Laser calibration apparatus for helical tomotherapy device

Abstract

The present invention belongs to the technical field of laser positioning of radiotherapy devices, and provides a laser calibration apparatus for a helical tomotherapy device. Said laser calibration apparatus comprises: a base, a leveling assembly being arranged at the bottom; a deflection frame assembly arranged on the base, the deflection frame assembly being provided with a first scale, a second scale, and two sets of electronic levels, wherein when the deflection frame assembly and the base are in a vertical state, an overhead laser lamp is calibrated, and when the deflection frame assembly and the base are in a parallel state, a backhead laser lamp is calibrated; an ionization chamber matrix arranged on the base, a first cross line being arranged at the top of the ionization chamber matrix, and the intersection point of the first cross line being located at the center of the top of the ionization chamber matrix; and a circular hole arranged on a side wall of the base, a second cross line being arranged on the side wall where the circular hole is located, and the intersection point of the second cross line being located above the center of the circular hole. According to the present invention, the operation of calibrating a laser lamp of the helical tomotherapy device can be simplified, and the calibration efficiency and calibration accuracy are improved.

Description

Laser calibration device for helical tomotherapy device TECHNICAL FIELD

[0001] The present application belongs to the technical field of laser positioning of radiotherapy equipment, and particularly relates to a laser calibration device for a helical tomotherapy device. BACKGROUND

[0002] The helical tomotherapy system (TOMO Therapy) integrates IMRT (intensity modulated radiotherapy), IGRT (image-guided intensity modulated radiotherapy) and DGRT (dose-guided intensity modulated radiotherapy), is a world-class tumor radiotherapy device, and has a unique design in a helical CT rotating scanning mode combined with computer tomographic image navigation adjustment, breaks through many limitations of traditional accelerators, focuses on tomographic irradiation of tumors under CT guidance in 360 degrees, and can realize efficient, accurate and safe radiotherapy for malignant tumor patients.

[0003] An important link in accurate radiotherapy is accurate positioning of a patient, and as an important positioning auxiliary tool, a laser lamp in a treatment room is a commonly used device of a radiotherapy department treatment equipment. Different from a conventional linear accelerator, the laser system of the helical tomotherapy device has two sets, which are green laser and red laser. The green laser is a fixed positioning system located at a position of 700mm outside the field center (in the direction of the tail of the treatment bed), and is used for physical quality control positioning and calibration of the red laser system. The laser system has two, which are located at the back wall (referred to as backhead laser) behind the treatment system and the ceiling side (referred to as overhead laser, located in the direction of the head of a person standing). The green laser lamp is first calibrated according to the field center of the helical tomotherapy device, and then is used for physical quality control positioning by a radiotherapy physicist. At the same time, the green laser lamp is calibrated to the red laser lamp, and the red laser lamp is used for positioning of the patient during treatment. Therefore, whether the laser lamp meets the requirements of the system center is very important. At present, the calibration of the laser lamp usually relies on manual search for a reference position by using a steel ruler and a solid water device, needs to use a film, and the operation steps and processes are relatively complicated. When the steel ruler is manually moved, the horizontal or vertical state cannot be guaranteed, and errors are prone to occur. In the later system use process, the laser lamp position is repeatedly adjusted, and visual fatigue is easily caused when the red laser is adjusted to align with the green laser. This manual alignment position method is very time-consuming and labor-consuming, and is low in efficiency.

[0004] SUMMARY

[0005] The purpose of the present application is to provide a laser calibration device for a helical tomotherapy device to solve the above problems, simplify the operation of calibration of the laser lamp of the helical tomotherapy device, improve the calibration efficiency, and improve the calibration accuracy.

[0006] To achieve the above object, the present application provides the following scheme: a laser calibration device for a helical tomotherapy device, comprising:

[0007] a base, the bottom of the base is provided with a leveling assembly;

[0008] a deflection frame assembly, the deflection frame assembly is provided on the base, the deflection frame assembly is respectively provided with a first scale, a second scale and two sets of electronic levels, when the deflection frame assembly is perpendicular to the base, the overhead laser lamp can be calibrated, when the deflection frame assembly is parallel to the base, the back wall laser lamp can be calibrated;

[0009] an ionization chamber matrix, the ionization chamber matrix is provided on the base, the top of the ionization chamber matrix is provided with a first cross line, the intersection point of the first cross line is located at the top center of the ionization chamber matrix;

[0010] a circular hole, the circular hole is provided on the side wall of the base, the side wall where the circular hole is located is provided with a second cross line, the intersection point of the second cross line is located above the center of the circular hole.

