Automatic calibration method and system for laser positioning system of radiotherapy machine room

Abstract

The invention provides an automatic calibration method and system for a laser positioning system of a radiotherapy machine room, and the method is applied to a plurality of optical sensors, and comprises the following steps: receiving a plurality of groups of crossed laser rays transmitted by a laser transmitting module in the radiotherapy machine room, and forming clear laser spots on the surface of a CMOS image sensor; converting the optical signal of the laser spot into a CMOS pixel gray level electric signal, and calculating the actual physical coordinate of the center of the laser spot on the wall surface of the machine room according to the CMOS pixel gray level electric signal; compared with the prior art, the method has the following beneficial effects: through the architecture of a high-precision sensor and an intelligent algorithm, on the premise of being completely compatible with an existing radiotherapy machine room, the upgrade from manual regular inspection to automatic continuous monitoring is realized, so that the problems that errors are easily introduced due to manual reading in a traditional calibration mode, and the calibration accuracy is high are solved; and moreover, real-time monitoring cannot be realized manually, deviation possibly occurs during the interval of two quality control but is not perceived, and potential risks are left for treatment.

Description

Technical Field

[0001] This invention relates to the field of medical equipment measurement technology, and in particular to an automatic calibration method and system for a laser positioning system in a radiotherapy room. Background Technology

[0002] Currently in clinical practice, radiotherapy equipment such as medical linear accelerators and Gamma Knife require three sets of intersecting laser lines (front, back, and sides) within the machine room as the benchmark for marking the patient's body surface and repositioning. The accuracy of these laser lines directly determines the accuracy of the treatment target alignment. However, traditional calibration methods have significant shortcomings: they rely entirely on engineers manually measuring and adjusting with physical rulers, which is not only cumbersome and time-consuming but also prone to errors introduced by manual readings. More importantly, the laser can slowly shift due to environmental factors such as changes in machine room temperature and equipment vibration, which cannot be monitored in real time. Deviations may occur undetected between two quality control intervals, posing potential risks to treatment.

[0003] Traditional calibration methods rely on a combination of manual tools to complete the calibration operation, which is a typical "non-specialized technical solution." The specific technical status is as follows:

[0004] 1. Composition and component connection of the "products" (tool sets) relied upon by traditional calibration: Traditional laser calibration has no integrated products and is completed only through the cooperation of scattered manual measuring tools. The core "products" and the relationship between components are as follows: 1) Core component composition: including physical measuring tools, marking tools, and auxiliary tools, without any electronic sensing or intelligent control components; 2) Component connection method: all tools are independent and scattered, without a fixed connection structure - the engineer must manually carry all tools into the radiotherapy room and operate through "hand-eye coordination": first, use a laser level to preliminarily determine whether the laser line is horizontal / vertical, then use a steel ruler and digital caliper close to the wall to manually align the edge of the laser line, read the scale value, and finally use a marker to mark the measurement points on the wall and compare them with the standard values ​​(usually the center axis of the treatment bed and the ground baseline) to determine the offset.

[0005] 2. Standard Operating Procedure for Traditional Calibration: Due to the lack of dedicated calibration products, the calibration of traditional laser positioning systems requires following fixed manual operation steps, as follows: 1) Manual Measurement Stage: The engineer first determines the standard reference positions of the three sets of laser lines in the machine room (front, back, and side). Then, using a steel ruler, the engineer measures the actual position of each set of laser lines at different heights on the wall. The engineer repeatedly checks the offset of key points using a digital caliper. Data is recorded once for each point measured. A total of 12-15 points need to be measured for the three sets of laser lines. 2) Manual Adjustment Stage: If an offset is found during measurement, the engineer needs to manually tighten the adjustment screw of the laser with a wrench. After each adjustment, the engineer needs to re-measure and confirm with a ruler until the offset is ≤ the preset threshold. 3) The calibration process is completed. The entire process usually takes 30-45 minutes.

[0006] 3. The core drawback of traditional technical solutions: Calibration methods based on distributed manual tools are limited by tool characteristics, operating modes, and computer room environments, resulting in intractable technical defects.

[0007] 1) Traditional tools lack automation functions and rely entirely on manual point-by-point measurement and repeated adjustments—a single calibration takes more than 30 minutes, and some hospitals need to extend their working hours to complete the day's treatment plan;

[0008] 2) Although the reading accuracy of tools such as digital calipers and steel rulers can reach 0.02mm, in actual operation, the angle deviation of the engineer holding the tool and the subjectivity of judging the edge of the laser line will introduce a human error of 0.1-0.3mm. Moreover, the difference in the operating methods of different engineers can lead to a deviation of up to 0.2mm in the measurement results of the same laser line, which directly affects the accuracy of the laser line after calibration, thereby increasing the risk of misalignment of the treatment target area.

