CT machine front collimator and manufacturing method thereof

Abstract

The invention discloses a CT machine front collimator and a manufacturing method thereof, and relates to the technical field of medical instruments. The CT machine front collimator comprises a filtering device, a slicing device and a box body, the filtering device comprises a filtering assembly and a filtering guide rail; the filtering assembly is in sliding connection with the filtering guide rail; the slicing device comprises a first slicing assembly, a second slicing assembly and a slicing guide rail, the slicing assemblies are slidably connected with the slicing guide rail, and a slicing opening with the adjustable opening size is formed between the slicing assemblies; the box body comprises two side plates and a detachable bottom plate, the two side plates are oppositely arranged and connected through two cross beams, the two filtering guide rails are fixed to the upper planes of the two cross beams respectively, the two slicing guide rails are fixed to the lower planes of the two cross beams respectively, and the bottom plate is provided with a bottom plate opening. Miniaturization and structure optimization of the collimator are realized, radiation dose is reduced by combining tungsten steel plate shielding, compact layout of a multi-source CT machine is supported, and the requirements of the CT machine for larger scanning aperture, lighter rotating body weight and higher rotating speed are met.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a front collimator of a CT machine and a manufacturing method thereof. Background Art

[0002] Different from single-source CT machines that usually only pursue reducing the size of the front collimator in the Y direction to obtain a larger scanning aperture size, multi-source CT machines have multiple groups of optical paths and have more requirements for the compact design of multiple groups of optical paths. For example, a triple-source CT machine includes three groups of X-ray optical paths. An X-ray source, a front collimator, and a detector are arranged on each group of X-ray optical paths. Each group of X-ray optical paths needs to cover a common central scanning area (FOV). The diameter of the FOV needs to be large enough to cover the scanning parts of the vast majority of patients. However, the expansion of the FOV will cause the arc length occupied by the detector on the annular gantry to increase, making the spatial arrangement of the three groups of X-ray sources, front collimators, and detectors challenging. To address this, usually, the method of increasing the distance between the focus of the X-ray source and the detector (SDD) or reducing the space occupied by the X-ray source and the front collimator is adopted to solve this problem. However, the increase in SDD will reduce the CT image resolution, and due to the attenuation characteristics of X-rays, the increase in SDD requires a larger ray dose to maintain the signal-to-noise ratio, resulting in an increase in the radiation dose received by the patient. The key to the other method lies in that the front collimator must be arranged in the narrow triangular area formed by the edges of the three groups of optical paths, reducing the size of the front collimator in the X direction and the Y direction, and reducing its occupation of the intersection area of the three groups of optical paths, which becomes the key to balancing space constraints and performance that can avoid optical path occlusion without sacrificing SDD or increasing the radiation dose.

[0003] In the prior art, most collimators are box structures with four closed sides, and only the upper and lower sides are open for collimating rays and installing internal parts. Cast aluminum or cast steel is used as the box material, and a lead shielding layer is pasted inside. This structure has high requirements for processing accuracy, and the box with four closed sides makes the disassembly and assembly of internal parts very inconvenient, and the structure is complex, with large size and weight. There are technical bottlenecks in the structural complexity, size and weight, maintenance convenience, and multi-source CT machine adaptability of the existing collimators. There is an urgent need for a collimator design that is miniaturized, lightweight, and adaptable to multi-source CT machines. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides a front collimator of a CT machine and a manufacturing method thereof. Through the open box frame and shared crossbeam design, the structural size of the front collimator is optimized, realizing the miniaturization, lightweight, and high-precision of the front collimator of the CT machine, and meeting the compact layout requirements of multi-source CT machines.

