A method and device for controlling the position of a beam target of a medical linear accelerator

Abstract

The present invention discloses a method and device for controlling the position of a beam target of a medical linear accelerator. The control method includes: controlling the verticality of a beam component: establishing a spatial coordinate system with an isocenter as the origin of the spatial coordinates, determining the fitting function of the straight line of the radiation beam axis in the spatial coordinate system, determining the angle θ between the radiation beam axis and the X0Y plane according to the fitting function of the straight line of the radiation beam axis, and controlling the verticality of the beam component according to the angle θ; controlling the horizontal position of the beam component: scanning the isocenter plane to obtain the center position of the radiation field of the radiation beam, determining the offset ΔL of the center of the radiation field of the radiation beam relative to the isocenter on the X0Y plane, decomposing it into the X and Y directions, determining the offset ΔX and ΔY of the radiation beam axis on the X and Y axes, and controlling the horizontal position of the beam component according to the offset ΔX and ΔY. The present invention first controls the verticality of the beam component, and then controls the horizontal position of the beam component, so as to realize the automatic control of the position of the beam target of the medical linear accelerator.

Description

Technical Field

[0001] The present invention relates to the technical field of radiotherapy equipment, and in particular to a method and device for controlling the position of a beam target of a medical linear accelerator. Background Art

[0002] Medical linear accelerators use electrons to bombard targets to generate X-rays for clinical tumor radiotherapy. For isocenter treatment with medical linear accelerators, the maximum offset of the radiation beam axis relative to the isocenter point cannot be greater than 2mm. After the beam assembly is installed on the accelerator gimbal, if the beam target position is not aligned with the accelerator gimbal ray outlet center or the radiation beam axis angle offset is too large, it will not meet the requirements of accelerator isocenter precision treatment, and the beam target position needs to be adjusted. At the same time, the beam assembly is very heavy. If there is no suitable method for beam target position adjustment, it will take many times to achieve the desired effect.

[0003] The existing beam target position control has the following problems:

[0004] (1) The control of beam target position mostly relies on manual calibration, and the control is mostly based on feel and experience. There is a lack of quantitative control methods, long debugging cycle, and poor control effect.

[0005] (2) The beam target position control structure is not very operable and requires a lot of time and effort.

[0006] (3) When adjusting the horizontal direction, each direction affects each other. When the target position moves in one direction, it will affect the other direction, causing the position of the other direction to shift, which requires repeated correction.

[0007] (4) The mass of the beam assembly is large. After the random frame moves, the radiation beam axis is prone to deviation relative to the isocenter. Regular inspection is required. If there is deviation, repeated calibration is required.

[0008] In view of this, the present invention patent is proposed. Summary of the invention

[0009] In order to solve the above technical problems, the present invention provides a medical linear accelerator beam target position control method and control device. The control method detects and obtains the deviation between the current beam target position of the medical linear accelerator and the target target position, calculates the control parameters of the medical linear accelerator beam target position, and the control device realizes adaptive control of the medical linear accelerator beam target according to the control method.

[0010] Specifically, the following technical solutions are adopted:

[0011] A method for controlling the position of a beam target of a medical linear accelerator, comprising:

[0012] Control the verticality of the beam assembly: establish a spatial coordinate system with the isocenter as the origin of the spatial coordinate system, determine the fitting function of the radiation beam axis line in the spatial coordinate system, determine the angle θ between the radiation beam axis and the X0Y plane according to the fitting function of the radiation beam axis line, and control the verticality of the beam assembly according to the angle θ;

[0013] Horizontal position control of the beam assembly: Scan the isocenter plane to obtain the center position of the radiation field of the radiation beam, determine the offset ΔL of the radiation field center relative to the isocenter on the X0Y plane, decompose it into the X and Y directions, determine the offset ΔX and ΔY of the radiation beam axis on the X and Y axes, and control the horizontal position of the beam assembly according to the offset ΔX and ΔY;

[0014] After the beam assembly is regulated, the radiation beam emitted by the regulated beam assembly is scanned to verify whether the verticality of the radiation beam axis and the coincidence between the radiation beam field center and the isocenter meet the preset requirements. If so, the beam target position regulation is completed; if not, the verticality regulation and horizontal position regulation of the beam assembly are continued until the preset requirements of the verification are met.

[0015] As an optional embodiment of the present invention, in a method for controlling the position of a medical linear accelerator beam target of the present invention, the verticality control of the beam assembly is performed using the isocenter as the origin of the spatial coordinate system to establish a spatial coordinate system, and determining the fitting function of the radiation beam axis line in the spatial coordinate system includes:

[0016] Establish a spatial coordinate system with the isocenter as the origin of the spatial coordinates;

[0017] Control the dose detector to scan along the Z axis to obtain the radiation beam at different depths Z in the Z axis. 1 …Z n The hash value of the radiation center position is recorded as {Z 1 (X 1 ,Y 1 )…Z i (X i ,Y i )…Z n (X n ,Y n )};

[0018] Assume that the fitting function of the radiation beam axis line is set to: AX+BY+CZ+D=0;

[0019] The sum of squares of the straight-line distances Q between each radiation center position and the target beam axis is obtained:

[0020]

[0021] Where: i——The influence factor of different source-skin distances. The closer to the isocenter plane, the greater the δ i The higher;

[0022] Partial derivatives to find the minimum:

[0023]

[0024]

[0025]

[0026]

[0027] The values ​​of A, B, C, and D in the fitting function of the radiation beam axis line are calculated, and finally the fitting function of the radiation beam axis line is determined.