[0011] Preferably, the deflection frame assembly comprises two sets of support seats fixedly connected to the top of the base, a rotating rod is rotatably connected between the two sets of support seats, angle limiting members are respectively arranged between the two ends of the rotating rod and the two sets of support seats, the angle limiting members are used for limiting the rotating rod when the rotating rod rotates by 90 degrees, longitudinal beams are respectively fixedly connected to the two ends of the rotating rod, the two sets of longitudinal beams are arranged in parallel, the axis of the longitudinal beams is perpendicular to the axis of the rotating rod, a cross beam is fixedly connected between the ends of the two sets of longitudinal beams away from the rotating rod, the first scale is rotatably connected to one of the longitudinal beams, the second scale is rotatably connected to the cross beam, and the two sets of electronic levels are respectively fixedly connected to the cross beam and one of the longitudinal beams.

[0012] Preferably, the cross section of the longitudinal beam and the cross beam is C-shaped.

[0013] Preferably, sliding sleeves are respectively slidably connected to the longitudinal beams and the cross beam, sliding driving members are arranged between the longitudinal beams, the cross beam and the sliding sleeves, the sliding driving members located on the longitudinal beams are drivingly connected to a first motor through a first transmission member, and the sliding driving members located on the cross beam are connected to a second motor through a second transmission member.

[0014] Preferably, the sliding driving part on the longitudinal beam comprises a screw rod rotationally connected in the longitudinal beam, an axis of the screw rod coincides with an axis of the longitudinal beam, a tooth block is fixedly connected on an inner wall of the sliding sleeve on the longitudinal beam, and a transmission tooth on the tooth block is engaged with the screw rod.

[0015] A rotation preventing part is further arranged between the sliding sleeve and the longitudinal beam, the rotation preventing part comprises a protrusion fixedly connected on the inner wall of the sliding sleeve and a groove opened on a side wall of the longitudinal beam, the groove is parallel to the axis of the longitudinal beam, and the protrusion is slidingly connected in the groove.

[0016] Preferably, two groups of the sliding sleeves are rotationally sleeved with rotation sleeves respectively, and the first scale and the second scale are fixedly connected on two groups of the rotation sleeves respectively.

[0017] Preferably, the angle limiting part comprises two groups of clamping grooves opened in the support base, an included angle between the two groups of clamping grooves is 90 degrees, an end of the rotation rod is provided with a sliding groove, a steel ball is slidingly connected in the sliding groove, a spring is abutted between the steel ball and a bottom of the sliding groove, and the steel ball is correspondingly arranged with the clamping groove.

[0018] Preferably, the leveling assembly comprises three groups of balance nuts, the three groups of balance nuts are threadedly connected on a bottom of the base respectively, and the three groups of balance nuts are distributed in a triangular shape.

[0019] Preferably, a top surface of the ionization chamber matrix is parallel to a top surface of the base.

[0020] The ionization chamber matrix is arranged with a plurality of ionization chambers, a top of the ionization chamber matrix is covered with an equivalent water material, and the first cross line is arranged on the equivalent water material.

[0021] Preferably, a diameter of the circular hole is 5mm, and a center of the circular hole is located 5mm below a cross point of the second cross line.

