A detection device for repairing medical linear accelerator

Abstract

The present invention discloses a detection device for repairing a medical linear accelerator, which relates to the technical field related to medical linear accelerators. An ionization chamber is used to convert an X-ray intensity signal into a current signal. Then, four groups of LED lights are used in conjunction with an undercurrent relay and an overcurrent relay. When the current intensity reaches the operating voltage range of the undercurrent relay and the overcurrent relay, the corresponding LED lights are illuminated, thereby utilizing the color differences of different LEDs to mark the X-ray intensities at different positions. At the same time, a rotating detection antenna is used to drive a large number of ionization chambers to rotate, and the visual persistence effect is used to display the X-ray irradiation trajectory and range. In this way, different light colors can be used to intuitively mark the X-ray intensities of different areas in a three-dimensional space, thereby realizing the visualization of the X-ray path and irradiation field, and facilitating on-site maintenance engineers to inspect and adjust the medical linear accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field related to linear accelerators, and in particular to a detection device for repairing medical linear accelerators. Background Art

[0002] A medical linear accelerator is a particle accelerator device used in biomedicine for radiotherapy of cancer patients. It is an important instrument for radiotherapy of cancer patients. The stability and reliability of its performance are directly related to the treatment effect and life safety of patients. Therefore, regular inspection and maintenance of medical linear accelerators are crucial.

[0003] Existing medical linear accelerator detection devices, such as a maintenance device for medical linear accelerators with publication number CN216310144U, use air conductive rods and LC circuits to convert X-ray intensity signals into electromagnetic wave signals, which are then rapidly detected using an oscilloscope. However, these detection devices can only detect X-ray intensity at a specific location and are unable to determine the X-ray irradiation field deviation or the X-ray intensity distribution in three dimensions. This makes maintenance and adjustment of medical linear accelerators difficult and can easily cause radiation damage to maintenance operators. Summary of the Invention

[0004] The purpose of the present invention is to provide a detection device for repairing a medical linear accelerator to solve the problem mentioned in the above background that the traditional medical linear accelerator detection device cannot detect the deviation of the X-ray irradiation field and the intensity distribution of the X-ray in three-dimensional space.

[0005] To achieve the above objectives, the present invention provides the following technical solutions: a detection device for repairing a medical linear accelerator, comprising an adjustment support frame and a detection antenna, the adjustment support frame being used to adjust the position and orientation of the detection antenna, the detection antenna comprising a central axis, a rotating rod being fixedly connected to the central axis, a fourth servo motor being provided at the bottom of the detection antenna, the fourth servo motor being used to drive the detection antenna to rotate, an ionization chamber being fixedly connected to the rotating rod, and a first LED lamp, a second LED lamp, a third LED lamp, and a fourth LED lamp being provided around the ionization chamber;

[0006] The ionization chamber is electrically connected to a capacitor and an inductor connected in parallel. The ionization chamber is electrically connected to a first LED lamp, a second LED lamp, a third LED lamp, and a fourth LED lamp, and the ionization chamber is connected in parallel to the first LED lamp, the second LED lamp, the third LED lamp, and the fourth LED lamp. The first LED lamp is connected in series with a first overcurrent relay and a first undercurrent relay, the second LED lamp is connected in series with a second overcurrent relay and a second undercurrent relay, the third LED lamp is connected in series with a third overcurrent relay and a third undercurrent relay, and the fourth LED lamp is connected in series with a fourth overcurrent relay and a fourth undercurrent relay. The ionization chamber is also connected in parallel with an oscilloscope.

[0007] In one embodiment, a transverse guide rail is provided on each side of the bottom of the adjustment support frame, a longitudinal slider is slidably connected to the transverse guide rail, a first servo motor is fixedly installed on one end of the transverse guide rail, a first synchronous wheel is fixedly connected to the main shaft of the first servo motor, and a second synchronous wheel is rotatably connected to the other end of the transverse guide rail, the first synchronous wheel and the second synchronous wheel are connected by a synchronous belt transmission, and the synchronous belt is fixedly connected to the longitudinal slider.