[0028] As an optional embodiment of the present invention, in a method for controlling the position of a beam target of a medical linear accelerator of the present invention, controlling the verticality of the beam component according to the angle θ in the verticality control of the beam component includes:

[0029] Project the angle θ onto the X0Z plane to obtain the angle θ X0Z , projected onto the Y0Z plane, the angle θ Y0Z ;

[0030] The theoretical control distances of the beam assembly in the X-axis direction are calculated as follows:

[0031] Elevation direction: d Y0Z仰 =-r.cosθ Y0Z

[0032] Depression direction: d Y0Z俯 =+r.cosθ Y0Z

[0033] The theoretical control distances of the beam assembly in the Y-axis direction are calculated as follows:

[0034] Elevation direction: d X0Z仰 =-r.cosθ X0Z

[0035] Depression direction: d X0Z俯 =+r.cosθ X0Z

[0036] in:

[0037] + / -——indicates the movement direction of the beam assembly on the Z axis;

[0038] r is the radius of the circle on the plane that controls the verticality of the beam assembly.

[0039] As an optional embodiment of the present invention, in a method for controlling the position of a beam target of a medical linear accelerator of the present invention, the verticality control of the beam assembly includes:

[0040] According to the calculated theoretical control distance d of the beam assembly in the X-axis direction Y0Z仰 ,d Y0Z俯 Determine the actual control distance of the beam assembly in the X-axis direction as k*d Y0Z仰 , k*d Y0Z俯 ;

[0041] According to the calculated theoretical control distance d of the beam assembly in the Y-axis direction X0Z仰 ,d X0Z俯 Determine the actual control distance of the beam assembly in the Y-axis direction as k*d X0Z仰 、k*d X0Z俯 ;

[0042] Wherein, the k is a preset value, 0<k<1.

[0043] As an optional embodiment of the present invention, in a method for controlling the position of a beam target of a medical linear accelerator of the present invention, controlling the horizontal position of the beam component according to the offsets ΔX and ΔY in the horizontal position control of the beam component includes:

[0044] Determining the adjustment direction of the beam assembly on the X0Y plane according to the offset direction of the field center of the radiation beam relative to the isocenter on the X0Y plane;

[0045] According to the offsets ΔX and ΔY, the control amounts of the beam assembly in the X-axis and Y-axis directions are determined to be k*ΔX and k*ΔY respectively.

[0046] The present invention also provides a control device for realizing the method for controlling the position of the beam target of a medical linear accelerator, comprising:

[0047] Beam assembly;

[0048] A verticality control seat, on which the beam assembly is installed;

[0049] An X-direction regulating seat, on which the verticality regulating seat is installed;

[0050] A Z-direction regulating mechanism is installed on the verticality regulating seat, and the verticality regulating seat is adjusted by the Z-direction regulating mechanism to form an angle θ with respect to the X-direction regulating seat, so as to achieve verticality regulation of the beam assembly;

[0051] A Y-direction regulating seat, on which the X-direction regulating seat is slidably mounted along the X-axis direction;

[0052] An X-direction regulating mechanism is installed on the Y-direction regulating seat, and the X-direction regulating seat is adjusted according to the offset ΔX by the X-direction regulating mechanism Y;

[0053] The accelerator gimbal, the Y-direction regulating seat is slidably mounted on the accelerator gimbal along the Y-axis direction;

[0054] A Y-direction regulating mechanism is mounted on the accelerator gimbal, and the Y-direction regulating seat is adjusted according to the offset ΔY by the Y-direction regulating mechanism Y;

[0055] The horizontal position adjustment of the beam assembly is achieved through the X-direction adjustment mechanism and the Y-direction adjustment mechanism.

[0056] As an optional embodiment of the present invention, a control device of the present invention, the accelerator gimbal includes an annular gimbal, the Y-direction control seat is an annular disk structure adapted to the annular gimbal, the Y-direction control seat is provided with a Y-direction threaded hole and a Y-direction slider at both ends of the diameter along the Y-axis direction, the annular gimbal is provided with a Y-direction slide groove, the Y-direction control seat is installed on the annular gimbal, and the Y-direction slider is slidably provided in the Y-direction slide groove;

[0057] The Y-axis control mechanism includes a Y-axis drive motor and a Y-axis lead screw. The Y-axis drive motor is fixedly mounted on the annular pan-tilt platform. The Y-axis lead screw is connected to the motor shaft of the Y-axis drive motor. The Y-axis lead screw is threadedly connected to the Y-axis threaded hole of the Y-axis control seat.

[0058] As an optional embodiment of the present invention, the X-direction regulating seat is an annular disk structure adapted to the Y-direction regulating seat, and the X-direction threaded holes and the X-direction sliders are respectively arranged at both ends of the diameter along the X-axis direction of the X-direction regulating seat, and the X-direction sliding groove is arranged on the Y-direction regulating seat, and the X-direction regulating seat is installed on the Y-direction regulating seat, and the X-direction slider is slidably arranged in the X-direction sliding groove;

[0059] The X-direction regulating mechanism comprises an X-direction driving motor and an X-direction screw rod. The X-direction driving motor is fixedly mounted on the Y-direction regulating seat. The X-direction screw rod is connected to the motor shaft of the X-direction driving motor. The X-direction screw rod is threadedly connected to the X-direction threaded hole of the X-direction regulating seat.

[0060] As an optional embodiment of the present invention, the verticality control seat is an annular disk structure adapted to the X-direction control seat, and the beam assembly is installed on the upper part of the verticality control seat;

[0061] The Z-direction regulating mechanism includes an XOZ plane tilt adjustment component and a YOZ plane tilt adjustment component:

[0062] The XOZ plane inclination adjustment assembly includes a first motor, a first top screw, a second motor and a second top screw, wherein the first top screw is connected to the motor shaft of the first motor, the second top screw is connected to the motor shaft of the second motor, the first motor is mounted on one end of the diameter of the verticality adjustment seat in the X-axis direction, the first top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat, the second motor is mounted on the other end of the diameter of the verticality adjustment seat in the X-axis direction, and the second top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat;

[0063] The YOZ plane inclination adjustment assembly includes a third motor, a third top screw, a fourth motor and a fourth top screw, the third top screw is connected to the motor shaft of the third motor, the fourth top screw is connected to the motor shaft of the fourth motor, the third motor is installed at one end of the diameter in the Y-axis direction of the verticality adjustment seat, the third top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat, the fourth motor is installed at the other end of the diameter in the Y-axis direction of the verticality adjustment seat, and the fourth top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat.