[0022] Compared with the prior art, the application has the following advantages and technical effects: the leveling assembly mainly functions to adjust the base to be in a horizontal state; the two sets of electronic levels mainly function to display that the base is in a horizontal state and that the deflection frame assembly is in a horizontal state or a vertical state; the first scale and the second scale mainly function to judge whether the cross section of the laser lamp is inclined or not through the projection of the laser lamp on the first scale or the second scale, thereby providing a basis for the next adjustment; the ionization chamber matrix and the first cross line mainly function to replace the traditional film, and the bar-shaped flux diagram obtained after the laser lamp irradiates the ionization chamber matrix is used to adjust the laser lamp; the round hole and the second cross line mainly function to replace the Cheese Phantom phantom, and the wall laser lamp is adjusted. Overall, the application can simplify the operation of calibrating the laser lamp of the helical tomotherapy device, improve the calibration efficiency, and improve the calibration accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0024] Fig. 1 is a schematic view of the deflection frame assembly in a tilted state of the calibration device of the present application;

[0025] Fig. 2 is a schematic view of the deflection frame assembly in an upright state of the calibration device of the present application;

[0026] Fig. 3 is a schematic view of the deflection frame assembly of the present application;

[0027] Fig. 4 is a schematic view of the end surface of the longitudinal beam and the sliding sleeve of the present application;

[0028] Fig. 5 is a schematic view of the angle limiting member of the present application;

[0029] Fig. 6 is a bottom view of the base of the present application;

[0030] Among them, 1, base; 2, ionization chamber matrix; 3, ionization chamber; 4, first cross line; 5, round hole; 6, second cross line; 7, support seat; 8, first motor; 9, rotating rod; 10, second motor; 11, longitudinal beam; 12, sliding sleeve; 13, rotating sleeve; 14, first scale; 15, electronic level; 16, steel ball; 17, second scale; 18, cross beam; 19, balance nut; 20, screw rod; 21, tooth block; 22, protrusion; 23, groove; 24, sliding groove; 25, clamping groove; 26, spring. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0032] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0033] Referring to FIGS. 1-6, the present application provides a laser calibration device for a helical tomotherapy device, comprising:

[0034] a base 1, the bottom of the base 1 is provided with a leveling assembly;

[0035] a deflection frame assembly, the deflection frame assembly is arranged on the base 1, the deflection frame assembly is respectively provided with a first scale 14, a second scale 17 and two sets of electronic levels 15, when the deflection frame assembly is in a vertical state with the base 1, the head laser lamp can be calibrated, when the deflection frame assembly is in a parallel state with the base 1, the back wall laser lamp can be calibrated;

[0036] an ionization chamber matrix 2, the ionization chamber matrix 2 is arranged on the base 1, the top of the ionization chamber matrix 2 is provided with a first cross line 4, the intersection point of the first cross line 4 is located at the top center of the ionization chamber matrix 2;

[0037] a round hole 5, the round hole 5 is arranged on the side wall of the base 1, the side wall where the round hole 5 is arranged is provided with a second cross line 6, the intersection point of the second cross line 6 is located above the center of the round hole 5.

[0038] The main function of the leveling assembly is to adjust the base 1 to be in a horizontal state; the main function of the two sets of electronic levels 15 is to display that the base 1 is in a horizontal state, and to display that the deflection frame assembly is in a horizontal state or a vertical state; the main function of the first scale 14 and the second scale 17 is to judge whether the cross section of the laser lamp is inclined or not through the projection of the laser lamp on the first scale 14 or the second scale 17, so as to provide a basis for the next adjustment; the main function of the ionization chamber matrix 2 and the first cross line 4 is to replace the traditional method of film, and to adjust the laser lamp through the strip flux diagram obtained after the laser lamp irradiates the ionization chamber matrix 2; the main function of the round hole 5 and the second cross line 6 is to replace the Cheese Phantom phantom, and to adjust the back wall laser lamp. Overall, the present application can simplify the operation of calibrating the laser lamp of the helical tomotherapy device, improve the calibration efficiency, and at the same time improve the calibration accuracy.

[0039] Further optimization scheme, the deflection frame assembly includes two groups of support seats 7 fixedly connected on the top of the base 1, a rotating rod 9 is rotatably connected between the two groups of support seats 7, angle limiting pieces are arranged between the two ends of the rotating rod 9 and the two groups of support seats 7 respectively, and the angle limiting pieces are used for limiting the rotating rod 9 when the rotating rod 9 rotates by 90 degrees, longitudinal beams 11 are fixedly connected to the two ends of the rotating rod 9 respectively, the two groups of longitudinal beams 11 are arranged in parallel, and the axis of the longitudinal beams 11 is perpendicular to the axis of the rotating rod 9, a cross beam 18 is fixedly connected between the ends of the two groups of longitudinal beams 11 away from the rotating rod 9, the first scale 14 is rotatably connected to one longitudinal beam 11, the second scale 17 is rotatably connected to the cross beam 18, and the two groups of electronic levels 15 are fixedly connected to the cross beam 18 and one longitudinal beam 11 respectively.

