A medical linear accelerator inter-laboratory quality control device and method

Abstract

The present invention relates to the field of medical device technology, and discloses an inter-laboratory quality control device and method for a medical linear accelerator, including a cross-shaped quality control phantom, the quality control phantom including four strip-shaped placement parts, two adjacent placement parts are perpendicular to each other, a plurality of first notches are evenly spaced on the front of each placement part, a first cover plate is buckled on the first notch, and a first film is embedded between the first notch and the first cover plate; a plurality of first holes for placing metal balls are opened on the back of each placement part, and the positions of the plurality of first holes correspond to the positions of the corresponding first notches; the quality control phantom is horizontally placed with the front side facing downward at the center of a frame of a medical linear accelerator, and the geometric center of the quality control phantom coincides with the convergence point of the light emitted by the medical linear accelerator. This technical solution improves the detection accuracy of the medical linear accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to an inter-laboratory quality control device and method for a medical linear accelerator. Background Art

[0002] Medical Linear Accelerators refer to products used for routine clinical X-ray or electron beam radiotherapy, which are composed of treatment heads, accelerating tubes, magnetrons / klystrons, collimators, positioning systems, treatment beds, control systems, modulators, water cooling units, and other components. Since the energy of the rays emitted by medical linear accelerators is relatively high, it is necessary to strictly control the operating accuracy of the equipment, that is, the quality assurance and quality control of medical linear accelerators are very important. As medical accidents such as accelerator mis-irradiation and missed irradiation during tumor radiotherapy at home and abroad are constantly exposed by the media, the relevant medical administration and management departments are facing increasing pressure to strengthen the quality control and management of medical linear accelerator radiotherapy, and are gradually aware of its importance and necessity. However, it is relatively complicated for conventional radiotherapy quality control equipment to conduct quality control inspections on the units being controlled, and the inspection accuracy of the units being controlled is relatively low, which cannot meet the increasingly stringent requirements for the quality of medical linear accelerator radiotherapy. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide an inter-laboratory quality control device for a medical linear accelerator, which can be used to detect the accuracy of a medical linear accelerator with high detection accuracy.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a medical linear accelerator inter-laboratory quality control device, comprising:

[0005] A cross-shaped quality control phantom, the quality control phantom comprising four strip-shaped placement parts, two adjacent placement parts are perpendicular to each other, a plurality of first notches are evenly spaced apart on the front side of each placement part, a first cover plate is buckled on the first notch, and a first film is embedded between the first notch and the first cover plate;

[0006] A plurality of first holes for placing metal balls are formed on the back of each placement portion, each of the first notches corresponds to two of the first holes arranged along the extension direction of the placement portion, and the distances from the two first holes to the two sides of the first notch perpendicular to the extension direction of the placement portion are consistent;

[0007] The quality control phantom is fixed horizontally with its front side facing downward on a radiotherapy bed of a medical linear accelerator;

[0008] When the medical linear accelerator emits square rays from directly above the quality control phantom toward the quality control phantom, the square rays penetrate each of the placement portions and expose the first films in the first slots. The exposed first films are used for analysis by an external analysis device to determine the radiotherapy accuracy of the medical linear accelerator.

[0009] Furthermore, before the quality control phantom performs quality control inspection on the medical linear accelerator, the radiotherapy bed is moved so that the geometric center of the plane where the first film of the quality control phantom is located coincides with the isocenter of the medical linear accelerator. Furthermore, the quality control phantom also includes a first intersection, the four placement parts intersect at the first intersection, a second slot is provided on the front of the first intersection, a second cover is buckled on the second slot, a second film is embedded between the second slot and the second cover, and a plurality of third holes for placing metal balls are provided on the back of the first intersection, each of the second slots corresponds to two third holes arranged along the extension direction of the first intersection, and the distances from the two third holes to the two side edges of the second slot perpendicular to the extension direction of the first intersection are consistent; when the medical linear accelerator repeatedly emits an elongated rectangular field intersecting at the center above the back of the first intersection by rotating the beam limiter angle to form accumulated cross-shaped rays, the cross-shaped rays penetrate the first intersection to expose the second film, and leave a cross-shaped irradiation field trace on the second film.