[0009] 3) Traditional tools can only be used during "periodic calibration" and cannot achieve continuous monitoring. Lasers are affected by fluctuations in room temperature and equipment vibration, resulting in a slow drift of 0.05-0.1 mm per day. The interval between two calibrations is usually 7-14 days. During this period, the drift may accumulate to 0.7-1.4 mm, far exceeding the safety threshold (0.5 mm), but it cannot be detected by humans, posing a potential risk of mis-irradiation of the treatment target area.

[0010] In summary, the calibration of existing radiotherapy laser positioning systems relies entirely on "dispersed manual tools and experience-based operation," lacking dedicated automated products. This results in core problems such as low efficiency, poor accuracy, and lack of real-time monitoring, which not only affects the utilization rate of radiotherapy equipment but also poses risks to treatment safety. Summary of the Invention

[0011] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an automatic calibration method and system for a laser positioning system in a radiotherapy room, which solves the problems that traditional calibration methods are not only cumbersome and time-consuming, but also prone to errors due to manual readings. Moreover, manual monitoring cannot be achieved in real time, and deviations may occur between two quality control intervals without being detected, leaving potential risks to treatment.

[0012] To achieve the above and other related objectives, the present invention provides the following technical solution:

[0013] An automatic calibration method for a laser positioning system in a radiotherapy room is provided, which is applied to multiple optical sensors. The multiple optical sensors are respectively installed on the wall of the radiotherapy room at monitoring points corresponding to multiple sets of intersecting laser lines in the room. The method includes the following steps: receiving multiple sets of intersecting laser lines emitted by a laser emitting module in the radiotherapy room and forming a clear laser spot on the surface of a CMOS image sensor; converting the light signal of the laser spot into a CMOS pixel grayscale electrical signal, and calculating the actual physical coordinates of the center of the laser spot on the wall of the room based on the CMOS pixel grayscale electrical signal.

[0014] In one embodiment of the present invention, applied to an intelligent main control system, the method includes the following steps: receiving the actual physical coordinates of the center of a laser spot on the wall of a computer room from multiple optical sensors, and determining the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot on the wall of the computer room; acquiring pre-set standard reference parameters in a built-in storage chip, and calculating the spatial offset and angle deviation of the current laser line relative to the standard reference based on the standard reference parameters; calculating the required adjustment amount of the laser line based on the spatial offset and angle deviation, and automatically determining the state and generating adjustment instructions for the laser emission module based on the calculation results.

[0015] In one embodiment of the present invention, the step of calculating the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the CMOS pixel grayscale electrical signal includes: converting the CMOS pixel grayscale electrical signal into pixel coordinates of the center of the laser spot; and determining the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the pixel coordinates of the center of the laser spot.

[0016] In one embodiment of the present invention, determining the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot on the wall of the computer room includes: determining the three-dimensional coordinates of the laser spot measured by each sensor based on the actual physical coordinates of the center of the laser spot;

[0017] The geometric center of the monitoring points corresponding to multiple optical sensors is calculated based on the three-dimensional coordinates of the laser spot measured by each sensor, wherein the geometric center of the multiple monitoring points is used as the reference point of the laser line; a covariance matrix is ​​constructed based on the three-dimensional coordinates of the laser spot measured by each sensor and the geometric center of the multiple monitoring points, wherein the covariance matrix is ​​used to describe the distribution direction and dispersion of the multiple monitoring points in three-dimensional space; the spatial position and angle data of the laser line are determined based on the geometric center of the multiple monitoring points and the covariance matrix.

[0018] In one embodiment of the present invention, determining the spatial position and angle data of the laser line based on the geometric center and covariance matrix of multiple monitoring points includes: determining the spatial equation of the laser line based on the geometric center and covariance matrix of multiple monitoring points; determining the intersection point of the spatial equation of the laser line with the radiotherapy isocenter plane to obtain the spatial position of the laser line; and determining the angle data of the laser line based on the covariance matrix.

[0019] In one embodiment of the present invention, determining the intersection point of the spatial equation of the laser line and the radiotherapy isocenter plane includes: determining the intersection point of the spatial equation of the laser line and the radiotherapy isocenter plane according to the following formula: , , ;in, These are the parameter values ​​for the corresponding intersection points in the equation of the line; The height of the isocenter plane of the radiotherapy in the Z direction; The geometric mean position of multiple monitoring points; For the corresponding largest eigenvalue eigenvectors, These are the eigenvalues ​​of the covariance matrix; The coordinates are the points where the laser line intersects the isocenter of the radiotherapy plane.

[0020] In one embodiment of the present invention, determining the angle data of the laser line based on the covariance matrix includes: determining the angle data of the laser line according to the following formula: , ;in, The angle of inclination of the laser line relative to the perpendicular direction in the XZ plane; The angle of inclination of the laser line relative to the perpendicular direction in the YZ plane.

[0021] In one embodiment of the present invention, calculating the required adjustment amount of the laser line based on the spatial offset and angular deviation includes: , ;in, This refers to the displacement of the laser head in the laser emitting module that needs to be adjusted. This represents the translation error in the horizontal and vertical directions; This refers to the distance from the laser head to the wall. This represents the tilt error relative to the vertical direction.

