Double-layer multi-leaf collimator with self-monitoring function and use method

Abstract

The invention relates to a double-layer multi-leaf collimator with a self-monitoring function and a using method thereof, and belongs to the technical field of radiotherapy equipment.The double-layer multi-leaf collimator is subjected to multiple times of image acquisition through an image acquisition assembly, the actual position and the preset position of a grating leaf are judged based on the self-monitoring function of a backlight path, and the real position of the grating leaf is determined. The leakage emission rate is further reduced, the dynamic intensity modulation capability is improved, an external sensor is not needed, and the system integration degree is high. Micron-scale control of the grating blade position is realized through optical feedback, and the high-precision treatment requirement is met. By utilizing the mutual shielding effect of the two layers of blades, the effects of simplifying the accelerator layout, reducing leakage radiation and improving the projection resolution of the blades are achieved, the device is mainly used for stereotactic radiotherapy of tumors and other adaptations, blade position errors caused by motor faults and mechanical faults of a multi-blade collimator are avoided, and the reliability of the device is improved. And irradiation errors are further avoided.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy equipment technology, specifically to a double-layer multi-leaf collimator with self-monitoring function and its usage method, and more particularly to a double-layer multi-leaf collimator for forming an X-ray irradiation area during radiotherapy and a self-monitoring method for the multi-leaf collimator blades. Background Technology

[0002] A multi-leaf collimator (MLC) is a relatively complex beam-limiting device, currently widely used in electron linear accelerators. It is installed between the X-ray target and the patient to form the radiation field required for treatment. The MLC consists of tungsten alloy blades, a blade box, and a drive motor.

[0003] In existing technologies, multi-leaf collimators include single-layer and double-layer multi-leaf collimators. The single-layer multi-leaf collimator is located at the radiation beam exit end of the electron linear accelerator. Its control software controls each leaf to move to a designated position according to treatment needs, forming a complex radiation field shape. It consists of two sets of opposing blades assembled in a blade box. Each blade is independently driven by a motor, making a linear or circular reciprocating motion along its length. Some electron linear accelerators have blade boxes divided into two independent parts, located on either side of the central axis of the radiation field, which can each move along the length of the blade to expand the range of blade movement. All blades are focused on the X-ray target or a nearby focal point in their height direction (i.e., the direction of the radiation field axis). The projected width of the multi-leaf collimator blades at the treatment position is generally in the range of several millimeters to one centimeter.

[0004] The double-layer multi-leaf collimator consists of a lower blade assembly and an upper blade assembly. The lower blade assembly and the upper blade assembly are staggered by half a blade width in the blade arrangement direction. The blades of each layer can shield the inter-blade leakage X-rays of the other layer, thereby significantly reducing the leakage radiation passing through the multi-leaf collimator.

[0005] A schematic diagram of the blade position detection method for the CyberKnife multi-leaf collimator from Accuray, Inc. This method uses a camera 125 to optically image the multi-leaf collimator 110 from an oblique position above it. By analyzing the groove positions near the end faces of each blade in the image, the current position of each blade is determined. However, when applied to a double-layer multi-leaf collimator, this method suffers from occlusion between the upper and lower layers of blades, and the oblique optical imaging method exacerbates this problem.

[0006] In the prior art, single-layer multi-leaf collimators utilize tungsten gates to shield the leakage radiation between the blades. However, in locations without tungsten gate shielding, there is still a high level of leakage radiation between the blades. Summary of the Invention

[0007] In view of the above problems, this invention provides a self-monitoring double-layer multi-leaf collimator and its usage method. This invention designs a small double-layer multi-leaf collimator for use in robotic arm radiotherapy. This invention utilizes an image acquisition component to acquire multiple images of the double-layer multi-leaf collimator. Based on the self-monitoring function of the reverse light path, it determines the actual position of the grating blades relative to the preset position, further reducing leakage rate and improving dynamic intensity modulation capability. It does not rely on external sensors and has a high degree of system integration. Micrometer-level control of the grating blade position is achieved through optical feedback, meeting the needs of high-precision treatment. Real-time adjustment of the blade position ensures that the beam intensity distribution accurately matches the tumor shape. This invention utilizes the mutual shielding effect of the two layers of blades to simplify accelerator layout, reduce leakage radiation, and improve blade projection resolution. It is mainly used for stereotactic radiotherapy for tumors and other indications, avoiding blade position errors caused by motor and mechanical failures in multi-leaf collimators, further preventing irradiation errors.