[0040] As shown in FIGS. 1 and 2, the longitudinal beams 11 and the cross beam 18 are made of metal, and the positive direction frame size formed by the longitudinal beams 11 and the cross beam 18 is 35cm*35cm. The electronic level 15 fixedly connected to the cross beam 18 is arranged in parallel with the axis direction of the cross beam 18, and the electronic level 15 fixedly connected to the longitudinal beam 11 is arranged in parallel with the axis of the longitudinal beam 11.

[0041] Further optimization scheme, the cross section of the longitudinal beams 11 and the cross beam 18 is C-shaped.

[0042] Further optimization scheme, sliding sleeves 12 are slidably connected to the longitudinal beams 11 and the cross beam 18 respectively, sliding driving pieces are arranged between the longitudinal beams 11, the cross beam 18 and the sliding sleeves 12, the sliding driving piece located on the longitudinal beam 11 is drivingly connected to the first motor 8 through a first transmission member, and the sliding driving piece located on the cross beam 18 is connected to the second motor 10 through a second transmission member.

[0043] Further optimization scheme, the sliding driving piece located on the longitudinal beam 11 includes a screw rod 20 rotatably connected in the longitudinal beam 11, the axis of the screw rod 20 coincides with the axis of the longitudinal beam 11, a tooth block 21 is fixedly connected to the inner wall of the sliding sleeve 12 located on the longitudinal beam 11, and the transmission teeth on the tooth block 21 are engaged with the screw rod 20.

[0044] A rotation preventing piece is further arranged between the sliding sleeve 12 and the longitudinal beam 11, the rotation preventing piece includes a protrusion 22 fixedly connected to the inner wall of the sliding sleeve 12 and a groove 23 formed in the side wall of the longitudinal beam 11, the groove 23 is parallel to the axis of the longitudinal beam 11, and the protrusion 22 is slidably connected in the groove 23.

[0045] Further optimization scheme, a battery and a control unit are arranged on the base 1, and the control unit can control the first motor 8 and the second motor 10 by receiving remote control instructions of an operator.

[0046] The control unit and the battery are conventional means, and the working process and the working principle thereof will not be described herein.

[0047] As shown in FIG. 3 and FIG. 4, the sliding sleeve 12 is supported on the longitudinal beam 11 to slide due to the limiting effect between the protrusion 22 and the groove 23. The screw rod 20 and the tooth block 21 form a linear guide rail structure. When the first motor 8 drives the screw rod 20 to rotate through the first transmission member, the screw rod 20 drives the tooth block 21 to move through the meshing between the screw rod 20 and the tooth block 21, thereby realizing the effect that the sliding sleeve 12 drives the first scale 14 to slide on the longitudinal beam 11.

[0048] Similarly, the control unit controls the second motor 10 to drive the screw rod 20 on the cross beam 18 to rotate through the second transmission member, thereby realizing the effect that the sliding sleeve 12 on the cross beam 18 slides along the cross beam 18.

[0049] In a further optimization, the first transmission member includes a first bevel gear fixedly sleeved on the output shaft of the first motor 8 and a second bevel gear fixedly connected to one end of the screw rod 20, and the first bevel gear is meshed with the second bevel gear.

[0050] In a further optimization, the second transmission member includes an intermediate rotating rod rotatably connected in another longitudinal beam 11 without the sliding sleeve 12, and the two ends of the intermediate rotating rod are fixedly connected with a third bevel gear. A fourth bevel gear is fixedly sleeved on the output shaft of the second motor 10, and one end of the screw rod 20 located in the cross beam 18 is fixedly connected with a fifth bevel gear. The fifth bevel gear and the fourth bevel gear are respectively meshed with the two groups of third bevel gears.