[0022] An automatic calibration system for a laser positioning system in a radiotherapy room includes multiple optical sensors. The optical sensors include: a laser receiving module for receiving multiple sets of intersecting laser lines emitted by a laser emitting module in the radiotherapy room and forming a clear laser spot on the surface of a CMOS image sensor; and a signal processing module for converting the optical signal of the laser spot into a CMOS pixel grayscale electrical signal and calculating the actual physical coordinates of the center of the laser spot on the wall of the room based on the CMOS pixel grayscale electrical signal.

[0023] In one embodiment of the present invention, an intelligent master control system is further included, the intelligent master control system including a data receiving module and a central processing unit electrically connected to the data receiving module.

[0024] As described above, the automatic calibration method and system for a laser positioning system in a radiotherapy room according to the present invention have the following beneficial effects:

[0025] 1. This invention can improve calibration efficiency, reduce equipment downtime, and ensure treatment progress: Through the design of "real-time capture of green laser by optical sensors + automatic calculation of offset", this invention eliminates the need for engineers to use hand tools to measure point by point - the time for a single calibration is reduced from the traditional 30-45 minutes to 5 minutes, and can be completed during patient changes without interrupting the operation of radiotherapy equipment; at the same time, it avoids hospitals from extending calibration intervals to compress time, thereby improving the utilization rate of radiotherapy equipment and ensuring that the treatment plan is carried out on time.

[0026] 2. This invention eliminates human error and drift blind spots, ensuring laser accuracy and treatment safety: Addressing the issues of human error in traditional calibration and the unmonitorable drift of the green laser, this invention employs a "CMOS sensor + real-time data transmission + automatic error calculation" architecture. On one hand, a built-in algorithm calculates the spot coordinates, reducing the measurement error from 0.1-0.3mm to ≤0.05mm, far exceeding the radiotherapy accuracy threshold of ≤0.1mm. On the other hand, the sensor monitors the laser position every 100ms, triggering an alarm immediately if the deviation exceeds 0.5mm, completely eliminating the drift blind spot between calibration intervals. In clinical applications, this can reduce the number of positional deviation events caused by green laser drift from an average of 3.2 per year to zero, avoiding the risk of mis-irradiation of the treatment target area and significantly improving radiotherapy positioning accuracy and treatment safety. Attached Figure Description

[0027] Figure 1 This is a flowchart of an automatic calibration method for a laser positioning system in a radiotherapy room according to the first embodiment of the present invention;

[0028] Figure 2 This is a detailed flowchart of the automatic calibration method for a laser positioning system in a radiotherapy room according to the first embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of an automatic calibration system for a laser positioning system in a radiotherapy room according to the second embodiment of the present invention. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. It should be noted that, unless otherwise specified, the following embodiments and features described herein can be combined with each other.

[0031] The first embodiment of the present invention relates to an automatic calibration method for a laser positioning system in a radiotherapy room, the process of which is as follows: Figure 1 As shown, the details are as follows:

[0032] Step 101: Multiple optical sensors receive multiple sets of intersecting laser lines emitted by the laser emission module in the radiotherapy room and form a clear laser spot on the surface of the CMOS image sensor.

[0033] Step 102: Multiple optical sensors convert the light signal of the laser spot into a CMOS pixel grayscale electrical signal, and calculate the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the CMOS pixel grayscale electrical signal.

[0034] Specifically, the sensor module detects laser signals and converts them into coordinate data. This is the system's signal input terminal, and its core function is to accurately capture the position of the laser line. In this embodiment, there are six photoelectric sensors, and the specific process is as follows:

[0035] 1. Laser Signal Detection: Three sets of laser lines—front, rear, and side—are positioned in the radiotherapy room and projected onto six sensor modules on the corresponding walls. Each sensor is 5cm long with an effective monitoring range of 4.8cm, completely covering the possible laser drift range. The optical lens at the front of the sensor focuses the green laser onto the surface of a 5cm long CMOS image sensor inside, forming a clear laser spot. The spectral response range of the CMOS image sensor is 400-700nm, completely covering the 532nm green laser wavelength, converting the light signal of the spot into an 8-bit grayscale electrical signal.

[0036] 2. Electrical signal to coordinate data conversion – The sensor's built-in signal processing chip calculates the center coordinates of the laser spot using the "grayscale centroid method": 1) Grayscale centroid calculation: The grayscale electrical signal of the CMOS pixel is converted into the pixel coordinates of the center of the laser spot, allowing the precise center position of the laser spot on each sensor to be obtained. ,in, For the first CMOS image sensor The row and column coordinates of each pixel; This is the grayscale value of that pixel; 1) The pixel coordinates corresponding to the grayscale centroid of the laser spot; 2) Convert the pixel units into the actual physical coordinates of the computer room wall, according to the calibration scaling factor. And offset, convert pixel coordinates to actual millimeter coordinates of the wall: ,in, The pixel-to-millimeter scaling factor (obtained through calibration); To correct the offset for installation errors; This represents the actual position of the light spot center in the wall coordinate system (unit: mm).

