Multifunctional radiotherapy positioning system and positioning method thereof

Abstract

The invention discloses a multifunctional radiotherapy positioning system and a positioning method thereof. The multifunctional radiotherapy positioning system comprises a multifunctional radiotherapy fixing bottom plate, a positioning frame arranged on the multifunctional radiotherapy fixing bottom plate, a positioning laser lamp detector installed on the positioning frame, a dynamic positioning calibration module, a non-contact monitoring module and an intelligent temperature control heating system. The multifunctional radiotherapy fixing bottom plate is used for being installed on a linear accelerator treatment bed. The multifunctional radiotherapy fixing bottom plate comprises a photochromic layer, a pressure sensor matrix layer, a temperature-sensitive layer, a heating layer, an upper carbon fiber skin layer, a foam layer and a lower carbon fiber skin layer which are sequentially stacked from top to bottom. The positioning laser lamp detector comprises a positioning laser lamp detector main body, a cross curve mark arranged on the surface of the positioning laser lamp detector main body, a laser sensor matched with the cross curve mark, and metal mark points which are arranged in the positioning laser lamp detector main body and are distributed around the isocenter.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy equipment technology, and in particular to a multifunctional radiotherapy positioning system and its positioning method. Background Technology

[0002] Radiotherapy is one of the important methods of cancer treatment. Clinically, linear accelerators are usually used to irradiate the patient's target area. In order to ensure that the irradiation beam can accurately cover the target area and reduce damage to normal tissues, high requirements are placed on the repeatability of the patient's position, the positioning accuracy of the treatment bed, the isocentric consistency of the linear accelerator, and the alignment accuracy of the positioning laser lamp in the treatment room during radiotherapy.

[0003] In current radiotherapy procedures, patient positioning is typically supported and fixed using a multi-functional radiotherapy fixation plate or positioning device. The laser beam from a positioning laser lamp in the treatment room is aligned with a reference line on the patient's body surface to complete the radiotherapy positioning. Simultaneously, to ensure treatment accuracy, hospitals usually conduct routine checks (such as morning checks) on the alignment of the positioning laser lamp and isocentric consistency, and verify the positioning using imaging such as IGRT or CBCT.

[0004] However, existing technologies still have the following shortcomings: 1) Positioning detection and fixation devices are independent of each other, the process is cumbersome and dependent on manual labor: Existing multifunctional radiotherapy fixation base plates usually only provide support and fixation functions. For the alignment deviation detection and isocenter verification of positioning laser lamps, external detection tools or additional quality control devices are often required. The operation steps are numerous, time-consuming, and easily affected by differences in human judgment, resulting in poor consistency of detection results.

[0005] 2) Lack of identifiable positioning reference structure to cooperate with image verification: When using IGRT or CBCT for positioning verification, if the fixation device lacks a stable and identifiable marker structure, it is difficult to achieve quantitative judgment and source analysis of the deviation of the center of gravity, which is not conducive to improving positioning accuracy and quality control efficiency.

[0006] 3) Minor positional shifts during treatment are difficult to detect in a timely manner, and there is a lack of dynamic calibration mechanisms: During radiotherapy, patients may experience positional shifts or changes in posture due to breathing, muscle tension, or involuntary movement. Traditional methods typically involve a single positioning before treatment and then begin irradiation, lacking real-time perception and linkage calibration capabilities for positional changes, which poses a risk of decreased irradiation accuracy.

[0007] 4) Insufficient comfort and temperature management affect body position stability and safety: Multifunctional radiotherapy fixation plates are mostly made of materials such as carbon fiber, which have a poor contact experience for patients in low-temperature environments and can easily cause muscle tension or discomfort. At the same time, existing technologies often lack monitoring and early warning of abnormal patient body temperature, and also lack the means to adjust the temperature of multifunctional radiotherapy fixation plates, making it difficult to balance comfort and treatment safety.