[0064] As an optional embodiment of the present invention, an adjustment device of the present invention includes a screw anti-loosening ring, and a plurality of mounting holes are respectively arranged on the circumference of the verticality adjustment seat, the X-axis adjustment seat, and the Y-axis adjustment seat, and the threaded columns of a plurality of connecting bolts sequentially penetrate the mounting holes on the verticality adjustment seat, the X-axis adjustment seat, and the Y-axis adjustment seat and are fastened to the annular pan-tilt platform, the inner diameter of the mounting hole is larger than the outer diameter of the threaded column of the connecting bolt, the screw anti-loosening ring is sleeved on the outer periphery of the nut of the connecting bolt, the locking screw radially penetrates the screw anti-loosening ring and abuts on the nut of the connecting bolt, and the locking top screw axially penetrates the screw anti-loosening ring and abuts on the verticality adjustment seat.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] The present invention provides a method for controlling the position of a medical linear accelerator beam target. The beam assembly target control is combined with a beam dose monitoring device. After accurately measuring the beam target position deviation, the target position is automatically adjusted. The main advantages include:

[0067] (1) It can be completely controlled by computer control. Compared with manual control, it avoids errors caused by multiple factors, has higher debugging accuracy, shorter control cycle, and is safer.

[0068] (2) The verticality control and horizontal position control of the radiation beam axis do not interfere with each other, and the controls in the orthogonal directions of the plane do not interfere with each other, which will not cause the position of another direction to shift during the control of a certain direction.

[0069] (3) Quantitative control method makes the beam target position control more accurate and reliable, the beam target position control is highly operational, and the adjustment process is simpler and more efficient.

[0070] The control device of this embodiment realizes vertical control of the beam assembly through the Z-direction control mechanism, and realizes horizontal position adjustment of the beam assembly through the X-direction control mechanism and the X-direction control mechanism, thereby realizing automatic control of the beam target position, which has the following advantages:

[0071] (1) The vertical control of the beam assembly and the horizontal control of the target do not affect each other.

[0072] (2) The horizontal X-axis direction control and the horizontal Y-axis direction control do not affect each other.

[0073] (3) The Z-direction control mechanism, the X-direction control mechanism, and the X-direction control mechanism can be driven independently to achieve the control of the beam assembly.

[0074] (4) A screw anti-loosening ring is added to the connecting bolt to reduce the risk of the beam assembly shifting in position after the accelerator gimbal rotates, and to avoid the need to re-calibrate the beam assembly position due to loosening of the connecting bolt. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 A flow chart of a method for controlling the position of a beam target of a medical linear accelerator according to an embodiment of the present invention;

[0076] Figure 2 A schematic diagram of the principle of controlling the verticality of a beam assembly by using a method for controlling the position of a beam target of a medical linear accelerator according to an embodiment of the present invention;

[0077] Figure 3 A schematic diagram of the principle of horizontal position control of a medical linear accelerator beam target position control method according to an embodiment of the present invention;

[0078] Figure 4 A schematic diagram of the three-dimensional structure of a control device according to an embodiment of the present invention;

[0079] Figure 5 A schematic diagram of the installation of the Z-direction regulating mechanism according to an embodiment of the present invention;

[0080] Fig. 6A Schematic diagram of the installation of the Y-direction regulating mechanism according to an embodiment of the present invention;

[0081] Figure 6B Exploded view of the installation of the Y-direction regulating mechanism of the embodiment of the present invention;

[0082] Fig. 7A Schematic diagram of the installation of the X-direction regulating mechanism according to an embodiment of the present invention;

[0083] Figure 7BAn exploded view of the installation of the X-direction regulating mechanism according to an embodiment of the present invention;

[0084] Figure 8 Schematic diagram of the installation of a screw locking ring according to an embodiment of the present invention. DETAILED DESCRIPTION

[0085] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0086] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0087] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions in the embodiments may be combined with each other.

[0088] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0089] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed when in use, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0090] See also Figure 1 As shown, a method for controlling the position of a beam target of a medical linear accelerator in this embodiment includes:

[0091] Control the verticality of the beam assembly: establish a spatial coordinate system with the isocenter as the origin of the spatial coordinate system, determine the fitting function of the radiation beam axis line in the spatial coordinate system, determine the angle θ between the radiation beam axis and the X0Y plane according to the fitting function of the radiation beam axis line, and control the verticality of the beam assembly according to the angle θ;

[0092] Horizontal position control of the beam assembly: Scan the isocenter plane to obtain the center position of the radiation field of the radiation beam, determine the offset ΔL of the radiation field center relative to the isocenter on the X0Y plane, decompose it into the X and Y directions, determine the offset ΔX and ΔY of the radiation beam axis on the X and Y axes, and control the horizontal position of the beam assembly according to the offset ΔX and ΔY;

[0093] After the beam assembly is regulated, the radiation beam emitted by the regulated beam assembly is scanned to verify whether the verticality of the radiation beam axis and the coincidence between the radiation beam field center and the isocenter meet the preset requirements. If so, the beam target position regulation is completed; if not, the verticality regulation and horizontal position regulation of the beam assembly are continued until the preset requirements of the verification are met.

[0094] In the present embodiment, a method for controlling the position of a target beam of a medical linear accelerator is firstly used to determine the fitting function of the straight line of the radiation beam axis in the spatial coordinate system. According to the fitting function, the angle θ between the radiation beam axis and the X0Y plane can be determined, which is used as the verticality control parameter of the beam assembly. The offset ΔL of the field center of the radiation beam relative to the isocenter on the X0Y plane is determined, which is used as the horizontal position control parameter of the beam assembly. In this way, the method for controlling the position of a target beam of a medical linear accelerator is firstly used to control the verticality of the beam assembly, and then to control the horizontal position of the beam assembly. After the control is completed, a check is performed to determine whether the axis of the radiation beam emitted by the beam assembly meets the preset requirements, thereby realizing the adaptive control of the position of the target beam of the medical linear accelerator.

