Radiotherapy device collision avoidance system based on multiple detection modes

Abstract

The invention discloses a radiotherapy device collision avoidance system based on multiple detection modes. The system comprises, from top to bottom, an upper computer for displaying alarm information, a PLC controller upwardly connected to the upper computer and downwardly connected to a motion device, the motion device controlled by the PLC controller, and a collision detection unit for providing collision detection information for the PLC controller. The movement equipment comprises a rotating rack, a treatment bed and other movement equipment related to the treatment head; the treatment bed is a robot treatment bed, and the treatment bed envelope comprises an envelope of the treatment bed and an envelope of a patient on the treatment bed; according to the invention, a distance real-time collision detection method, a pressure real-time collision detection method and a space coordinate real-time collision detection method are combined to form a set of complete collision avoidance system; through multi-level detection means, comprehensive protection is provided for potential collision threats in the radiotherapy process, and the occurrence rate of collision accidents is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the field of radiotherapy, and more specifically, relates to a collision avoidance system for a radiotherapy device based on multiple detection methods. Background Art

[0002] Radiotherapy equipment (radiotherapy equipment) is currently mainly used for radiotherapy of malignant tumors. Radiotherapy equipment usually includes: a gantry that can rotate around a rotation axis, a treatment head mounted on the rotating gantry, a DR flat panel (image-guided X-ray flat panel) for image guidance, and a treatment bed that accurately delivers the patient to the bottom of the treatment head for treatment. In the actual radiotherapy process, mechanical movements of different amplitudes, such as the rotation of the gantry, the swing of the treatment head and DR flat panel, and the movement of the treatment bed, all have potential collision risks. Such collisions pose a safety hazard to patients and staff, and may also cause serious damage to the radiotherapy equipment.

[0003] The difficulty in designing a collision avoidance system for radiotherapy equipment is that in the existing radiotherapy equipment design, the anti-collision detection means are mostly single detection methods, and a single detection method often cannot solve the collision avoidance problem for the complex and changeable environmental factors in actual situations. For example 1, collision detection is performed through distance sensors, but the premise is that the radiotherapy equipment must have enough space to arrange distance sensors in all places where collisions may occur. If distance sensors are arranged in all places where danger may occur, it will take up additional space for the rotation of the treatment bed or the rotation of the rotating rack. Obviously, this is not allowed. Then, distance sensors can only be arranged in a few limited areas without affecting the operating space of the treatment bed and the rotating rack. Most places where it is inconvenient to install distance sensors cannot detect collisions; for example 2: some collision detection cannot reflect the problem through distance sensors. Not all collisions can be measured by the distance. For example, a piece of iron plate suddenly falls and presses on the treatment bed and the patient. When the thickness of the iron plate is not large, the distance from the treatment bed + iron plate to the distance detector is not much different from the distance from the treatment bed to the detector alone. At this time, relying solely on distance sensors will not work. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention proposes a collision avoidance system for radiotherapy devices based on multiple detection methods, aiming to solve the problem that a single anti-collision detection method often cannot meet the complex and changeable environmental factors in actual situations.

[0005] The present invention adopts the following technical solutions to solve the technical problems:

[0006] A collision avoidance system for radiotherapy devices based on multiple detection methods is characterized in that: the system comprises, from top to bottom, a host computer for displaying alarm information, a PLC controller connected to the host computer upward and to a motion device downward, a motion device controlled by the PLC controller, and a collision detection unit that provides collision detection information to the PLC controller; the motion device comprises a rotating frame, a treatment bed, and other motion devices related to a treatment head; the treatment bed is a robot treatment bed, and the treatment bed envelope comprises the treatment bed envelope itself and the patient envelope on the treatment bed;

[0007] The collision detection unit includes: a distance comparison collision detection subunit based on the current treatment bed distance comparison, a pressure comparison collision detection subunit based on the current treatment bed pressure comparison, and a VxWorks space position comparison collision detection subunit based on the current treatment bed space position comparison;

[0008] The distance comparison collision detection subunit includes detectors and laser distance sensors arranged around the treatment head, DR flat panel and treatment bed, as well as multi-level warning areas divided around the detectors and laser distance sensors, and a warning area boundary calculation unit;

[0009] The pressure comparison collision detection subunit includes a pressure sensor arranged on the treatment bed and a pressure comparison module for comparing whether the current pressure is normal or not;

[0010] The VxWorks spatial position comparison collision detection subunit includes programming software and three-dimensional modeling software, a position comparison collision detection database, and a position information acquisition and calculation module based on VxWorks; the programming software and three-dimensional modeling software save the 3D modeling model to the position comparison collision detection database, and the position information acquisition and calculation module based on VxWorks obtains 3D modeling information from the position comparison collision detection database on the one hand, and obtains position information of related motion equipment including the treatment bed and the rotating frame on the other hand, and calculates these two types of information in VxWorks to obtain a collision prediction result at the next moment, and reports it to the PLC. In dangerous situations, the PLC will quickly shut down or brake the related motion equipment; the 3D modeling model is a model of the safe movement range of the treatment bed.

[0011] Furthermore, the multi-level warning area of ​​the distance comparison collision detection subunit includes a treatment head warning area and a treatment head danger area based on the treatment head; a zone a and a zone b centered on the treatment bed; the treatment head warning area surrounds the treatment head danger area; the shape of the treatment head warning area is approximately trapezoidal, and the shape of the treatment head danger area is approximately an envelope formed by the treatment head and the DR plate when they are unfolded; the zone a is the treatment bed danger area, and the zone b is the treatment bed secondary danger area; when the distance between the treatment bed and the treatment head enters the warning area of ​​the treatment head, the system alarms; when the distance between a person or an object and the treatment head enters the danger area of ​​the treatment head, the motion equipment of each radiotherapy facility stops moving; the motion equipment includes but is not limited to a rotating frame, a treatment bed, a DR plate, and a range shifter on the treatment head; when a person or an object is detected in the zone b around the treatment bed, the system issues a warning and the treatment bed slows down; when a person or an object is detected in the zone a around the treatment bed, the system issues an audible and visual alarm and the treatment bed brakes.