[0051] In a further optimization, a rotating sleeve 13 is rotatably sleeved on each of the two groups of sliding sleeves 12, and the first scale 14 and the second scale 17 are fixedly connected to the two groups of rotating sleeves 13, respectively.

[0052] As shown in FIG. 1 and FIG. 2, the main function of the rotating sleeve 13 is to make the first scale 14 and the second scale 17 rotate around the axis of the two groups of sliding sleeves 12, respectively.

[0053] In a further optimization, a rotating resistance exists between the rotating sleeve 13 and the sliding sleeve 12 to ensure that the rotating sleeve 13 will not automatically rotate on the sliding sleeve 12 without external force.

[0054] In a further optimization, the angle limiting member includes two groups of clamping grooves 25 opened in the support base 7, and the included angle between the two groups of clamping grooves 25 is 90 degrees. The end of the rotating rod 9 is provided with a sliding groove 24, the steel ball 16 is slidably connected in the sliding groove 24, the spring 26 abuts between the steel ball 16 and the bottom of the sliding groove 24, and the steel ball 16 is correspondingly arranged with the clamping groove 25.

[0055] As shown in Fig. 5, by partially engaging the steel ball 16 in the clamping groove 25, a moving resistance is formed between the sliding groove 24 and the clamping groove 25, which limits the rotation of the rotating rod 9 and ensures that the longitudinal beam 11 can be stably in the horizontal state or the vertical state.

[0056] In a further optimization, the leveling assembly includes three sets of balancing nuts 19, which are respectively threadedly connected to the bottom of the base 1 and are arranged in a triangular shape.

[0057] As shown in Fig. 6, by screwing the three sets of balancing nuts 19 to change the length of the protrusion from the base 1, the horizontal state of the base 1 can be adjusted.

[0058] In a further optimization, the top surface of the ionization chamber matrix 2 is parallel to the top surface of the base 1.

[0059] The ionization chamber matrix 2 is provided with a plurality of ionization chambers 3, and the top of the ionization chamber matrix 2 is covered with equivalent water material, and the first cross line 4 is arranged on the equivalent water material.

[0060] By making the top surface of the ionization chamber matrix 2 parallel to the top surface of the base 1, when the base 1 is in the horizontal state, it means that the top surface of the ionization chamber matrix 2 is in the horizontal state.

[0061] The thickness of the equivalent water material is 1 cm, which can be used as a building material when the ionization chamber matrix 2 is irradiated by high-energy X-rays.

[0062] In a further optimization, the diameter of the circular hole 5 is 5 mm, and the center of the circular hole 5 is located 5 mm below the intersection point of the second cross line 6.

[0063] The working process of the embodiment is as follows:

[0064] In the first step, the base of the device is placed on the treatment bed during use, and the opening of the circular hole 5 can face the TOMO gantry aperture or face away from the gantry aperture. The longitudinal beam 11 is lifted to form an angle of about 90 degrees with the plane of the base 1. The three balancing nuts 19 under the base 1 are adjusted respectively to make the readings of the electronic levels 15 arranged on the longitudinal beam 11 and the cross beam 18 be 90 degrees and 0 degrees respectively. At this time, the plane of the cross beam 18 and the base 1 is in the horizontal state, and the longitudinal beam 11 is in the absolute vertical state. By controlling the first motor 8 and the second motor 10, the first scale 14 and the second scale 17 are moved in the vertical direction and the horizontal direction respectively. The cross section of the overhead laser projects on the scale line of the first scale 14 moving in the vertical direction, and the projection position of the overhead laser on the scale line can be observed to determine whether the cross section of the overhead laser is tilted, and then adjusted. Thus, the first step is completed.

[0065] Second step, no film is needed in this step. The X direction of the first cross line 4 is positioned according to the overhead laser cross section projection, and then the subprogram Overhead laser in TG-148 in the physical quality control program is called. After the beam is emitted, the bar-shaped flux map obtained by irradiating the ionization chamber matrix 2 is directly exported to the computer system scanning software for analysis by using wireless transmission, and the offset and twist values are obtained. If the offset exceeds the allowed offset range, the up and down keys of the laser remote controller are used to adjust the offset.