[0008] Furthermore, the longitudinal slider is fixedly connected to a vertical support column by bolts, a vertical guide rail is fixedly connected to the inner side of the vertical support column, a lifting slider is slidably connected to the vertical guide rail, a lifting screw rod passes through the lifting slider, a screw nut is fixedly connected to the lifting slider, the screw nut is transmission connected to the screw nut through a thread, one end of the lifting screw rod is transmission connected to a second servo motor, and the second servo motor is fixedly mounted on the longitudinal slider.

[0009] Furthermore, a support cross bar is rotatably connected between the lifting sliders on both sides of the adjustment support frame, a third servo motor is fixedly connected to one of the lifting sliders, the output shaft of the third servo motor is fixedly connected to one end of the support cross bar, a fixed sleeve is fixedly connected to the support cross bar, and the fixed sleeve is rotatably connected to the detection antenna.

[0010] In one embodiment, the rotating rod and the central axis are perpendicular to each other, and the connection between the rotating rod and the central axis is located at the midpoint of the rotating rod. There are more than two rotating rods, and the projections of two adjacent rotating rods do not overlap.

[0011] In one embodiment, the ionization chambers are fixedly connected to the rotating rod by bolts, the ionization chambers are arranged at equal intervals on the rotating rod, and all the ionization chambers on the rotating rod are symmetrical about the central axis.

[0012] In one embodiment, the first LED light is red, the second LED light is green, the third LED light is yellow, and the fourth LED light is blue.

[0013] In one embodiment, the ionization chamber is filled with helium.

[0014] In one embodiment, the operating current of the first undercurrent relay is less than the operating current of the first overcurrent relay, the operating current of the first overcurrent relay is equal to the operating current of the second undercurrent relay, the operating current of the second undercurrent relay is less than the operating current of the second overcurrent relay, the operating current of the second overcurrent relay is equal to the operating current of the third undercurrent relay, the operating current of the third undercurrent relay is less than the operating current of the third overcurrent relay, the operating current of the third overcurrent relay is equal to the operating current of the fourth undercurrent relay, and the operating current of the fourth undercurrent relay is less than the operating current of the fourth overcurrent relay.

[0015] Furthermore, the method for setting the operating current of the first overcurrent relay, the first undercurrent relay, the second overcurrent relay, the second undercurrent relay, the third overcurrent relay, the third undercurrent relay, the fourth overcurrent relay and the fourth undercurrent relay comprises the following steps:

[0016] S1. First, for the model of medical linear accelerator, query the upper limit of X-ray dose D output during normal operation. max and lower limit D min ;

[0017] S2. Detect the output dose at D max The ionization current in the ionization chamber is I max , and the output dose at D min The ionization current in the ionization chamber is I min , then I max and I min The interval is divided into four equal intervals, namely [I min ,I1], [I1,I2], [I2,I3] and [I3,I max ];

[0018] Then, according to the linear correspondence, the interval of ionization current size is matched with the interval of X-ray output dose, that is, when the ionization current is [I min , I1], it means that the X-ray output dose of the area where the ionization chamber 19 is located is [D min , D1]; when the ionization current is within [I1, I2], it means that the X-ray output dose of the area where the ionization chamber 19 is located is between [D1, D2]; when the ionization current is within [I2, I3], it means that the X-ray output dose of the area where the ionization chamber 19 is located is between [D2, D3]; when the ionization current is within [I3, I max ], it means that the X-ray output dose of the area where the ionization chamber 19 is located is within [D3,D max]between;

[0019] S3. Select appropriate overcurrent relay and undercurrent relay according to the divided ionization current size interval, that is, the operating current of the first undercurrent relay is I min , the operating current of the first overcurrent relay is I1; the operating current of the second undercurrent relay is I1, and the operating current of the second overcurrent relay is I2; the operating current of the third undercurrent relay is I2, and the operating current of the third overcurrent relay is I3; the operating current of the fourth undercurrent relay is I3, and the operating current of the fourth overcurrent relay is I max .

