Developing support

Abstract

The application relates to a developing support which comprises a support body, the support body comprising a middle annular support structure and end annular support structures connected at both ends of the middle annular support structure, the middle annular support structure being composed of a group of first supporting rods connected in sequence at the head and tail, the end annular support structure being composed of a group of second supporting rods connected in sequence at the head and tail, the axial length of the middle annular support structure being greater than the axial length of the end annular support structure, the circumferences of the two being equal, the two middle annular support structures being connected along the axial direction, forming developing sections, and having a plurality of connecting points connecting the two and a plurality of middle developing installation parts between the two, the connecting points and the middle developing installation parts between the two middle annular support structures being arranged adjacently in the circumferential direction of the support body, the developing sections being multiple, the middle developing installation parts of adjacent developing sections being arranged in the axial direction of the support body in a staggered manner, the middle developing installation parts being provided with first developing main bodies, and the end annular support structures being connected to both ends of the multiple developing sections.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to a radiopaque stent. Background Technology

[0002] Treatment of cerebral vascular hemorrhage typically involves using a dense mesh stent to reconstruct blood flow or using an auxiliary stent-coil embolization procedure. The usual surgical strategy is to first establish a pathway, then deliver the stent or coil to the lesion site, deploy the stent or coil, and seal the lesion aneurysm to complete the surgery.

[0003] Among them, stent-assisted coil embolization is a common treatment method. The stent is mainly used to treat intracranial vascular stenosis. This treatment method has high requirements for the stent. The stent must have sufficient compliance and good wall adhesion performance, and it also needs to be visible under X-ray so that the operator can judge the stent's opening status.

[0004] However, in the current technology, after the stent is deployed, the imaging structure on the stent is not conducive to medical personnel to determine whether the blood vessel will restenosis immediately after the operation or in the short term after the operation. Therefore, it is necessary to use angiography to further observe and confirm whether the blood vessel has restenosis and take further measures.

[0005] In summary, the existing technology for determining whether there is restenosis in the blood vessel after stent deployment is rather cumbersome, affecting the efficiency of the treatment process. Summary of the Invention

[0006] In view of this, this application proposes a developing support, including a support body; the support body includes a central annular support structure and end annular support structures connected to its two ends; the central annular support structure is an annular structure formed by a set of first support rods connected end to end in sequence; the axial length of the central annular support structure is greater than the axial length of the end annular support structures, and their circumferences are equal; every two central annular support structures are connected along their axial direction to form a developing segment, and there are multiple connection points and multiple central developing mounting parts between two central annular support structures, the connection points and the central developing mounting parts between two central annular support structures are arranged adjacent to each other in the circumferential direction of the support body; the number of developing segments is multiple, and the central developing mounting parts on adjacent developing segments are arranged axially offset in the support body; a first developing body is provided on the central developing mounting part; the end annular support structure is an annular structure formed by a set of second support rods connected end to end in sequence; the end annular support structure is connected to both ends of the multiple developing segments.

[0007] In one possible implementation, the central developing mounting portion is evenly arranged axially in the central annular support structure.

[0008] In one possible implementation, the line connecting the nearest middle developing mounting portions on adjacent developing sections in the same direction forms a spiral on the support body, with the spiral angle being 20°-45°.

[0009] In one possible implementation, the end ring support structure is connected to the intersection of the first support rods, and there are two end ring support structures at one end of the middle ring support structure. Two adjacent end ring support structures are connected to form a closed loop structure, and at least one end of the middle ring support structure has the closed loop structure.

[0010] In one possible implementation, an end-developing mounting portion is provided at one end of the end-ring support structure away from the middle ring support structure. The number of end-developing mounting portions is 2 to 4, which are evenly distributed around the circumference of the support body. A second developing body is provided on the end-developing mounting portion.

[0011] In one possible implementation, the central developing mounting portion is a straight rod-shaped structure, and the central developing mounting portion is arranged parallel to the axial direction of the support body.