[0008] This invention provides a method for using a double-layer multi-leaf collimator with self-monitoring function, comprising:

[0009] Step S1: Start the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2 of the double-layer multi-leaf collimator to emit beam radiation;

[0010] The treatment plan includes the preset positions of each grating leaf in the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2;

[0011] Step S2: Determine whether the end faces 7 of each grating blade in the upper and lower multi-leaf grating components can be identified in the current beam irradiation field shape;

[0012] If so, the image acquisition component is used to obtain the first image, and the actual position of each grating leaf is obtained based on the first image. It is then determined whether the position is consistent with the corresponding preset position. If so, the detection is completed and the beam treatment is performed. If not, the position detection of the upper multi-leaf grating component and the lower multi-leaf grating component needs to be performed, and the process proceeds to step S3.

[0013] Step S3: Return the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2 to their initial positions;

[0014] Based on the treatment plan, control each grating leaf 2 of the lower multi-leaf grating assembly 2 to reach the preset position, use the image acquisition component to obtain the second image, obtain the actual position of each grating leaf 2 based on the second image, and determine whether it is consistent with the preset position. If it is, adjust the lower multi-leaf grating assembly to return to the initial position and proceed to the next step. If not, repair, obtain the repaired double-layer multi-leaf collimator and perform beam radiation, and return to step S2.

[0015] Step S4: Control each grating leaf 1 in the upper multi-leaf grating assembly to reach the preset position, obtain the third image based on the image acquisition component, obtain the actual position of each grating leaf 1 based on the third image, and determine whether it is consistent with the preset position. If yes, adjust the upper multi-leaf grating assembly to return to the initial position and proceed to the next step. If no, repair, obtain the repaired double-layer multi-leaf collimator 2 and perform beam radiation, and return to step S2.

[0016] Step S5: Based on the treatment plan, control each grating leaf in the upper and lower multi-leaf grating components to reach the preset position. Obtain image four based on the image acquisition component. Obtain the actual position of each grating leaf one based on image four and determine whether it is consistent with the preset position. If yes, obtain the detected double-layer multi-leaf collimator and proceed to the next step. If no, repair it, obtain the repaired double-layer multi-leaf collimator three and perform beam radiation, then return to step S2.

[0017] Step S6: Perform beam delivery treatment using the tested double-layer multi-leaf collimator.

[0018] Optionally, the treatment plan is set according to the patient's lesion area.

[0019] Optionally, step S2 includes the following specific steps:

[0020] Determine whether the end faces of each grating blade in the upper and lower multi-leaf grating components can be identified in the current beam irradiation field shape;

[0021] If so, turn on the light source 8, and obtain the first image based on the CCD camera 5 through the diffuse reflection plate assembly 9. Based on the first image, obtain the actual positions of each grating leaf 1 in the upper multi-leaf grating assembly 1 and each grating leaf 2 in the lower multi-leaf grating assembly 2.

[0022] Determine whether the actual positions of each grating blade one and each grating blade two are consistent with the preset positions in the treatment plan. If they are, the detection is completed and beam treatment is performed.

[0023] If not, then it is necessary to perform position detection of the upper multi-leaf grating assembly and the lower multi-leaf grating assembly, and proceed to step S3.

[0024] Optionally, step S3 includes the following specific steps:

[0025] Return the upper multileaf grating assembly 1 and the lower multileaf grating assembly 2 to their initial positions;

[0026] Based on the treatment plan, the electrical boxes 1 and 2 of the double-layer multi-leaf collimator are adjusted to control the motors corresponding to each grating blade 2 in the lower multi-leaf grating assembly 2, so that each grating blade 2 reaches the preset position. The light source 8 is turned on, and the lower multi-leaf grating assembly 2 is illuminated through the diffuse reflection plate assembly 9. The image is acquired by the CCD camera 5 to obtain the second acquired image.

[0027] Determine whether the actual position of each grating blade 2 in the acquired image 2 is consistent with the preset position. If yes, adjust the lower multi-leaf grating assembly to restore it to the initial position and proceed to the next step. If no, repair the motor corresponding to each grating blade 2, obtain the repaired double-layer multi-leaf collimator and perform beam radiation, and return to step S2.

[0028] Optionally, step S4 includes the following specific steps:

[0029] Control the motor corresponding to each grating leaf in the upper multi-leaf grating assembly so that each grating leaf reaches the preset position, turn on the light source 8, and illuminate the upper multi-leaf grating assembly through the diffuse reflection plate assembly 9. Use the CCD camera 5 to acquire the image and obtain the acquired image 3.