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention proposes a detection device for repairing a medical linear accelerator. This device converts X-ray intensity signals into current signals using an ionization chamber. Four sets of LED lights, in conjunction with undercurrent and overcurrent relays, illuminate corresponding LED lights when the current intensity reaches the operating voltage range of the undercurrent and overcurrent relays. The color differences of the different LEDs are used to mark the X-ray intensities at different locations. A rotating detection antenna simultaneously drives a large number of ionization chambers to rotate, and the persistence of vision effect is used to display the X-ray irradiation trajectory and range. Different light colors can be used to visually mark the X-ray intensities of different areas in three-dimensional space, thereby visualizing the X-ray path and irradiation field. This facilitates on-site maintenance engineers to inspect and adjust the medical linear accelerator to ensure that the irradiation field is centered and that the X-ray intensity and distribution meet requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a structural schematic diagram of a urine collector of a detection device for repairing a medical linear accelerator according to the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the adjustable support frame of the present invention;

[0024] Figure 3 This is a schematic diagram of the detection antenna structure of the present invention;

[0025] Figure 4 This is a schematic diagram of the distribution structure of the rotating rods of the present invention;

[0026] Figure 5 Schematic diagram of the movement trajectory of the ionization chamber of the present invention;

[0027] Figure 6 Schematic diagram of the ionization chamber structure of the present invention;

[0028] Figure 7 Schematic diagram of the circuit of the present invention.

[0029] Numbers in the figure: 1, adjustment support frame; 2, horizontal guide rail; 3, longitudinal slider; 4, first servo motor; 5, first synchronous wheel; 6, second synchronous wheel; 7, synchronous belt; 8, vertical support column; 9, vertical guide rail; 10, lifting slider; 11, lifting screw; 12, screw nut; 13, second servo motor; 14, supporting crossbar; 15, third servo motor; 16, fixed sleeve; 17, detection antenna; 1701, center axis; 1702, rotating rod; 18 , fourth servo motor; 19. ionization chamber; 20. capacitor; 21. inductor; 22. first LED lamp; 23. second LED lamp; 24. third LED lamp; 25. fourth LED lamp; 26. first overcurrent relay; 27. first undercurrent relay; 28. second overcurrent relay; 29. ​​second undercurrent relay; 30. third overcurrent relay; 31. third undercurrent relay; 32. fourth overcurrent relay; 33. fourth undercurrent relay; 34. oscilloscope. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] like Figure 1-7 As shown, a detection device for repairing a medical linear accelerator includes an adjustment support frame 1 and a detection antenna 17 . The adjustment support frame 1 is used to adjust the position and orientation of the detection antenna 17 .

[0032] Specifically, a transverse guide rail 2 is provided on each side of the bottom of the adjustment support frame 1, and a longitudinal slider 3 is slidably connected to the transverse guide rail 2. A first servo motor 4 is fixedly installed at one end of the transverse guide rail 2, and a first synchronous wheel 5 is fixedly connected to the main shaft of the first servo motor 4. The other end of the transverse guide rail 2 is rotatably connected to the second synchronous wheel 6. The first synchronous wheel 5 and the second synchronous wheel 6 are connected by a synchronous belt 7. The synchronous belt 7 is fixedly connected to the longitudinal slider 3, so that when the first servo motor 4 drives the first synchronous wheel 5 to rotate, the longitudinal slider 3 can be pulled by the synchronous belt 7, so that the longitudinal slider 3 slides back and forth along the transverse guide rail 2, thereby adjusting the front and rear orientation of the detection antenna 17 to change the detection range.