[0005] In one aspect of the present invention, a front collimator of a CT machine is provided, including: A filtering device, a slicing device, and a box; The filtering device includes a filtering component and two filtering guide rails, and both ends of the filtering component are slidably connected to the two parallel filtering guide rails; The slicing device includes a first slicing component, a second slicing component and two parallel slicing guide rails. Both ends of the first slicing component and the second slicing component are respectively slidably connected to the two slicing guide rails. An adjustable slicing opening is formed between the first slicing component and the second slicing component; The box body includes two side plates and a detachable bottom plate. The two side plates are oppositely arranged and connected by two cross beams. The two filtering guide rails are respectively fixed on the upper planes of the two cross beams, and the two slicing guide rails are respectively fixed on the lower planes of the two cross beams. The bottom plate is provided with a bottom plate opening.

[0006] Furthermore, the filtering component includes a plurality of filters, a filter fixing seat, a filtering motor and two filtering sliders. The plurality of filters are fixedly arranged in parallel on the filter fixing seat. Filter sliders are respectively fixed at both ends of the filter fixing seat. The filtering sliders are slidably connected to the filtering guide rails. The filtering motor is connected to the filter fixing seat and drives the filter fixing seat to slide along the filtering guide rails through the two filtering sliders, so as to switch different filters.

[0007] Furthermore, the first slicing component includes a first slicing blade, a first slicing blade fixing seat, a first slicing motor and two first slicing sliders. The first slicing blade is fixed on the first slicing blade fixing seat. A first slicing slider is respectively connected to both ends of the first slicing blade fixing seat. The first slicing sliders are slidably connected to the slicing guide rails. The first slicing motor is connected to the first slicing blade fixing seat and drives the first slicing blade fixing seat to slide along the slicing guide rails through the first slicing sliders, thereby driving the first slicing blade to move axially along the slicing guide rails; The second slicing component includes a second slicing blade, a second slicing blade fixing seat, a second slicing motor and two second slicing sliders. The second slicing blade is fixed on the second slicing blade fixing seat. A second slicing slider is respectively connected to both ends of the second slicing blade fixing seat. The second slicing sliders are slidably connected to the slicing guide rails. The second slicing motor is connected to the second slicing blade fixing seat and drives the second slicing blade fixing seat to slide along the slicing guide rails through the second slicing sliders, thereby driving the second slicing blade to move axially along the slicing guide rails; The first slicing blade and the second slicing blade move relatively or oppositely axially along the slicing guide rails.

[0008] Furthermore, flanging is provided on both sides of the bottom plate on the same side as the cross beam.

[0009] Further, the filter includes a flat filter and an arc filter.

[0010] Further, the first slice and the second slice shield the X-rays outside the slice opening to adjust the X-ray layer thickness, and the bottom plate shields the X-rays outside the bottom plate opening to limit the X-ray width.

[0011] Further, the surface where the cross beam of the box body is located is covered with a detachable cover plate, and the top of the box body is covered with a detachable cover plate including an optical path inlet to shield the scattered X-rays.

[0012] Further, the cover plate, the first slice, the second slice and the bottom plate are made of tungsten steel plates.

[0013] Further, the first slice and the second slice are arranged in an arc with the focus of the X-rays as the center.

[0014] On the other hand, the present invention provides a manufacturing method of a front collimator of a CT machine as described above, including: Making two tangents from the focus of the X-rays to the central scanning area, and the distance between the two intersection points of the two tangents and the plane where the bottom plate of the front collimator is located is the opening size of the bottom plate opening along the radial direction of the slice guide rail; Connecting the two arc-shaped edges of the detector with the focus of the X-rays, and taking the distance between the two intersection points of the two connecting lines on both sides and the plane where the lowest points of the first slice and the second slice are located as the maximum opening size of the slice opening along the axial direction of the slice guide rail. Among them, the opening size of the bottom plate opening of the front collimator along the axial direction of the slice guide rail is not less than the maximum opening size of the slice opening along the axial direction of the slice guide rail.