[0030] Determine whether the actual position of each grating blade in the acquired image 3 is consistent with the preset position. If yes, adjust the upper multi-leaf grating assembly to restore it to the initial position and proceed to the next step. If no, repair the motor corresponding to each grating blade, obtain the repaired double-layer multi-leaf collimator 2 and perform beam radiation, and return to step S2.

[0031] Optionally, step S5 includes the following specific steps:

[0032] Based on the treatment plan, the movement of each grating leaf in the upper and lower multi-leaf grating components is controlled to reach the preset position, the light source is turned on, and the upper multi-leaf grating component is illuminated through the diffuse reflection plate component 9. The image is acquired by the CCD camera 5, and the acquired image four is obtained.

[0033] Determine whether the actual position of each grating blade in the acquired image 4 is consistent with the preset position. If yes, obtain the detected double-layer multi-leaf collimator and proceed to the next step. If no, repair the motor corresponding to each grating blade, obtain the repaired double-layer multi-leaf collimator 3 and perform beam radiation, then return to step S2.

[0034] Another objective of this invention is to provide a dual-layer multi-leaf collimator with self-monitoring function, comprising: an image acquisition component, an upper multi-leaf grating component 1, and a lower multi-leaf grating component 2;

[0035] The upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2 are connected to the image acquisition assembly via a connecting plate 11;

[0036] The image acquisition component includes a CCD camera 5, a reflector 6, a light source 8, and a diffuse reflector assembly 9;

[0037] The CCD camera 5 is mounted on the connecting plate 11; the reflector 6 is mounted on the connecting plate 11 via the bracket 6-1;

[0038] The light source 8 includes multiple LED lights;

[0039] The diffuse reflector assembly (9) includes a diffuse reflector 9-1 and a diffuse reflector 9-2; the plurality of LEDs are arranged at equal intervals between the diffuse reflector 9-1 and the diffuse reflector 9-2.

[0040] Optionally, the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2 are stacked in the beam direction, wherein the upper multi-leaf grating assembly 1 is closer to the X-ray source and the lower multi-leaf grating assembly 2 is closer to the area to be irradiated.

[0041] The upper multi-leaf grating assembly 1 includes a first leaf group 1-1 and a second leaf group 1-2 arranged opposite to each other, and the lower multi-leaf grating assembly 2 includes a third leaf group 2-1 and a fourth leaf group 2-2 arranged opposite to each other.

[0042] The first blade group 1-1 and the third blade group 2-1 are located in blade box one; the second blade group 1-2 and the fourth blade group 2-2 are located in blade box two.

[0043] Optionally, it also includes electrical box 10-1, electrical box 2 10-2, and connector 10-3;

[0044] The connector 10-3 is connected to electrical box 10-1 and electrical box 2 10-2 respectively.

[0045] The third objective of this invention is to provide an application of a double-layer multi-leaf collimator with self-monitoring function, which is applied to a robotic arm radiotherapy system.

[0046] Compared with the prior art, the present invention has at least the following beneficial effects:

[0047] (1) The self-monitoring method of the present invention ensures that the actual position of the grating blade is consistent with the preset position given by the treatment planning system during the treatment process;

[0048] (2) This invention achieves non-contact, high-precision real-time monitoring of the position of grating blades by combining a light source, a diffuse reflector and a CCD camera;

[0049] (3) The present invention uses an optical imaging system to monitor the position of the grating blades, which can quickly and accurately identify the position of the blade end face, and has high accuracy and strong real-time performance.

[0050] (4) In the present invention, during the operation of the double-layer multi-leaf collimator, the lower multi-leaf grating blades and the upper multi-grating blades are in place one after the other, and the position information of all grating blades can be obtained by two optical imaging, thereby improving the safety of the double-layer multi-leaf collimator.

[0051] (5) The present invention detects the position of the upper and lower grating blades respectively, so as to avoid beam treatment when the blades that do not participate in the formation of radiation field are abnormal, thereby improving the accuracy and safety of radiotherapy dose. Attached Figure Description

[0052] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0053] Figure 1 This is a schematic top view of the double-layer multi-leaf collimator in an embodiment of the present invention;

[0054] Figure 2 This is a schematic diagram of the hardware related to the multi-leaf collimator and its corresponding locations in an embodiment of the present invention;

[0055] Figure 3 This is a schematic diagram of a flowchart illustrating the usage method of the double-layer multi-leaf collimator in an embodiment of the present invention;

[0056] Figure 4 This is a schematic diagram of the focusing method of the double-layer multi-leaf collimator blades in an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of a double-layer multi-leaf collimator in an embodiment of the present invention;

[0058] Figure 6 This is a schematic diagram of a cross-sectional view of the diffuse reflector assembly and the light source in an embodiment of the present invention.