[0033] Specifically, the longitudinal slider 3 is fixedly connected to a vertical support column 8 by bolts, a vertical guide rail 9 is fixedly connected to the inner side of the vertical support column 8, a lifting slider 10 is slidably connected to the vertical guide rail 9, a lifting screw 11 passes through the lifting slider 10, a screw nut 12 is fixedly connected to the lifting slider 10, the screw nut 12 is transmission connected to the screw nut 12 through a thread, one end of the lifting screw 11 is transmission connected to the second servo motor 13, the second servo motor 13 is fixedly installed on the longitudinal slider 3, so that the second servo motor 13 can drive the lifting slider 10 to move up and down along the vertical guide rail 9 through the cooperation of the lifting screw 11 and the screw nut 12.

[0034] Specifically, a support cross bar 14 is rotatably connected between the lifting sliders 10 on both sides, a third servo motor 15 is fixedly connected to one of the lifting sliders 10, the output shaft of the third servo motor 15 is fixedly connected to one end of the support cross bar 14, a fixed sleeve 16 is fixedly connected to the support cross bar 14, and a detection antenna 17 is rotatably connected to the fixed sleeve 16. The third servo motor 15 is used to drive the detection antenna 17 to rotate 360° to detect rays in different directions.

[0035] In one example, the detection antenna 17 includes a central axis 1701, to which a rotating rod 1702 is fixedly connected. The rotating rod 1702 and the central axis 1701 are perpendicular to each other, and the connection between the rotating rod 1702 and the central axis 1701 is located at the midpoint of the rotating rod 1702. There are more than two rotating rods 1702, and the projections of two adjacent rotating rods 1702 do not overlap. A fourth servo motor 18 is provided at the bottom of the detection antenna 17, and the fourth servo motor 18 is used to drive the detection antenna 17 to rotate. An ionization chamber 19 is fixedly connected to the rotating rod 1702, and the ionization chambers 19 are arranged at equal intervals on the rotating rod 1702, and all ionization chambers 19 on the rotating rod 1702 are symmetrical with the central axis 1701 as the axis of symmetry.

[0036] The ionization chamber 19 is filled with an inert gas. Helium can be used to obtain a relatively obvious stable ionization current. A first LED lamp 22, a second LED lamp 23, a third LED lamp 24 and a fourth LED lamp 25 are arranged around the ionization chamber 19. The first LED lamp 22 is red, the second LED lamp 23 is green, the third LED lamp 24 is yellow, and the fourth LED lamp 25 is blue, so that the radiation intensity of the X-rays is distinguished by color.

[0037] like Figure 7As shown, the ionization chamber 19 is electrically connected to a capacitor 20 and an inductor 21 connected in parallel, and the ionization chamber 19 is electrically connected to a first LED lamp 22, a second LED lamp 23, a third LED lamp 24 and a fourth LED lamp 25, and the ionization chamber 19 and the first LED lamp 22, the second LED lamp 23, the third LED lamp 24 and the fourth LED lamp 25 are all connected in parallel. The first LED lamp 22 is connected in series with a first overcurrent relay 26 and a first undercurrent relay 27, the second LED lamp 23 is connected in series with a second overcurrent relay 28 and a second undercurrent relay 29, the third LED lamp 24 is connected in series with a third overcurrent relay 30 and a third undercurrent relay 31, and the fourth LED lamp 25 is connected in series with a fourth overcurrent relay 32 and a fourth undercurrent relay 33. When X-rays irradiate the ionization chamber 19, the X-rays It interacts with the molecules in the dielectric gas in the ionization chamber 19 to produce ion pairs consisting of an electron and a positive ion. Under the action of the electric field, the positive and negative ions drift toward the negative and positive poles respectively, forming an ionization current. The ionization current is proportional to the intensity of the radiation. When the ionization current is exactly between the operating currents of the overcurrent relay and the undercurrent relay, the LED lamp connected in series with the corresponding overcurrent relay and undercurrent relay can be lit. In this way, by reasonably setting the operating currents of the first overcurrent relay 26, the first undercurrent relay 27, the second overcurrent relay 28 and the second undercurrent relay 29, the third overcurrent relay 30 and the third undercurrent relay 31, the fourth overcurrent relay 32 and the fourth undercurrent relay 33, it can be achieved that different X-ray radiation intensities can just light up different LED lamps.