[0012] In one possible implementation, one end of the central developing mounting portion is a fixed end, connected to the central annular support structure on one side of the developing section, and the other end is a free end, not in contact with the central annular support structure on the other side; wherein, on the same developing section, the central developing mounting portions arranged alternately are fixed to the central annular support structure located on the same side; or on the same developing section, the central developing mounting portions arranged alternately are fixed to the central annular support structure located on opposite sides, and the developing body is axially offset within the same developing section.

[0013] In one possible implementation, the fixed end of the central developing mounting part is fixed to one side of the central annular support structure adjacent to the other side of the central annular support structure, and the central developing mounting part is connected to the intersection of the first support rod.

[0014] In one possible implementation, the first support rod is a straight rod structure with a straight length of 1mm-3mm; the included angle between two adjacent first support rods in the same group is within [40°-100°]; the axial length of the first developing body along the support body is 0.4mm-0.8mm, and the included angle between two adjacent second support rods in the same group is within [35°, 90°].

[0015] In one possible implementation, the connection between the central annular support structure and the end annular support structure forms an open-loop structure; wherein the ratio of the number of a set of first support rods to the number of a set of second support rods is 2:3; the number of the central developing mounting parts on the developing section is 2 to 4; and the developing body is a radiopaque spring coil or metal ring.

[0016] In one possible implementation, the two ends of the support body have flared structures; wherein the end annular support structure extends outward circumferentially from one end of the middle annular support structure, and the end annular support structure and the middle annular support structure form a preset angle, the preset angle being within [30°, 60°].

[0017] The beneficial effects of this application are as follows: By installing a central imaging mounting section (excluding necessary connection points) between two central annular support structures, and setting a first imaging body on it, with the central imaging mounting sections on adjacent imaging sections offset along the axial direction of the stent body, while ensuring sufficient structural strength at the connection points, after the stent is deployed, appropriate imaging observation equipment can be used to achieve a near-complete imaging effect of the stent body within the blood vessel. The stent is clearly imaged during transport, providing good assistance to medical personnel in locating the stent and assessing its opening status. Furthermore, compared to existing stent structures with fewer imaging points, it is easier for medical personnel to visually determine whether restenosis has occurred immediately after surgery and shortly afterward. In other words, using the contrast-enhancing stent of this application, the follow-up work on vascular restenosis can be completed through non-contact observation during postoperative examinations, reducing complicated and redundant judgment steps. For example, by using CT scans of relevant areas, medical personnel can use CT images taken at different times to see if the positions of more contrasting points have changed (such as the spacing between multiple contrasting points narrowing), which is helpful in judging whether vascular restenosis has occurred in the short term. Compared with previous stents with fewer contrasting points, there is no need to use contact observation methods, avoiding contact surgery and thus avoiding the damage to the human body caused by surgery. Contact observation methods, such as angiography, require puncture of relevant parts of the human body before contrast agents can be used to judge whether vascular restenosis has occurred.

[0018] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0019] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0020] Figure 1 This is a plan view of the developing bracket according to an embodiment of this application;

[0021] Figure 2 This is a plan view of a developing bracket according to another embodiment of this application;

[0022] Figure 3 This is a side view of a developing bracket with a flared structure according to an embodiment of this application.

[0023] Figure 4 A side view of a developing bracket according to an embodiment of this application is shown;

[0024] Figure 5 This is a partially enlarged view of the developing section according to an embodiment of this application. Detailed Implementation

[0025] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0026] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0027] 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 one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0029] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0030] Figure 1 This is a plan view of the developing bracket according to an embodiment of this application; Figure 2 This is a plan view of a developing bracket according to another embodiment of this application; Figure 3 This is a side view of a developing bracket with a flared structure according to an embodiment of this application. Figure 4 A side view of a developing bracket according to an embodiment of this application is shown; Figure 5 This is a partially enlarged view of the developing section according to an embodiment of this application.