[0010] Furthermore, a placement bracket for placing unexposed photos is detachably connected to the back side of the first intersection, a first positioning laser light is fixedly arranged at a first distance above the quality control phantom, and a second positioning laser light and a third positioning laser light are fixedly arranged on the left and right sides of the quality control phantom, respectively. The geometric center of the photo is located near a vertical line passing through the isocenter positions of the first positioning laser light, the second positioning laser light and the third positioning laser light, and the first positioning laser light, the second positioning laser light and the third positioning laser light are used to converge laser to expose the photo and leave exposure marks.

[0011] Furthermore, the second positioning laser light comprises a first laser for emitting horizontal fan-shaped light and a second laser for emitting vertical fan-shaped light, and the second laser is arranged directly above the first laser.

[0012] Furthermore, the third positioning laser light includes a third laser for emitting horizontal fan-shaped light and a fourth laser for emitting vertical fan-shaped light, the fourth laser is arranged directly above the third laser, the third laser is located on the same horizontal line as the first laser, and the fourth laser is located on the same horizontal line as the second laser.

[0013] Furthermore, the radiotherapy bed is mounted on the middle part of the frame of the medical linear accelerator, the quality control phantom is fixed on the upper end of the radiotherapy bed, and the first positioning laser lamp includes a fifth laser for emitting vertical fan-shaped light, and the fifth laser is arranged at the upper end of the foot of the radiotherapy bed.

[0014] Furthermore, a T-shaped bed detection phantom is included, and the bed detection phantom is used to be fixed on the upper end of the radiotherapy bed when the quality control phantom is removed from the upper end of the radiotherapy bed.

[0015] Further, the bed position detection phantom includes three strip-shaped connecting parts and a second intersection, the adjacent connecting parts are perpendicular to each other and intersect at the second intersection, a plurality of third notches are evenly spaced apart on the front of each connecting part and the second intersection, a third cover is buckled on the third notch, a third film is embedded between the third notch and the third cover, a plurality of second holes for placing the metal balls are opened on the back of each connecting part and the second intersection, each third notch corresponds to two second holes arranged along the extension direction of the connecting part, and the distances from the two second holes to the two side edges of the third notch perpendicular to the extension direction of the connecting part are consistent; the bed position detection phantom is horizontally fixed on the radiotherapy bed of the medical linear accelerator with the front side facing downward; when the medical linear accelerator emits rectangular rays, the rectangular rays irradiate and penetrate through each connecting part and expose the third film in the third notch, and the exposed third film is used for analysis by an external analysis device to determine the moving position of the radiotherapy bed.

[0016] A medical linear accelerator inter-laboratory quality control method, applied to the above-mentioned medical linear accelerator inter-laboratory quality control device, comprising:

[0017] Step S1, placing a first film in the first notches on the front of the four placement parts of the quality control phantom, and buckling a first cover plate on the first notches, placing metal balls in advance in a plurality of first holes on the back of the four placement parts, each of the first notches corresponds to two first holes arranged along the extension direction of the placement part, and the distances from the two first holes to the two side edges of the first notch perpendicular to the extension direction of the placement part are consistent, and proceeding to step S2;

[0018] Step S2, fix the quality control phantom horizontally with its front side facing downward on a radiotherapy bed of a medical linear accelerator, move the radiotherapy bed so that the geometric center of the plane where the first film of the quality control phantom is located coincides with the isocenter of the medical linear accelerator, and proceed to step S3;

[0019] Step S3, controlling the medical linear accelerator to emit square rays from above the quality control phantom to the quality control phantom, wherein the square rays penetrate through each of the placement portions and expose the first film in the first slot, and then proceeding to step S4;

[0020] Step S4, using an external analysis device to analyze each of the irradiated first films to determine the radiotherapy accuracy of the medical linear accelerator.