[0038] The ionization chamber 19 is also connected in parallel with an oscilloscope 34. When X-rays irradiate the ionization chamber 19, information about the current changes generated by the ionization process in the ionization chamber 19 can be obtained through the oscilloscope 34. This information mainly reflects the movement of ion pairs generated by the ionization of gas molecules in the ionization chamber 19 under the action of the electric field after the X-rays irradiate the ionization chamber 19, and can further infer the intensity and irradiation conditions of the X-rays.

[0039] Working principle: When testing a medical linear accelerator, the detection device is placed on the inspection table below the detection device, and the position and direction of the detection antenna 17 are adjusted by the first servo motor 4, the second servo motor 13 and the third servo motor 15, so that the central axis 1701 of the detection antenna 17 points to the head of the medical linear accelerator, and then the fourth servo motor 18 is started to drive the detection antenna 17 to rotate, and then the medical linear accelerator is started to emit X-rays. When the X-rays irradiate the ionization chamber 19, an ionization current is formed in the ionization chamber 19. The ionization current is proportional to the intensity of the radiation. When the ionization current is exactly between the operating currents of the overcurrent relay and the undercurrent relay, the LED lamp connected in series with the corresponding overcurrent relay and undercurrent relay can be lit.

[0040] like Figure 5As shown, since the moving light will cause the persistence of vision phenomenon, from the perspective of the maintenance engineer, the LED light will form a ring-shaped light band as the detection antenna 17 rotates. The ring-shaped light bands of different diameters formed by a large number of LED lights on the same rotating rod 1702 will form a plane, and the multiple planar light bands of multiple groups of rotating rods 1702 at different heights will form a three-dimensional visual effect. As the intensity of the X-rays in the three-dimensional space varies, the color of the illuminated LED light will also vary. Since the irradiation field of the medical linear accelerator is usually square and emitted from a point, the irradiation path of the X-ray will appear to the maintenance engineer as a quadrangular pyramid, and the division of different colors within the quadrangular pyramid-shaped irradiation path represents the different X-ray intensities. This realizes the visualization of the X-ray path and irradiation field, making it convenient for on-site maintenance engineers to inspect and adjust the medical linear accelerator to ensure that the irradiation field is centered and the X-ray intensity and distribution meet the requirements.

[0041] In order to achieve the above visual effect corresponding to the X-ray intensity, we need to properly set the operating current of the overcurrent relay and undercurrent relay. The specific setting method includes the following steps:

[0042] 1. First, for the model of medical linear accelerator, check the upper limit of X-ray dose D it outputs during normal operation. max and lower limit D min The output dose of conventional medical linear accelerators is usually between 30cGy / min and 600cGy / min.

[0043] 2. Detect the output dose at D max The ionization current in the ionization chamber 19 is I max , and the output dose at D min The ionization current in the ionization chamber 19 is I min , then I max and I min The interval is divided into four equal parts, namely [I min ,I1], [I1,I2], [I2,I3] and [I3,I max ].

[0044] Then, according to the linear correspondence, the interval of ionization current size is matched with the interval of X-ray output dose, that is, when the ionization current is [I min , I1], it means that the X-ray output dose of the area where the ionization chamber 19 is located is [D min, D1]; when the ionization current is within [I1, I2], it means that the X-ray output dose of the area where the ionization chamber 19 is located is between [D1, D2]; when the ionization current is within [I2, I3], it means that the X-ray output dose of the area where the ionization chamber 19 is located is between [D2, D3]; when the ionization current is within [I3, I max ], it means that the X-ray output dose of the area where the ionization chamber 19 is located is within [D3,D max ]between.