[0095] Therefore, in a method for controlling the position of a medical linear accelerator beam target in this embodiment, the beam assembly target control is combined with a beam dose monitoring device, and after accurately measuring the beam target position deviation, the target position is automatically adjusted. The main advantages include:

[0096] (1) It can be completely controlled by computer control. Compared with manual control, it avoids errors caused by multiple factors, has higher debugging accuracy, shorter control cycle, and is safer.

[0097] (2) The verticality control and horizontal position control of the radiation beam axis do not interfere with each other, and the controls in the orthogonal directions of the plane do not interfere with each other, which will not cause the position of another direction to shift during the control of a certain direction.

[0098] (3) Quantitative control method makes the beam target position control more accurate and reliable, the beam target position control is highly operational, and the adjustment process is simpler and more efficient.

[0099] In a method for controlling the position of a medical linear accelerator beam target of this embodiment, the verticality control of the beam assembly is performed using the isocenter as the origin of the spatial coordinate system to establish a spatial coordinate system, and determining the fitting function of the radiation beam axis line in the spatial coordinate system includes:

[0100] Establish a spatial coordinate system with the isocenter as the origin of the spatial coordinates;

[0101] Control the dose detector to scan along the Z axis to obtain the radiation beam at different depths Z in the Z axis. 1 …Z n The hash value of the radiation center position is recorded as {Z 1 (X 1 ,Y 1 )…Z i (X i ,Y i )…Z n (X n ,Y n )};

[0102] Assume that the fitting function of the radiation beam axis line is set to: AX+BY+CZ+D=0;

[0103] The sum of squares of the straight-line distances Q between each radiation center position and the target beam axis is obtained:

[0104]

[0105] Where: i ——According to the experimental results, the influence factors of different source-skin distances are as follows: the closer to the isocenter plane, the greater the i The higher;

[0106] Partial derivatives to find the minimum:

[0107]

[0108]

[0109]

[0110]

[0111] The values ​​of A, B, C, and D in the fitting function of the radiation beam axis line are calculated, and finally the fitting function of the radiation beam axis line is determined.

[0112] See also Figure 2 As shown in the figure, L 1 ,……,L i ,……,L n is a series of radiation beam axis straight lines, L 0 For L 1 ,……,Li ,……,L n The target radiation beam axis line that will eventually approach has different coordinate positions corresponding to the radiation center positions at the same equal height Z, and there is a deviation. This embodiment can obtain the fitting function of the radiation beam axis line through the above calculation process, and determine the deviation angle θ to provide a basis for automatic control.

[0113] Furthermore, in a method for controlling the position of a beam target of a medical linear accelerator of this embodiment, controlling the verticality of the beam component according to the angle θ in the verticality control of the beam component includes:

[0114] Project the angle θ onto the X0Z plane to obtain the angle θ X0Z , projected onto the Y0Z plane, the angle θ Y0Z ;

[0115] The theoretical control distances of the beam assembly in the X-axis direction are calculated as follows:

[0116] Elevation direction: d Y0Z仰 =-r.cosθ Y0Z

[0117] Depression direction: d Y0Z俯 =+r.cosθ Y0Z

[0118] The theoretical control distances of the beam assembly in the Y-axis direction are calculated as follows:

[0119] Elevation direction: d X0Z仰 =-r.cosθ X0Z

[0120] Depression direction: d X0Z俯 =+r.cosθ X0Z

[0121] in:

[0122] + / -——indicates the movement direction of the beam assembly on the Z axis;

[0123] r is the radius of the circle on the plane that controls the verticality of the beam assembly.

[0124] Thus, in this embodiment, the angle θ adjustment for verticality is converted into the tilt height adjustment in the X-axis direction and the Y-axis direction to achieve the angle θ X0Z , angle θ Y0Z , so that the verticality adjustment of the medical linear accelerator beam target position control method of this embodiment can be performed by the verticality adjustment mechanism.

[0125] As an optional implementation of this embodiment, in a method for controlling the position of a beam target of a medical linear accelerator of this embodiment, the verticality control of the beam assembly includes:

[0126] According to the calculated theoretical control distance d of the beam assembly in the X-axis direction Y0Z仰 ,d Y0Z俯 Determine the actual control distance of the beam assembly in the X-axis direction as k*d Y0Z仰 , k*d Y0Z俯 ;

[0127] According to the calculated theoretical control distance d of the beam assembly in the Y-axis direction X0Z仰 ,d X0Z俯 Determine the actual control distance of the beam assembly in the Y-axis direction as k*d X0Z仰 、k*d X0Z俯 ;

[0128] Wherein, the k is a preset value, 0<k<1.

[0129] The above adjustment method is mainly to prevent over-adjustment. After multiple adjustments and verifications, the radiation beam axis is parallel to the mechanical rotation center, thus completing the verticality control of the beam assembly.

[0130] Optionally, in this embodiment, k=1 / 2.

[0131] See also Figure 3 As shown, in a method for controlling the position of a beam target of a medical linear accelerator of this embodiment, controlling the horizontal position of the beam component according to the offsets ΔX and ΔY in the horizontal position control of the beam component includes:

[0132] Determining the adjustment direction of the beam assembly on the X0Y plane according to the offset direction of the field center of the radiation beam relative to the isocenter on the X0Y plane;

[0133] According to the offsets ΔX and ΔY, the control amounts of the beam assembly in the X-axis and Y-axis directions are determined to be k*ΔX and k*ΔY respectively.