[0015] A front collimator of a CT machine and a manufacturing method thereof provided by the present invention adopt an open box body frame and a shared cross beam design, which facilitate the disassembly, assembly and maintenance of the internal components of the collimator, simplify the fixing method, combine the tungsten steel plate covering and the bottom plate hemming process, effectively shield the scattered X-ray radiation, reduce the radiation dose, effectively reduce the size of the collimator in the X direction and the Y direction, reduce the overall weight, provide key technical support for the compact layout requirements of multiple groups of X-ray optical paths of a multi-source CT machine, and can meet the requirements of a CT machine for a larger scanning aperture, a lighter rotating body weight and a higher rotating speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present application will become more obvious: Figure 1 is a schematic structural diagram of a front collimator of a CT machine provided by an embodiment of the present invention; Figure 2 is a schematic structural diagram of a slicing device of a front collimator of a CT machine provided by an embodiment of the present invention; Figure 3 is the bottomless upward view of a front collimator of a CT scanner provided by an embodiment of the present invention; Figure 4 is the right view of a front collimator of a CT scanner provided by an embodiment of the present invention; Figure 5 is the first perspective view of the bottom plate of a front collimator of a CT scanner provided by an embodiment of the present invention; Figure 6 is the second perspective view of the bottom plate of a front collimator of a CT scanner provided by an embodiment of the present invention; Figure 7 is the structural schematic diagram of a three-source CT scanner provided by an embodiment of the present invention.

[0017] 1 - front collimator; 2 - X-ray source; 3 - detector; 11 - filtering device; 12 - slicing device; 13 - box body; 111 - filtering component; 1111 - filter; 1112 - filter fixing seat; 1113 - filtering motor; 1114 - filtering slider; 112 - filtering guide rail; 121 - first slicing component; 1211 - first slice; 1212 - first slice fixing seat; 1213 - first slicing motor; 1214 - first slicing guide rail; 122 - second slicing component; 1221 - second slice; 1222 - second slice fixing seat; 1223 - second slicing motor; 1224 - second slicing slider; 123 - slicing guide rail; 124 - slicing opening; 131 - side plate; 132 - bottom plate; 133 - cross beam; 134 - bottom plate opening; 135 - hem. Detailed implementation manners

[0018] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention are also intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present invention to describe the acquisition modules, these acquisition modules should not be limited to these terms. These terms are only used to distinguish the acquisition modules from each other.

[0021] Depending on the context, as used herein, the word "if" can be interpreted as "when" or "while" or "in response to determining" or "in response to detecting". Similarly, depending on the context, the phrase "if determined" or "if detecting (stated condition or event)" can be interpreted as "when determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)".

[0022] It should be noted that the orientation terms such as "upper", "lower", "left", and "right" described in the embodiments of the present invention are described from the angles shown in the drawings and should not be construed as limitations on the embodiments of the present invention. In addition, in the context, it should also be understood that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also be indirectly formed "on" or "under" another element through an intermediate element.

[0023] Reference Figures 1-6 , an embodiment of the present invention provides a front collimator 1 for a CT machine, including: A filtering device 11, a slicing device 12, and a box body 13; The filtering device 11 includes a filtering component 111 and two filtering guide rails 112. Both ends of the filtering component 111 are slidably connected to the two parallel filtering guide rails 112; Specifically, referring to Figure 1 , the filtering component 111 includes a plurality of filters 1111, a filter fixing seat 1112, a filtering motor 1113, and two filtering sliders 1114. The plurality of filters 1111 are fixedly arranged in parallel on the filter fixing seat 1112. Filtering sliders 1114 are respectively fixed at both ends of the filter fixing seat 11112. The filtering sliders 1114 are slidably connected to the filtering guide rails 112. The filtering motor 1113 is connected to the filter fixing seat 1112 and drives the filter fixing seat 1112 to slide along the filtering guide rails 112 through the two filtering sliders 1114, so as to switch different filters 1111. Optionally, the plurality of filters 1111 include filters of different materials and different thicknesses, such as flat filters and arc filters, which are used to selectively filter x-rays by switching different filters according to different scanning requirements, remove low-energy x-rays, optimize the imaging quality, and reduce the radiation dose.