[0031] like Figures 1-5 As shown, the developing support includes: a support body 1, which includes a central annular support structure 110 and end annular support structures 120 connected to its two ends. The central annular support structure 110 is a ring structure formed by a group of first support rods 111 connected end to end. The axial length of the central annular support structure 110 is greater than the axial length of the end annular support structures 120, and their circumferences are equal. Every two central annular support structures 110 are connected along their axial direction to form a developing section 10. There are multiple connecting links between two central annular support structures 110. The connection point and multiple central developing mounting parts 112 are arranged adjacent to each other in the circumferential direction of the support body 1 between the two central annular support structures 110. There are multiple developing sections 10. The central developing mounting parts 112 on adjacent developing sections 10 are arranged axially offset in the support body 1. A first developing body 11 is provided on the central developing mounting part 112. The end annular support structure 120 is a ring structure formed by a group of second support rods 121 connected end to end. The end annular support structure 120 is connected to both ends of multiple developing sections 10.

[0032] In this embodiment, a central imaging mounting part 112, excluding necessary connection points, is installed between two central annular support structures 110, and a first imaging body 11 is set on it. The central imaging mounting parts 112 on adjacent imaging sections 10 are offset along the axial direction of the stent body 1. On the basis of ensuring that the connection points have sufficient structural strength, after the stent is released into place, a corresponding imaging observation device is used so that the stent body 1 can achieve a basic whole-body imaging observation effect in the blood vessel. When the stent is transported, the whole-body imaging is clear, which has a good auxiliary role in locating the stent position and judging the stent opening status for medical personnel.

[0033] Furthermore, compared to existing stent structures with fewer contrast points, this method allows medical personnel to more easily and intuitively determine whether restenosis has occurred immediately after surgery and in the short term post-surgery. In other words, using the contrast-enhancing stent of this application, post-operative follow-up on restenosis can be completed through non-contact observation, reducing cumbersome and redundant assessment steps. For example, by using CT scans of relevant areas, medical personnel can observe changes in the positions of contrast points on CT images taken at different times (such as narrowing of the spacing between multiple contrast points), thus facilitating the assessment of whether restenosis has occurred in the short term. Compared to previous stents with fewer contrast points, this method eliminates the need for contact-based observation, avoiding contact surgery and thus minimizing surgical damage. Contact-based observation methods, such as angiography, require puncture of relevant areas to allow contrast agents to be used to assess restenosis.

[0034] In one specific embodiment, preferably, the central developing mounting portion 112 is evenly arranged axially within the central annular support structure 110.

[0035] In one specific embodiment, the line formed by the nearest middle developing mounting part 112 on adjacent developing sections 10 along the same direction forms a spiral on the support body 1, with a spiral angle of 20°-45°.

[0036] In this embodiment, when the first developing bodies 11 are arranged relatively densely, the overall developed structure appears as a double helix or multiple helixes when observed in the developing equipment. The specific number depends on the number of first developing bodies 11 evenly distributed circumferentially on each developing segment 10. When there are two first developing bodies 11, the overall developed structure is a DNA-like double helix. Because the first developing bodies 11 on adjacent developing segments 10 are arranged relatively densely, the intervals between the undeveloped portions are small. From the developed image, the double helix structure with multiple gaps can be clearly identified. Furthermore, the developing segment 10 may have a maximum of four coaxial helical structures.

[0037] Therefore, preferably, the spiral lines formed by the closest middle developing mounting portions 112 on adjacent developing sections 10 in the same direction have a spiral angle of 20°-45°. The support body 1 composed of spiral angles within this range of 20°-45° not only ensures that the developing points are densely arranged, allowing for more intuitive and clear observation from the drawing, but also ensures that the support has a suitable length, avoiding the waste of materials and unnecessary increase in costs caused by setting more developing points on a single product.

[0038] In one specific embodiment, the end ring support structure 120 is connected to the intersection of the first support rod 111. There are two end ring support structures 120 at one end of the middle ring support structure 110. Two adjacent end ring support structures 120 are connected to form a closed loop structure 140. At least one end of the middle ring support structure 110 has a closed loop structure 140.