[0134] In this embodiment, a method for controlling the position of a medical linear accelerator beam target is provided, wherein a dose detector is controlled to scan a plurality of radiation beam planes at different Z-direction heights to determine the radiation center point Z of each radiation beam plane. 1 …Z n , combined with the influence weight factor δ corresponding to each radiation beam plane i, through calculation, the discrete center points in the space are fitted into the straight line where the radiation beam axis is located, and the verticality of the radiation beam axis is determined; the inclination angle of the radiation beam axis is decomposed into the X and Y directions, and instructions are issued to the corresponding verticality control mechanism; the verticality control mechanism completes the instruction control, and the dose detector scans to confirm the verticality of the radiation beam axis again to determine whether the verticality meets the requirements. If the requirements are met, the horizontal direction of the target is controlled. If the requirements are not met, the control is continued in the above manner until the requirements are met.

[0135] The dose detector scans the plane where the isocenter is located, determines the offset between the radiation field center and the isocenter, decomposes the offset into the X and Y directions, and sends instructions to the corresponding horizontal position control mechanism; the actuator completes the instruction control, and the dose detector scans to confirm the offset of the radiation field center again; determines whether the offset between the radiation field center and the isocenter meets the requirements. If so, perform a verticality check on the radiation beam axis. If not, continue to control in the above manner until the requirements are met.

[0136] After the horizontal position of the target is adjusted, check the verticality of the radiation beam axis. If the verticality meets the requirements, the adjustment is completed. If the verticality does not meet the requirements, the beam target position adjustment is performed from the beginning.

[0137] See also Figure 4-Figure 8 As shown, this embodiment also provides a control device for realizing the medical linear accelerator beam target position control method, including:

[0138] Beam assembly 1;

[0139] A verticality control seat 10, on which the beam assembly 1 is mounted;

[0140] An X-direction regulating seat 2, on which the verticality regulating seat 10 is installed;

[0141] A Z-direction regulating mechanism is installed on the verticality regulating seat 10, and the verticality regulating seat 10 is adjusted to form an angle θ with respect to the X-direction regulating seat 2 by the Z-direction regulating mechanism to achieve verticality regulation of the beam assembly 1;

[0142] The Y-direction regulating seat 3, the X-direction regulating seat 2 is slidably mounted on the Y-direction regulating seat 3 along the X-axis direction;

[0143] An X-direction regulating mechanism 8 is installed on the Y-direction regulating seat 3, and the X-direction regulating mechanism 8 adjusts the X-direction regulating seat 2 according to the offset ΔX;

[0144] An accelerator platform 4, on which the Y-axis regulating seat 3 is slidably mounted along the Y-axis direction;

[0145] A Y-direction regulating mechanism 5, mounted on the accelerator gimbal 4, the Y-direction regulating mechanism 5 adjusts the Y-direction regulating seat 3 according to the offset ΔY;

[0146] The horizontal position adjustment of the beam assembly 1 is achieved through the X-direction adjustment mechanism 8 and the Y-direction adjustment mechanism 5 .

[0147] The control device of this embodiment realizes vertical control of the beam assembly 1 through the Z-direction control mechanism, and realizes horizontal position adjustment of the beam assembly 1 through the X-direction control mechanism 8 and the X-direction control mechanism 5, thereby realizing automatic control of the beam target position.

[0148] The control device of this embodiment has the following advantages:

[0149] (1) The vertical control of the beam assembly and the horizontal control of the target do not affect each other.

[0150] (2) The horizontal X-axis direction control and the horizontal Y-axis direction control do not affect each other.

[0151] (3) The Z-direction control mechanism, the X-direction control mechanism, and the X-direction control mechanism can be driven independently to achieve the control of the beam assembly.

[0152] See also Fig. 6A and Figure 6B As shown, the accelerator platform 4 described in this embodiment includes an annular platform, the Y-axis adjustment seat 3 is an annular disk structure adapted to the annular platform, and the Y-axis adjustment seat 3 is provided with a Y-axis threaded hole 303 and a Y-axis slider 304 at both ends of the diameter along the Y-axis direction (see Figure 7B As shown), a Y-direction slide groove (not shown) is arranged on the annular platform, the Y-direction regulating seat 3 is installed on the annular platform, and the Y-direction slider 304 is slidably arranged in the Y-direction slide groove;

[0153] The Y-axis control mechanism 5 includes a Y-axis drive motor 501 and a Y-axis screw rod 503. The Y-axis drive motor 501 is fixedly mounted on the annular platform. The Y-axis screw rod 503 is connected to the motor shaft of the Y-axis drive motor 501 through a first coupling 502. The Y-axis screw rod 503 is threadedly connected to the Y-axis threaded hole 303 of the Y-axis control seat 3. The Y-axis drive motor 501 of this embodiment is fixedly mounted on the annular platform through a mounting plate 6.

[0154] In this embodiment, the Y-direction slider 304 of the Y-direction control seat 3 cooperates with the Y-direction slide groove of the accelerator gimbal 4 to limit the movement of the X-direction position. The first coupling 502 connects the motor shaft of the Y-direction drive motor 501 and the Y-direction screw rod 503. The Y-direction screw rod 503 is screwed into the Y-direction threaded hole 303 of the Y-direction control seat 3. The Y-direction drive motor 501 controls the rotation of the Y-direction screw rod 503 to achieve the adjustment of the Y-direction control seat 3 in the Y direction, thereby achieving the adjustment of the target position in the Y direction.

[0155] See also Fig. 7A and Figure 7B As shown, the X-direction regulating seat 2 described in this embodiment is an annular disk structure adapted to the Y-direction regulating seat 3, and the X-direction threaded hole 201 and the X-direction slider 202 are respectively arranged at both ends of the diameter along the X-axis direction on the X-direction regulating seat 2, and the X-direction sliding groove 301 is arranged on the Y-direction regulating seat 3 (see Fig. 6A ), the X-direction regulating seat 2 is installed on the Y-direction regulating seat 3, and the X-direction slider 202 is slidably arranged in the X-direction slide groove 301;

[0156] The X-axis control mechanism 8 includes an X-axis drive motor 801 and an X-axis screw rod 803. The X-axis drive motor 801 is fixedly mounted on the Y-axis control seat 3. The X-axis screw rod 803 is connected to the motor shaft of the X-axis drive motor 801. The X-axis screw rod 803 is threadedly connected to the X-axis threaded hole 201 of the X-axis control seat 2.