[0012] Furthermore, the warning zone boundary calculation unit of the distance comparison collision detection subunit calculates the envelope boundary of the dangerous area of ​​the treatment head according to the sizes of the rotating gantry, the treatment head, the DR plate, and the maximum braking angle of the rotating gantry.

[0013] Furthermore, the pressure contrast module of the pressure contrast collision detection subunit divides the pressure detection process into four time points: 0, t1, t2, and t3; from time 0 to time t1, this time period simulates the process of the patient lying on the treatment bed; from time t1 to time t2, this time period simulates the process of the patient lying steadily on the treatment bed to receive treatment. Although the curve has jitters in this stage, it eventually tends to be flat; from time t2 to time t3, this time period simulates the process of a sudden increase or decrease in pressure. The sudden change is a sudden increase or decrease in pressure in a short period of time. This process is defined as an abnormal pressure sudden change stage. The equipment is very likely to have collided or encountered other abnormal conditions during this time period; when the pressure contrast unit detects such a sudden change, the operation of the radiotherapy equipment will be terminated.

[0014] Furthermore, the VxWorks spatial position comparison collision detection subunit includes a 3D modeling module, a VxWorks spatial position coordinate acquisition module, and a real-time judgment module; the 3D modeling module models a safe movement interval model of the treatment bed in the rotating frame through programming software and three-dimensional modeling software, and repeatedly adjusts the position and angle of the established safe movement interval model in the program, and saves the adjusted position to the position comparison collision detection database; the VxWorks spatial position coordinate acquisition module acquires the current position and movement speed of the treatment bed and the rotating frame in real time through the VxWorks system; the real-time judgment unit judges whether the treatment bed and its peripheral equipment will collide at the next moment based on the data obtained by the spatial position coordinate unit, and sends the judgment information to the PLC controller. If it is judged that a collision is about to occur, the PLC controller will brake the treatment bed in time.

[0015] Further, the 3D modeling module includes a coordinate system establishment submodule, a treatment head angular position division submodule, a first-level loose grid division submodule, and a second-level precise grid division submodule; the treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, each part corresponding to an angle of the treatment head; the first-level loose grid division submodule uses the activity area of ​​the treatment bed away from the collision object or away from the danger zone of the treatment head as multiple first-level loose grid areas according to the current angle of the treatment head, and saves the multiple first-level loose grid areas to the database, the grids of the multiple first-level loose grid areas are relatively sparse, the grid size is relatively coarse, and each loose grid is a detection point; the second-level precise grid division submodule uses the activity area of ​​the treatment bed close to the collision object or close to the danger zone of the treatment head as multiple second-level precise grid areas according to the current angle of the treatment head, and saves the multiple second-level precise grid areas to the database, the grids of the multiple second-level precise grid areas are relatively dense, the grid size is relatively small, and each second-level precise grid division submodule is a detection point; the collision objects include but are not limited to the rotating frame, treatment head, DR plate, and rolling floor around the treatment bed.

[0016] Furthermore, the coordinate system establishment submodule establishes a three-dimensional rectangular coordinate system (X, Y, Z) with the center of the front cross-section ring of the rotating frame as the coordinate origin, and the coordinate system is the basis for all subsequent position calculations.

[0017] Furthermore, the VxWorks spatial position coordinate acquisition module acquires the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, and the moving speed and direction of the treatment bed; and also acquires the angle, rotation speed and direction of the rotating frame.

[0018] Furthermore, the real-time judgment module judges whether the treatment bed and the surrounding equipment will collide at the next moment according to the current safe movement range model of the treatment bed, the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, the movement speed and direction of the treatment bed, the angle of the rotating frame, and the rotation speed and direction. If it is judged that a collision is about to occur, it is reported to the PLC controller, and the PLC controller will brake the treatment bed in time.

[0019] Furthermore, the treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, the several equal parts include 72 parts, each interval of 5° is one part; the multiple first-level loose grid areas include 72 first-level loose grid areas; the multiple second-level precise grid areas include 72 second-level precise grid areas.

[0020] Advantages and effects of the present invention

[0021] 1. The present invention has an accurate distance detection and response mechanism: it determines the specific position of the target to be detected in the radiotherapy equipment and monitors its surrounding area, detects the target position in real time through the detection device, and responds according to the settings of the safe distance, sub-dangerous distance and dangerous distance; it realizes accurate monitoring of the radiotherapy equipment and its surrounding objects, and can take corresponding safety measures within different distance ranges, such as slowing down or stopping operation, so as to avoid collision.

[0022] 2. The present invention also has a unique mechanism for detecting and suspending operation due to abnormal pressure: the pressure detection device monitors the changes in the pressure and extrusion pressure of the target to be detected in real time to determine whether there is an abnormality; the operation of the radiotherapy equipment can be suspended in time when the pressure is abnormal to avoid collision or damage caused by pressure changes.

[0023] 3. The present invention relates to a method for using C# programming language to realize interaction with a scaled three-dimensional model in a three-dimensional design simulation software to construct a query table for collision-free safe positioning. The system is equipped with a component for real-time monitoring of the three-dimensional coordinates and movement rate of the treatment bed. The collision prevention algorithm runs on a control board equipped with a VxWorks operating system. By matching the real-time collected data with the query table pre-stored in the database, the system can instantly evaluate whether there is a potential collision risk in the next position of the treatment bed, and automatically adjust the speed of related equipment or implement emergency stop measures when a risk is detected to ensure safe operation.