[0059] Figure label:

[0060] Upper multi-leaf grating assembly 1, lower multi-leaf grating assembly 2, first blade group 1-1, second blade group 1-2, third blade group 2-1, fourth blade group 2-2, electronic linear accelerometer 3, primary collimator 4, CCD camera 5, reflector 6, bracket 6-1, end face 7, light source 8, diffuse reflector assembly 9, diffuse reflector one 9-1, diffuse reflector two 9-2, electrical box one 10-1, electrical box two 10-2, connector 10-3, connecting plate 11, main box one 12-1, support seat one 12-2, main box two 13-1, support seat two 13-2, included angle one 14, included angle two 15. Detailed Implementation

[0061] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0062] A specific embodiment of the present invention, such as Figure 1-6 A dual-layer multi-leaf collimator with self-monitoring function is disclosed, comprising: an image acquisition component, an upper multi-leaf grating component 1, and a lower multi-leaf grating component 2; the upper multi-leaf grating component 1 and the lower multi-leaf grating component 2 are stacked in the X-ray beam direction, wherein the upper multi-leaf grating component 1 is closer to the X-ray source side, and the lower multi-leaf grating component 2 is closer to the area to be irradiated, as shown below. Figure 1 As shown;

[0063] Optionally, each multi-leaf grating assembly includes two sets of relatively moving leaf groups, each leaf group including multiple independently movable grating leaves to form a complex opening shape to match the tumor contour.

[0064] For example, the grating blades in each blade group move in an alternating manner in the horizontal direction;

[0065] Optionally, the grating blades of the upper multi-leaf grating assembly and the lower multi-leaf grating assembly are arranged in parallel and staggered order;

[0066] Furthermore, the horizontal center line of the blades of the upper multi-leaf grating assembly coincides with the horizontal edge line of the blades of the corresponding lower multi-leaf grating assembly. That is, the blades of the upper multi-leaf grating assembly and the blades of the corresponding lower multi-leaf grating assembly are staggered to form a staggered arrangement. Even if the rays pass through the gaps between the grating blades in the upper multi-leaf grating assembly, they will be blocked by the grating blades of the lower multi-leaf grating assembly. This allows the lower grating blade group to block the gaps between the upper grating blade groups, reducing leakage and protecting the normal tissue around the target area.

[0067] Optionally, the upper multi-leaf grating assembly 1 includes a first leaf group 1-1 and a second leaf group 1-2 arranged opposite to each other, and the lower multi-leaf grating assembly 2 includes a third leaf group 2-1 and a fourth leaf group 2-2 arranged opposite to each other.

[0068] The first blade group 1-1 and the third blade group 2-1 are disposed in blade box one; the second blade group 1-2 and the fourth blade group 2-2 are disposed in blade box two.

[0069] Furthermore, the first blade box includes a main box body 12-1 and a support base 12-2 disposed on the lower end face of the main box body; the second blade box includes a main box body 2 13-1 and a support base 2 13-2 disposed on the lower end face of the main box body 2.

[0070] For example, the blades of the first blade group and the third blade group are misaligned in the longitudinal direction;

[0071] The blades of the second and fourth blade groups are misaligned and aligned in the longitudinal direction.

[0072] Optionally, the first focal point of the lateral extension line of each blade in the upper multi-leaf grating assembly may or may not coincide with the second focal point of the lateral extension line of the blade in the lower multi-leaf grating assembly.

[0073] Optionally, the two sides of each grating blade in the first and second blade groups have an included angle of -14°.

[0074] The two sides of each grating blade in the third and fourth blade groups have an included angle of 15°.

[0075] The ratio of included angle 14 to included angle 15 is 1:0.5-1;

[0076] In this invention, the two sides of the grating blade have an included angle; since the two sides of the grating blade along the arrangement direction are not parallel and have an included angle, the blade can be focused, reducing the penumbra of the field of view.

[0077] Optionally, the end face 7 of the grating blade is an arc end face, which is used for monitoring the light source or radiation at a fixed position to obtain the distance between the light source and the target end face. It is tangent to the beam at any position, reducing the penumbra at the edge of the radiation field.

[0078] Optionally, each grating blade is driven by a motor;

[0079] Optionally, the image acquisition component includes a CCD camera 5, a reflector 6, a light source 8, and a diffuser assembly 9;

[0080] The CCD camera 5 is mounted on the connecting plate 11, and the lens axis of the CCD camera 5 is parallel to the direction of movement of the grating blades.

[0081] The reflector 6 is mounted on the connecting plate 11 via the bracket 6-1, and the angle between the reflector 6 and the connecting plate 11 is 45°-60°.