[0008] Therefore, there is an urgent need for a radiotherapy positioning system that can be adapted to linear accelerator treatment beds and integrates positioning laser alignment detection, image verification, dynamic body position monitoring and calibration, and temperature control monitoring to improve radiotherapy positioning efficiency, positioning consistency, and the safety of the treatment process. Summary of the Invention

[0009] To address the problems existing in the prior art, this invention provides a multifunctional radiotherapy positioning system and its positioning method.

[0010] To achieve the above objectives, the present invention provides a multifunctional radiotherapy positioning system, including a multifunctional radiotherapy fixation base plate, a positioning frame disposed on the multifunctional radiotherapy fixation base plate, a positioning laser lamp detector mounted on the positioning frame, a dynamic positioning calibration module, a non-contact monitoring module, and an intelligent temperature control heating system; The multifunctional radiotherapy fixation base plate is used for installation on the linear accelerator treatment bed; The multifunctional radiotherapy fixation base plate includes, from top to bottom, a photochromic layer, a pressure sensor matrix layer, a thermosensitive layer, a heating layer, an upper carbon fiber skin layer, a foam layer, and a lower carbon fiber skin layer. The positioning laser lamp detector includes a main body, crosshair marks on the surface of the main body, a laser sensor that works in conjunction with the crosshair marks, and metal markers distributed equicenterly inside the main body. The laser sensor detects the alignment deviation of the laser line formed by the positioning laser lamp relative to the crosshair marks and outputs a detection signal. The metal markers form identifiable marks in IGRT or CBCT images. The non-contact monitoring module includes a flexible graphene temperature sensing layer and a multi-parameter fusion algorithm unit electrically connected to the flexible graphene temperature sensing layer. The flexible graphene temperature sensing layer covers a multifunctional radiotherapy fixation base plate and is used to acquire patient surface temperature data. The multi-parameter fusion algorithm unit evaluates the patient surface temperature data, outputs a warning signal when an abnormal temperature is detected, and outputs a treatment pause signal when the abnormal temperature reaches a preset safety threshold. The dynamic positioning calibration module includes a pressure sensor matrix, an accelerometer, an inertial measurement unit (IMU), and an FPGA control unit. The pressure sensor matrix, embedded in the pressure sensor matrix layer, is used to collect pressure distribution data changes in the patient's position and detect patient positional deviations. The IMU is fixed to the patient's body surface or the linear accelerator treatment bed and is used to collect three-dimensional acceleration and angular velocity data of the patient's position to output attitude data characterizing changes in posture. The accelerometer is used to collect acceleration change data of the patient's position and output displacement-related data. The corresponding terminals of the FPGA control unit are electrically connected to the corresponding terminals of the pressure sensor, accelerometer, and inertial measurement unit to receive pressure distribution data, displacement-related data, and attitude data and generate dynamic correction commands. The intelligent temperature control heating system is electrically connected to the heating layer and is used to adjust the temperature of the multifunctional radiotherapy fixation base plate and maintain it within a preset temperature range.

[0011] Preferably, the positioning frame includes a positioning plate, an electronic level mounted on the positioning plate, and a positioning post mounted at the bottom of the positioning plate; The electronic level is adjustable and mounted on the positioning plate via a fine-tuning screw, and the positioning laser light detector is located on the leveling reference of the electronic level. The multifunctional radiotherapy fixation base plate has positioning holes that are compatible with the positioning columns.

[0012] Preferably, the positioning laser light detector further includes a data acquisition unit and a wireless communication module disposed inside the main body of the positioning laser light detector. The corresponding terminals of the data acquisition unit are electrically connected to the corresponding terminals of the laser sensor. The data acquisition unit is used to acquire the detection signal of the laser sensor and output laser deviation data. The corresponding end of the data acquisition unit is also electrically connected to the wireless communication module; the wireless communication module is used to send laser deviation data to an external terminal. The external terminal includes at least one of the HIS system and the TPS system.

[0013] Preferably, the FPGA control unit communicates with the linear accelerator's control system via the EtherCAT protocol to send dynamic correction commands to the linear accelerator, driving the linear accelerator to perform positioning compensation and adjust the beam direction.