[0024] 4. The invention proposes a multi-level in-depth defense collision avoidance method based on the existing anti-collision detection means of radiotherapy equipment. The invention combines the distance real-time collision detection method, the pressure real-time collision detection method and the space coordinate real-time collision detection method to form a complete collision avoidance system; through multi-level detection means, it provides comprehensive protection for potential collision threats during radiotherapy, effectively reducing the incidence of collision accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Application effect diagram for radiotherapy device;

[0026] Figure 2 This is a schematic diagram of the six-dimensional spatial motion of the robotic treatment bed;

[0027] Figure 3a This is the front view of the radiotherapy device along the xy axis;

[0028] Figure 3b This is the yz-axis side view of the radiotherapy device;

[0029] Figure 4a A schematic diagram of the multi-level warning areas of the distance comparison collision detection mechanism of the present invention;

[0030] Figure 4b A schematic diagram of calculating the boundary of the warning zone of the distance comparison collision detection mechanism of the present invention;

[0031] Figure 4c Schematic diagram of area a and area b of the treatment bed of the distance comparison and collision detection mechanism of the present invention;

[0032] Figure 4d The logical flow chart of the distance comparison collision detection mechanism of the present invention is

[0033] Figure 5a The logic flow chart of the pressure comparison collision detection mechanism of the present invention is

[0034] Figure 5b A schematic diagram of simulating four time points for the pressure comparison unit of the pressure comparison collision detection mechanism of the present invention;

[0035] Figure 6a A first perspective of 3D modeling of a safe moving range of a spatial position comparison collision detection mechanism of the present invention;

[0036] Figure 6b A second viewing angle for 3D modeling of a safe moving range of the spatial position comparison collision detection mechanism of the present invention;

[0037] Figure 7 It is a schematic diagram of the 3D modeling superposition effect of the multi-level warning areas and safe movement intervals of the present invention.

[0038] Figure 8 The logic flow chart of the spatial position comparison collision detection mechanism of the present invention is

[0039] Fig. 9 This is an architecture diagram of a collision avoidance system for a radiotherapy device based on multiple detection methods according to the present invention. DETAILED DESCRIPTION

[0040] Design principle of the present invention

[0041] 1. The innovation of the present invention is to combine three collision detection methods. The three methods each make up for the shortcomings of others with their own strengths and support each other to achieve the effect after the combination. The effect after the combination is: to meet the needs of collision detection in the radiotherapy process under the complex and changeable environmental factors in actual situations. The distance detection method is only suitable for the treatment head and the DR flat plate, because the treatment head and the DR flat plate can be equipped with sensors. Although the distance detection method takes up additional space for arranging sensors, the collision detection is relatively simple and direct, effectively saving computing resources; the pressure detection method can make up for the limitations of the distance detection method; the detection area of ​​the spatial position detection method accounts for 100% of the remaining space of the rotating frame, or the detection area accounts for 100% of the remaining space outside the dangerous area of ​​the treatment head of the rotating frame, and the remaining space of the rotating frame is the remaining space in the rotating frame after the treatment head, DR flat plate, rolling floor, and treatment bed are discarded. The remaining space outside the dangerous area of ​​the treatment head of the rotating frame is the remaining space in the rotating frame after the treatment head, DR flat plate, rolling floor, treatment bed, and treatment head dangerous area are discarded. The spatial position detection method is a sensorless collision detection method, which does not rely on traditional detection equipment but adopts modeling and model comparison methods, thereby solving the collision detection problem without sensors. It is a major innovation of the present invention.

[0042] 2. Design difficulties and solutions of the present invention: The difficulty lies in that the spatial position detection method occupies too much computing resources. There are 72 sets of models. If each set of grids is a 1 cm fine grid, each set of models will have about hundreds of millions of data (determined by the six-axis movement parameters of the treatment bed). If 100 data can be calculated in 1 second, it will take more than 11 days to calculate a set of models. In order to reduce computing power and save time, first, build the model in advance. Modeling takes the longest time, so do the modeling work in advance; second, due to the insufficient response speed and flexibility of the PLC, and its hardware and software architecture is relatively fixed, it is difficult to meet the needs of the spatial position comparison collision detection program. The present invention adopts a VxWorks system with a priority-driven preemptive scheduling strategy, a low-latency interrupt processing mechanism, and an optimized inter-task communication means to obtain the current spatial position and motion data of the treatment bed and the rotating frame and the pre-generated modeling data in real time, and calculates the collision state at the next moment based on these data, ensuring that the system can respond to external events within a few microseconds to a few milliseconds; third, the detection grid is divided into a primary loose grid and a secondary fine grid. For the area far away from the collision object, the primary loose grid is used as the detection point, and for the area close to the collision object, the secondary fine grid is used as the detection point. When the area size is the same, the data volume of the secondary fine grid is about 1000 times that of the primary loose grid (the length, width, and height of the primary grid are 10 cm, respectively, and the second grid is 1 cm), and the primary loose grid occupies more than 90% of the total grid space. This means that when the area size is the same, the time used to calculate the primary loose grid is 1 / 1000 of the time used to calculate the secondary precise grid, so the total calculation time is reduced to less than 10.09% of the original calculation time. The reason for using a secondary fine grid is that the treatment accuracy is high. The movement of the treatment bed is often not in units of 10 cm, but in units of less than 1 cm. Therefore, a secondary fine grid is very necessary for determining the safe position of the treatment bed. In addition, the 72 sets of models are independent of each other and can be calculated using multiple computers to save computing time. Assuming that 10 computers are used for calculation at the same time, the original 792 days required to calculate all 72 sets of models can be shortened to about 8 days. This grid division method effectively reduces the computing power while maintaining the accuracy of detection.

[0043] 3. Methods for handling overlapping areas: Figure 7 As shown, when the third spatial position detection method is used, VxWorks obtains the current spatial position of the treatment bed. When the spatial position enters the warning area or danger area of ​​the treatment head, the PLC processes the braking or warning of the equipment according to the distance detection method.

[0044] The present invention will be further explained below in conjunction with the accompanying drawings:

[0045] Based on the above principles, the present invention designs a radiation therapy device collision avoidance system based on multiple detection methods. Fig. 9 As shown, the system is characterized in that: the system comprises, from top to bottom: a host computer for displaying alarm information, a PLC controller connected to the host computer upward and to the motion equipment downward, the motion equipment controlled by the PLC controller, and a collision detection unit that provides collision detection information to the PLC controller; the motion equipment comprises a rotating frame, a treatment bed and other motion equipment related to the treatment head; the treatment bed is a robot treatment bed, and the treatment bed envelope comprises the treatment bed envelope itself and the patient envelope on the treatment bed;

[0046] like Fig. 9 As shown, the collision detection unit includes: a distance comparison collision detection subunit based on the current treatment bed distance comparison, a pressure comparison collision detection subunit based on the current treatment bed pressure comparison, and a VxWorks space position comparison collision detection subunit based on the current treatment bed space position comparison;