[0082] The connecting plate 11 is connected to the upper end face of blade box one and blade box two respectively;

[0083] Optionally, the angle between the reflector 6 and the connecting plate 11 is 45°;

[0084] Optionally, the light source 8 includes a plurality of LEDs;

[0085] The diffuse reflector assembly 9 includes a diffuse reflector 9-1 and a diffuse reflector 9-2; the plurality of LED lights are arranged at equal intervals between the diffuse reflector 9-1 and the diffuse reflector 9-2.

[0086] The diffuse reflector assembly 9 is connected to the lower end faces of the first main housing 12-1 and the second main housing 13-1, respectively, and is parallel to the direction of movement of the grating blades;

[0087] The first support 12-2 is also connected to the diffuse reflector assembly 9, and the second support 13-2 is also connected to the diffuse reflector assembly 9.

[0088] Optionally, the diffuse reflector 9-1 and the diffuse reflector 9-2 are diffuse reflectors with crosshairs;

[0089] It is understandable that the light generated by the light source is diffusely reflected by the diffuse reflector assembly and then propagates in the opposite direction along the beam. The light passes through the reflector and the CCD camera completes the image acquisition.

[0090] Optionally, the position of the CCD camera can be adjusted so that its focusing position is symmetrical with respect to the plane mirror with respect to the blade end face of the lower grating blade group, thereby reducing the difficulty of image processing.

[0091] Optionally, it also includes electrical box 10-1, electrical box 2 10-2, and connector 10-3;

[0092] The connector 10-3 is connected to electrical box 10-1 and electrical box 2 10-2 respectively;

[0093] Optionally, the connector 10-3 is hollow in shape, either a rectangle or a square;

[0094] Optionally, the electrical box one and the electrical box two are also respectively connected to the blade box one and the blade box two;

[0095] The electrical box one and electrical box two respectively include a power module, a control circuit board and a communication unit;

[0096] The control circuit board is used to process blade position commands and feedback signals, and convert the commands into drive signals for the motor to precisely control the opening and closing position and movement speed of each blade.

[0097] The power module provides a stable DC power supply for the micro motor;

[0098] The communication unit is connected to the control computer via a cable to enable real-time transmission of treatment plans.

[0099] Optionally, the dual-layer multi-leaf collimator is used in a robotic arm radiotherapy system.

[0100] Another objective of this invention is to disclose a method of using a double-layer multi-leaf collimator with self-monitoring function, comprising:

[0101] Step S1: Develop a treatment plan and, according to the treatment plan, activate the double-layer multi-leaf collimator to emit beam radiation; the treatment plan includes the preset positions of each grating leaf in the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2.

[0102] The treatment plan is set according to the area of ​​the patient's lesion.

[0103] Step S2: Obtain the shape of the radiation field of the current emitted beam, such as... Figure 1 ;

[0104] Determine whether the end faces of each grating blade in the upper and lower multi-leaf grating assemblies can be identified in the shape of the irradiation field;

[0105] If so, turn on the light source 8, and obtain the first image based on the CCD camera 5 through the diffuse reflection plate assembly 9. Based on the first image, obtain the actual positions of each grating leaf 1 in the upper multi-leaf grating assembly 1 and each grating leaf 2 in the lower multi-leaf grating assembly 2.

[0106] Determine whether the actual positions of each grating blade one and each grating blade two are consistent with the preset positions in the treatment plan. If they are, the detection is completed and beam treatment is performed.

[0107] If not, then it is necessary to perform position detection of the upper multi-leaf grating assembly and the lower multi-leaf grating assembly, and proceed to step S3;

[0108] Step S3: Return the upper multi-leaf grating assembly 1 and the lower multi-leaf grating assembly 2 to their initial positions;

[0109] Based on the treatment plan, the electrical boxes 1 and 2 of the double-layer multi-leaf collimator are adjusted to control the motors corresponding to each grating blade 2 in the lower multi-leaf grating assembly 2, so that each grating blade 2 reaches the preset position. The light source 8 is turned on, and the lower multi-leaf grating assembly 2 is illuminated through the diffuse reflection plate assembly 9. The image is acquired by the CCD camera 5 to obtain the second acquired image.

[0110] Determine whether the actual position of each grating blade 2 in the acquired image 2 is consistent with the preset position. If yes, adjust the lower multi-leaf grating assembly to restore it to the initial position and proceed to the next step. If no, repair the motor corresponding to each grating blade 2, obtain the repaired double-layer multi-leaf collimator and perform beam radiation, and return to step S2.