[0021] Beneficial effects of the present invention:

[0022] The technical solution sets a cross-shaped quality control phantom and sets a metal ball on the back of the quality control phantom, so that when the medical linear accelerator emits square rays, the square rays can irradiate the front of the quality control phantom and leave a projection at the position where the metal ball is, and then the irradiation field area of ​​the square rays can be determined according to the position of each projection, thereby improving the detection accuracy of the medical linear accelerator; at the same time, the technical solution also sets a photo on the back of the first intersection of the quality control phantom and sets a second film on the front of the quality control phantom, so as to detect the position accuracy of each positioning laser lamp according to the distance between the exposure point of the photo and the second film. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the front structure of the quality control phantom of the present invention;

[0024] Figure 2 It is a schematic diagram of the back structure of the quality control phantom of the present invention;

[0025] Figure 3 It is a schematic diagram of the overall structure of the inter-laboratory quality control device for a traditional Chinese medicine linear accelerator of the present invention;

[0026] Figure 4 It is a front structural schematic diagram of the bed detection phantom in the present invention;

[0027] Figure 5 It is a schematic diagram of the back structure of the bed detection phantom in the present invention;

[0028] Figure 6 It is a flow chart of the inter-laboratory quality control method of a traditional Chinese medicine linear accelerator according to the present invention.

[0029] Figure numerals: 1, quality control model; 11, placement part; 12, first slot; 13, first cover plate; 14, first film; 15, first hole; 16, first intersection; 17, second slot; 18, second cover plate; 181, second film; 19, placement bracket; 10, photo; 1A, metal ball; 2, medical linear accelerator; 3, fifth laser; 41, first laser; 42, second laser; 51, third laser; 52, fourth laser; 6, radiotherapy bed; 7, bed detection model; 71, connection part; 72, second intersection; 73, third slot; 74, third cover plate; 75, second hole; 76, third film. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The same parts are represented by the same reference numerals. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to directions in the accompanying drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0031] like Figure 1 As shown, a medical linear accelerator inter-laboratory quality control device of this embodiment includes:

[0032] The cross-shaped quality control phantom 1 includes four strip-shaped placement parts 11, two adjacent placement parts 11 are perpendicular to each other, and a plurality of first notches 12 are evenly spaced on the front of each placement part 11, a first cover plate 13 is buckled on the first notch 12, and a first film 14 is embedded between the first notch 12 and the first cover plate 13. By buckling the first cover plate 13 on the first notch 12, the first film 14 is fixed in the first notch 12 to prevent the first film 14 from falling out of the first notch 12.

[0033] like Figure 2 As shown, the back side of each placement portion 11 is provided with a plurality of first holes 15 for placing metal balls 1A, each first slot 12 corresponds to two first holes 15 arranged along the extension direction of the placement portion 11, and the distances from the two first holes 15 to the two side edges of the first slot 12 perpendicular to the extension direction of the placement portion 11 are consistent.

[0034] The quality control phantom 1 is horizontally fixed with its front side facing downward on a radiotherapy bed 6 of a medical linear accelerator 2;

[0035] Furthermore, before the quality control phantom 1 performs quality control inspection on the medical linear accelerator 2, the radiotherapy bed 6 is moved so that the geometric center of the plane where the first film 14 of the quality control phantom 1 is located coincides with the isocenter of the medical linear accelerator 2.

[0036] When the medical linear accelerator 2 emits square rays from directly above the quality control phantom 1, the square rays penetrate through each placement portion 11 and expose the first films 14 in the first slots 12. The exposed first films 14 are used for analysis by an external analysis device to determine the radiotherapy accuracy of the medical linear accelerator 2.