[0037] Step 103: The intelligent main control system receives the actual physical coordinates of the center of the laser spot on the wall of the computer room from multiple optical sensors, and determines the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot.

[0038] Step 104: The intelligent main control system obtains the pre-set standard reference parameters in the built-in storage chip and calculates the spatial offset and angular deviation of the current laser line relative to the standard reference based on the standard reference parameters.

[0039] Step 105: The intelligent main control system calculates the required adjustment amount of the laser line based on the spatial offset and angular deviation, and automatically determines the status and generates adjustment instructions for the laser emission module based on the calculation results.

[0040] Specifically, before the intelligent main control system receives the actual physical coordinates of the laser spot center from multiple optical sensors, it also includes: data encryption and wireless transmission - secure transmission of coordinate information: This is the system's "signal transmission channel" used to securely and without delay transmit the real-time coordinate data of the laser line calculated by the six sensors to the intelligent main control system.

[0041] 1. Data Packaging and Encryption: Each sensor's built-in Bluetooth chip transmits the real-time coordinate data of the laser line output by the signal processing module. 1. Packaging into AES-128 encrypted data packets to prevent electromagnetic interference or signal interception by other devices in the computer room; 2. Wireless transmission and decryption: The encrypted data packets are sent to the LoRa module of the main control terminal via 2.4GHz wireless signal. After receiving the data, the intelligent main control system automatically decrypts it and sends the coordinate data to the central processing chip for error analysis and adjustment calculation.

[0042] More specifically, after receiving the actual physical coordinates of the laser spot center from multiple optical sensors, the intelligent main control system performs the following steps: 1. Three-dimensional coordinate establishment: This represents the positions of the six monitoring points in space, providing basic data for subsequent calculations of the laser line's translation and angular deviation. ;in, For the first The three-dimensional coordinates of the laser spot measured by a sensor; This refers to the sensor's height or depth position in the room coordinate system;

[0043] 2. Spatial centroid calculation: Calculate the geometric center of six points, which will be used as reference points for the laser line. ,in, The geometric mean position of the six points serves as the central reference for the fitted line, reducing single-point measurement errors.

[0044] 3. Construction of the covariance matrix, used to describe the distribution direction and dispersion of the six points in three-dimensional space: , ;in, For three dimensions Covariance matrix; The offset vector of each point relative to the center point; The symbol for vector transpose; These are the eigenvalues ​​of the covariance matrix; For the corresponding largest eigenvalue The eigenvectors represent the direction of the laser line;

[0045] 4. Laser line spatial equation: representing the path of a laser line in three-dimensional space in mathematical form: ,in, Let be any point in space where the laser line is located; The parameter is linear; the equation defines a line passing through the center point. And the direction is A straight line in space;

[0046] 5. Coordinates of the intersection point with the isocenter plane (z=z0): Calculate the position of the intersection point between the laser line and the radiotherapy isocenter plane (usually z=z0): ,in, The height of the isocenter plane of the radiotherapy in the Z direction; The coordinates of the intersection point between the laser line and the isocentric plane; These are the parameter values ​​for the corresponding intersection points in the equation of the line;

[0047] 6. Calculation of laser line angle data: , , The angle of inclination of the laser line relative to the perpendicular direction in the XZ plane; The angle of inclination of the laser line relative to the perpendicular direction in the YZ plane.

[0048] Furthermore, the intelligent main control system—error calculation and adjustment calculation: This is the "core calculation terminal" of the device, responsible for determining the offset direction, angle tilt, and appropriate adjustment amount of the laser line;

[0049] 1. Data Reception and Reference Retrieval: Based on the spatial position and angle data calculated in the above steps, the standard reference parameters in the built-in memory chip are retrieved. As a reference for comparison;

[0050] 2. Error Calculation: Calculate the spatial offset and angular deviation of the current laser line relative to the standard reference. ,in: The translational error of the laser line in the horizontal and vertical directions (unit: mm); The tilt error of the laser line relative to the vertical direction (in degrees);

[0051] 3. Adjustment Calculation: The main control system calculates the adjustment amount based on the installation geometric parameters of the laser module (distance from the laser head to the wall). Calculate the required adjustment amount: ,in: This represents the laser head displacement to be adjusted (in mm); the negative sign indicates that the adjustment direction is opposite to the deviation direction; if the deviation mainly comes from angular tilt, then adjust using the angle correction item. offset.

[0052] To elaborate further, the results output and calibration guidance—automatic prompts and manual assistance based on deviation—is the device's "output and calibration end," which automatically determines the status and generates adjustment instructions based on the calculation results.

