A collimator, CT equipment, calibration method and preparation method
By designing a single motor-driven collimator in a CT device, using the encoder to monitor the rotation angle, low-cost stepless adjustment and precise calibration are achieved, solving the problems of high cost and complex structure of existing collimators, improving the Control accuracy.
Patent Information
- Application Number
- CN202111578880.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-22
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2041-12-22
AI Technical Summary
The stepless adjustment scheme of collimator in existing CT equipment is costly and complex in structure, making it difficult to achieve low-cost accurate calibration.
A collimator including motor, coupling and encoder was designed to achieve stepless adjustment through a single motor drive shaft, and the encoder was used to monitor the rotation angle, ensuring precise control of the opening dimensions, reducing costs and increasing the Control accuracy.
A low-cost stepless adjustment collimator is realized, which reduces costs, improves control accuracy, and is suitable for the seam size requirements of different CT equipment.
Smart Images
Figure CN114305478B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of medical equipment, and in particular to a collimator, a CT device, a calibration method and a preparation method. Background Art
[0002] Computerized tomography scanners, commonly known as CT, are currently widely used in clinical practice. They use a combination of highly sensitive medical detectors such as X-rays, Y-rays, and ultrasound to perform tomographic scans around a certain part of the human body to form multiple clear tomographic images, which are provided to doctors for diagnosis. Currently, the main clinical application is the computerized X-ray tomography scanner, which is based on the tomographic scanning of the past X-ray scanners, plus computer post-processing, to form what people now commonly call CT.
[0003] When using CT to scan the human body, the X-rays of the collimator need to be calibrated so that the X-rays form scanning layer thicknesses of different widths on the detector. This is to achieve accurate pre-calibration processing of the X-rays and improve dose utilization.
[0004] For example, the application number is: 201910956836.1, which discloses a collimator with a slit segmented stepless adjustment, including a base, two supports are slidably connected on the base, a plurality of gates are arranged on the supports, and a slit is formed between the gates on the two supports; the gate is connected to a connecting plate, a follower is connected to the connecting plate, a fixed plate is connected to both sides of the base, a spring is connected between the connecting plate and the fixed plate, an eccentric shaft is provided on the side of the support far from the slit, an eccentric wheel is arranged on the eccentric shaft, and a driving part is arranged on the base; the advantage is that: two motors drive the two eccentric shafts to rotate, so as to drive multiple collimators to realize stepless adjustment of the slit size, a follower is arranged on the gate that is close to the eccentric wheel, and when the scanning layer thickness is different, the slit curve of the gate on one side can be steplessly adjusted in sections with respect to each other, so as to realize the adjustable curvature of the slit curve. However, this scheme obviously requires two motors to drive separately, so the cost is high and the structure is complicated.
[0005] In summary, the technical problem actually solved by the present invention is how to provide a low-cost stepless adjustable collimator. Summary of the invention
[0006] In order to overcome the above technical defects, the purpose of the present invention is to provide a collimator, a CT device, a calibration method and a preparation method. A low-cost collimator is provided.
[0007] The present invention discloses a collimator, comprising: a motor, a coupling, and an encoder; wherein the collimator is surrounded by a first blocking surface, a second blocking surface, a third blocking surface, and a fourth blocking surface to form an adjustment gap; the third blocking surface and the fourth blocking surface of the collimator are respectively provided with a first connecting shaft and a second connecting shaft on the opposite sides; one end of the collimator is connected to one end of the coupling through the second connecting shaft, and the other end of the coupling is connected to the motor, and the coupling transmits the kinetic energy of the motor to the collimator; the other end of the collimator is connected to the encoder through the first connecting shaft, so that the encoder rotates coaxially with the collimator, and the encoder monitors the actual angle of the collimator after rotating from the initial angle; when the motor rotates, the coupling, the collimator, and the encoder are driven in sequence to rotate around the axis center line to adjust the opening size of the adjustment gap.