[0014] Preferably, the photochromic material comprises rare earth-doped organic compounds, which develop color after being irradiated with X-rays and heated to 50-80°C, with a color contrast ratio ≥90%. The temperature-sensitive layer is coated with a polyurethane coating containing temperature-sensitive pigments, and its color changes from purple to green when the temperature reaches the standard (37±1℃). The heating layer is made of epoxy resin with carbon nanotube conductive filler, and the heating temperature control range is 30-42℃. The thickness of the upper carbon fiber skin layer is 1.5 mm, and the tensile strength is ≥3500 MPa. The foam layer is made of polyurethane closed-cell foam with a density of 40 kg / m³, which is used to buffer pressure and improve patient comfort. The thickness of the lower carbon fiber skin layer is 1.0 mm.

[0015] Preferably, the flexible graphene temperature sensing layer includes a thermopile sensor array for acquiring the body surface temperature data, the thermopile sensor array including 64 channels.

[0016] Preferably, the intelligent temperature control heating system includes a PID temperature control module and a safety protection unit; the control output terminal of the PID temperature control module is electrically connected to the heating layer via the safety protection unit, and the temperature acquisition terminal of the PID temperature control module is electrically connected to the temperature-sensitive layer to adjust the heating power of the heating layer according to temperature feedback; the safety protection unit is used to cut off the power supply to the heating layer when an over-temperature abnormality is detected.

[0017] This invention also provides a multifunctional radiotherapy positioning method, applied to a multifunctional radiotherapy positioning system, comprising the following steps: S1, multifunctional radiotherapy fixation base plate installation and fixation: placing the multifunctional radiotherapy fixation base plate on the linear accelerator treatment bed and fixing it; S2, isocenter alignment: adjusting the electronic level on the positioning frame to zero, and adjusting the position of the positioning laser lamp detector by the fine-tuning screws to align the positioning laser lamp detector with the isocenter of the linear accelerator; S3, morning inspection detection: starting the positioning laser lamp detector, using a laser sensor to detect the alignment deviation of the laser line formed by the positioning laser lamp relative to the crosshair mark and outputting a deviation detection signal, the data acquisition unit acquiring and processing the deviation detection signal to output laser deviation data; simultaneously acquiring CBCT images, identifying the position of the metal marker points in the CBCT images and calculating the isocenter offset to obtain isocenter deviation data; S4, data transmission and report generation: wirelessly transmitting the laser deviation data and isocenter deviation data to an external terminal and generating a detection report, the detection report including at least the isocenter deviation parameter and the laser lamp angle error. S5. Treatment Preparation: Adjust the linear accelerator treatment parameters according to the test report, and start the intelligent temperature control heating system to heat the heating layer of the multifunctional radiotherapy fixation plate to achieve the preset temperature range; S6. Dynamic Monitoring of Treatment Process: During radiotherapy, pressure distribution data changes of the patient's position are collected in real time through a pressure sensor matrix, three-dimensional acceleration data and angular velocity data of the patient's position are collected through an inertial measurement unit to output attitude data, and acceleration change data of the patient's position is collected through an accelerometer to output displacement-related data; S7. Dynamic Calibration: When the patient's position deviation or attitude change is detected to exceed the preset threshold, the FPGA control unit fuses the pressure distribution data, attitude data and displacement-related data and generates a dynamic correction command, which is sent to the linear accelerator control system to drive the linear accelerator to perform positioning compensation and adjust the beam direction; S8. Abnormal Handling: When an abnormal temperature or abnormal position is detected to reach the preset safety threshold, an early warning signal is output and a treatment pause signal is triggered.

[0018] Preferably, in step S3, the metal marker is a titanium alloy marker, which appears as a high-density shadow in the CBCT image. The algorithm extracts the center coordinates of the marker by image segmentation and compares the actual position coordinates with the theoretical position coordinates to calculate the offset Δd. The offset Δd satisfies: Δd=√((xactual-xtheoretical)²+(yactual-ytheoretical)²).