[0053] 1. Normal state (deviation ≤ threshold): If the following conditions are met: If the laser line position is normal, the system will display "laser line position is normal" on the touch screen and store the detection data (time, coordinates, angle, deviation value) into the database.

[0054] 2. Abnormal State (Deviance > Threshold): Alarm and calibration are triggered when any of the following conditions are met: ,in, The allowable threshold for translation deviation (e.g., 0.5 mm); The allowable threshold for angle deviation (e.g., 0.1°); if any deviation exceeds the threshold (e.g., ... , The main control system will display the deviation direction and recommended adjustment amount on the screen: for example, "The front wall laser line is deviated 0.6mm to the right and tilted 0.08°. It is recommended to adjust it 0.6mm to the left along the X direction." An audible and visual alarm will be triggered: the LED red light will flash at 1Hz, and the buzzer will sound intermittently. A "real-time guidance mode" will be provided, displaying the adjustment direction and angle correction trend graphically on the touchscreen. Subsequent calibration confirmation will follow: after the engineer completes the adjustment, the six sensors will re-detect the new coordinate and angle data; the main control system will recalculate the error. If all deviations are ≤ the threshold, a "calibration completion record" will be automatically generated, and the parameter difference before and after adjustment will be stored. For the overall process, please refer to [link to documentation]. Figure 2 .

[0055] In practical applications, this embodiment is based on a "green laser calibration device that has been installed and debugged" (compatible with medical linear accelerator rooms). It details the daily clinical usage process, including core operations such as power-on, monitoring, calibration, and data management. No additional equipment modifications are required, and radiation oncology engineers can directly refer to and implement it.

[0056] I. Preparations before use: 1. Equipment status check: 1) Sensor check: Observe the 6 sensors (5cm long ABS shell) on the front / back / side walls of the machine room, and confirm that the shell is not damaged and the lens surface is free of dust (if there is dust, wipe it gently with a lint-free cloth dipped in 75% alcohol). The sensor indicator light (red light) is always on (indicating that the lithium battery is fully charged. When the battery is low, the red light flashes and needs to be charged with a Micro-USB cable); 2) Main control system check: Check the main control host (with 7-inch touch screen) on the operating table, and confirm that the power adapter is plugged in (220V AC power), the touch screen is free of cracks, and the sound and light alarm module (top LED light, built-in buzzer) is not obstructed; 2. Laser emitter coordination check: Start the green laser emitter of the medical linear accelerator (press the "Laser Start" button on the accelerator operation panel), and observe whether the laser line is projected normally onto the wall (1 set of green lasers in front / back / side, no light interruption, no obvious deviation).

[0057] II. Power-on Operation (approximately 1 minute): 1. Start the main control system: 1) Press the "Power Button" on the side of the main control unit (press and hold for 2 seconds). The touch screen will light up and enter the system startup interface (the main menu will be displayed after about 30 seconds, including 4 options: "Real-time Monitoring", "Automatic Calibration", "Historical Data", and "System Settings"); 2) Click "Real-time Monitoring" in the main menu. The system will automatically search for sensors (complete within 10 seconds). The top of the touch screen will display "Sensor connection successful (6 / 6)" (if "Connection failed (e.g., 5 / 6)" is displayed, check the power supply of the corresponding sensor and restart the sensor).

[0058] 2. Confirm the reference value: On the "Real-time Monitoring" interface, check the "Current Coordinates" and "Standard Reference Value" of the 6 lasers (e.g., standard X=1500mm for side wall lasers, current X=1500.0mm). Confirm that the reference value is consistent with the preset parameters of the computer room (if you need to modify it, go to "System Settings → Reference Value Adjustment", enter the new value and save).

[0059] III. Daily Real-time Monitoring (Continuously running during treatment, no manual intervention required): 1. Real-time Status View: 1) The "Real-time Monitoring" interface displays data in a table + graph format; 2) Table area: Displays the laser coordinates monitored by each sensor in 6 rows (e.g., "Front Wall No. 1: X=1800.0mm, Y=1500.0mm") and offset (current coordinates - standard reference value, e.g., "0.0mm"); 3) Graph area: Simulates the layout of the machine room, using green lines to mark the laser line positions. When the offset is ≤0.5mm, the line is green, and when it exceeds the threshold, it turns red; 4) During treatment, engineers can view the interface at any time to confirm that all laser offsets display "≤0.5mm" (safe threshold), and the system status bar displays "Monitoring Normal";

[0060] 2. Abnormal Alarm Handling (if triggered, takes approximately 1-2 minutes): 1) When a laser deviates by more than 0.5mm (e.g., the side wall laser deviates by 0.6mm), the main control system immediately triggers: 2) Audible and visual alarm: The top LED light (red) flashes at a frequency of 1Hz, and the built-in buzzer sounds intermittently (80-90dB); 3) Interface prompt: A red pop-up window appears on the touch screen, indicating "Deviation warning: The side wall green laser deviates 0.6mm to the right. It is recommended to pause treatment and calibrate," while displaying a diagram of the deviation direction (arrow pointing to the deviated side); 3. Handling steps: 1) Press the "Alarm Mute" button on the main control screen (pauses the buzzer, the LED light continues to flash); 2) Pause the current patient's treatment (press the "Pause" button on the accelerator); 3) Enter the "Automatic Calibration" interface, start calibration (see the procedure below), the alarm will automatically deactivate after calibration is completed, and treatment will resume.