[0008] Preferably, the collimator comprises: a first baffle, a second baffle, a first baffle sheet, and a second baffle sheet; wherein, two ends of the first baffle sheet are respectively connected to the first baffle sheet and the second baffle sheet, and the axis of the first baffle sheet and the axis of the second baffle sheet are on the same axis line, and the first baffle sheet is not on the axis line; two ends of the second baffle sheet are respectively connected to the first baffle sheet and the second baffle sheet; the opposite surfaces of the first baffle plate and the second baffle plate are respectively the first baffle surface and the second baffle surface, and the opposite surfaces of the first baffle sheet and the second baffle sheet are respectively the third baffle surface and the fourth baffle surface; the first baffle surface, the second baffle surface, the third baffle surface, and the fourth baffle surface are respectively surrounded to form an adjustment gap.
[0009] Preferably, the cross section of a plane perpendicular to the axis is circular, and the center of the cross section is on the axis.
[0010] Preferably, the first stop surface and the second stop surface protrude toward the axis line respectively, and the first stop surface and the second stop surface are continuous curved surfaces, and the curvatures of the first stop surface and the second stop surface gradually increase from both ends of the first stop surface and both ends of the second stop surface toward the middle of the collimator respectively, so that the width of the gap at both ends of the adjustment gap is greater than the width of the gap in the middle of the adjustment gap; when the collimator rotates, the width of the opening size of the adjustment gap is adjusted.
[0011] Preferably, the center of the cross section is used as a rectangular coordinate system, and when any parallel line of the axis line intersects the longitudinal coordinate axis of the rectangular coordinate system, the collimator is in an initial position; when the collimator is in the initial position, the center of the first block surface and the second block surface deviate from the transverse coordinate axis of the rectangular coordinate system, and the center of the first block surface and the center of the second block surface are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system.
[0012] Preferably, the intersection of the first baffle surface and the first baffle plate includes a first intersection and a second intersection, the intersection of the second baffle surface and the second baffle plate includes a third intersection and a fourth intersection, the first intersection, the second intersection, the third intersection, and the fourth intersection all deviate from the transverse coordinate axis of the rectangular coordinate system; and the first intersection and the second intersection, the third intersection, and the fourth intersection are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system; the first intersection and the second intersection, the third intersection, and the fourth intersection respectively deviate from the same parallel line of the longitudinal coordinate axis of the rectangular coordinate system.
[0013] In view of this, the second object of the present invention is to provide a CT device, a collimator is arranged on the CT device, and also includes a focus and a detector; wherein the focus and the detector are respectively arranged on the same vertical line on both sides of the axis of the collimator when it is in the initial position, and the focus is on the middle vertical line of the collimator; X-rays are generated at the focus on one side of the collimator, and when the distance between the focus and the collimator is the shortest, when the X-ray contacts the collimator, the width of the X-ray is greater than or equal to the maximum diameter of the collimator; the X-ray takes the focus as the initial position, radiates the X-ray toward the collimator, and when irradiating the collimator, it is diffracted on the detector after being blocked by the first blocking surface and the second blocking surface of the collimator; the blocking points of the X-ray and the first blocking surface and the second blocking surface of the adjustment slit are the first tangent point and the second tangent point, and the vertical distance between the first tangent point and the second tangent point is the slit size; when a certain slit size is required, after the collimator is rotated, the X-ray passes through the two tangent points of the first blocking surface and the second blocking surface and is diffracted on the detector to obtain the slit size.
[0014] In view of this, a third object of the present invention is to provide a calibration method for a CT device, comprising the steps of:
[0015] A rotation angle after rotation from an initial angle is set for each slit size in a computer, and a deviation threshold is set in the computer; when a certain slit size is required, the encoder monitors the actual angle of the collimator after rotation from the initial angle, and sends the actual angle to the computer, and compares the difference with the rotation angle after rotation from the initial angle set for the slit size, when the difference is greater than the deviation threshold, the computer calculates a compensation value based on the difference, and the computer controls the motor to drive the collimator to rotate based on the compensation value; after the motor drives the collimator to rotate, the above steps are repeated until the difference is less than or equal to the deviation threshold.