[0047] like Fig. 9 As shown, the distance comparison collision detection subunit includes detectors and laser distance sensors arranged around the treatment head, DR flat panel and treatment bed, as well as multi-level warning areas divided around the detectors and laser distance sensors, and a warning area boundary calculation unit;

[0048] like Fig. 9 As shown, the pressure comparison collision detection subunit includes a pressure sensor arranged on the treatment bed, and a pressure comparison module for comparing whether the current pressure is normal or not;

[0049] like Fig. 9 As shown, the VxWorks spatial position comparison collision detection subunit includes programming software and three-dimensional modeling software, a position comparison collision detection database, and a position information acquisition and calculation module based on VxWorks; the programming software and three-dimensional modeling software save the 3D modeling model to the position comparison collision detection database, and the position information acquisition and calculation module based on VxWorks, on the one hand, obtains 3D modeling information from the position comparison collision detection database, and on the other hand, obtains the position information of related motion equipment including the treatment bed and the rotating frame, and calculates these two types of information in VxWorks to obtain the collision prediction result at the next moment, and reports it to the PLC. In dangerous situations, the PLC will quickly shut down or brake the related motion equipment; the 3D modeling model is a model of the safe movement range of the treatment bed.

[0050] like Figure 4a , 4bAs shown in 4c, the multi-level warning area of ​​the distance comparison collision detection subunit includes a treatment head warning area and a treatment head danger area based on the treatment head; a zone a and a zone b are divided with the treatment bed as the center; the treatment head warning area surrounds the treatment head danger area; the shape of the treatment head warning area is approximately trapezoidal, and the shape of the treatment head danger area is approximately the envelope formed by the treatment head and the DR plate when they are unfolded; the zone a is the treatment bed danger area, and the zone b is the treatment bed secondary danger area; when the distance between the treatment bed and the treatment head enters the warning area of ​​the treatment head, the system alarms; when the distance between a person or an object and the treatment head enters the danger area of ​​the treatment head, the motion equipment of each radiotherapy facility stops moving; the motion equipment includes but is not limited to a rotating frame, a treatment bed, a DR plate, and a range shifter on the treatment head; when a person or an object is detected in the zone b around the treatment bed, the system issues a warning and the treatment bed slows down; when a person or an object is detected in the zone a around the treatment bed, the system issues an audible and visual alarm and the treatment bed brakes.

[0051] like Figure 4a , 4b As shown in 4c, the warning zone boundary calculation unit of the distance comparison collision detection subunit calculates the envelope boundary of the treatment head danger zone according to the size of the rotating frame, the treatment head, the DR plate, and the maximum braking angle of the rotating frame.

[0052] like Figure 5b As shown, the pressure contrast module of the pressure contrast collision detection subunit divides the pressure detection process into four time points: 0, t1, t2, and t3; from time 0 to time t1, this time period simulates the process of the patient lying on the treatment bed; from time t1 to time t2, this time period simulates the process of the patient lying steadily on the treatment bed to receive treatment. Although the curve has jitters in this stage, it eventually tends to be flat; from time t2 to time t3, this time period simulates the process of sudden increase or decrease in pressure. The sudden change is the sudden increase or decrease in pressure in a short period of time. This process is defined as the abnormal pressure sudden change stage. The equipment is very likely to have collided or encountered other abnormal conditions during this time period; when the pressure contrast unit detects such a sudden change, the operation of the radiotherapy equipment will be terminated.

[0053] The VxWorks spatial position comparison collision detection subunit includes a 3D modeling module, a VxWorks spatial position coordinate acquisition module, and a real-time judgment module; the 3D modeling module models a safe movement interval model of the treatment bed in the rotating frame through programming software and three-dimensional modeling software, and repeatedly adjusts the position and angle of the established safe movement interval model in the program, and saves the adjusted safe movement interval model to the position comparison collision detection database; the VxWorks spatial position coordinate acquisition module acquires the current position and movement speed of the treatment bed and the rotating frame in real time through the VxWorks system; the real-time judgment unit judges whether the treatment bed and its peripheral equipment will collide at the next moment based on the data obtained by the spatial position coordinate unit, and sends the judgment information to the PLC controller. If it is judged that a collision is about to occur, the PLC controller will brake the treatment bed in time.

[0054] like Figure 6a , 6b As shown, the 3D modeling module includes a coordinate system establishment submodule, a treatment head angular position division submodule, a first-level loose grid division submodule, and a second-level precise grid division submodule; the treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, each of which corresponds to an angle of the treatment head; the first-level loose grid division submodule uses the activity area of ​​the treatment bed away from the collision object or away from the danger zone of the treatment head as multiple first-level loose grid areas according to the current angle of the treatment head, and saves the multiple first-level loose grid areas to the database, the grids of the multiple first-level loose grid areas are relatively sparse, the grid size is relatively coarse, and each loose grid is a detection point; the second-level precise grid division submodule uses the activity area of ​​the treatment bed close to the collision object or close to the danger zone of the treatment head as multiple second-level precise grid areas according to the current angle of the treatment head, and saves the multiple second-level precise grid areas to the database, the grids of the multiple second-level precise grid areas are relatively dense, the grid size is relatively small, and each second-level precise grid division submodule is a detection point; the collision object includes but is not limited to the rotating frame around the treatment bed, the treatment head, the DR plate, and the rolling floor.

[0055] like Figure 6a , 6b As shown, the coordinate system establishment submodule uses the center of the front cross-section ring of the rotating frame as the coordinate origin to establish a three-dimensional rectangular coordinate system (X, Y, Z), which is the basis for all subsequent position calculations.

[0056] like Figure 6a , 6bAs shown, the VxWorks spatial position coordinate acquisition module acquires the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, and the moving speed and direction of the treatment bed; and also acquires the angle, rotation speed and direction of the rotating frame.

[0057] like Figure 6a , 6b As shown, the real-time judgment module judges whether the treatment bed and the surrounding equipment will collide at the next moment according to the current safe movement range model of the treatment bed, the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, the movement speed and direction of the treatment bed, the angle of the rotating frame, and the rotation speed and direction. If it is judged that a collision is about to occur, it will be reported to the PLC controller, and the PLC controller will brake the treatment bed in time.