[0157] In this embodiment, the X-direction slider 202 of the X-direction regulating seat 2 cooperates with the X-direction slide groove 301 of the Y-direction regulating seat 3 to limit the movement of the position in the Y direction. The second coupling 802 connects the motor shaft of the X-direction driving motor 801 and the X-direction screw 803, and the X-direction screw 803 is screwed into the X-direction threaded hole 201 of the X-direction regulating seat 2. The X-direction driving motor 801 is fixed to the Y-direction regulating seat 3 through the mounting plate 6. The X-direction driving motor 801 controls the rotation of the X-direction screw 803 to achieve the adjustment of the X-direction regulating seat 2 in the X direction, thereby achieving the adjustment of the target position in the X direction.

[0158] In the meantime, see Fig. 6A As shown, an avoidance groove 302 is provided on the other end of the Y-axis regulating seat 3 of the present embodiment, which is in the same radial direction as the X-axis slide groove 301. Due to the need to set the X-axis threaded hole 201, the X-axis regulating seat 2 has an increased thickness at the corresponding position to form a threaded hole protrusion for opening the threaded hole. The threaded hole protrusion can be slidably set in the avoidance groove 302.

[0159] See also Figure 4 As shown, the verticality control seat 10 of this embodiment is an annular disk structure adapted to the X-direction control seat, and the beam assembly 1 is installed on the upper part of the verticality control seat 10;

[0160] The Z-direction regulating mechanism includes an XOZ plane tilt adjustment component 7B and a YOZ plane tilt adjustment component 7A:

[0161] The XOZ plane inclination adjustment assembly 7B includes a first motor, a first top screw, a second motor and a second top screw, wherein the first top screw is connected to the motor shaft of the first motor, the second top screw is connected to the motor shaft of the second motor, the first motor is mounted on one end of the diameter of the verticality adjustment seat in the X-axis direction, the first top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat, the second motor is mounted on the other end of the diameter of the verticality adjustment seat in the X-axis direction, and the second top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat;

[0162] The specific adjustment distance of the XOZ plane tilt adjustment component 7B is the elevation direction d calculated by the above-mentioned medical linear accelerator beam target position control method. X0Z仰 =-r.cosθ X0Z , depression angle direction d X0Z俯 =+r.cosθ X0Z , where r is the distance between the setting position of the XOZ plane inclination adjustment component 7B and the central axis of the accelerator gimbal.

[0163] The YOZ plane inclination adjustment assembly 7A includes a third motor, a third top screw, a fourth motor and a fourth top screw. The third top screw is connected to the motor shaft of the third motor, and the fourth top screw is connected to the motor shaft of the fourth motor. The third motor is installed at one end of the diameter in the Y-axis direction of the verticality adjustment seat, and the third top screw passes through the verticality adjustment seat and abuts against the X-direction adjustment seat. The fourth motor is installed at the other end of the diameter in the Y-axis direction of the verticality adjustment seat, and the fourth top screw passes through the verticality adjustment seat and abuts against the X-direction adjustment seat.

[0164] The specific adjustment distance of the YOZ plane inclination adjustment component 7A is the elevation direction d calculated by the above-mentioned medical linear accelerator beam target position control method. Y0Z仰 =-r.cosθ Y0Z , depression angle direction d Y0Z俯 =+r.cosθ Y0Z , where r is the distance between the setting position of the YOZ plane inclination adjustment component 7A and the central axis of the accelerator gimbal.

[0165] In this embodiment, the first motor, the second motor, the third motor, and the fourth motor are arranged on the same circumference of the verticality adjustment seat 10, and the r values ​​in the above formula are equal.

[0166] See also Figure 2As shown, the specific way in which the YOZ plane tilt adjustment assembly 7A and the XOZ plane tilt adjustment assembly 7B are installed on the verticality adjustment seat 10 is that the motor 701 (including the first motor, the second motor, the third motor, and the fourth motor) is fixed on the verticality adjustment seat 10 through the mounting bracket 702, and the motor shaft of the motor is connected to the top screw 704 (including the first top screw, the second top screw, the third top screw, and the fourth top screw) through the third coupling 703. The mounting bracket 702 has a mounting plate and a support leg 705 fixed to the bottom of the mounting plate, and the support leg 705 is installed on the verticality adjustment seat 10 by fastening screws. The motor 701 is installed on the mounting plate so that the motor 701 is higher than the plane of the verticality adjustment seat 10.

[0167] See also Figure 1 and Figure 8 As shown, a control device of the present embodiment includes a screw anti-loosening ring 9, and a plurality of mounting holes 11 are respectively arranged on the circumference of the verticality control seat 10, the X-axis control seat 2, and the Y-axis control seat 3. The threaded columns of a plurality of connecting bolts 12 sequentially penetrate the mounting holes 11 on the verticality control seat 10, the X-axis control seat 2, and the Y-axis control seat 3 and are fastened to the annular pan-tilt head 4. The inner diameter of the mounting hole 11 is larger than the outer diameter of the threaded column of the connecting bolt 12. Since the X-axis and Y-axis directions of the beam assembly are both fine-tuned, such a setting does not affect the X-axis and Y-axis adjustments of the beam assembly; the screw anti-loosening ring 9 is sleeved on the outer periphery of the nut of the connecting bolt 12, the locking screw 901 radially penetrates the screw anti-loosening ring 9 and abuts on the nut of the connecting bolt 12, and the locking top screw 902 axially penetrates the screw anti-loosening ring 9 and abuts on the verticality control seat 10.

[0168] On the basis of installing the spring washer and the flat washer, the beam assembly 1 fixes the screw anti-loosening ring 9 on the nut of the connecting bolt 12 to limit the rotation of the screw and increase the anti-loosening effect.