[0016] In view of this, the fourth object of the present invention is to provide a method for preparing a collimator, comprising the steps of: presetting a plurality of deviation angles of the collimator from an initial angle to a rotation angle, and setting a corresponding slit size for each deviation angle;
[0017] A vertical section about the axis is made at any position of the collimator, the midpoint of the line connecting the two end points of the slit size is on any parallel line of the axis, and when a vertical extension line is made through the two end points of the slit size, the vertical extension line is parallel to the vertical line of the axis;
[0018] The collimator is rotated according to each deviation angle, and the X-rays generated by the focus intersect with the vertical extension lines of the two end points of each slit size;
[0019] Connect several intersection points on the same side of the perpendicular lines of the axis line in sequence to form a curve;
[0020] The highest points of the curves of several cross sections of the first baffle plate and / or the second baffle plate of the collimator are sequentially connected to form an upper surface, and the lowest points of the curves of several cross sections of the first baffle plate and / or the second baffle plate of the collimator are sequentially connected to form a lower surface, and a first baffle surface and a second baffle surface are formed on the first baffle plate and the second baffle plate respectively;
[0021] The first baffle plate and the second baffle plate are fixedly connected by the first baffle plate and the second baffle plate to form the collimator.
[0022] Preferably, each of the deviation angles is inversely proportional to the corresponding slot size.
[0023] After adopting the above technical scheme, compared with the prior art, the beneficial effect of the present invention is that a low-cost collimator is provided, and by adopting one shaft and designing a special curved surface, stepless adjustment is achieved, and the shaft is directly driven by a motor, which reduces the cost. The encoder and the collimator are directly connected, and the rotation is driven in sequence to avoid the deviation of the rotation angle caused by the flexible structure of the coupling, and the control accuracy is improved. Moreover, the corresponding collimator can be prepared separately according to the slit size required for each CT. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 A schematic diagram of the shape of a collimator, a CT device, a calibration method, and a preparation method of the collimator of the present invention;
[0025] Figure 2 A schematic diagram of the cross-sectional shape of a collimator, a CT device, a calibration method, and a preparation method of the present invention;
[0026] Figure 3 A schematic diagram of the collimator structure of a collimator, a CT device, a calibration method and a preparation method of the present invention;
[0027] Figure 4 The present invention is a schematic diagram of a collimator, a CT device, a calibration method and a preparation method of the focal point diffraction on a detector.
[0028] Figure 5A schematic diagram of a collimator, a CT device, a calibration method, and a preparation method of the present invention when the collimator is rotating;
[0029] Figure 6 The present invention provides a curve fitting schematic diagram of a collimator, a CT device, a calibration method and a preparation method.
[0030] Reference numerals:
[0031] 101 is the first baffle, 102 is the second baffle, 103 is the third baffle, 104 is the fourth baffle, 105 is the first connecting axis, 106 is the second connecting axis, 2 is the collimator, 201 is the motor, 202 is the coupling, 203 is the encoder, 204 is the first support, 205 is the second support, 3 is the focus, 4 is the detector, 5 is the slit size, 6 is the first tangent point, and 7 is the second tangent point. DETAILED DESCRIPTION
[0032] The advantages of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments.
[0033] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.
[0034] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.
[0035] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".
[0036] In the description of the present invention, it is necessary to understand that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0037] In the description of the present invention, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.
[0038] In the following description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present invention, and have no specific meanings. Therefore, "module" and "component" can be used interchangeably.
[0039] See also Figure 1 As shown, the collimator 2 provided in this embodiment includes: a first baffle 101, a second baffle 102, a first baffle 103, and a second baffle 104; wherein the two ends of the first baffle 101 are respectively fixedly connected to the first baffle 103 and the second baffle 104, and the axes of the first baffle 103 and the second baffle 104 are on the same axis, and the first baffle 101 is not on the axis of the first baffle 103 and the second baffle 104, that is, the axis of the first baffle 101 deviates from the axis, but the first baffle 103 and the second baffle 104 are symmetrical about the first baffle 101, and refer to Figure 1 As shown, the first baffle 103 and the second baffle 104 are of the same shape. The two ends of the second baffle 102 are connected to the first baffle 103 and the second baffle 104 respectively, the opposite surfaces of the first baffle 101 and the second baffle 102 are the first baffle surface and the second baffle surface respectively, and the opposite surfaces of the first baffle 103 and the second baffle 104 are the third baffle surface and the fourth baffle surface respectively; the first baffle surface, the second baffle surface, the third baffle surface, and the fourth baffle surface are respectively surrounded to form an adjustment gap. When adjustment is required, the size of the opening size 5 is adjusted through the adjustment gap.