[0111] Step S4: Control the motor corresponding to each grating leaf in the upper multi-leaf grating assembly so that each grating leaf reaches the preset position, turn on the light source 8, and illuminate the upper multi-leaf grating assembly through the diffuse reflection plate assembly 9. Use the CCD camera 5 to acquire the image and obtain the acquired image 3.

[0112] Determine whether the actual position of each grating blade 1 in the acquired image 3 is consistent with the preset position. If yes, adjust the upper multi-leaf grating assembly to restore it to the initial position and proceed to the next step. If no, repair the motor corresponding to each grating blade 1, obtain the repaired double-layer multi-leaf collimator 2 and perform beam radiation, and return to step S2.

[0113] Step S5: Based on the treatment plan, control the movement of each grating leaf in the upper and lower multi-leaf grating components to reach the preset position, turn on the light source, and illuminate the upper multi-leaf grating component through the diffuse reflection plate component 9. Use the CCD camera 5 to acquire the image and obtain the acquired image four.

[0114] Determine whether the actual position of each grating blade in the acquired image 4 is consistent with the preset position. If yes, obtain the detected double-layer multi-leaf collimator and proceed to the next step. If no, repair the motor corresponding to each grating blade, obtain the repaired double-layer multi-leaf collimator 3 and perform beam radiation, then return to step S2.

[0115] Step S6: Perform beam delivery treatment using the tested double-layer multi-leaf collimator.

[0116] In one embodiment of the present invention, a method of using a double-layer multi-leaf collimator with self-monitoring function includes:

[0117] The physicist will provide a treatment plan using a double-layered multi-leaf collimator.

[0118] According to the treatment plan, beam output is performed, and multiple beam output results are obtained. Based on the multiple beam output results, it is determined whether the lower multi-leaf grating component needs to be monitored for its position.

[0119] If not needed, the electrical boxes 1 and 2 of the double-layer multi-leaf collimator control the corresponding motors to move the grating blades of the upper and lower multi-leaf grating components to the designated positions. After the grating blades are in place, the light source 8 is turned on to generate visible light. The light is uniformly diffused by the diffuse reflector assembly, blocked by the grating blades of the lower multi-leaf grating component, and then reaches the radiation-proof CCD camera 5 through the reflector 6. The camera converts the received light signal into an electrical signal, and then converts the electrical signal into the position information of the blades of the lower multi-leaf grating component.

[0120] After obtaining the position information of the blades of the lower multi-leaf grating assembly, it is compared with the treatment position in the treatment plan. If it fails, the problem of blade motion control is detected and repaired in time. If it succeeds, the lower multi-leaf grating assembly is adjusted to return to the initial position and the next step is carried out.

[0121] After the optical signal acquisition of the lower multi-leaf grating assembly is completed, the control system of the double-layer multi-leaf collimator moves the blades of the upper multi-leaf grating assembly to the designated position by controlling the corresponding motor and at the same time retracts the lower multi-leaf grating assembly of the double-layer multi-leaf collimator.

[0122] After the blades of the upper multi-leaf grating assembly move into position, the light source is turned on. The visible light generated is blocked by the extended double-layer multi-leaf collimator blades through the diffuse reflector and reaches the radiation-proof CCD camera through the reflector.

[0123] The signal can be processed to obtain the blade position information of the upper multi-leaf grating assembly;

[0124] Based on the leaf position information of the upper multi-leaf grating assembly and the leaf position information of the lower multi-leaf grating assembly, the treatment position is compared with the treatment position in the treatment plan. If the correspondence is successful, the position of the lower leaf given in the treatment plan is restored, and the beam treatment is performed after confirming that the formed radiation field is consistent with the preset.

[0125] This invention uses two imaging acquisitions to determine the positioning of the upper and lower multi-leaf grating components, respectively. This allows for the timely detection of abnormal situations where the position of the leaf that does not participate in the formation of the radiation field is inconsistent with the position given in the treatment plan. This reduces the unnecessary radiation to the patient caused by inter-leaf leakage due to the leaf being in an unexpected position.

[0126] In this invention, the double-layer multi-leaf collimator, with its double-layer blade structure, may cause mutual occlusion between the blades. By monitoring the position of the blades involved in forming the radiation field through optical imaging, the discrepancy between the actual and expected radiation field due to mechanical failure of the multi-leaf collimator blades is avoided. However, the position of the occluded blades used to reduce leakage between blades is difficult to monitor.