[0066] Third step, the back wall laser lamp crown plane is adjusted to be horizontal:

[0067] The longitudinal beam 11 is rotated to be parallel to the base 1, the first scale 14 is rotated by 90 degrees around the longitudinal beam 11, the second scale 17 is rotated by 90 degrees around the cross beam 18, and the three balance nuts 19 of the base 1 are adjusted so that the readings of the two sets of electronic levels 15 are both 0 degrees. The TOMO treatment bed is raised, and the back wall crown plane laser lamp is projected on the scale lines of the first scale 14 and the second scale 17. The first scale 14 and the second scale 17 are controlled to move along the longitudinal beam 11 and the cross beam 18 respectively by the first motor 8 and the second motor 10, so that whether the back wall crown plane laser lamp is always projected on the same scale line during the movement of the scales can be checked. If not, the tilt and rotate are adjusted respectively, and thus the tilt of the back wall laser lamp sagittal plane is also adjusted to be zero.

[0068] Fourth step, the tilt of the overhead sagittal plane is adjusted to coincide with the tilt of the back wall laser lamp sagittal plane, and then the tilt of the back wall sagittal plane is adjusted to coincide with the tilt of the overhead sagittal plane.

[0069] Fifth step, the Cheese Phantom phantom is no longer needed, and the circular hole 5 of the device is positioned towards the back wall laser lamp. When positioning, the green laser sagittal plane and the crown plane are projected on the second cross line 6. The bed is advanced by 700 mm, and the relative positions of the laser lamp and the device are observed from the back wall. The bed value is adjusted so that the green lamp is aligned with the second cross line 6. At this time, the green laser sagittal plane is perpendicular to the center of the circular hole 5 which is lowered by 5 mm. The bed is retreated by 700 mm, and the device is scanned in the treatment room. The image position of the phantom is adjusted in the registration interface so that the geometric center of the transverse plane coincides with the center of the second cross line 6. The X and Z direction registration deviation values are obtained, which are positive or negative. The bed X and Z are adjusted by using the registration deviation values in the treatment room. The bed is advanced by 700 mm again, and the positions of the laser lamp and the device are observed from the back wall. At this time, the center position of the second cross line 6 is the position of the image and the treatment center. The back wall laser lamp is adjusted to coincide with the center of the cross line by using the laser remote controller.

[0070] Sixth step, the overhead sagittal plane is adjusted to coincide with the back wall sagittal plane: the overhead laser lamp sagittal plane is adjusted by move to coincide with the back wall laser lamp sagittal plane. At this time, the alignment of the green laser lamp is completed.

[0071] Seventh step, the cross section, the sagittal plane and the coronal plane of the red laser lamp are respectively coincided with the green laser lamp, and the alignment and calibration of the red laser lamp is completed. The process is easy to cause visual fatigue when adjusting the red laser lamp in the prior art. The coincidence accuracy of the red laser lamp and the green laser lamp is difficult to be accurately identified by naked eyes due to chromatic aberration. When the device is used, the scale lines of the transverse moving scale and the longitudinal moving scale can be first completely coincided with the green laser during the moving process, then the green laser is turned off, and then the adjustment is performed according to the projection position of the red laser on the scale lines of the moving scale.

[0072] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0073] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A laser calibration device for a helical tomotherapy apparatus, characterized in that, The utility model relates to a laser calibration device for laser screen, which comprises: a base (1) provided with a leveling assembly at the bottom; a deflection frame assembly provided on the base (1), which is provided with a first scale (14), a second scale (17) and two groups of electronic levels (15) respectively, and can calibrate overhead laser lamps when the deflection frame assembly is perpendicular to the base (1), and can calibrate back wall laser lamps when the deflection frame assembly is parallel to the base (1); an ionization chamber matrix (2) provided on the base (1), which is provided with a first cross line (4) at the top, and the intersection of the first cross line (4) is located at the top center of the ionization chamber matrix (2); a round hole (5) provided on the side wall of the base (1), and a second cross line (6) is provided on the side wall where the round hole (5) is located, and the intersection of the second cross line (6) is located above the center of the round hole (5).