[0040] It should be noted that the above-mentioned first baffle 101, second baffle 102, first baffle 103, and second baffle 104 are actually a whole. The separation here is only for the convenience of description and understanding of the structural separation, and should not be understood as different parts and / or components.
[0041] It should be noted that the working principle of the above-mentioned collimator is that when the collimator is used for adjustment, X-rays will pass through the adjustment slit of the collimator, and after being diffracted by the first and second blocking surfaces of the adjustment slit of the collimator, they will irradiate the detector at the other end of the collimator, forming an irradiation area of a specific shape on the detector.
[0042] It should be noted that the cross section of the vertical plane of the above-mentioned axis is circular, and the center of the cross section is on the axis. The appearance of the collimator 2 is shown here. A cross section is obtained by cutting from the vertical direction of the axis. The shape of the cross section is as follows: Figure 2 As shown, the outer diameter of the obtained cross section is a circle, and the center of the circle of the obtained cross section is on the axis center line of the axis center line.
[0043] It should be noted that the first baffle surface and the second baffle surface on the first baffle plate 101 and the second baffle plate 102 are respectively convex toward the axis center line, and the first baffle surface and the second baffle surface are continuous curved surfaces when they are convex, and the curvatures of the first baffle surface and the second baffle surface gradually increase from both ends of the first baffle surface and both ends of the second baffle surface toward the middle of the collimator 2, so that the width of the gaps at both ends of the adjustment gap is greater than the width of the gap in the middle of the adjustment gap.
[0044] See also Figure 4 As shown, when the collimator 2 rotates, the width of the slit size 5 of the adjustment slit is adjusted. The principle is: since the adjustment slit is a continuous curved surface, when the collimator 2 is in the initial position, the slit size 5 is the widest. Therefore, the angle of the adjustment slit will change during rotation, so the diffraction points of the X-rays with the first blocking surface and the second blocking surface will change, thereby adjusting the width of the slit size 5 of the X-ray irradiation.
[0045] It should be noted that, see Figure 2 As described above, when the aforementioned cross section is used as a rectangular coordinate system, when any parallel line of the axis line intersects with the longitudinal coordinate axis of the established rectangular coordinate system, it means that the position of the collimator 2 is the initial position. When the collimator 2 is in the initial position, the centers of the first baffle and the second baffle are respectively deviated from the transverse coordinate axis of the rectangular coordinate system, that is, the first baffle and the second baffle are respectively continuous curved surfaces. Therefore, when a vertical cross section is made on an axis line, the first baffle and the second baffle in the cross section correspond to curves, and the curves are also continuous curves. Therefore, the continuous curve must have a center. The deviation of the centers of the aforementioned first baffle and the second baffle from the transverse coordinate axis of the rectangular coordinate system refers to the center of the curve. And the centers of the first baffle and the second baffle are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system.
[0046] It should be noted that, referring to the aforementioned cross-section, the intersection of the first baffle surface and the first baffle plate 101 includes a first intersection and a second intersection, and the intersection of the second baffle surface and the second baffle plate 102 includes a third intersection and a fourth intersection; the first intersection, the second intersection, the third intersection, and the fourth intersection are all deviated from the transverse coordinate axis of the rectangular coordinate system, and deviate from the longitudinal coordinate axis of the rectangular coordinate system, and the first intersection and the second intersection, the third intersection, and the fourth intersection are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system, and the first intersection and the second intersection, the third intersection, and the fourth intersection are respectively deviated from the same parallel line of the longitudinal coordinate axis of the rectangular coordinate system.
[0047] It should be noted that the description here is only for explanation Figure 2 The cross-sectional shape of the collimator 2 is not limited to the above-mentioned shape, and the first intersection point, the second intersection point, the third intersection point, and the fourth intersection point can be located at any position of the first baffle 101 and the second baffle 102 according to the design of the collimator 2.