[0039] In one specific embodiment, an end annular support structure 120 is provided with an end developing mounting part 122 at one end away from the middle annular support structure 110. The number of end developing mounting parts 122 is 2 to 4, which are evenly distributed around the circumference of the support body 1, and a second developing body 12 is provided on the end developing mounting part 122.

[0040] like Figure 1 As shown, in one specific embodiment, the central developing mounting part 112 is a straight rod-shaped structure, and the central developing mounting part 112 is arranged parallel to the axis of the support body 1.

[0041] In this embodiment, the central imaging mounting part 112 is a solid straight rod-shaped structure, specifically a solid rod-shaped structure, and the imaging body is sleeved and fixed on the central imaging mounting part 112. The central imaging mounting part 112 is parallel to the axis of the support body 1, so that the surgeon can observe the largest imaging area from outside the body.

[0042] In one specific embodiment, the central developing mounting part 112 can be a hollow rod-shaped structure with grooves and slots inside. After the developing body is sleeved and fixed on the central developing mounting part 112, the developing body can be further pressed into the slot of the central developing mounting part 112 through processing, thereby increasing the contact area between the developing body 500 and the central developing mounting part 112 and thus improving the connection strength between the two.

[0043] like Figure 2 As shown, in one specific embodiment, the end developing mounting part 12 can be a hollow rod-shaped structure with grooves and slots inside.

[0044] In one specific embodiment, the developing body is a spring ring or metal ring made of radiopaque material. After the spring ring or metal ring is sleeved and fixed on the central developing mounting part 112, it can be fixed on the central developing mounting part 112 by laser welding or glue application.

[0045] In one specific embodiment, one end of the central developing mounting part 112 is a fixed end, connected to the central annular support structure 110 on one side of the developing section 10, and the other end is a free end, not in contact with the central annular support structure 110 on the other side. In the same developing section 10, the central developing mounting parts 112 arranged alternately are fixed to the central annular support structure 110 located on the same side, or in the same developing section 10, the central developing mounting parts 112 arranged alternately are fixed to the central annular support structure 110 located on opposite sides, and the developing body is axially offset in the same developing section 10.

[0046] In this embodiment, one end of the central developing mounting part 112 is a fixed end connected to the central annular support structure 110 on one side, and the other end is a free end. The central developing mounting part 112 does not contact the central annular support structure 110 on this side, so that those skilled in the art can fit and fix the developing body on the central developing mounting part 112 during processing.

[0047] The interleaved central imaging mounting section 112 referred to in this article means that two central imaging mounting sections 112 are arranged with a connection point between them. These two central imaging mounting sections 112 can be fixed to the central annular support structure 110 located on the same side, or they can be located on the central annular support structure 110 on opposite sides. Compared with the central imaging mounting sections 112 fixed to the same side, the imaging area that can be observed is increased, so that the surgeon can more clearly observe the internal condition of the lesion.

[0048] In one specific embodiment, the lengths of the two first support rods 111 on the developing section 10 that provide the central developing mounting part 112 are less than the lengths of the two first support rods 111 that intersect to form a connection point, providing a larger space for the rod-shaped central developing mounting part 112 and providing more sufficient installation space for those skilled in the art to install the developing body.

[0049] In this embodiment, the length of the first support rod 111 varies at different positions, specifically including a long rod 1111, a middle rod 1112, and a short rod 1113. The long rod 1111 is the longest first support rod 111 at the connection point of two adjacent middle annular support structures 110 on the same developing section 10, with a straight length between 1mm and 3mm. The short rod 1113 is the first support rod 111 at the end connection point where a middle developing mounting part 112 is provided, with a straight length between 1mm and 1.5mm. The middle rod 1112 is the first support rod 111 on the opposite side of the middle developing mounting part 112, with a straight length between 1mm and 2mm. The length of the long rod 1111 is always greater than that of the middle rod 1112, and the length of the middle rod 1112 is always greater than that of the short rod 1113.