[0058] like Figure 6a , 6b As shown, the treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, the several equal parts include 72 parts, each part is 5° apart; the multiple first-level loose grid areas include 72 first-level loose grid areas; the multiple second-level precise grid areas include 72 second-level precise grid areas.

[0059] Embodiment 1: Distance comparison collision detection based on the current distance comparison between the treatment bed and the treatment head

[0060] (1) The components of radiotherapy facilities that need to be collided are: Figure 1 As shown, the treatment head, treatment bed and rotating frame are the main environmental components during the treatment process. For example, the target to be detected is most likely to collide with the treatment head or rotating frame of the radiotherapy equipment and other components that need to be moved during the radiotherapy process. The collision risk described in the step can be said to be the collision risk between the target to be detected and the rotating frame, treatment head and other components of the radiotherapy equipment. In order to facilitate the definition of the distance detection of collision during the treatment process, we divide the parts containing collision risks into two types.

[0061] (2) Two detection standards: The first type of distance comparison collision detection uses the treatment bed as the detection basis to determine the collision-prone positions around the treatment bed and define the treatment bed danger zone and treatment bed sub-danger zone. The second type of distance comparison collision detection uses the treatment head as the detection basis. During the treatment process, the treatment head will move with the rotation of the rotating frame to adjust the treatment distance. While looking for the best treatment position, it is necessary to prevent collisions with moving parts such as the treatment bed and the patient on the treatment bed. We use this to define the treatment head warning zone and treatment head danger zone.

[0062] (3) Six-axis treatment bed Figure 2As shown, the treatment couch has six independent axes of rotation, giving it six degrees of freedom. These axes allow precise positioning of the robotic treatment couch in translation (along all three axes X, Y, Z) and rotation (around all three axes Rx, Ry, Rz) within specified motion limits.

[0063] (4) Division of the dangerous area and sub-dangerous area of ​​the six-axis treatment bed: Taking the bed plate and rotating frame of the treatment bed as an example, the dangerous distance detection is based on the treatment bed. Figure 4c As shown, Figure 4c The treatment bed is shown in its unfolded and unfolded states. Because the base is fixed to the ground, the ascending space of the base as a column is immovable. The axis fixed to the base will not collide within this range, so we do not include this part of the range in the collision distance detection range. At the same time, the axis fixed in other rotation directions can also be defined in this way. Figure 2 We can clearly see that in the horizontal direction, axis 1 rotates along the J1 direction, axis 2 rotates along the J2 direction, driving the axis 3 of the treatment bed to rotate along the J6 direction. Each axis that can rotate independently horizontally may collide. Figure 4c The collision detection range shown for a single axis actually applies to every axis in the detection. Figure 4c With J1 as a collision detection distance center axis of the treatment bed, range a and range b are defined.

[0064] like Figure 4c As shown in the figure, the dark shaded area a is the dangerous area of ​​the treatment bed, and the light shaded area b is the secondary dangerous area of ​​the treatment bed. The dangerous area of ​​the treatment bed is the robot body around the J1 axis. If a person or object appears in this range, the treatment bed will brake quickly; the secondary dangerous area of ​​the treatment bed is the range of 15cm outside the J1 axis body to ensure that at least a safe anti-pinch space is reserved between the machine and the object. The dangerous area and the secondary dangerous area of ​​the treatment bed both take the edge of the axis detected at this time as an important position. We define the edge of area b as the threshold of the envelope of the secondary dangerous area of ​​the treatment bed; define the edge of area a as the threshold of the envelope of the dangerous area of ​​the treatment bed. When the target to be detected falls outside areas a and b, it is judged to be in a safe area, and the radiotherapy-related motion equipment runs normally; when the target to be detected falls in area b, it is judged that the target to be detected is in a secondary dangerous distance, and the radiotherapy-related motion equipment will slow down; when the target to be detected falls in area a, it is judged that the target to be detected is in a dangerous distance, and the radiotherapy-related motion equipment will stop running immediately.

[0065] (5) Division of the danger zone and warning zone of the treatment head: Figure 4aAs shown in the figure, when the treatment head is used as the distance detection benchmark, the type of sensor used to detect the target to be detected and the detection area it covers should also be clearly defined. These sensors should have high precision and high sensitivity to ensure that they can accurately capture the real-time position information of the target to be detected. The sensor uses, for example, a safety-related laser distance sensor. Figure 4a The range shown is the detection range of the sensor, which is divided into detection areas according to the risk probability of collision. When a person or object is detected in the warning area of ​​the treatment head, a warning will be issued to remind the staff of the possible risk of collision; when a person or object is detected in the danger area of ​​the treatment head, an audible and visual alarm will be issued and the current motion equipment will be emergency braked.

[0066] (6) Calculation of the dangerous area of ​​the treatment head: Figure 4b As shown, ①Set parameters: Assume that the maximum braking angle of the rotating frame is θ max , the maximum braking angle is the angle of rotation of the rotating frame from receiving the braking command to stopping the braking. Let θ0 be the angle between the lowest end of the DR plate and the horizontal line of the axis of the rotating frame, let L1 be the distance from the lowest end of the DR plate to the axis of the rotating frame, let L2 be the horizontal component of the distance from the lowest end of the DR plate to the axis of the rotating frame, let L max is the vertical distance from the lowest point of the DR plate to the envelope of the danger zone. ② Solve the triangle to calculate L max :The above four parameters are all known numbers. On this basis, the first step is to calculate the length L of the side opposite to θ0 θ0 ; The second step is to calculate θ0-θ max Length of opposite side L θ0-θmax ; The third step is to calculate L max =L θ0 -L θ0-θmax ; Step 4: Considering the safety threshold, the calculated L max Multiply by a safety factor of 1.5 to get L ref , the fifth step will be L ref The distance from the dangerous area to the treatment head and the DR plate is used as the threshold of the envelope line, and the curve enclosing the treatment head and the DR plate is used with this threshold as the envelope line of the dangerous area.