[0019] Preferably, in step S5, the intelligent temperature control heating system uses a PID control algorithm to adjust the heating power of the heating layer so that the temperature of the multifunctional radiotherapy fixation base plate is maintained at 37±0.5℃, and the temperature is indicated by the color of the temperature-sensitive layer changing from purple to green. The intelligent temperature control heating system includes an initial heating stage, a steady-state temperature control stage, and a cooling stage. In the initial heating stage, the heating layer is driven to heat up to 35°C at maximum power. In the steady-state temperature control stage, the heating power is dynamically adjusted through a PID algorithm to keep the temperature stable. In the cooling stage, the heating is turned off and the fan is activated for heat dissipation. In step S7, when the accelerometer detects that the Z-axis displacement reaches 0.3 mm or the pressure sensor matrix detects that the pressure distribution has changed by a preset value, the FPGA control unit generates the dynamic correction command within 5 ms, and drives the positioning motor used to adjust the angle of the positioning laser lamp according to the dynamic correction command to adjust the angle error of the positioning laser lamp. The single adjustment angle Δθ is 0.02°, and the direction of the linear accelerator beam is corrected simultaneously.

[0020] The technical solution of this invention has the following beneficial effects: 1) Positioning laser alignment deviation can be quantified and detected, improving the consistency of placement: By setting up a positioning laser detector and using a laser sensor to detect the alignment deviation of the laser line formed by the positioning laser relative to the crosshair mark and outputting a detection signal, the alignment status of the positioning laser can be objectively detected, reducing manual visual inspection errors and improving the consistency and reliability of placement and quality control.

[0021] 2) Supports image recognition for positioning verification and improves isocenter verification capability: The positioning laser lamp detector is equipped with metal markers distributed around the isocenter, which can form identifiable marks in IGRT or CBCT images, providing a stable reference for image verification. This facilitates the quantitative assessment and verification of positioning-related deviations and improves the traceability of radiotherapy positioning verification.

[0022] 3) The body position deviation can be monitored in real time and dynamic correction commands can be generated to improve the safety of treatment: The dynamic positioning calibration module collects pressure distribution change data through the pressure sensor matrix, attitude data through the inertial measurement unit, and displacement related data through the accelerometer. The data is then processed by the FPGA control unit to generate dynamic correction commands, thereby enabling real-time monitoring and response to the patient's body position deviation or attitude change, reducing the risk of positioning error caused by body position changes during treatment.

[0023] 4) The detection signal acquisition and transmission link is clear, which is conducive to the retention and retrieval of clinical quality control data: By setting up a data acquisition unit to acquire the detection signal of the laser sensor and output the laser deviation data, the laser deviation data is sent to an external terminal (such as a HIS system or TPS system) by a wireless communication module. This facilitates the rapid transmission, centralized management and quality control retention of positioning detection data, which is convenient for subsequent statistical analysis and quality tracking.

[0024] 5) Dynamic correction command generation based on multi-source data improves positioning and calibration response capability: The FPGA control unit receives pressure distribution data, displacement-related data, and attitude data, processes them to generate dynamic correction commands, which, compared to single-signal judgment methods, helps improve the stability and response efficiency of abnormal body position recognition, thereby enhancing the dynamic calibration capability during treatment. The FPGA control unit communicates with the linear accelerator control system via the EtherCAT protocol, sending dynamic correction commands to the linear accelerator to drive it to perform positioning compensation and adjust the beam direction. This facilitates the realization of a closed-loop linkage of "monitoring-judgment-correction," improving the synergy of radiotherapy positioning control.

[0025] 6) Improved surface temperature monitoring and abnormal early warning mechanism enhances risk protection capabilities: The non-contact monitoring module acquires the patient's surface temperature data through a flexible graphene temperature sensing layer, which is then evaluated by a multi-parameter fusion algorithm unit. When an abnormal temperature is detected, an early warning signal is output, and when the abnormal temperature reaches a preset safety threshold, a treatment pause signal is output, thereby improving the safety protection capabilities of the treatment process.

[0026] 7) Provides temperature-controlled heating and heat preservation capabilities to improve comfort and body position stability: The intelligent temperature-controlled heating system is electrically connected to the heating layer, which can adjust and maintain the temperature of the multifunctional radiotherapy fixation base plate within the preset temperature range, making the temperature of the patient's contact surface more suitable, which helps to improve patient comfort, reduce body position fluctuations caused by discomfort, and improve body position stability and repeatability.