[0050] Furthermore, the straight length of the central developing mounting section 112 is preferably 0.4 mm.

[0051] In one specific embodiment, the fixed end of the central developing mounting part 112 is fixed to one side of the central annular support structure 110 adjacent to the other side of the central annular support structure 110, and the central developing mounting part 112 is connected to the intersection of the first support rod 111.

[0052] In this embodiment, the connection point referred to in this application is the intersection point where the first support rod 111 is connected end to end, the intersection point where the first support rod 111 and the second support rod 121 are connected, and the intersection point where the second support rod 121 is connected end to end.

[0053] In one specific embodiment, the first support rod 111 is a straight rod structure with a straight length of 1mm-3mm. The included angle between two adjacent first support rods 111 in the same group is within [40°-100°]. The axial length of the first developing body 11 along the support body 1 is 0.4mm-0.8mm. The included angle between two adjacent second support rods 121 in the same group is within [35°, 90°].

[0054] In this embodiment, the included angles between two adjacent first struts 111 and two adjacent second struts 121 within the same group are mainly to accommodate blood vessels of different diameters. While ensuring equal circumferential lengths, the smaller the included angle between two adjacent, end-to-end first struts 111, the smaller the stent diameter; conversely, the larger the included angle between adjacent struts, the larger the stent diameter. Similarly, the stent diameter for adjacent, end-to-end second struts 121 can be achieved by cutting the same tubing and then expanding and heat-setting it. These methods can directly utilize existing technologies and will not be elaborated upon further in this paper.

[0055] In one specific embodiment, the connection position of the central annular support structure 110 and the end annular support structure 120 forms an open-loop structure 130, wherein the ratio of the number of a set of first support rods 111 to the number of a set of second support rods 121 is 2:3, the number of central developing mounting parts 112 on the developing section 10 is 2 to 4, and the developing body is a non-transparent spring ring or metal ring.

[0056] In this embodiment, the ratio of the number of a set of first support rods 111 to the number of a set of second support rods 121 is 2:3, that is, for every four first support rods 111 connected end to end, there are six second support rods 121 connected end to end.

[0057] Preferably, the four developing bodies are evenly distributed around the circumference of the developing section 102, that is, the angle between the line connecting two adjacent developing bodies to the axis of the support body 1 is 90°.

[0058] Preferably, the number of first struts 111 is 16 and the number of second struts 121 is 24. The stent body 1 composed of this number has a reasonable structural strength while ensuring that the number of struts on the stent body 1 is appropriate and can adapt to most blood vessel diameters.

[0059] More specifically, there are 16 first support rods 111 and 24 second support rods 121. There are only four connection points between the first and second annular support structures 20 connected by this number. Compared with the conventional method of setting the first support rods 111 and the second support rods 121 of equal length and with all connection points corresponding one-to-one, this method ensures that the centrally open-ring contrast-enhanced vascular stent of this application has good radial support performance while significantly improving its compliance and wall adhesion.

[0060] It should also be emphasized that the open-loop structure 130 referred to in this application is a structure in which the middle annular support structure 110 and the end annular support structures 120 are axially connected, and only the intersection points formed by their partial end-to-end connections are interconnected, while the remaining connection points are not connected to the overall structure of the adjacent annular support structures. The closed-loop structure 140 referred to in this application is an overall structure in which the intersection points between two adjacent end annular support structures 120 are completely corresponding and interconnected after axial connection.

[0061] In one specific embodiment, the two ends of the support body 1 have flared structures 150, wherein the end annular support structure 120 extends outward circumferentially from one end of the middle annular support structure 110, and the end annular support structure 120 and the middle annular support structure 110 form a preset angle α, the preset angle α being within [30°, 60°].

[0062] In this embodiment, the flaring structure 150 is provided such that when the contrast-enhancing stent is in a compressed state before it is released, the flaring structure 150 tends to extend parallel into the guide sheath. Therefore, after the stent body 1 is released, the flaring structure 150 is more conducive to the end ring support structure 120 located at both ends of the stent body 1 being more stably and firmly anchored to the inner wall of the blood vessel.