[0067] (7) PLC controller: The present invention adopts a safety-type PLC as the core of the judgment module. The PLC is specially designed for safety-critical fields and has powerful logical computing capabilities and high reliability. It plays an important role in the collision avoidance system of radiotherapy equipment. The PLC program complies with safety standards, receives distance detection data in real time, and makes rapid and accurate judgments based on preset safety logic. Once a collision risk is detected, a safety response is triggered. The processing module is composed of relays, photoelectric converters, etc., and responds quickly after receiving PLC instructions to control lower-level equipment. When the PLC issues a key instruction, the processing module immediately activates the corresponding components to achieve precise control of the radiotherapy equipment, ensuring that the system responds quickly to potential collision risks and ensuring the safety of personnel and equipment.

[0068] Embodiment 2: Pressure contrast collision detection based on current treatment bed pressure contrast

[0069] The purpose of the present invention is to provide a pressure detection device and a method of using the same that can effectively detect and prevent collision accidents of radiotherapy equipment. The specific detection principle is as follows: Figure 5a shown.

[0070] (1) Pressure vs. collision detection threshold and mechanism: When the patient slightly turns over or adjusts his posture on the treatment bed, the pressure generated will change accordingly. In order to accurately capture these dynamic changes, we not only focus on the real-time pressure value, but also pay more attention to the new pressure generated when the action occurs and the average value. and the difference between This ratio, as a key indicator for evaluating whether an action causes abnormal force, is set within the range of +-10%. As long as the ratio remains within this range, the system considers the force state to be normal and the treatment can continue. However, once the ratio exceeds the preset safety range, it is considered to be abnormal force. At this time, the treatment bed will immediately activate the safety mechanism and automatically stop operation to avoid potential harm to the patient.

[0071] Considering that the treatment bed may encounter external collisions or interference during use, the system also has keen monitoring capabilities. Such external forces often manifest as a sharp change in pressure, which is completely different from the pressure fluctuations caused by normal turning over or adjusting posture (irregular, small changes and short duration). When the system detects that the pressure curve appears When there is a significant mutation, it will be quickly recognized as a sign of external collision (or the patient turning over or adjusting his posture significantly, which is usually unsafe during treatment), and emergency measures will be taken immediately, including stopping all sports equipment to ensure the absolute safety of the patient.

[0072] (2) Pressure curve simulation during treatment: Figure 5b The pressure detection process of a treatment bed from normal to abnormal pressure is simulated.

[0073] ①0~t1 time period: This time period simulates the process of the patient lying on the treatment bed. The initial pressure is zero. When the patient lies on the treatment bed, a pressure formed by the weight distribution will be immediately generated. This pressure fluctuates and rises as the patient lies completely. After the patient lies completely, the average pressure monitored by the pressure detection module is marked as This value becomes an important benchmark for evaluating individual stress conditions. That is, before time t1, the pressure changes greatly in a short period of time. Therefore, the exercise equipment will not be allowed to move at 0-t1 to prevent the patient from being injured by the exercise equipment when the patient is not lying down completely;

[0074] ②T1~T2 time period: This time period simulates the process of the patient lying steadily on the treatment bed and receiving treatment. Although the pressure fluctuates, the overall fluctuation is not large. It can be considered that no collision occurred during this period, and the sports equipment can operate normally during this period;

[0075] ③T2~T3 period: During this period, we can clearly see that the pressure changes suddenly. We define this process of sudden increase or decrease in pressure in a short period of time as an abnormal pressure mutation. The equipment is very likely to have collided or encountered other abnormal conditions (such as the patient moving the body significantly) during this period of time. When the pressure sensor detects such a mutation, it will stop the operation of the radiotherapy equipment.

[0076] (3) Pressure detection module: The detection process of the above simulation situation is completed by the pressure detection module. The pressure detection module is responsible for collecting the pressure value of the target to be detected (such as a treatment bed or a patient) in real time, especially focusing on the squeezing pressure that may be generated between devices. The pressure detection device installed in the key position continuously monitors the pressure condition of the above target. Once an abnormal pressure change (such as a sudden increase in pressure) is found, the subsequent processing flow is immediately triggered.

[0077] (4) PLC controller: In the pressure detection device of the present invention, the judgment module is integrated on the safety PLC, which is responsible for receiving pressure data in real time and performing rapid analysis and judgment according to the preset range. Once a pressure abnormality is detected, the PLC immediately activates the emergency braking program and quickly stops the equipment to avoid a collision accident. If the pressure is normal, it will not affect the operation of the radiotherapy equipment. The processing module is a key part of the collision avoidance system, which includes actuators such as relays, which are used to receive emergency braking instructions from the PLC and respond quickly. When the PLC determines that there is a risk of collision, the processing module quickly cuts off or adjusts the power of the equipment through the actuator to achieve immediate stop or deceleration. The execution process is highly reliable and fast, which significantly reduces the possibility of collision accidents.

[0078] Example 3: VxWorks spatial position comparison collision detection based on current treatment bed spatial position comparison

[0079] The present invention further provides a real-time position comparison and collision detection device for radiotherapy equipment, which monitors the precise position of the radiotherapy equipment (such as a treatment bed, a patient on the treatment bed, a treatment head, a rotating frame, etc.) in real time, and uses a pre-established real-time model to analyze the real-time data, detect the current motion trajectory of the equipment, and identify potential collision risks.

[0080] (1) Division of spatial position comparison collision detection mechanism: Fig. 9 As shown, the spatial position comparison collision detection mechanism consists of a 3D modeling unit, a spatial position coordinate acquisition unit, and a real-time judgment unit. The 3D modeling unit is responsible for establishing a safe movement range model of the treatment bed in the rotating frame and adjusting the position and angle of the model in the program. The spatial position coordinate acquisition unit acquires the position and movement speed of the treatment bed and the rotating frame in real time. The real-time judgment unit determines whether the treatment bed will collide with its peripheral equipment at the next moment based on the acquired data, and brakes the treatment bed in time if a collision is about to occur.