[0061] IV. Automatic Calibration Operation (performed during patient treatment intervals, taking approximately 5 minutes): 1. Start Automatic Calibration: Select the patient change interval (e.g., after the previous patient's treatment is completed and before the next patient gets into bed), click the "Automatic Calibration" option on the main control screen. The system will pop up a prompt: "Start automatic calibration? The laser must remain on during calibration." Click "Confirm." 2. Calibration Process (fully automatic, no manual operation required): Step 1: Sensor data acquisition (coordinate acquisition of 6 lasers is completed within 10 seconds, once every 100ms, and the average value of 10 acquisitions is taken); Step 2: System calculates the offset (automatically compares the current average value with the standard reference value and generates a "calibration suggestion," such as "the side wall laser needs to be adjusted to the left by 0.6mm"); Step 3: Interface-guided adjustment (the touch screen displays "Please adjust according to the following steps: 1. Use the laser adjustment wrench to tighten the screw on the left side of the side wall laser; observe the real-time offset dropping to ≤0.1mm").

[0062] 3. Calibration Confirmation: 1) The engineer follows the on-screen instructions and uses a special wrench to adjust the laser screws (the touchscreen updates the offset in real time after each adjustment) until the offset is ≤0.1mm; 2) Click "Calibration Complete", the system automatically records the calibration data (time, offset before adjustment, offset after adjustment), the touchscreen displays "Calibration qualified, laser accuracy is normal", and the audible and visual alarm module returns to standby mode.

[0063] It should also be noted that this invention is based on the following reasons:

[0064] First, radiotherapy requires precise positioning of a 532nm green laser. However, traditional manual calibration requires carrying a dispersive tool to measure 12-15 points one by one, taking 30-45 minutes and requiring machine downtime. This results in tertiary hospitals experiencing downtime of over 30 minutes per day and patients waiting for an additional 15-20 minutes. Some hospitals have even extended the calibration interval to 14 days, amplifying the risks. This invention reduces a single calibration to ≤5 minutes through "real-time capture by a 5cm sensor + automatic calculation," which can be completed during patient changes without machine downtime, balancing efficiency and safety. Second, traditional calibration has a human error of 0.1-0.3mm, and the green laser drifts by 0.05-0.1mm per day due to temperature changes and equipment vibration. Traditional 7-14 day periodic checks cannot detect this, and the cumulative drift can easily exceed the 0.5mm safety threshold. This invention uses a 5cm CMOS sensor to capture the laser position every 100ms, compares it with the standard value in real time, and alarms when the deviation exceeds the threshold, eliminating errors and monitoring blind spots.

[0065] Therefore, this patent designs a distributed wall monitoring network based on high-precision optical sensors, employing a six-sensor layout of "monitoring the opposite side from the same side." For vertical laser lines, monitoring points are set at the foot and front of the wall, totaling six monitoring points, which can accurately capture the real-time position of the laser line. The sensors calculate the center coordinates of the laser spot through built-in algorithms and transmit the data to the main control system in real time. When the system detects that any laser line offset exceeds a preset threshold, such as 0.5mm, it will issue a reminder through the control panel screen display, audible and visual alarms, etc. It can also intuitively mark the direction of deviation and the amount of adjustment through a graphical interface, guiding engineers to quickly complete accurate calibration.

[0066] The second embodiment of the present invention relates to an automatic calibration system for a laser positioning system in a radiotherapy room. Please refer to [link to relevant documentation]. Figure 3 It includes multiple optical sensors, which include:

[0067] The laser receiving module is used to receive multiple sets of intersecting laser lines emitted by the laser emitting module in the radiotherapy room and form a clear laser spot on the surface of the CMOS image sensor;

[0068] The signal processing module is used to convert the optical signal of the laser spot into a CMOS pixel grayscale electrical signal, and calculate the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the CMOS pixel grayscale electrical signal.

[0069] It also includes an intelligent main control system, which includes a data receiving module and a central processing unit that is wired to the data receiving module;

[0070] The data receiving module receives the actual physical coordinates of the center of the laser spot on the wall of the computer room from multiple optical sensors; the central processing unit determines the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot on the wall of the computer room; it acquires the pre-set standard reference parameters in the built-in storage chip and calculates the spatial offset and angle deviation of the current laser line relative to the standard reference based on the standard reference parameters; it calculates the required adjustment amount of the laser line based on the spatial offset and angle deviation, and automatically determines the status and generates adjustment instructions for the laser emitting module based on the calculation results.