[0027] 8) The multi-layer structure of the multi-functional radiotherapy fixation plate facilitates functional integration while balancing strength and comfort: The multi-functional radiotherapy fixation plate adopts a stacked structure of photochromic layer, pressure sensor matrix layer, temperature-sensitive layer, heating layer, carbon fiber skin layer and foam layer. It can achieve integrated functions such as pressure monitoring, temperature indication and heating adjustment while meeting the support strength requirements. The foam layer enhances the cushioning effect and further improves the comfort of use.

[0028] 9) High system integration and clear module relationships facilitate standardized deployment and maintenance: This invention integrates modules such as fixed multifunctional radiotherapy fixation base plate, laser detection, dynamic calibration, temperature monitoring and temperature-controlled heating into the same system framework. The module input / output relationships are clear, which helps to reduce the switching of external equipment and repeated clamping steps, improves the ease of use, and facilitates maintenance and upgrades. Attached Figure Description

[0029] Figure 1 This is an assembly diagram of the multifunctional radiotherapy fixation base plate, positioning frame, and positioning laser lamp detector of the present invention; Figure 2 This is a schematic diagram of the multi-level structure of the multifunctional radiotherapy fixation base plate of the present invention; Figure 3 This is a schematic diagram of the positioning frame of the present invention; Figure 4 This is a schematic diagram of the bottom structure of the positioning frame of the present invention. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0031] Reference Figures 1 to 4 This embodiment provides a multifunctional radiotherapy positioning system that integrates linear accelerator isocenter detection, positioning laser calibration, dynamic body position correction, and non-contact vital sign monitoring, aiming to meet the high-precision and high-efficiency requirements of tumor radiotherapy. The multifunctional radiotherapy positioning system includes: a multifunctional radiotherapy fixation base plate 100, a positioning frame 200, a positioning laser lamp detector 300, a dynamic positioning calibration module, a non-contact monitoring module, and an intelligent temperature control heating system. These components work together to achieve precise patient positioning and real-time monitoring and calibration of the treatment process.

[0032] The multifunctional radiotherapy fixation base plate 100 adopts a "sandwich" multi-layer composite structure, adapted for installation on the treatment bed surface of the linear accelerator, and used to support and fix the patient's position. The multifunctional radiotherapy fixation base plate 100 consists of multiple functional layers stacked sequentially from top to bottom, with each layer having the following functions: Photochromic layer (top layer) 101: Composed of organic photochromic material doped with rare earth elements. This layer will develop color when irradiated with X-rays and heated to 50–80°C, with a color contrast ≥90%. This characteristic is used to verify the consistency between the accelerator field and the optical field—that is, a 100×100 mm laser-etched wireframe is pre-printed on the surface of the multifunctional radiotherapy fixation base plate 100. After adjusting the accelerator optical field / field to the same size and irradiating the multifunctional radiotherapy fixation base plate 100 with the beam, the top layer material is heated to develop the image. If the developed image completely overlaps with the wireframe (allowable error ≤0.5 mm), it proves that the field and the optical field are in good consistency.

[0033] Pressure sensor matrix layer (second layer) 102: Embedded with a high-sensitivity pressure sensor array. This layer collects real-time pressure distribution data of various parts of the patient's body in contact with the multifunctional radiotherapy fixation base plate 100, and generates changes in pressure distribution when the patient's body position shifts slightly. The pressure sensor has a detection accuracy of approximately ±0.1 N and a response time of ≤1 second, enabling it to accurately capture subtle positional changes such as sliding of the patient's hips or shoulders, thereby helping to determine whether the patient's position has deviated from the predetermined location.

[0034] Thermosensitive layer (third layer) 103: Composed of a polyurethane coating mixed with temperature-sensitive color-changing pigments. When the temperature of the multifunctional radiotherapy fixation plate 100 reaches the preset 37±1 ℃, the color of this layer changes from purple to green, with a response time ≤2 seconds, serving as a direct indication that the temperature target has been reached. The color-changing indication mechanism of the thermosensitive layer ensures that the multifunctional radiotherapy fixation plate 100 has been heated to a comfortable temperature close to body temperature before the patient lies down, thereby improving patient comfort.

