plane of the B-class collimator. The distance from the focal point to the center of gravity. The imaging field range perpendicular to the light plane is set for scanning. This is the focal spot size of the X-ray tube.

4. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 3, characterized in that, The perpendicular bisector is the imaging field that passes through the center of the X-ray source focal spot and is perpendicular to the light plane. A straight line in the width direction, the opening width of the Class A collimator and Class B collimator is based on the... and stated The calculation formula is linked to the symmetrical setting position.

5. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 1, characterized in that, The X-ray filtering device is a Bowtie filter, the A-level collimator is the front-end adjustable collimation structure of the X-ray attenuation system, and the B-level collimator is the secondary adjustable collimation structure of the X-ray attenuation system. The X-rays pass through the A-level collimator, the X-ray filtering device, and the B-level collimator in sequence to form the target X-ray beam.

6. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 3, characterized in that, The SAD, SBD, and SID are all geometric parameters of the X-ray attenuation system of the X-ray computed tomography system. The SAD, SBD, and SID are fixed parameters or configurable adjustable parameters inherent to the X-ray computed tomography system. The geometric parameters satisfy the distance relationship that SAD < SBD < SID.

7. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 3, characterized in that, The and stated The aperture adjustment range is the same as the imaging field range perpendicular to the light plane. The width setting range matches, and the and stated The adjustment range is adapted to each other, and the adaptation relationship is determined by the geometric ratio of the SAD, the SBD and the SID.

8. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 3, characterized in that, Both the Class A and Class B collimators are adjustable mechanical collimation structures. Each adjustable mechanical collimation structure includes symmetrically arranged adjusting blades, a blade drive assembly, and a position detection module. The blade drive assembly is based on the... and stated The formula calculation value drives the movement of the corresponding adjusting blade, and the position detection module provides real-time feedback on the opening position of the adjusting blade.

9. The collimating device on the ray attenuation system with variable incident ray angle as described in claim 8, characterized in that, The Class A collimator and Class B collimator are synchronized and linked; the linked adjustment mechanism means that when scanning the set imaging field range perpendicular to the light plane... When the width is adjusted in real time, the blade drive assembly synchronously adjusts according to the... and stated The formula calculation value synchronously drives the two sets of adjustable mechanical collimation structures to adjust the adjusting blades to the target opening width, and the opening adjustment of the two sets of adjusting blades is completed synchronously.

10. A CT scanner, characterized in that, Collimation device on a ray attenuation system with a variable incident ray angle as described in any one of claims 1-9.

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