[0071] It is not difficult to see that this embodiment is a system implementation corresponding to the first embodiment, and this embodiment can be implemented in conjunction with the first embodiment. The relevant technical details mentioned in the first embodiment are still valid in this embodiment, and will not be repeated here to reduce repetition. Accordingly, the relevant technical details mentioned in this embodiment can also be applied to the first embodiment.

[0072] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0073] In summary, the main objective of this invention is to provide an automated calibration device specifically designed for laser positioning systems in radiotherapy rooms. This device aims to address the problems of low efficiency, poor accuracy, and lack of real-time monitoring capabilities associated with manual calibration using a combination of tools in existing technologies. It particularly addresses the pain points of time-consuming calibration during radiotherapy equipment downtime and the difficulty in detecting laser drift caused by environmental interference. The invention achieves a balance between "fully automated continuous monitoring" and "precise and rapid calibration," ensuring the stability of the radiotherapy positioning reference and treatment safety. Specifically, this invention utilizes an innovative architecture of "high-precision optical sensors + intelligent main control system," which, while compatible with existing radiotherapy rooms, avoids the shortcomings of traditional manual calibration. Its main objectives include:

[0074] 1. Improved calibration efficiency and reduced downtime losses for radiotherapy equipment: This invention addresses the problem of traditional manual calibration taking 30-45 minutes per session and requiring a pause in treatment plans. It adopts a distributed optical sensor network and real-time data transmission technology, eliminating the need for manual point-by-point measurement. The system can automatically collect the positions of 12-15 points across three sets of laser lines (front, back, and sides). The entire process from monitoring to calibration completion takes ≤5 minutes, a reduction of more than 85% compared to traditional methods. Furthermore, the calibration process does not require shutting down the air conditioning in the machine room or waiting for the environment to stabilize. It can be completed quickly during radiotherapy intervals (such as when patients change intervals), avoiding delays in treatment plans due to prolonged downtime and increasing the daily utilization rate of radiotherapy equipment by approximately 15%. This is particularly suitable for use in radiotherapy departments of tertiary hospitals with high patient volumes.

[0075] 2. Eliminating human error and ensuring laser line calibration accuracy: This invention addresses the issues of 0.1-0.3mm error introduced by traditional manual operation and 0.2mm deviation between different engineers. It uses a built-in high-precision algorithm to calculate the laser spot center coordinates, coupled with a six-sensor layout that monitors the opposite side from the same side. This allows for precise capture of minute laser line offsets, completely avoiding human errors such as handheld measuring tool angle deviations and subjective laser halo judgment. After calibration, the laser line offset can be stably controlled within ≤0.1mm, compared to the ≤0.5mm threshold of traditional manual calibration, improving accuracy by 80%. This directly reduces the risk of treatment target alignment caused by laser line deviation, providing a reliable benchmark for precise radiotherapy irradiation of tumor areas.

[0076] 3. Achieve 24-hour continuous monitoring and mitigate potential risks from environmental interference: This invention addresses the problem that traditional tools can only perform periodic calibration and cannot detect laser drift between two quality control intervals. It constructs an all-weather monitoring network—sensors collect laser position data every 100ms, and the main control system compares it with standard reference values ​​in real time. When laser line drift is detected due to temperature fluctuations or equipment vibration, and the offset exceeds a preset threshold, an immediate warning is issued via audible and visual alarms and a pop-up window on the control panel, with a response time of ≤1 second. This completely eliminates the blind spot of "manual periodic checks" and ensures the continuous accuracy of radiotherapy positioning references.

[0077] 4. Compatible with existing equipment in radiotherapy rooms, lowering the threshold for clinical application: This invention fully considers equipment compatibility in radiotherapy scenarios during its design, requiring no modification to existing laser emitters—the sensor is wall-mounted and fixed to the wall with strong adhesive; the main control system connects to the sensor wirelessly and can be directly integrated into the existing quality control management platform of the hospital's radiotherapy department, eliminating the need for an additional independent control system; at the same time, the sensor's shell is made of radiation-resistant ABS material, which can withstand the radiation environment of the radiotherapy room and has a service life of ≥5 years, avoiding the high cost of modifying existing equipment (saving approximately 50,000 yuan in modification costs per radiotherapy room) and lowering the threshold for hospitals to introduce new technologies.

[0078] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. All equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this invention should still be covered by the claims of this invention.

Claims

1. An automatic calibration method for a laser positioning system in a radiotherapy room, characterized in that, The method involves applying multiple optical sensors, wherein the multiple optical sensors are respectively installed on the wall of the radiotherapy room at monitoring points corresponding to multiple sets of intersecting laser lines in the room, and includes the following steps: It receives multiple sets of intersecting laser lines emitted by the laser emission module in the radiotherapy room and forms a clear laser spot on the surface of the CMOS image sensor; The optical signal of the laser spot is converted into a CMOS pixel grayscale electrical signal, and the actual physical coordinates of the center of the laser spot on the wall of the computer room are calculated based on the CMOS pixel grayscale electrical signal.