[0035] Heating layer (fourth layer) 104: Composed of flexible epoxy resin containing carbon nanotube conductive filler. This layer serves as the heating element of the multifunctional radiotherapy fixation base plate 100, generating heat when voltage is applied. The temperature is controllable within a range of 30–42°C, with a heating uniformity of approximately ±0.3°C. The heating layer is connected to an intelligent temperature control system to achieve active heating and constant temperature control of the multifunctional radiotherapy fixation base plate. This heating layer can be divided into several independent regional units (e.g., 10 cm × 10 cm per unit) for zoned temperature control as needed. Carbon nanotubes improve the material's electrical conductivity and thermal properties, enabling the heating layer to heat up rapidly and uniformly.

[0036] The upper carbon fiber skin layer (fifth layer) 105: approximately 1.5 mm thick, made of high-strength carbon fiber composite material with a tensile strength ≥3500 MPa. This layer provides the multifunctional radiotherapy fixation base plate 100 with the necessary structural strength and rigidity, and ensures good X-ray permeability, meeting the requirements for radiation penetration in radiotherapy.

[0037] Foam layer (sixth layer) 106: Made of polyurethane closed-cell foam material with a density of approximately 40 kg / m³. The foam layer provides elastic support and cushioning, dispersing pressure and reducing local pressure while ensuring the patient's body is stably fixed, thereby improving the patient's comfort while lying down.

[0038] The lower carbon fiber skin layer (seventh layer) 107: approximately 1.0 mm thick, also made of carbon fiber composite material, and with a surface anti-slip treatment. The bottom carbon fiber skin provides structural support and serves as the interface between the multifunctional radiotherapy fixation base plate and the positioning frame, ensuring that the multifunctional radiotherapy fixation base plate can be stably installed on the positioning frame without slipping.

[0039] The aforementioned multi-layered structure enables the multifunctional radiotherapy fixation plate to combine positioning accuracy with patient comfort. For example, the embedded pressure sensing matrix can monitor the pressure distribution of the patient's position in real time during treatment; an abnormal decrease in pressure in a certain area may indicate a deviation in the patient's position. Furthermore, the photochromic layer acts as a radiation field calibration sheet, verifying the isocenter of the gantry and the accuracy of laser positioning during daily morning checks. The integrated multifunctional radiotherapy fixation plate 100 design eliminates the cumbersome steps of repeatedly disassembling and assembling the multifunctional radiotherapy fixation plate in traditional morning checks, significantly improving testing efficiency; compared to the 15–20 minutes of a single test using traditional methods, this invention's system can control the morning check within 3 minutes. Simultaneously, the preheating function of the multifunctional radiotherapy fixation plate avoids patient discomfort caused by a cold bed in winter, improving the patient experience.