[0048] See the above embodiments and Figure 3 As shown, this embodiment provides a collimator 2, which includes the above-mentioned collimator 2, and also includes a motor 201, a coupling 202, and an encoder 203; wherein the first connecting shaft 105 and the second connecting shaft 106 are respectively provided on the opposite surfaces of the third blocking surface and the fourth blocking surface of the collimator 2, and the diameters of the first connecting shaft 105 and the second connecting shaft 106 are smaller than the diameter of the collimator 2, one end of the collimator 2 is connected to one end of the coupling 203 through the second connecting shaft 105, and the other end of the coupling 202 is connected to the motor 201. On the machine 201, the function of the coupling 202 is to transfer the kinetic energy of the motor 201 to the collimator 2, so that the collimator 2 rotates; the other end of the collimator 2 is connected to the encoder 202 through the first connecting shaft 105, so that the encoder 203 rotates coaxially with the collimator 2, and the encoder 203 monitors the actual angle of the collimator 2 after rotating from the initial angle. When the motor 201 starts to rotate, it can sequentially drive the coupling 202, the collimator 2, and the encoder 203 to rotate around the axis, and adjust the opening size 5 of the adjustment gap.
[0049] It should be noted that the above-mentioned collimator 2 also includes a first support 204 and a second support 205, and the shape of the first support 204 and the second support 205 is a rectangle, and the middle part of the rectangle is provided with a first circular through hole and a second circular through hole; the second connecting shaft 106 passes through the second circular through hole to connect to the coupling 202; the first connecting shaft 105 passes through the first circular through hole to connect to the encoder 203, and the first support 204 and the second support 205 are respectively used as bases for placing the collimator 2; the collimator 2 also includes a first bearing and a second bearing, the second bearing is arranged in the second circular through hole, and the second connecting shaft passes through the second bearing through hole to connect to the coupling 202; the first bearing is arranged in the first circular through hole, and the first connecting shaft 105 passes through the center through hole of the first bearing to connect to the encoder 203.
[0050] Referring to the above embodiment, this embodiment provides a CT device, which includes the aforementioned collimator 2, and the collimator 2 is arranged on the CT device through the first support 204 and the second support 205, and the CT device also includes a focus 3 and a detector 4; Figure 4 As shown, the focus 3 and the detector 4 are respectively arranged on the same vertical line on both sides of the axis of the collimator 2 when the collimator 2 is in the initial position, and the focus 3 is on the vertical line in the middle of the collimator 2; when the intersection on one side of the collimator 2 generates X-rays, the distance between the focus 3 and the collimator 2 is the shortest, and when the X-rays contact the collimator 2, the width of the X-rays is greater than or equal to the maximum diameter of the collimator 2. When light is emitted from the focus 3, it is in the shape of a cone. Therefore, in order for the cone generated by the X-rays to be effectively blocked by the first blocking surface and the second blocking surface when it contacts the collimator 2 and diffracted onto the detector 4, when the cone of the X-rays contacts the collimator 2, the diameter of the circle at the bottom of the cone of the X-rays must be greater than or equal to the maximum diameter of the collimator 2 to effectively block and diffract. Refer to Figure 4 and Figure 5 As shown, the shielding points of the X-rays and the first and second blocking surfaces of the adjustment slit are the first tangent point 6 and the second tangent point 7, and the vertical distance between the first and second tangent points 6 and 7 is the slit size 5; when a certain slit size 5 is required, after the collimator 2 is rotated, the X-rays pass through the two tangent points of the first and second blocking surfaces and are diffracted on the detector 4 to obtain the required slit size 3.
[0051] Referring to the above embodiment, this embodiment provides a calibration method for the above CT device, comprising the steps of: setting a rotation angle after rotation from an initial angle for each slit size in a computer, and also setting a deviation threshold in the computer; when a certain slit size 5 is required, the encoder 203 monitors the actual angle of the collimator 2 after rotation from the initial angle, and sends the actual angle to the computer, the computer compares the received actual angle with the actual angle after rotation from the initial angle set by the slit size, and calculates the difference, and then compares the calculated difference with the deviation threshold, when the difference is greater than the deviation threshold, the computer calculates a compensation value according to the value of the difference, and the computer controls the motor 201 to drive the collimator 2 to rotate according to the calculated compensation value, and after the collimator 2 rotates, repeats the above steps until the difference calculated by the computer is less than or equal to the deviation threshold.