2. The automatic calibration method for a laser positioning system in a radiotherapy room according to claim 1, characterized in that: When applied to an intelligent main control system, the following steps are included: The system receives the actual physical coordinates of the center of the laser spot on the wall of the computer room from multiple optical sensors, and determines the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot on the wall of the computer room. Obtain the pre-set standard reference parameters from the built-in storage chip, and calculate the spatial offset and angular deviation of the current laser line relative to the standard reference based on the standard reference parameters; The required adjustment amount of the laser line is calculated based on the spatial offset and angular deviation, and the state is automatically determined and adjustment instructions for the laser emission module are generated based on the calculation results.

3. The automatic calibration method for a laser positioning system in a radiotherapy room according to claim 1, characterized in that: The calculation of the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the grayscale electrical signal of the CMOS pixel includes: The CMOS pixel grayscale electrical signal is converted into pixel coordinates of the laser spot center; The actual physical coordinates of the center of the laser spot on the wall of the computer room are determined based on the pixel coordinates of the center of the laser spot.

4. The automatic calibration method for a laser positioning system in a radiotherapy room according to claim 2, characterized in that: The step of determining the spatial position and angle data of the laser line based on the actual physical coordinates of the center of the laser spot on the wall of the computer room includes: The three-dimensional coordinates of the laser spot measured by each sensor are determined based on the actual physical coordinates of the laser spot center. The geometric center of the monitoring point corresponding to the multiple optical sensors is calculated based on the three-dimensional coordinates of the laser spot measured by each sensor, wherein the geometric center of the multiple monitoring points is used as the reference point of the laser line; A covariance matrix is ​​constructed based on the three-dimensional coordinates of the laser spot measured by each sensor and the geometric center of multiple monitoring points. The covariance matrix is ​​used to describe the distribution direction and dispersion of multiple monitoring points in three-dimensional space. The spatial position and angle data of the laser line are determined based on the geometric center and covariance matrix of multiple monitoring points.

5. An automatic calibration method for a laser positioning system in a radiotherapy room according to claim 4, characterized in that: The process of determining the spatial position and angle data of the laser line based on the geometric center and covariance matrix of multiple monitoring points includes: The spatial equation of the laser line is determined based on the geometric center and covariance matrix of multiple monitoring points. The spatial position of the laser line is obtained by determining the intersection point between the spatial equation of the laser line and the radiotherapy isocenter plane, and the angle data of the laser line is determined based on the covariance matrix.

6. An automatic calibration method for a laser positioning system in a radiotherapy room according to claim 5, characterized in that: Determining the location of the intersection point between the spatial equation of the laser line and the isocenter plane of radiotherapy includes: The location of the intersection point between the spatial equation of the laser line and the radiotherapy isocenter plane is determined according to the following formula: ， ， ； in, These are the parameter values ​​for the corresponding intersection points in the equation of the line; The height of the isocenter plane of the radiotherapy in the Z direction; The geometric mean position of multiple monitoring points; For the corresponding largest eigenvalue eigenvectors, These are the eigenvalues ​​of the covariance matrix; The coordinates are the points where the laser line intersects the isocenter of the radiotherapy plane.

7. An automatic calibration method for a laser positioning system in a radiotherapy room according to claim 6, characterized in that: The step of determining the angle data of the laser line based on the covariance matrix includes: The angle data of the laser line is determined using the following formula: ， ； in, The angle of inclination of the laser line relative to the perpendicular direction in the XZ plane; The angle of inclination of the laser line relative to the perpendicular direction in the YZ plane.

8. An automatic calibration method for a laser positioning system in a radiotherapy room according to claim 2, characterized in that: The step of calculating the required adjustment amount of the laser line based on the spatial offset and angular deviation includes: ， ； in, This refers to the displacement of the laser head in the laser emitting module that needs to be adjusted. This represents the translational error of the laser line in the horizontal and vertical directions; This refers to the distance from the laser head to the wall. This represents the tilt error of the laser line relative to the vertical direction.

9. An automatic calibration system for a laser positioning system in a radiotherapy room, characterized in that: It includes multiple optical sensors, the optical sensors including: The laser receiving module is used to receive multiple sets of intersecting laser lines emitted by the laser emitting module in the radiotherapy room and form a clear laser spot on the surface of the CMOS image sensor; The signal processing module is used to convert the optical signal of the laser spot into a CMOS pixel grayscale electrical signal, and calculate the actual physical coordinates of the center of the laser spot on the wall of the computer room based on the CMOS pixel grayscale electrical signal.

10. An automatic calibration system for a laser positioning system in a radiotherapy room according to claim 9, characterized in that: It also includes an intelligent main control system, which includes a data receiving module and a central processing unit that is wiredly connected to the data receiving module.

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