[0169] This embodiment adds a screw anti-loosening ring 9 to the connecting bolt 12 to reduce the risk of the beam assembly 1 being offset after the accelerator gimbal 4 rotates in the later stage, and avoids the re-calibration of the position of the beam assembly 1 due to the loosening of the connecting bolt 12 in the later stage.

[0170] This embodiment also provides a computer-readable storage medium storing a computer-executable program. When the computer-executable program is executed, the method for controlling the position of a beam target of a medical linear accelerator as described above is implemented.

[0171] The computer-readable storage medium described in this embodiment may include a data signal propagated in a baseband or as part of a carrier wave, wherein a readable program code is carried. This propagated data signal may take a variety of forms, including but not limited to an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer-readable storage medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in combination with an instruction execution system, an apparatus, or a device. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination of the above.

[0172] This embodiment also provides an electronic device, including a processor and a memory, wherein the memory is used to store a computer executable program, and when the computer program is executed by the processor, the processor executes the method for controlling the position of a beam target of a medical linear accelerator.

[0173] The electronic device is presented in the form of a general-purpose computing device. The processor may be one or more than one and work in coordination. The present invention does not exclude distributed processing, that is, the processor may be dispersed in different physical devices. The electronic device of the present invention is not limited to a single entity, but may also be the sum of multiple physical devices.

[0174] The memory stores a computer executable program, which is usually a machine-readable code. The computer-readable program can be executed by the processor to enable the electronic device to perform the method of the present invention, or at least part of the steps in the method.

[0175] The memory includes a volatile memory, such as a random access memory unit (RAM) and / or a cache memory unit, and may also be a non-volatile memory, such as a read-only memory unit (ROM).

[0176] It should be understood that the electronic device of the present invention may also include elements or components not shown in the above examples. For example, some electronic devices also include display units such as display screens, and some electronic devices also include human-computer interaction elements such as buttons and keyboards. As long as the electronic device can execute the computer-readable program in the memory to implement the method of the present invention or at least part of the steps of the method, it can be considered as an electronic device covered by the present invention.

[0177] Through the above description of the implementation mode, it is easy for those skilled in the art to understand that the present invention can be implemented by hardware capable of executing a specific computer program, such as the system of the present invention, and the electronic processing unit, server, client, mobile phone, control unit, processor, etc. contained in the system. The present invention can also be implemented by computer software that executes the method of the present invention, such as control software executed by a microprocessor, an electronic control unit, a client, a server, etc. However, it should be noted that the computer software that executes the method of the present invention is not limited to being executed by one or a specific hardware entity, and it can also be implemented in a distributed manner by unspecified specific hardware. For computer software, the software product can be stored in a computer-readable storage medium (which can be a CD-ROM, a U disk, a mobile hard disk, etc.), and can also be distributed and stored on the network, as long as it can enable the electronic device to execute the method according to the present invention.

[0178] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the above specific implementation methods. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the invention are included in the scope of the claims of the present invention.

Claims

1. A method for controlling the position of a beam target of a medical linear accelerator. It is characterized in that include: Control the verticality of the beam assembly: establish a spatial coordinate system with the isocenter as the origin of the spatial coordinate system, determine the fitting function of the radiation beam axis line in the spatial coordinate system, determine the angle θ between the radiation beam axis and the X0Y plane according to the fitting function of the radiation beam axis line, and control the verticality of the beam assembly according to the angle θ; Horizontal position control of the beam assembly: Scan the isocenter plane to obtain the center position of the radiation field of the radiation beam, determine the offset ΔL of the radiation field center relative to the isocenter on the X0Y plane, decompose it into the X and Y directions, determine the offset ΔX and ΔY of the radiation beam axis on the X and Y axes, and control the horizontal position of the beam assembly according to the offset ΔX and ΔY; After the beam assembly is regulated, the radiation beam emitted by the regulated beam assembly is scanned to verify whether the verticality of the radiation beam axis and the coincidence between the radiation beam field center and the isocenter meet the preset requirements. If so, the beam target position regulation is completed; if not, the verticality regulation and horizontal position regulation are continued for the beam assembly until the preset requirements of the verification are met; In the verticality control of the beam assembly, a spatial coordinate system is established with the isocenter as the origin of the spatial coordinate system, and a fitting function of the radiation beam axis line in the spatial coordinate system is determined, which includes: Establish a spatial coordinate system with the isocenter as the origin of the spatial coordinates; Control the dose detector to scan along the Z axis to obtain the radiation beam at different depths Z in the Z axis. 1 …Z n The hash value of the radiation center position is recorded as {Z 1 (X 1 ,Y 1 )…Z i (X i ,Y i )…Z n (X n ,Y n )}; Assume that the fitting function of the radiation beam axis line is set to: AX+BY+CZ+D=0; The sum of squares of the straight-line distances Q between each radiation center position and the target beam axis is obtained: Where: i ——The influence factor of different source-skin distances. The closer to the isocenter plane, the greater the δ i The higher; Partial derivatives to find the minimum: Calculate the values ​​of A, B, C, and D in the fitting function of the radiation beam axis straight line, and finally determine the fitting function of the radiation beam axis straight line; In the verticality control of the beam assembly, controlling the verticality of the beam assembly according to the angle θ includes: Project the angle θ onto the X0Z plane to obtain the angle θ X0Z , projected onto the Y0Z plane, the angle θ Y0Z ; The theoretical control distances of the beam assembly in the X-axis direction are calculated as follows: Elevation direction: d Y0Z仰 =-r.cosθ Y0Z Depression direction: d Y0Z俯 =+r.cosθ Y0Z The theoretical control distances of the beam assembly in the Y-axis direction are calculated as follows: Elevation direction: d X0Z仰 =-r.cosθ X0Z Depression direction: d X0Z俯 =+r.cosθ X0Z in: + / -——indicates the movement direction of the beam assembly on the Z axis; r is the radius of the circle on the plane that controls the verticality of the beam assembly.