[0045] 3. Select appropriate overcurrent relay and undercurrent relay according to the divided ionization current size range, that is, the operating current of the first undercurrent relay 27 is I min The operating current of the first overcurrent relay 26 is I1; the operating current of the second undercurrent relay 29 is I1, and the operating current of the second overcurrent relay 28 is I2; the operating current of the third undercurrent relay 31 is I2, and the operating current of the third overcurrent relay 30 is I3; the operating current of the fourth undercurrent relay 33 is I3, and the operating current of the fourth overcurrent relay 32 is I max .

[0046] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A detection device for repairing a medical linear accelerator, comprising an adjustment support frame (1) and a detection antenna (17), characterized in that: The adjustment support frame (1) is used to adjust the position and orientation of the detection antenna (17), the detection antenna (17) includes a central axis (1701), a plurality of stacked rotating rods (1702) are fixedly connected to the central axis (1701), more than two rotating rods (1702) are provided, and the projections of two adjacent rotating rods (1702) do not overlap, a fourth servo motor (18) is provided at the bottom of the detection antenna (17), the fourth servo motor (18) is used to drive the detection antenna (17) to rotate, an ionization chamber (19) is fixedly connected to the rotating rod (1702), and a first LED lamp (22), a second LED lamp (23), a third LED lamp (24) and a fourth LED lamp (25) are provided around the ionization chamber (19); The ionization chamber (19) is electrically connected to a capacitor (20) and an inductor (21) connected in parallel. The ionization chamber (19) is electrically connected to a first LED lamp (22), a second LED lamp (23), a third LED lamp (24), and a fourth LED lamp (25). The ionization chamber (19) is connected in parallel to the first LED lamp (22), the second LED lamp (23), the third LED lamp (24), and the fourth LED lamp (25). The first LED lamp (22) is connected in series with a first overcurrent relay (26) and a first undercurrent relay (27). The second LED lamp (23) is connected in series with a second overcurrent relay (28) and a second undercurrent relay (29). The third LED lamp (24) is connected in series with a third overcurrent relay (30) and a third undercurrent relay (31). The fourth LED lamp (25) is connected in series with a fourth overcurrent relay (32) and a fourth undercurrent relay (33). The ionization chamber (19) is also connected in parallel with an oscilloscope (34). The first LED light (22) is red, the second LED light (23) is green, the third LED light (24) is yellow, and the fourth LED light (25) is blue; The operating current of the first undercurrent relay (27) is less than the operating current of the first overcurrent relay (26), the operating current of the first overcurrent relay (26) is equal to the operating current of the second undercurrent relay (29), the operating current of the second undercurrent relay (29) is less than the operating current of the second overcurrent relay (28), the operating current of the second overcurrent relay (28) is equal to the operating current of the third undercurrent relay (31), the operating current of the third undercurrent relay (31) is less than the operating current of the third overcurrent relay (30), the operating current of the third overcurrent relay (30) is equal to the operating current of the fourth undercurrent relay (33), and the operating current of the fourth undercurrent relay (33) is less than the operating current of the fourth overcurrent relay (32).

2. The detection device for repairing a medical linear accelerator according to claim 1, characterized in that: A transverse guide rail (2) is provided on each side of the bottom of the adjustment support frame (1), a longitudinal slider (3) is slidably connected to the transverse guide rail (2), a first servo motor (4) is fixedly mounted on one end of the transverse guide rail (2), a first synchronous wheel (5) is fixedly connected to the main shaft of the first servo motor (4), and a second synchronous wheel (6) is rotatably connected to the other end of the transverse guide rail (2), the first synchronous wheel (5) and the second synchronous wheel (6) are connected by a synchronous belt (7), and the synchronous belt (7) is fixedly connected to the longitudinal slider (3).