[0024] Referring to Figure 2 , the slicing device 12 includes a first slicing component 121, a second slicing component 122, and two parallel slicing guide rails 123. Both ends of the first slicing component 121 and the second slicing component 122 are slidably connected to the two slicing guide rails 123. A slicing opening 124 with an adjustable size is formed between the first slicing component 121 and the second slicing component 122; Specifically, the first slicing component 121 includes a first slicing blade 1211, a first slicing blade fixing base 1212, a first slicing blade motor 1213, and two first slicing blade sliders 1214. The first slicing blade 1211 is fixed on the first slicing blade fixing base 1212. One first slicing blade slider 1214 is connected to each end of the first slicing blade fixing base 1212. The first slicing blade sliders 1214 are slidably connected to the slicing guide rail 123. The first slicing blade motor 1213 is connected to the first slicing blade fixing base 1212 and drives the first slicing blade fixing base 1212 to slide along the slicing guide rail 123 through the first slicing blade sliders 1214, thereby driving the first slicing blade 1211 to axially move along the slicing guide rail 123; The second slicing component 122 includes a second slicing blade 1221, a second slicing blade fixing base 1222, a second slicing blade motor 1223, and two second slicing blade sliders 1224. The second slicing blade 1221 is fixed on the second slicing blade fixing base 1222. One second slicing blade slider 1224 is connected to each end of the second slicing blade fixing base 1222. The second slicing blade sliders 1224 are slidably connected to the slicing guide rail 123. The second slicing blade motor 1223 is connected to the second slicing blade fixing base 1222 and drives the second slicing blade fixing base 1222 to slide along the slicing guide rail 123 through the second slicing blade sliders 1224, thereby driving the second slicing blade 1221 to axially move along the slicing guide rail 123; Moreover, the first slicing blade 1211 and the second slicing blade 1221 are arranged as arcs centered on the focus of the X-ray, and they move axially relative to or in opposite directions along the slicing guide rail 123 to form a slicing opening 124. The first slicing blade 1211 and the second slicing blade 1221 are made of shielding materials to shield the X-rays outside the slicing opening 124. Preferably, the first slicing blade 1211 and the second slicing blade 1221 are made of tungsten steel plates. By adjusting the opening width of the slicing opening 124 in the long axis direction of the human body, i.e., the Z direction, the thickness of the X-ray layer passing through the slicing opening 124 can be adjusted, thereby limiting the scanning imaging range of the X-ray in the Z direction and reducing the radiation dose. The smaller the thickness of the X-ray layer, the higher the resolution of the CT image.

[0025] See Figure 1 、 3 As shown in, the box body 13 includes two side plates 131 and a detachable bottom plate 132. The two side plates 131 are arranged oppositely and connected by two cross beams 133. Two filter guide rails 112 are respectively fixed on the upper planes of the two cross beams 133, and two slicing guide rails 123 are respectively fixed on the lower planes of the two cross beams 133. The open structure on both sides of the box body in the X direction reduces the size of the collimator in the X direction and facilitates the disassembly, installation, and maintenance of the internal components of the collimator. The filtering layer and the slicing layer, the two functional areas on the upper and lower layers, are fixed and connected through the shared cross beam, which simplifies the fixing method, saves the size of the collimator in the Y direction, and optimizes the space utilization rate of the collimator; See Figure 3 、4 The filtering motor 1113, the first slicing motor 1213, and the second slicing motor 1223 are fixed on the outer walls of the two side plates; See Figure 5 , 6 , the bottom plate 132 is provided with a rectangular bottom plate opening 134, directly below the slicing opening 124. The X-ray starts from the X-ray source focus and sequentially passes through the filter 1111, the slicing opening 124, and the bottom plate opening 134 to reach the detector; preferably, the two side edges of the bottom plate 132 on the same side as the cross beam 133 are provided with flanges 135. Exemplarily, a front collimator of a CT machine provided in this embodiment can be applied to a triple-source CT machine. Refer to Figure 7 a triple-source CT machine shown in the figure, which includes three groups of X-ray optical paths. An X-ray source 2, a front collimator 1, and a detector 3 are arranged on each group of X-ray optical paths. Each group of X-ray optical paths needs to cover a common central scanning area (FOV). The two side edges of the collimator bottom plate in one group of X-ray optical paths can be set as flanges parallel to the edge path directions of the other two groups of X-ray optical paths. According to the X-ray optical path and space requirements, the flange angles and lengths can also be changed to make full use of the triangular area, which can increase the internal space of the collimator or make room for other components of the CT machine.