[0037] In this embodiment, three first slots 12 are opened on the front side of each placement portion 11. The first slots 12 can be square, and the side length of the first slots 12 can be 4 cm. The distance between the first slots 12 on the same placement portion 11 can be 5 cm, and the distance between two adjacent first slots 12 of two relatively arranged placement portions 11 can be 10 cm. Therefore, when the irradiation field of the square ray is 12*12cm, the square ray just irradiates the center of the four first notches 12 on the innermost side of the quality control phantom 1. Therefore, half of the first film 14 in the four first notches 12 on the innermost side is exposed. Since the metal balls 1A cannot be penetrated by the square ray, the metal balls 1A in each first hole 15 leave a projection on the first film 14. When the irradiation field of the square ray is 17*17cm, the square ray just irradiates the center of the four first notches 12 in the middle layer of the quality control phantom 1. Therefore, half of the first film 14 in the four first notches 12 in the middle layer is exposed. Since the metal balls 1A cannot be penetrated by the square ray, the metal balls 1A in each first hole 15 leave a projection on the first film 14. The metal balls 1A in each first hole 15 are penetrated by the square rays, so they leave projections on the first film 14; when the irradiation field of the square rays is 22*22cm, the square rays just irradiate the centers of the four first slots 12 on the outermost side of the quality control phantom 1, so the irradiated half of the first film 14 in the four first slots 12 on the outermost side is exposed, and since the metal balls 1A are not penetrated by the square rays, the metal balls 1A in each first hole 15 leave projections on the first film 14; when the external analysis device can determine the irradiation field area of ​​the square rays according to the positions of the projections on the irradiated first film 14, the detection accuracy of the medical linear accelerator 2 is improved.

[0038] Preferably, the quality control phantom 1 also includes a first intersection 16, four placement portions 11 intersect at the first intersection 16, a second slot 17 is provided on the front of the first intersection 16, a second cover plate 18 is buckled on the second slot 17, a second film 181 is embedded between the second slot 17 and the second cover plate 18, a plurality of third holes (not shown in the figure) for placing the metal balls 1A are provided on the back of the first intersection 16, each second slot 17 corresponds to two third holes arranged along the extension direction of the first intersection 16, and the distances from the two third holes to the two side edges of the second slot 17 perpendicular to the extension direction of the first intersection 16 are consistent; when the medical linear accelerator 2 repeatedly emits an elongated rectangular field intersecting at the center above the back of the first intersection 16 by rotating the beam limiter angle to form accumulated cross-shaped rays, the cross-shaped rays penetrate the first intersection 16 to expose the second film 181, and leave a cross-shaped irradiation field trace on the second film 181. The cross-shaped irradiation field trace on the second film 181 is used to represent the relative position between the medical linear accelerator 2 and the quality control phantom 1 .

[0039] Preferably, a placement bracket 19 for placing an unexposed photo 10 is detachably connected to the back of the first intersection 16, a first positioning laser light is fixedly arranged at a first distance above the quality control phantom 1, and a second positioning laser light and a third positioning laser light are fixedly arranged on the left and right sides of the quality control phantom 1, respectively. The geometric center of the photo 10 is located near a vertical line passing through the isocenter positions of the first positioning laser light, the second positioning laser light and the third positioning laser light, and the convergent lasers of the first positioning laser light, the second positioning laser light and the third positioning laser light expose the photo 10 and leave exposure marks, so that an external analysis device can compare and analyze the exposed second film 181 with the photo 10 to determine the position accuracy between the first positioning laser light, the second positioning laser light and the third positioning laser light and the medical linear accelerator 2. The exposure marks of the first positioning laser light, the second positioning laser light and the third positioning laser light on the photo 10 are used to characterize the relative positions between each positioning laser light and the quality control phantom 1. The external analysis device processes the distance between the center point of the cross-shaped irradiation field trace on the second film 181 and the center point of the exposure trace on the photographic paper to obtain the distance deviation, and detects the position accuracy of each positioning laser lamp according to the distance deviation. When the distance deviation is less than 0.3 mm, the distance deviation is within the controllable deviation range allowed by this embodiment.