[0081] (2) Establishment of spatial position comparison model:

[0082] ① 3D model establishment: Link the program written in C# language with the 3D modeling software, name the model components, and ensure that the program name matches the modeling component. The 3D modeling unit includes a coordinate system establishment unit, a treatment head angular position division unit, a first-level loose grid division unit, and a second-level precise grid division unit. The treatment head angular position division unit divides the 360-degree treatment head into 72 equal parts, each of which corresponds to a treatment head angle (such as Figure 6a and Figure 6bAs shown in the figure, they represent the grid division at the angular position of the treatment head at 0° and 90° respectively). In order to reduce the amount of data stored in the database and improve the search speed, the first-level loose grid division unit divides the activity area of ​​the treatment bed away from the collision object into multiple first-level loose grid areas according to the angle of the treatment head, and saves them to the database. The grid is relatively sparse and the amount of data is relatively small. The second-level precise grid division unit divides the activity area of ​​the treatment bed close to the collision object into multiple second-level precise grid areas according to the angle of the treatment head, and saves them to the database. The grid is relatively dense and the amount of data is relatively large. Collision objects include rotating racks, treatment heads, DR plates, rolling floors, etc. A three-dimensional rectangular coordinate system (x, y, z) is established with the center of the circular ring of the forward section of the rotating rack as the coordinate origin, which serves as the basis for subsequent position calculations.

[0083] ②C# controls the movement of 3D models: Figure 2 As shown in the figure, the six independent rotation axes that control the movement of the treatment bed give it six degrees of freedom, allowing precise positioning of translation and rotation within the specified motion limits. The real-time comparison collision detection database generation program written in C# language is operated cyclically to simulate the spatial position of the treatment bed under different postures and treatment head positions. The spatial coordinate range of the six-axis treatment bed is determined by the length of its robotic arm: the x-direction range is (-1500, 1500), the y-direction range is (-1200, 200), and the z-direction range is (-1500, 1300). The units are all in mm, and each unit is 100 mm under the first-level loose grid and 10 mm under the second-level fine grid. The rotation angle (Euler angle) range of the treatment bed: the yaw angle ψ is -95°~+95°, the pitch angle θ is -5°~+5°, and the roll angle φ is -5°~+5°, and each unit is 5°. The rotation range of the rotating gantry is from -185° to +185°, with every 5° as a simulation step, and a total of 72 different positions are simulated.

[0084] ③Data recording and storage: Record the spatial coordinates of the treatment bed in different postures and treatment head positions and the eight-dimensional information of whether a collision occurs (including the rotation angle of the rotating frame, the treatment bed roll, the treatment bed pitch, the treatment bed yaw, the treatment bed x, the treatment bed y, the treatment bed z, and whether a collision occurs). The total data volume can reach hundreds of millions of rows. Use a high-performance non-relational (NoSQL) database to store the recorded data to ensure query speed.

[0085] (3) VxWorks obtains spatial position coordinates and collision detection:

[0086] ① Obtain spatial position coordinates: After the database is established, the components of the radiotherapy equipment communicate with the PowerPC architecture hardware board equipped with the VxWorks system through the HTTP protocol and the Snap7 protocol, and the moving parts of the radiotherapy equipment are monitored in real time. Determine the current position of the treatment head, the posture of the treatment bed, and the position comparison collision detection to ensure the best real-time performance and low latency.

[0087] ② Collision detection program: The program of the real-time position comparison collision detection unit runs on a hardware board loaded with the VxWorks system. The VxWorks system sends instructions to the treatment bed system through the HTTP protocol, reads the spatial coordinates and speed information of the treatment bed, and collects the angle, direction and speed of the rotating frame through the Snap7 protocol. The collision detection program calculates the position at the next moment based on the current position and movement speed of the treatment bed, and compares it with the pre-sorted lookup table. If a collision may occur, it will be immediately transmitted to the PLC through an electrical signal to brake the related motion equipment.

[0088] (4) Collision prediction logic of the treatment bed: The movement of the treatment bed only involves coordinate changes in a single direction at a time, and if the movement direction and speed of the treatment bed are known, then the position and posture at the next moment and the collision situation can be predicted. Figure 8 As shown in the figure, if the treatment bed is moving in the x direction at a speed of 2 cm per second and the current position is known, the database search shows that if it runs at the current speed, it will collide with the equipment at the next moment. In actual application scenarios, by real-time detection of the current position and motion state of the treatment bed, the processing module will immediately respond to brake the relevant motion equipment when it is predicted that a collision will occur at the next moment.

[0089] (5) PLC controller: The processing module of the present invention adopts a safety functional PLC. The safety functional PLC integrates a dual redundant power supply module, a safety-specific CPU, and a safety-specific I / O module in the overall architecture. Its main responsibility is to implement safety interlocking control of the subsystem. The PLC can monitor the operating status of the subsystem in real time and connect with external devices and the VxWorks system through digital hard-wired signals. The PLC is responsible for the safety interlocking control of the entire radiotherapy equipment. If it is determined that a collision is about to occur based on the current position and motion information, the device that receives the braking command will immediately activate the preset emergency braking system, quickly decelerate until it stops completely, thereby avoiding the occurrence of a collision. After the braking is completed, the system will automatically perform a reset operation, check the status of all equipment, and ensure that everything returns to normal before continuing the treatment process.

Claims

1. A radiation therapy device collision avoidance system based on multiple detection methods, characterized in that: The system includes, from top to bottom: a host computer for displaying alarm information, a PLC controller connected to the host computer upward and to a motion device downward, a motion device controlled by the PLC controller, and a collision detection unit that provides collision detection information to the PLC controller; the motion device includes a rotating frame, a treatment bed, and other motion devices related to a treatment head; the treatment bed is a robot treatment bed, and the envelope of the treatment bed includes the envelope of the treatment bed itself and the envelope of the patient on the treatment bed; The collision detection unit includes: a distance comparison collision detection subunit based on the current treatment bed distance comparison, a pressure comparison collision detection subunit based on the current treatment bed pressure comparison, and a VxWorks space position comparison collision detection subunit based on the current treatment bed space position comparison; The distance comparison collision detection subunit includes detectors and laser distance sensors arranged around the treatment head, DR flat panel and treatment bed, as well as multi-level warning areas divided around the detectors and laser distance sensors, and a warning area boundary calculation unit; The pressure comparison collision detection subunit includes a pressure sensor arranged on the treatment bed and a pressure comparison module for comparing whether the current pressure is normal or not; The VxWorks spatial position comparison collision detection subunit includes programming software and three-dimensional modeling software, a position comparison collision detection database, and a position information acquisition and calculation module based on VxWorks; the programming software and three-dimensional modeling software save the 3D modeling model to the position comparison collision detection database, and the position information acquisition and calculation module based on VxWorks obtains 3D modeling information from the position comparison collision detection database on the one hand, and obtains position information of related motion equipment including the treatment bed and the rotating frame on the other hand, and calculates these two types of information in VxWorks to obtain a collision prediction result at the next moment, and reports it to the PLC. In dangerous situations, the PLC will quickly shut down or brake the related motion equipment; the 3D modeling model is a model of the safe movement range of the treatment bed.

2. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 1, characterized in that: The multi-level warning area of ​​the distance comparison collision detection subunit includes a treatment head warning area and a treatment head danger area based on the treatment head; an a zone and a b zone centered on the treatment bed; the treatment head warning area surrounds the treatment head danger area; the shape of the treatment head warning area is approximately trapezoidal, and the shape of the treatment head danger area is approximately an envelope formed by the treatment head and the DR plate when they are unfolded; the a zone is the treatment bed danger area, and the b zone is the treatment bed secondary danger area; when the distance between the treatment bed and the treatment head enters the warning area of ​​the treatment head, the system alarms; when the distance between a person or an object and the treatment head enters the danger area of ​​the treatment head, the motion equipment of each radiotherapy facility stops moving; the motion equipment includes but is not limited to a rotating frame, a treatment bed, a DR plate, and a range shifter on the treatment head; when a person or an object is detected in the b zone around the treatment bed, the system issues a warning and the treatment bed slows down; when a person or an object is detected in the a zone around the treatment bed, the system issues an audible and visual alarm and the treatment bed brakes.

3. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 1, characterized in that: The warning zone boundary calculation unit of the distance comparison collision detection subunit calculates the envelope boundary of the treatment head danger zone according to the sizes of the rotating frame, the treatment head, the DR plate, and the maximum braking angle of the rotating frame.

4. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 1, characterized in that: The pressure contrast module of the pressure contrast collision detection subunit divides the pressure detection process into four time points: 0, t1, t2, and t3; from time 0 to time t1, this time period simulates the process of the patient lying on the treatment bed; from time t1 to time t2, this time period simulates the process of the patient lying steadily on the treatment bed to receive treatment. Although the curve has jitters in this stage, it eventually tends to be flat; from time t2 to time t3, this time period simulates the process of a sudden increase or decrease in pressure. The sudden change is a sudden increase or decrease in pressure in a short period of time. This process is defined as an abnormal pressure sudden change stage. The equipment is very likely to have collided or encountered other abnormal conditions during this time period; when the pressure contrast unit detects such a sudden change, the operation of the radiotherapy equipment will be terminated.

5. The radiation therapy device collision avoidance system based on multiple detection methods according to claim 1, characterized in that: The VxWorks spatial position comparison collision detection subunit includes a 3D modeling module, a VxWorks spatial position coordinate acquisition module, and a real-time judgment module; the 3D modeling module models a safe movement interval model of the treatment bed in the rotating frame through programming software and three-dimensional modeling software, and repeatedly adjusts the position and angle of the established safe movement interval model in the program, and saves the adjusted safe movement interval model to the position comparison collision detection database; the VxWorks spatial position coordinate acquisition module acquires the current position and movement speed of the treatment bed and the rotating frame in real time through the VxWorks system; the real-time judgment unit judges whether the treatment bed and its peripheral equipment will collide at the next moment based on the data obtained by the spatial position coordinate unit, and sends the judgment information to the PLC controller. If it is judged that a collision is about to occur, the PLC controller will brake the treatment bed in time.

6. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 5, characterized in that: The 3D modeling module includes a coordinate system establishment submodule, a treatment head angular position division submodule, a first-level loose grid division submodule, and a second-level precise grid division submodule; the treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, each of which corresponds to an angle of the treatment head; the first-level loose grid division submodule uses the activity area of ​​the treatment bed away from the collision object or the dangerous area of ​​the treatment head as multiple first-level loose grid areas according to the current angle of the treatment head, and saves the multiple first-level loose grid areas to the database, the grids of the multiple first-level loose grid areas are relatively sparse, the grid size is relatively coarse, and each loose grid is a detection point; the second-level precise grid division submodule uses the activity area of ​​the treatment bed close to the collision object or the dangerous area of ​​the treatment head as multiple second-level precise grid areas according to the current angle of the treatment head, and saves the multiple second-level precise grid areas to the database, the grids of the multiple second-level precise grid areas are relatively dense, the grid size is relatively small, and each second-level precise grid division submodule is a detection point; the collision object includes but is not limited to the rotating frame around the treatment bed, the treatment head, the DR plate, and the rolling floor.

7. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 6, characterized in that: The coordinate system establishment submodule uses the center of the front section ring of the rotating frame as the coordinate origin to establish a three-dimensional rectangular coordinate system (X, Y, Z), which is the basis for all subsequent position calculations.

8. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 6, characterized in that: The VxWorks spatial position coordinate acquisition module acquires the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, and the moving speed and direction of the treatment bed; and also acquires the angle, rotation speed and direction of the rotating frame.

9. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 5, characterized in that: The real-time judgment module judges whether the treatment bed and the surrounding equipment will collide at the next moment according to the current safe movement range model of the treatment bed, the three-dimensional coordinates of the treatment bed, the Euler angles (rX, rY, rZ) of the treatment bed, the movement speed and direction of the treatment bed, the angle of the rotating frame, and the rotation speed and direction. If it is judged that a collision is about to occur, it will be reported to the PLC controller, and the PLC controller will brake the treatment bed in time.

10. A radiation therapy device collision avoidance system based on multiple detection methods according to claim 6, characterized in that: The treatment head angular position division submodule is used to divide the treatment head 360 degrees into several equal parts, the several equal parts include 72 parts, each part is 5° apart; the multiple first-level loose grid areas include 72 first-level loose grid areas; the multiple second-level precise grid areas include 72 second-level precise grid areas.

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