[0026] Optionally, a detachable cover plate is covered on the open surface where the cross beam 133 of the box body 13 is located, and a detachable cover plate including an optical path entrance is covered on the upper open surface of the box body 13, which can play a role in shielding X-ray scattered rays. Preferably, the cover plate (not shown in the figure) and the bottom plate 132 of this embodiment are made of tungsten steel plates. The tungsten steel plates have higher hardness and better ray shielding effect, can reduce the required lead shielding layer inside the traditional collimator box body, further reduce the box body size. The bottom plate 132 made of tungsten steel shields the X-ray outside the bottom plate opening 134 to limit the X-ray width, that is, the range of the X-ray in the X direction, and reduces the radiation dose.

[0027] A front collimator of a CT machine provided by an embodiment of the present invention adopts an open box body frame and a shared cross beam design, which is convenient for disassembly, installation, and maintenance of internal components of the collimator, simplifies the fixing method, combines the tungsten steel plate covering and the bottom plate flanging process, effectively shields X-ray scattered radiation, reduces the radiation dose, effectively reduces the size of the collimator in the X direction and the Y direction, reduces the overall weight, provides key technical support for the compact layout requirements of multiple groups of X-ray optical paths of a multi-source CT machine, and can meet the requirements of a CT machine for a larger scanning aperture, a lighter rotating body weight, and a higher rotating speed. In addition, the front collimator of the CT machine provided in this embodiment can also be applied to a single-source CT machine.

[0028] Another embodiment of the present invention provides a manufacturing method of a front collimator of a CT machine as described above, including: Two tangents are drawn from the focus of the X-ray to the central scanning area, and the distance between the two intersection points of the two tangents and the plane where the bottom plate 132 of the front collimator is located is the opening size of the bottom plate opening 134 along the radial direction of the slice guide 123; The two arcs of the detector 3 are connected to the focus of the X-ray, and the distance between the two intersection points of the two connecting lines on both sides and the plane where the lowest points of the first slice 1211 and the second slice 1221 are located is taken as the maximum opening size of the slice opening 124 along the axial direction of the slice guide 123. Among them, the opening size of the bottom plate opening 134 of the front collimator along the axial direction of the slice guide 123 is not less than the maximum opening size of the slice opening 124 along the axial direction of the slice guide 123.

[0029] When applied to a triple-source CT machine as Figure 7 shown, the marginal rays of the other two groups of X-ray optical paths on both sides of the front collimator 1 distributed in a group of X-ray optical paths are the limiting position sizes that the front collimator 1 can occupy in the X direction. The radial distance between the positions of the three optical paths and the X-ray source without affecting them is the limiting position size of the front collimator 1 in the Y direction; In a triple-source CT machine, the three groups of X-ray optical paths have a common FOV and the same SDD size. Each group of X-ray sources can work independently or the three groups can work simultaneously. Each group of optical paths is equivalent to a single-source CT machine. According to different design requirements, the FOV and SDD of the three groups of X-ray optical paths can be designed with different sizes, and the size of the front collimator 1 changes accordingly.

[0030] The above description is only a preferred embodiment of the present invention. Those skilled in the art should understand that the disclosed scope of the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present invention.