[0040] like Figure 3 As shown, preferably, the radiotherapy bed 6 is mounted on the middle part of the frame of the medical linear accelerator 2, the quality control phantom 1 is fixed to the upper end of the radiotherapy bed 6, and the first positioning laser lamp includes a fifth laser 3 for emitting vertical fan-shaped light, and the fifth laser 3 is arranged at the upper end of the foot of the radiotherapy bed 6.

[0041] Preferably, the second positioning laser light comprises a first laser 41 for emitting horizontal fan-shaped light and a second laser 42 for emitting vertical fan-shaped light, and the second laser 42 is arranged directly above the first laser 41. The second positioning laser light is fixed on the left wall of the radiotherapy bed 6.

[0042] Preferably, the third positioning laser light includes a third laser 51 for emitting horizontal fan-shaped light and a fourth laser 52 for emitting vertical fan-shaped light, the fourth laser 52 is arranged directly above the third laser 51, the third laser 51 and the first laser 41 are located on the same horizontal line, and the fourth laser 52 and the second laser 42 are located on the same horizontal line. The third positioning laser light is fixed on the right wall of the radiotherapy bed 6.

[0043] like Figure 4 As shown, preferably, a T-shaped bed detection phantom 7 is also included, and the bed detection phantom 7 is used to be fixed on the upper end of the radiotherapy bed 6 when the quality control phantom 1 is removed from the upper end of the radiotherapy bed 6.

[0044] Preferably, the bed detection model 7 includes three strip-shaped connecting parts 71 and a second intersection part 72, adjacent connecting parts 71 are perpendicular to each other and intersect at the second intersection part 72, and a plurality of third slots 73 are evenly spaced apart on the front of each connecting part 71 and the second intersection part 72, a third cover plate 74 is buckled on the third slot 73, and a third film 76 is embedded between the third slot 73 and the third cover plate 74.

[0045] like Figure 5 As shown, a plurality of second holes 75 for placing the metal balls 1A are provided on the back of each connecting portion 71 and the second intersection portion 72, and each third notch 73 corresponds to two second holes 75 arranged along the extending direction of the connecting portion 71, and the distances from the two second holes 75 to the two sides of the third notch 73 perpendicular to the extending direction of the connecting portion 71 are consistent; the bed position detection phantom 7 is horizontally fixed on the radiotherapy bed 6 of the medical linear accelerator 2 with its front side facing downward; when the medical linear accelerator 2 emits rectangular rays, the rectangular rays irradiate and penetrate through each connecting portion 71 and expose the third film 76 in the third notch 73, and the irradiated third film 76 is used for analysis by an external analysis device to determine the moving position of the radiotherapy bed 6.

[0046] In this embodiment, the third film 76 is a 3*3cm square film, the rectangular ray is 1*3cm, the distance between each third notch 73 is 5cm, and the center of the second intersection 72 coincides with the convergence point of the light emitted by the medical linear accelerator 2. In this embodiment, each third notch 73 corresponds to two second holes 75 arranged vertically. In an ideal state, the rectangular ray just irradiates the third notch 73 on the front of the second intersection 72, and at the same time exposes the central part of the third film 76 corresponding to the third notch 73, and leaves an exposure mark on the third film 76. When the radiotherapy bed 6 moves 5cm to the left, the rectangular ray just irradiates the third notch 73 on the right end connecting part 71 that is closest to the intersection, and at the same time exposes the central part of the third film 76 corresponding to the third notch 73, and leaves an exposure mark on the third film 76. After the radiotherapy bed 6 moves 5 cm to the right, the rectangular ray just irradiates the third notch 73 of the left end connection part 71 closest to the intersection, and at the same time exposes the central part of the third film 76 corresponding to the third notch 73, and leaves an exposure mark on the third film 76. The external analysis device can analyze the relative position between the radiotherapy bed 6 and the medical linear accelerator 2 according to the exposure marks on each third film 76. This technical solution realizes the detection of the relative position between the radiotherapy bed 6 and the medical linear accelerator 2 by setting the bed position detection phantom 7.