[0127] This invention utilizes a two-stage imaging method to obtain the positioning status of all blades, enabling more timely detection of abnormalities in blades not involved in radiation field formation and improving the safety of radiotherapy. Since this method involves multiple separate blade positioning steps, it increases treatment time. In practical applications, a combination of separate blade positioning and single-stage positioning methods can be used, allowing the user to balance the safety of blade leakage with treatment time. For example, the multiple-stage blade position monitoring method can be used throughout the first patient's treatment each day. Alternatively, the user can freely set a maximum permissible threshold for blade non-detection. For each blade, the program records the number of times the blade position is not monitored due to mutual obstruction during beam exit. When this number exceeds the threshold, the multiple-stage blade position monitoring method is applied.

[0128] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A method of using a double-layered multi-leaf collimator with self-monitoring function, characterized in that, The application relates to a double-layer multileaf collimator and a treatment method thereof. Step S1, starting the upper-layer multileaf grating assembly (1) and the lower-layer multileaf grating assembly (2) of the double-layer multileaf collimator to emit radiation; The treatment plan comprises preset positions of each grating blade in the upper-layer multileaf grating assembly (1) and the lower-layer multileaf grating assembly (2); Step S2, judging whether the end surface (7) of each grating blade in the upper-layer multileaf grating assembly and the lower-layer multileaf grating assembly can be recognized in the current radiation field shape of the emitted radiation; If yes, obtaining an acquisition image one by using the image acquisition assembly, obtaining the actual positions of each grating blade based on the acquisition image one, and judging whether the actual positions are consistent with the corresponding preset positions; if yes, the detection is completed, and the emitted treatment is performed; if no, the in-place detection of the upper-layer multileaf grating assembly and the lower-layer multileaf grating assembly needs to be performed, and step S3 is entered; Step S3, restoring the upper-layer multileaf grating assembly (1) and the lower-layer multileaf grating assembly (2) to the initial positions; Based on the treatment plan, each grating blade two of the lower-layer multileaf grating assembly (2) is controlled to reach the preset position, an acquisition image two is obtained by using the image acquisition assembly, the actual positions of each grating blade two are obtained based on the acquisition image two, and whether the actual positions are consistent with the preset positions is judged; if yes, the lower-layer multileaf grating assembly is controlled to restore to the initial position, the next step is performed; if no, the lower-layer multileaf grating assembly is repaired, the double-layer multileaf collimator one after the repair is obtained, and the emitted radiation is performed, and the step S2 is returned; Step S4, controlling each grating blade one in the upper-layer multileaf grating assembly to reach the preset position, obtaining an acquisition image three based on the image acquisition assembly, obtaining the actual positions of each grating blade one based on the acquisition image three, and judging whether the actual positions are consistent with the preset positions; if yes, the upper-layer multileaf grating assembly is controlled to restore to the initial position, the next step is performed; if no, the upper-layer multileaf grating assembly is repaired, the double-layer multileaf collimator two after the repair is obtained, and the emitted radiation is performed, and the step S2 is returned; Step S5, based on the treatment plan, controlling each grating blade in the upper-layer multileaf grating assembly and the lower-layer multileaf grating assembly to reach the preset position, obtaining an acquisition image four based on the image acquisition assembly, obtaining the actual positions of each grating blade one based on the acquisition image four, and judging whether the actual positions are consistent with the preset positions; if yes, the double-layer multileaf collimator after the detection is obtained, the next step is entered; if no, the double-layer multileaf collimator three after the repair is obtained, and the emitted radiation is performed, and the step S2 is returned; Step S6, performing the emitted treatment by using the double-layer multileaf collimator after the detection.

2. The method of using a double-layered multi-leaf collimator with self-monitoring function according to claim 1, wherein, The treatment plan is set according to the lesion region of a patient.

3. The method of using a double-layered multi-leaf collimator with self-monitoring function according to claim 1, wherein, The specific steps of step S2 comprise: judging whether the end surface (7) of each grating blade in the upper-layer multileaf grating assembly and the lower-layer multileaf grating assembly can be recognized in the current radiation field shape of the emitted radiation; if yes, turning on the light source (8), passing through the diffuse reflection plate assembly (9), obtaining the acquisition image one based on the CCD camera (5), and obtaining the actual positions of each grating blade one in the upper-layer multileaf grating assembly (1) and each grating blade two in the lower-layer multileaf grating assembly (2) based on the acquisition image one; If the actual positions of the leaf banks one and two are consistent with the corresponding preset positions in the treatment plan, the detection is completed, and the beam treatment is performed. If not, the in-place detection of the upper and lower multileaf collimator assemblies needs to be performed, and step S3 is entered.