[0063] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A developing cradle characterized by comprising: Including the main body of the support frame; The main body of the support includes a central annular support structure and end annular support structures connected to its two ends; The central annular support structure is a ring structure formed by connecting a set of first support rods end to end in sequence; The end ring support structure is a ring structure formed by a set of second support rods connected end to end in sequence; The axial length of the central annular support structure is greater than the axial length of the end annular support structure, and their circumferences are equal. Two of the central annular support structures are connected along their axial direction to form a developing section. There are multiple connection points and multiple central developing mounting parts between the two central annular support structures. The central developing mounting part is a hollow rod-shaped structure with grooves and slots inside. The connection points between the two central annular support structures and the central developing mounting parts are arranged adjacent to each other in the circumferential direction of the support body. The number of developing sections is multiple, and the middle developing installation parts on adjacent developing sections are axially offset on the support body. The length of the two first support rods on the developing section with the middle developing installation parts is less than the length of the two first support rods that intersect to form a connection point, thus providing a larger space for the rod-shaped middle developing installation parts. The middle developing mounting part is provided with a first developing body. The line formed by connecting the adjacent middle developing mounting parts on the adjacent developing sections in the same direction forms a spiral line on the support body. The spiral line has a helix angle of 20°-45°. The end ring support structure is connected to both ends of the plurality of developing sections.

2. The developing cradle according to claim 1, wherein The central developing mounting section is evenly arranged axially within the central annular support structure.

3. The developing bracket according to claim 1, characterized in that, The end ring support structure is connected to the intersection of the first support rod. There are two end ring support structures at one end of the middle ring support structure. Two adjacent end ring support structures are connected to form a closed loop structure. At least one end of the middle ring support structure has the closed loop structure.

4. The developing bracket according to claim 1, characterized in that, An end annular support structure is provided with an end developing mounting part at one end away from the middle annular support structure. The number of end developing mounting parts is 2 to 4, which are evenly distributed around the circumference of the support body. A second developing body is provided on the end developing mounting part.

5. The developing bracket according to any one of claims 1-4, characterized in that, The central developing mounting section is a straight rod-shaped structure, and the central developing mounting section is arranged parallel to the axis of the support body.

6. The developing bracket according to any one of claims 1-4, characterized in that, One end of the central developing mounting part is a fixed end, which is connected to the central annular support structure on one side of the developing section, and the other end is a free end, which does not contact the central annular support structure on the other side. In this development section, the alternating central developing mounting portions are fixed to the central annular support structure located on the same side; or in the same developing section, the alternating central developing mounting portions are fixed to the central annular support structure located on opposite sides, and the first developing body is axially offset in the same developing section.

7. The developing bracket according to claim 6, characterized in that, The fixed end of the central developing mounting part is fixed to one side of the central annular support structure adjacent to the other side of the central annular support structure, and the central developing mounting part is connected to the intersection of the first support rod.

8. The developing bracket according to any one of claims 1-4, characterized in that, The first support rod is a straight rod structure, and the straight length of the first support rod is 1mm-3mm; The included angle between two adjacent first supports in the same group is within [40°-100°]; The axial length of the first developing body along the support body is 0.4mm-0.8mm. The included angle between two adjacent second supports in the same group is within [35°, 90°]; The two ends of the main body of the bracket have flared structures; Wherein, the end annular support structure extends outward circumferentially from one end of the middle annular support structure, and the end annular support structure and the middle annular support structure form a preset angle, the preset angle being within [30°, 60°].

9. The developing bracket according to any one of claims 1-4, characterized in that, The connection between the central annular support structure and the end annular support structure forms an open-loop structure. The ratio of the number of the first set of support rods to the number of the second set of support rods is 2:3; The number of the middle developing mounting parts on the developing section is 2 to 4; The first developing body and the second developing body are radiopaque spring coils or metal rings.

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