[0047] A medical linear accelerator inter-laboratory quality control method is applied to the above-mentioned medical linear accelerator inter-laboratory quality control device, such as Figure 6 As shown, including:

[0048] Step S1, placing a first film in the first notches on the front of the four placement parts of the quality control phantom, and buckling a first cover plate on the first notches, placing metal balls in advance in a plurality of first holes on the back of the four placement parts, each first notch corresponds to two first holes arranged along the extension direction of the placement part, and the distances from the two first holes to the two side edges of the first notch perpendicular to the extension direction of the placement part are consistent, and proceeding to step S2;

[0049] Step S2, fix the quality control phantom horizontally with its front side facing downward on a radiotherapy bed of a medical linear accelerator, move the radiotherapy bed so that the geometric center of the plane where the first film of the quality control phantom is located coincides with the isocenter of the medical linear accelerator, and proceed to step S3;

[0050] Step S3, controlling the medical linear accelerator to emit a square ray from above the quality control phantom to the quality control phantom, the square ray penetrates each placement portion and exposes the first film in the first slot, and then proceeding to step S4;

[0051] Step S4, using an external analysis device to analyze each first film that has been irradiated to determine the radiotherapy accuracy of the medical linear accelerator.

[0052] The above are only preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A medical linear accelerator inter-laboratory quality control device, characterized in that: include: A cross-shaped quality control phantom, the quality control phantom comprising four strip-shaped placement parts, two adjacent placement parts are perpendicular to each other, a plurality of first notches are evenly spaced apart on the front side of each placement part, a first cover plate is buckled on the first notch, and a first film is embedded between the first notch and the first cover plate; A plurality of first holes for placing metal balls are formed on the back of each placement portion, each of the first notches corresponds to two of the first holes arranged along the extension direction of the placement portion, and the distances from the two first holes to the two sides of the first notch perpendicular to the extension direction of the placement portion are consistent; The quality control phantom is fixed horizontally with its front side facing downward on a radiotherapy bed of a medical linear accelerator; When the medical linear accelerator emits square rays from directly above the quality control phantom toward the quality control phantom, the square rays penetrate each of the placement portions and expose the first films in the first slots. The exposed first films are used for analysis by an external analysis device to determine the radiotherapy accuracy of the medical linear accelerator.

2. The medical linear accelerator inter-laboratory quality control device according to claim 1, characterized in that: Before the quality control phantom performs quality control inspection on the medical linear accelerator, the radiotherapy bed is moved so that the geometric center of the plane where the first film of the quality control phantom is located coincides with the isocenter of the medical linear accelerator.

3. The medical linear accelerator inter-laboratory quality control device according to claim 1, characterized in that: The quality control phantom also includes a first intersection, the four placement parts intersect at the first intersection, a second notch is provided on the front of the first intersection, a second cover is buckled on the second notch, a second film is embedded between the second notch and the second cover, a plurality of third holes for placing metal balls are provided on the back of the first intersection, each of the second notches corresponds to two third holes arranged along the extension direction of the first intersection, and the distances from the two third holes to the two sides of the second notch perpendicular to the extension direction of the first intersection are consistent; When the medical linear accelerator repeatedly emits elongated rectangular fields intersecting at the center to form accumulated cross-shaped rays by rotating the beam limiter angle above the back side of the first intersection, the cross-shaped rays penetrate the first intersection to expose the second film and leave a cross-shaped irradiation field trace on the second film.