[0052] Referring to the above embodiments, this embodiment provides a method for preparing a collimator 2, comprising the steps of:
[0053] S1: Preset a number of deviation angles of the collimator 2 after rotating from the initial angle, and set a slit size 5 corresponding to each deviation angle;
[0054] S2: A vertical section about the axis is made at any position of the collimator 2, the midpoint of the line connecting the two end points of the slit size 5 is on any parallel line of the axis, and when a vertical extension line is made through the two end points of the slit size 5, the vertical extension line is parallel to the vertical line of the axis;
[0055] S3: the collimator 2 is rotated according to each deviation angle, and the X-rays generated by the focus 3 intersect with the vertical extension lines of the two end points of each slit size 5, that is, the intersection points appear in pairs on the two vertical extension lines;
[0056] S4: Connect several intersection points on the same side of the perpendicular lines of the axis line to form a curve, see Figure 6 As shown;
[0057] S5: sequentially connect the highest points of the curves of several cross sections of the first baffle 101 and / or the second baffle 102 of the collimator 2 to form an upper surface, sequentially connect the lowest points of several cross sections of the first baffle 101 and / or the second baffle 102 of the collimator to form a lower surface, and form a first baffle surface and a second baffle surface on the first baffle 101 and the second baffle 102 respectively;
[0058] S6: The first baffle plate 101 and the second baffle plate 102 are fixedly connected by the first baffle plate 103 and the second baffle plate 104 to form a collimator.
[0059] It should be noted that when connecting several intersections, arc smooth connection is adopted so that the first blocking surface and the second blocking surface formed are continuous curved surfaces. The explanation here does not exclude the use of straight lines to connect them.
[0060] It should be noted that, in order to increase the adjustment dose of the collimator 2 , multiple groups of slit sizes can be set to prepare the collimator 2 .
[0061] It should be noted that each deviation angle is inversely proportional to the corresponding slot size 5, that is, the smaller the rotation angle, the larger the slot size 5, so that the first stop surface and the second stop surface of the adjustment slot formed by this design can form a continuous curved surface.
[0062] It should be noted that the embodiments of the present invention have better practicability and do not impose any form of limitation on the present invention. Any technician familiar with the field may use the technical content disclosed above to change or modify it into an equivalent effective embodiment. However, any modification or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.
Claims
1. A collimator, characterized in that: include: Motor, coupling, encoder; among them, The collimator is surrounded by a first stop surface, a second stop surface, a third stop surface, and a fourth stop surface to form an adjustment gap; The first connecting shaft and the second connecting shaft are respectively disposed on the opposite surfaces of the third blocking surface and the fourth blocking surface of the collimator; One end of the collimator is connected to one end of the coupling via the second connecting shaft, and the other end of the coupling is connected to the motor, and the coupling transmits the kinetic energy of the motor to the collimator; The other end of the collimator is connected to the encoder through the first connecting shaft, so that the encoder rotates coaxially with the collimator, and the encoder monitors the actual angle of the collimator after rotating from the initial angle; When the motor rotates, it drives the coupling, the collimator, and the encoder to rotate around the axis in sequence to adjust the size of the opening of the adjustment gap; The collimator comprises: a first baffle, a second baffle, a first baffle sheet, and a second baffle sheet; wherein, The two ends of the first baffle are respectively connected to the first baffle and the second baffle, and the axis of the first baffle and the axis of the second baffle are on the same axis line, and the first baffle is not on the axis line; The two ends of the second baffle are respectively connected to the first baffle and the second baffle; the opposite surfaces of the first baffle and the second baffle are respectively the first baffle surface and the second baffle surface, and the opposite surfaces of the first baffle and the second baffle are respectively the third baffle surface and the fourth baffle surface; The first stop surface and the second stop surface are respectively convex toward the axis center line, and the first stop surface and the second stop surface are continuous curved surfaces, and the curvatures of the first stop surface and the second stop surface gradually increase from both ends of the first stop surface and both ends of the second stop surface toward the middle of the collimator, so that the width of the slit at both ends of the adjustment slit is greater than the width of the slit in the middle of the adjustment slit, the first stop surface and the second stop surface are basically centrally symmetrical with respect to the vertical direction but not axisymmetric, and the first stop surface itself is not axisymmetric with respect to the horizontal direction, and the second stop surface itself is not axisymmetric with respect to the horizontal direction; When the collimator rotates, the width of the opening size of the adjustment slit is adjusted.