3. The detection device for repairing a medical linear accelerator according to claim 2, characterized in that: The longitudinal slider (3) is fixedly connected to a vertical support column (8) by bolts, the inner side of the vertical support column (8) is fixedly connected to a vertical guide rail (9), the vertical guide rail (9) is slidably connected to a lifting slider (10), a lifting screw (11) passes through the lifting slider (10), a screw nut (12) is fixedly connected to the lifting slider (10), the screw nut (12) is transmission-connected to the lifting screw (11) through a thread, a second servo motor (13) is fixedly mounted on the longitudinal slider (3), and the second servo motor (13) is transmission-connected to the lifting screw (11).

4. The detection device for repairing a medical linear accelerator according to claim 3, characterized in that: A support cross bar (14) is rotatably connected between the lifting sliders (10) on both sides of the adjustment support frame (1), a third servo motor (15) is fixedly connected to one of the lifting sliders (10), an output shaft of the third servo motor (15) is fixedly connected to one end of the support cross bar (14), a fixed sleeve (16) is fixedly connected to the support cross bar (14), and the fixed sleeve (16) is rotatably connected to the detection antenna (17).

5. The detection device for repairing a medical linear accelerator according to claim 1, characterized in that: The rotating rod (1702) and the central axis (1701) are perpendicular to each other, and the connection between the rotating rod (1702) and the central axis (1701) is located at the midpoint of the rotating rod (1702).

6. The detection device for repairing a medical linear accelerator according to claim 1, characterized in that: The ionization chambers (19) are fixedly connected to the rotating rod (1702) by bolts. The ionization chambers (19) are arranged at equal intervals on the rotating rod (1702), and all the ionization chambers (19) on the rotating rod (1702) are symmetrical with the central axis (1701) as the symmetry axis.

7. The detection device for repairing a medical linear accelerator according to claim 1, characterized in that: The ionization chamber (19) is filled with helium.

8. The detection device for repairing a medical linear accelerator according to claim 1, characterized in that: The method for setting the operating current of the first overcurrent relay (26), the first undercurrent relay (27), the second overcurrent relay (28), the second undercurrent relay (29), the third overcurrent relay (30), the third undercurrent relay (31), the fourth overcurrent relay (32) and the fourth undercurrent relay (33) comprises the following steps: S1. First, for the model of medical linear accelerator, query the upper limit of X-ray dose D output during normal operation. max and lower limit D min ; S2. Detect the output dose at D max The ionization current I in the ionization chamber (19) is max , and the output dose at D min The ionization current I in the ionization chamber (19) is min , then I max and I min The interval is divided into four equal intervals, namely [I min ,I1], [I1,I2], [I2,I3] and [I3,I max ]; Then, according to the linear correspondence, the interval of ionization current size is matched with the interval of X-ray output dose, that is, when the ionization current is [I min ,I1], it means that the X-ray output dose in the area where the ionization chamber (19) is located is within [D min , D1]; when the ionization current is within [I1, I2], it means that the X-ray output dose of the area where the ionization chamber (19) is located is between [D1, D2]; when the ionization current is within [I2, I3], it means that the X-ray output dose of the area where the ionization chamber (19) is located is between [D2, D3]; when the ionization current is within [I3, I max ], it means that the X-ray output dose in the area where the ionization chamber (19) is located is within [D3,D max ]between; S3. Select appropriate overcurrent relay and undercurrent relay according to the divided ionization current size range, that is, the operating current of the first undercurrent relay (27) is I min , the operating current of the first overcurrent relay (26) is I1; the operating current of the second undercurrent relay (29) is I1, and the operating current of the second overcurrent relay (28) is I2; the operating current of the third undercurrent relay (31) is I2, and the operating current of the third overcurrent relay (30) is I3; the operating current of the fourth undercurrent relay (33) is I3, and the operating current of the fourth overcurrent relay (32) is I max .

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