4. The medical linear accelerator inter-laboratory quality control device according to claim 3, characterized in that: A placement bracket for placing unexposed photos is detachably connected to the back side of the first intersection, a first positioning laser light is fixedly arranged at a first distance above the quality control phantom, a second positioning laser light and a third positioning laser light are fixedly arranged on the left and right sides of the quality control phantom, respectively, the geometric center of the photo is located near a vertical line passing through the isocenter positions of the first positioning laser light, the second positioning laser light and the third positioning laser light, and the first positioning laser light, the second positioning laser light and the third positioning laser light are used to converge laser to expose the photo and leave exposure marks.

5. The medical linear accelerator inter-laboratory quality control device according to claim 4, characterized in that: The second positioning laser light comprises a first laser for emitting horizontal fan-shaped light and a second laser for emitting vertical fan-shaped light, and the second laser is arranged directly above the first laser.

6. The medical linear accelerator inter-laboratory quality control device according to claim 5, characterized in that: The third positioning laser light includes a third laser for emitting horizontal fan-shaped light and a fourth laser for emitting vertical fan-shaped light. The fourth laser is arranged directly above the third laser. The third laser is located on the same horizontal line as the first laser, and the fourth laser is located on the same horizontal line as the second laser.

7. The medical linear accelerator inter-laboratory quality control device according to claim 4, characterized in that: The radiotherapy bed is mounted on the middle part of the frame of the medical linear accelerator, the quality control phantom is fixed on the upper end of the radiotherapy bed, the first positioning laser lamp includes a fifth laser for emitting vertical fan-shaped light, and the fifth laser is arranged at the upper end of the foot of the radiotherapy bed.

8. The medical linear accelerator inter-laboratory quality control device according to claim 7, characterized in that: It also includes a T-shaped bed detection phantom, which is used to be fixed on the upper end of the radiotherapy bed when the quality control phantom is removed from the upper end of the radiotherapy bed.

9. The medical linear accelerator inter-laboratory quality control device according to claim 8, characterized in that: The bed position detection phantom comprises three strip-shaped connecting parts and a second intersection part, the adjacent connecting parts are perpendicular to each other and intersect at the second intersection part, a plurality of third notches are evenly spaced apart on the front of each connecting part and the second intersection part, a third cover plate is buckled on the third notch, a third film is embedded between the third notch and the third cover plate, a plurality of second holes for placing the metal balls are opened on the back of each connecting part and the second intersection part, each third notch corresponds to two second holes arranged along the extension direction of the connecting part, and the distances from the two second holes to the two sides of the third notch perpendicular to the extension direction of the connecting part are consistent; the bed position detection phantom is horizontally fixed on the radiotherapy bed of the medical linear accelerator with the front side facing downward; when the medical linear accelerator emits rectangular rays, the rectangular rays irradiate and penetrate through each connecting part and expose the third film in the third notch, and the exposed third film is used for analysis by an external analysis device to determine the moving position of the radiotherapy bed.

10. A medical linear accelerator inter-laboratory quality control method, applied to the medical linear accelerator inter-laboratory quality control device according to any one of claims 1 to 9, characterized in that: include: Step S1, placing a first film in the first notches on the front of the four placement parts of the quality control phantom, and buckling a first cover plate on the first notches, placing metal balls in advance in a plurality of first holes on the back of the four placement parts, each of the first notches corresponds to two first holes arranged along the extension direction of the placement part, and the distances from the two first holes to the two side edges of the first notch perpendicular to the extension direction of the placement part are consistent, and proceeding to step S2; Step S2, fix the quality control phantom horizontally with its front side facing downward on a radiotherapy bed of a medical linear accelerator, move the radiotherapy bed so that the geometric center of the plane where the first film of the quality control phantom is located coincides with the isocenter of the medical linear accelerator, and proceed to step S3; Step S3, controlling the medical linear accelerator to emit square rays from directly above the quality control phantom to the quality control phantom, wherein the square rays penetrate through each of the placement portions and expose the first film in the first slot, and then proceeding to step S4; Step S4, using an external analysis device to analyze each of the irradiated first films to determine the radiotherapy accuracy of the medical linear accelerator.

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