Claims

1. A CT front collimator, characterized in that: include: Filtering device, slicing device and box; The filtering device comprises a filtering assembly and two filtering guide rails, and two ends of the filtering assembly are slidably connected to the two filtering guide rails arranged in parallel; The slicing device comprises a first slicing assembly, a second slicing assembly and two parallel slicing guide rails, the two ends of the first slicing assembly and the second slicing assembly are respectively slidably connected to the two slicing guide rails, and a slicing opening with an adjustable opening size is formed between the first slicing assembly and the second slicing assembly; The box body includes two side panels and a detachable bottom panel, the two side panels are arranged opposite to each other and connected by two cross beams, the two filtering guide rails are respectively fixed on the upper planes of the two cross beams, the two slicing guide rails are respectively fixed on the lower planes of the two cross beams, and the bottom panel is provided with a bottom panel opening.

2. A CT front collimator according to claim 1, characterized in that: The filter assembly includes multiple filters, a filter fixing seat, a filter motor and two filter sliders. The multiple filters are fixed in parallel on the filter fixing seat. The filter sliders are respectively fixed at both ends of the filter fixing seat. The filter sliders are slidably connected to the filter guide rail. The filter motor is connected to the filter fixing seat and drives the filter fixing seat to slide along the filter guide rail through two filter sliders, thereby switching different filters.

3. The CT front collimator according to claim 1, characterized in that: The first slicing assembly includes a first slicing member, a first slicing member fixing seat, a first slicing motor and two first slicing sliders, wherein the first slicing member is fixed on the first slicing member fixing seat, and two ends of the first slicing member fixing seat are respectively connected to a first slicing slider, and the first slicing slider is slidably connected to the slicing guide rail, and the first slicing motor is connected to the first slicing member fixing seat and drives the first slicing member fixing seat to slide along the slicing guide rail through the first slicing slider, thereby driving the first slicing member to move axially along the slicing guide rail; The second slice assembly includes a second slice, a second slice fixing seat, a second slice motor and two second slice sliders, the second slice is fixed on the second slice fixing seat, two ends of the second slice fixing seat are respectively connected to a second slice slider, the second slice slider is slidably connected to the slice guide rail, the second slice motor is connected to the second slice fixing seat, and drives the second slice fixing seat to slide along the slice guide rail through the second slice slider, thereby driving the second slice to move axially along the slice guide rail; The first slice and the second slice move relative to or oppositely along the axial direction of the slice guide.

4. The CT front collimator according to claim 1, characterized in that: The two side edges of the bottom plate and the cross beam on the same side are provided with folded edges.

5. The CT front collimator according to claim 2, characterized in that: The filter includes a flat filter and a curved filter.

6. The CT front collimator according to claim 3, characterized in that: The first slice and the second slice shield the x-ray outside the slice opening to adjust the x-ray layer thickness, and the bottom plate shields the x-ray outside the bottom plate opening to limit the x-ray width.

7. The CT front collimator according to claim 6, characterized in that: The surface where the cross beam of the box body is located is covered with a detachable cover plate, and the top of the box body is covered with a detachable cover plate including an optical path entrance to shield the scattered X-rays.

8. The CT front collimator according to claim 7, characterized in that: The cover plate, the first slice, the second slice and the bottom plate are made of tungsten steel plates.

9. The CT front collimator according to claim 3, characterized in that: The first slice and the second slice are arranged in an arc shape with the focus of the x-ray as the center.

10. A method for manufacturing a front collimator for a CT machine according to any one of claims 1 to 9, characterized in that: include: Draw two tangent lines from the focus of the x-ray to the central scanning area. The distance between the two intersections of the two tangent lines and the plane where the bottom plate of the front collimator is located is the opening size of the bottom plate opening along the radial direction of the slicing guide rail. Connect the two arc edges of the detector with the focus of the x-ray, and take the distances between the two intersections of the two connecting lines and the planes where the lowest points of the first slice and the second slice are located as the maximum opening size of the slice opening along the axial direction of the slice guide, wherein the opening size of the bottom plate opening of the front collimator along the axial direction of the slice guide is not less than the maximum opening size of the slice opening along the axial direction of the slice guide.

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