2. A laser calibration device for a helical tomotherapy apparatus as defined in claim 1, characterized in that: The deflection frame assembly comprises two groups of support seats (7) fixedly connected to the top of the base (1), a rotating rod (9) rotatably connected between the two groups of support seats (7), angle limiting pieces provided between the two ends of the rotating rod (9) and the two groups of support seats (7) for limiting the rotating rod (9) when the rotating rod (9) rotates by 90 degrees, longitudinal beams (11) fixedly connected to the two ends of the rotating rod (9), the two groups of longitudinal beams (11) being arranged in parallel and the axis of the longitudinal beams (11) being perpendicular to the axis of the rotating rod (9), a cross beam (18) fixedly connected between the ends of the two groups of longitudinal beams (11) away from the rotating rod (9), the first scale (14) being rotatably connected to one of the longitudinal beams (11), the second scale (17) being rotatably connected to the cross beam (18), and the two groups of electronic levels (15) being fixedly connected to the cross beam (18) and one of the longitudinal beams (11) respectively.

3. A laser calibration device for a helical tomotherapy apparatus as defined in claim 2, characterized in that: The cross section of the longitudinal beams (11) and the cross beam (18) is C-shaped.

4. A laser calibration device for a helical tomotherapy apparatus as defined in claim 3, characterized in that: Sliding sleeves (12) are slidably connected to the longitudinal beams (11) and the cross beam (18) respectively, sliding driving pieces are arranged between the longitudinal beams (11), the cross beam (18) and the sliding sleeves (12), the sliding driving piece located on the longitudinal beam (11) is drivingly connected to a first motor (8) through a first transmission member, and the sliding driving piece located on the cross beam (18) is connected to a second motor (10) through a second transmission member.

5. A laser calibration device for a helical tomotherapy apparatus as defined in claim 4, wherein: The sliding driving piece located on the longitudinal beam (11) comprises a screw rod (20) rotatably connected in the longitudinal beam (11), the axis of the screw rod (20) coincides with the axis of the longitudinal beam (11), a tooth block (21) is fixedly connected to the inner wall of the sliding sleeve (12) located on the longitudinal beam (11), and the transmission teeth on the tooth block (21) are engaged with the screw rod (20). A rotation prevention piece is arranged between the sliding sleeve (13) and the longitudinal beam (11), which comprises a protrusion (22) fixedly connected to the inner wall of the sliding sleeve (13) and a groove (23) arranged on the side wall of the longitudinal beam (11), the groove (23) is parallel to the axis of the longitudinal beam (11), and the protrusion (22) is slidingly connected in the groove (23).

6. A laser calibration device for a helical tomotherapy apparatus as defined in claim 4, wherein: Two groups of rotating sleeves (13) are rotatably sleeved on the two groups of sliding sleeves (12), and the first scale (14) and the second scale (17) are fixedly connected to the two groups of rotating sleeves (13) respectively.

7. A laser alignment device for a helical tomotherapy apparatus as defined in claim 2, wherein: The angle limiting piece comprises two groups of clamping grooves (25) arranged in the support base (7), the included angle between the two groups of clamping grooves (25) is 90 degrees, the end of the rotating rod (9) is provided with a sliding groove (24), a steel ball (16) is slidingly connected in the sliding groove (24), a spring (26) is in abutment between the steel ball (16) and the bottom of the sliding groove (24), and the steel ball (16) is arranged in correspondence with the clamping groove (25).

8. A laser alignment device for a helical tomotherapy apparatus as defined in claim 2, wherein: The leveling assembly comprises three groups of balance nuts (19), which are threadedly connected to the bottom of the base (1) respectively, and the three groups of balance nuts (19) are distributed in a triangular shape.

9. The laser alignment device for a helical tomotherapy apparatus of claim 1, wherein: The top surface of the ionization chamber matrix (2) is parallel to the top surface of the base (1); A plurality of ionization chambers (3) are arranged in the ionization chamber matrix (2) in an array, the top of the ionization chamber matrix (2) is covered with equivalent water material, and the first cross line (4) is arranged on the equivalent water material.

10. A laser calibration device for a helical tomotherapy apparatus as defined in claim 1, wherein: The diameter of the circular hole (5) is 5mm, and the center of the circular hole (5) is located 5mm below the intersection point of the second cross line (6).

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