4. The method of using a double-layered multi-leaf collimator with self-monitoring function according to claim 1, wherein, The specific steps of step S3 include: The upper multileaf collimator assembly (1) and the lower multileaf collimator assembly (2) are restored to the initial positions. Based on the treatment plan, the electrical boxes one and two of the double-layer multileaf collimator are controlled to control the motors corresponding to the leaf banks two in the lower multileaf collimator assembly (2) so that the leaf banks two reach the preset positions, the light source (8) is turned on, the lower multileaf collimator assembly (2) is irradiated through the diffuse reflection plate assembly (9), the CCD camera (5) is used for image acquisition, and the acquired image two is obtained. If the actual positions of the leaf banks two in the acquired image two are consistent with the preset positions, the lower multileaf collimator assembly is restored to the initial position, the next step is performed, and if not, the motors corresponding to the leaf banks two are repaired, the double-layer multileaf collimator one after the repair is obtained, and the beam radiation is performed, and the step S2 is returned.

5. The method of using a double-layered multi-leaf collimator with self-monitoring function according to claim 1, wherein, The specific steps of step S4 include: The motors corresponding to the leaf banks one in the upper multileaf collimator assembly are controlled so that the leaf banks one reach the preset positions, the light source (8) is turned on, the upper multileaf collimator assembly is irradiated through the diffuse reflection plate assembly (9), the CCD camera (5) is used for image acquisition, and the acquired image three is obtained. If the actual positions of the leaf banks one in the acquired image three are consistent with the preset positions, the upper multileaf collimator assembly is restored to the initial position, the next step is performed, and if not, the motors corresponding to the leaf banks one are repaired, the double-layer multileaf collimator two after the repair is obtained, and the beam radiation is performed, and the step S2 is returned.

6. The method of using a double-layered multi-leaf collimator with self-monitoring function according to claim 1, wherein, The specific steps of step S5 include: Based on the treatment plan, the movements of the leaf banks in the upper and lower multileaf collimator assemblies are controlled to reach the preset positions, the light source is turned on, the upper multileaf collimator assembly is irradiated through the diffuse reflection plate assembly (9), the CCD camera (5) is used for image acquisition, and the acquired image four is obtained. If the actual positions of the leaf banks one in the acquired image four are consistent with the preset positions, the double-layer multileaf collimator after the detection is obtained, the next step is entered, and if not, the motors corresponding to the leaf banks one are repaired, the double-layer multileaf collimator three after the repair is obtained, and the beam radiation is performed, and the step S2 is returned.

7. The double-layered multi-leaf collimator with self-monitoring function according to any one of claims 1-6, characterized in that, It includes: The image acquisition assembly, the upper multileaf collimator assembly (1), and the lower multileaf collimator assembly (2); The upper multileaf collimator assembly (1) and the lower multileaf collimator assembly (2) are connected with the image acquisition assembly through the connecting plate (11); The image acquisition assembly includes the CCD camera (5), the reflector (6), the light source (8), and the diffuse reflection plate assembly (9); The CCD camera (5) is arranged on the connecting plate (11); the reflector (6) is arranged on the connecting plate (11) through the support (6-1); The light source (8) includes a plurality of LED lamps; The diffuse reflection plate assembly (9) comprises a diffuse reflection plate one (9-1) and a diffuse reflection plate two (9-2); and the plurality of LED lamps are arranged at equal intervals between the diffuse reflection plate one (9-1) and the diffuse reflection plate two (9-2).

8. The double-layered multi-leaf collimator with self-monitoring function according to claim 7, characterized in that, The upper multileaf collimator assembly (1) and the lower multileaf collimator assembly (2) are stacked in the direction of the ray beam, wherein the upper multileaf collimator assembly (1) is close to the X-ray source side, and the lower multileaf collimator assembly (2) is close to the to-be-radiated region side. The upper multileaf collimator assembly (1) comprises a first leaf group (1-1) and a second leaf group (1-2) arranged oppositely, and the lower multileaf collimator assembly (2) comprises a third leaf group (2-1) and a fourth leaf group (2-2) arranged oppositely. The first leaf group (1-1) and the third leaf group (2-1) are arranged in a leaf box one, and the second leaf group (1-2) and the fourth leaf group (2-2) are arranged in a leaf box two.

9. The double-layer multileaf collimator with a self-monitoring function according to claim 7, characterized in that, Further comprising an electrical box one (10-1), an electrical box two (10-2) and a connecting piece (10-3); The connecting piece (10-3) connects the electrical box one (10-1) and the electrical box two (10-2) respectively.

10. Use of a double layer multi-leaf collimator with self-monitoring function, characterized in that, The double-layer multileaf collimator is applied to a mechanical arm radiotherapy system.

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