2. The collimator according to claim 1, characterized in that: The cross section of a plane perpendicular to the axis is circular, and the center of the cross section is on the axis.
3. The collimator according to claim 2, characterized in that: Taking the center of the cross section as a rectangular coordinate system, when any parallel line of the axis line intersects with the longitudinal coordinate axis of the rectangular coordinate system, the collimator is in the initial position; When the collimator is in the initial position, the centers of the first stop surface and the second stop surface deviate from the transverse coordinate axis of the rectangular coordinate system, and the centers of the first stop surface and the second stop surface are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system.
4. The collimator according to claim 3, characterized in that: The intersection of the first blocking surface and the first blocking plate includes a first intersection and a second intersection, the intersection of the second blocking surface and the second blocking plate includes a third intersection and a fourth intersection, the first intersection, the second intersection, the third intersection, and the fourth intersection are all deviated from the transverse coordinate axis of the rectangular coordinate system; and the first intersection and the second intersection, the third intersection, and the fourth intersection are respectively on both sides of the transverse coordinate axis of the rectangular coordinate system; The first intersection point and the second intersection point, the third intersection point and the fourth intersection point are respectively deviated from the same parallel line of the longitudinal coordinate axis of the rectangular coordinate system.
5. A CT device comprising the collimator according to any one of claims 1 to 4, characterized in that: The collimator is arranged on the CT device and also includes a focus and a detector; wherein, The focus and the detector are respectively arranged on the same vertical line on both sides of the axis line of the collimator when the collimator is in the initial position, and the focus is on the middle vertical line of the collimator; The focus on one side of the collimator generates X-rays, and when the focus is closest to the collimator, the width of the X-rays is greater than or equal to the maximum diameter of the collimator when the X-rays contact the collimator; The X-ray takes the focal point as the initial position, radiates the X-ray toward the collimator, and when irradiating the collimator, is blocked by the first blocking surface and the second blocking surface of the collimator and then diffracted onto the detector; The shielding points of the X-ray and the first blocking surface and the second blocking surface of the adjustment slit are the first tangent point and the second tangent point, and the vertical distance between the first tangent point and the second tangent point is the slit size; When a certain slit size is required, after the collimator rotates, the X-ray passes through two intersection points of the first blocking surface and the second blocking surface and then diffracts on the detector to obtain the slit size.
6. A calibration method using the CT device according to claim 5, characterized in that: Includes steps: A rotation angle after rotation from an initial angle is set for each slit size in a computer, and a deviation threshold is set in the computer; When a certain slit size is required, the encoder monitors the actual angle of the collimator after rotating from the initial angle, sends the actual angle to the computer, and compares the difference with the rotation angle after rotating from the initial angle set by the slit size. When the difference is greater than the deviation threshold, the computer calculates a compensation value according to the difference, and the computer controls the motor to drive the collimator to rotate according to the compensation value; The motor drives the collimator to rotate and then repeats the above steps until the difference is less than or equal to the deviation threshold.
7. A method for preparing the collimator according to any one of claims 1 to 5, characterized in that: Includes steps: Preset a number of deviation angles of the collimator from the initial angle to the rotation, and set a corresponding slit size for each deviation angle; A vertical section about the axis is made at any position of the collimator, the midpoint of the line connecting the two end points of the slot size is on any parallel line of the axis, and when a vertical extension line is made through the two end points of the slot size, the vertical extension line is parallel to the vertical line of the axis; The collimator is rotated according to each of the deviation angles, so that the X-rays generated by the focus intersect with the vertical extension lines of the two end points of each slit size; Connecting a plurality of intersection points on the same side of the perpendicular line of the axis line in sequence to form a curve; The highest points of the curves of several cross sections of the first baffle and / or the second baffle of the collimator are sequentially connected to form an upper surface, and the lowest points of the curves of several cross sections of the first baffle and / or the second baffle of the collimator are sequentially connected to form a lower surface, and a first baffle surface and a second baffle surface are formed on the first baffle and the second baffle respectively; The first baffle plate and the second baffle plate are fixedly connected by the first baffle plate and the second baffle plate to form the collimator.
8. The method according to claim 7, characterized in that Each of the deviation angles is inversely proportional to the corresponding slot size.