2. A method for controlling the position of a medical linear accelerator beam target according to claim 1, It is characterized in that The verticality control of the beam assembly includes: According to the calculated theoretical control distance d of the beam assembly in the X-axis direction Y0Z仰 ,d Y0Z俯 Determine the actual control distance of the beam assembly in the X-axis direction as k*d Y0Z仰 , k*d Y0Z俯 ; According to the calculated theoretical control distance d of the beam assembly in the Y-axis direction X0Z仰 ,d X0Z俯 Determine the actual control distance of the beam assembly in the Y-axis direction as k*d X0Z仰 、k*d X0Z俯 ; Wherein, the k is a preset value, 0<k<1.

3. A method for controlling the position of a medical linear accelerator beam target according to claim 2, It is characterized in that The horizontal position control of the beam assembly according to the offsets ΔX and ΔY comprises: Determining the adjustment direction of the beam assembly on the X0Y plane according to the offset direction of the field center of the radiation beam relative to the isocenter on the X0Y plane; According to the offsets ΔX and ΔY, the control amounts of the beam assembly in the X-axis and Y-axis directions are determined to be k*ΔX and k*ΔY respectively.

4. A control device, It is characterized in that include: Beam assembly; A verticality control seat, on which the beam assembly is installed; An X-direction regulating seat, on which the verticality regulating seat is installed; A Z-direction regulating mechanism is installed on the verticality regulating seat, and the verticality regulating seat is adjusted by the Z-direction regulating mechanism to form an angle θ with respect to the X-direction regulating seat, so as to achieve verticality regulation of the beam assembly; A Y-direction regulating seat, the X-direction regulating seat being slidably mounted on the Y-direction regulating seat along the X-axis direction; An X-direction regulating mechanism is installed on the Y-direction regulating seat, and the X-direction regulating mechanism adjusts the X-direction regulating seat according to an offset ΔX; The accelerator gimbal, the Y-direction regulating seat is slidably mounted on the accelerator gimbal along the Y-axis direction; A Y-direction regulating mechanism, mounted on the accelerator gimbal, the Y-direction regulating mechanism adjusts the Y-direction regulating seat according to an offset ΔY; The horizontal position adjustment of the beam assembly is achieved by the X-axis control mechanism and the Y-axis control mechanism; the accelerator platform includes an annular platform, the Y-axis control seat is an annular disk structure adapted to the annular platform, the Y-axis control seat is provided with a Y-axis threaded hole and a Y-axis slider at both ends of the diameter along the Y-axis direction, the annular platform is provided with a Y-axis slide groove, the Y-axis control seat is installed on the annular platform, and the Y-axis slider is slidably arranged in the Y-axis slide groove; The Y-direction regulating mechanism comprises a Y-direction driving motor and a Y-direction screw rod, wherein the Y-direction driving motor is fixedly mounted on the annular pan-tilt platform, the Y-direction screw rod is connected to the motor shaft of the Y-direction driving motor, and the Y-direction screw rod is threadedly connected to the Y-direction threaded hole of the Y-direction regulating seat; The X-direction regulating seat is an annular disk structure adapted to the Y-direction regulating seat, and the X-direction threaded holes and the X-direction sliders are respectively arranged at the two ends of the diameter along the X-axis direction of the X-direction regulating seat, and the X-direction sliding groove is arranged on the Y-direction regulating seat, and the X-direction regulating seat is installed on the Y-direction regulating seat, and the X-direction slider is slidably arranged in the X-direction sliding groove; The X-direction regulating mechanism comprises an X-direction driving motor and an X-direction screw rod, wherein the X-direction driving motor is fixedly mounted on the Y-direction regulating seat, the X-direction screw rod is connected to the motor shaft of the X-direction driving motor, and the X-direction screw rod is threadedly connected to the X-direction threaded hole of the X-direction regulating seat; The verticality control seat is an annular disk structure adapted to the X-direction control seat, and the beam assembly is installed on the upper part of the verticality control seat; The Z-direction regulating mechanism includes an XOZ plane tilt adjustment component and a YOZ plane tilt adjustment component: The XOZ plane inclination adjustment assembly includes a first motor, a first top screw, a second motor and a second top screw, wherein the first top screw is connected to the motor shaft of the first motor, the second top screw is connected to the motor shaft of the second motor, the first motor is mounted on one end of the diameter of the verticality adjustment seat in the X-axis direction, the first top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat, the second motor is mounted on the other end of the diameter of the verticality adjustment seat in the X-axis direction, and the second top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat; The YOZ plane inclination adjustment assembly includes a third motor, a third top screw, a fourth motor and a fourth top screw, the third top screw is connected to the motor shaft of the third motor, the fourth top screw is connected to the motor shaft of the fourth motor, the third motor is installed at one end of the diameter in the Y-axis direction of the verticality adjustment seat, the third top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat, the fourth motor is installed at the other end of the diameter in the Y-axis direction of the verticality adjustment seat, and the fourth top screw passes through the verticality adjustment seat and abuts on the X-direction adjustment seat.

5. The control device according to claim 4, It is characterized in that It includes a screw anti-loosening ring, and a plurality of mounting holes are respectively arranged on the circumference of the verticality adjustment seat, the X-axis adjustment seat, and the Y-axis adjustment seat. The threaded columns of a plurality of connecting bolts sequentially penetrate the mounting holes on the verticality adjustment seat, the X-axis adjustment seat, and the Y-axis adjustment seat and are fastened to the annular pan-tilt platform. The inner diameter of the mounting hole is larger than the outer diameter of the threaded column of the connecting bolt. The screw anti-loosening ring is sleeved on the outer periphery of the nut of the connecting bolt, the locking screw radially penetrates the screw anti-loosening ring and abuts on the nut of the connecting bolt, and the locking top screw axially penetrates the screw anti-loosening ring and abuts on the verticality adjustment seat.

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