[0040] Furthermore, the positioning frame 200 includes a base plate 201, with positioning posts 204 at the bottom of the positioning plate 201. These posts are inserted and fixed into the positioning holes on the multifunctional radiotherapy fixation base plate 100, ensuring that the multifunctional radiotherapy fixation base plate 100 has a unique installation position and orientation relative to the positioning frame 200, thus avoiding installation errors. The base plate 201 also houses an electronic level 202 with a measurement accuracy of ±0.01°. The electronic level 202 is adjustablely mounted on the positioning plate via fine-tuning screws 203. During installation and debugging, the horizontal orientation of the positioning frame can be adjusted by adjusting the fine-tuning screws 203 on the frame. When the electronic level 202 reads zero, it indicates that the multifunctional radiotherapy fixation base plate 100 is in a horizontal reference state. The positioning laser lamp detector 300 is mounted on the positioning frame 200 and is installed and calibrated based on the leveling reference of the electronic level 202 (the position of the positioning laser lamp detector 300 can be finely adjusted via the aforementioned fine-tuning screws 203). This positioning laser lamp detector 300 is used for isocenter and laser positioning accuracy verification before daily radiotherapy. It mainly includes the main body of the positioning laser lamp detector, laser sensor, and internal marking components. The positioning laser lamp detector body has multiple sets (e.g., four sets) of precisely engraved crosshair marks (i.e., laser collimation targets) on its outer shell. When the positioning laser lamp in the accelerator room shines on the positioning laser lamp detector, a laser line corresponding to the crosshair marks is formed on its surface. Inside the positioning laser lamp detector body, metal markers are embedded around the isocenter of the linear accelerator, for example, at isocenter radii of 5 mm and 10 mm, with a 1 mm diameter titanium alloy ball marker in each quadrant. These metal markers appear as high-density bright spots in image-guided radiotherapy (IGRT) or cone-beam CT (CBCT) images, serving as markers for isocenter alignment. The laser sensor is installed inside the positioning laser lamp detector body, aligned with the crosshair marks on the outer shell surface. This laser sensor detects the deviation of the laser line projected by the positioning laser lamp relative to the crosshair marks. The laser sensor has high angular resolution (e.g., 0.01°) and high sensitivity, enabling precise measurement of the laser line deviation angle. By detecting the position of the laser lines in both vertical and horizontal directions, the computer can determine the alignment error between the laser positioning light and the machine's center.

[0041] Data Acquisition and Communication Unit: The positioning laser light detector integrates a signal acquisition circuit (e.g., a 16-bit ADC with a sampling rate up to 10 kHz) to digitize the analog signals output by the aforementioned laser sensor and calculate laser deviation data. Simultaneously, the positioning laser light detector is equipped with a wireless communication module (supporting the latest Wi-Fi 6 or Bluetooth 5.0 standards), which can transmit the acquired laser deviation data to external terminals in real time, such as hospital information systems (HIS) or treatment planning systems (TPS). Wireless transmission features low latency (<50 ms), ensuring rapid feedback of detection data to operators. During daily morning checks, the data wirelessly transmitted by the positioning laser light detector can be used to automatically generate detection reports. These reports include at least the center deviation parameters of the linear accelerator and the angular error parameters of the positioning laser light, for medical staff to reference and adjust.

[0042] Coordinated calibration of the positioning frame and the positioning laser lamp detector: In use, first place the multi-functional radiotherapy fixation base plate on the accelerator treatment bed, then adjust the electronic level on the positioning frame to zero to ensure the multi-functional radiotherapy fixation base plate is level. Next, install the positioning laser lamp detector and adjust its position and angle using the fine-tuning screws until its center coincides with the mechanical isocenter of the linear accelerator. When the laser lamp illuminates the positioning laser lamp detector, the projected laser line should precisely fall on the crosshair marks on the detector's casing. If there is a deviation, the laser sensor will detect it and output a signal, which is processed by the data acquisition unit to obtain the numerical deviation. This data is transmitted wirelessly to a computer or control system, thereby achieving automated detection and recording of isocenter alignment calibration and laser positioning calibration. It is worth mentioning that the titanium alloy markers inside the positioning laser light detector are also collected during the daily morning CBCT scan to verify the machine's isocentric position: the algorithm identifies the center coordinates of these high-density markers in the CBCT image and compares them with their theoretical coordinates to calculate the isocentric offset Δd (the formula is Δd = √((x_real))). x(theoretical)² +(yactual) When Δd exceeds the preset tolerance, a prompt will appear indicating that the isocenter of the linear accelerator needs to be recalibrated.

[0043] Furthermore, the dynamic positioning and calibration module is used to monitor changes in patient position in real time during radiotherapy and automatically corrects the position by linking the linear accelerator when a deviation is detected. This dynamic positioning and calibration module includes a pressure sensor matrix, an accelerometer, an inertial measurement unit (IMU), and an FPGA control unit. Some sensors are embedded in the aforementioned multifunctional radiotherapy fixation base plate, while others are fixed to the patient or bed. Pressure sensor matrix: Located on the second layer of the multifunctional radiotherapy fixation plate, the pressure sensor matrix is ​​used to acquire changes in the pressure distribution of the patient's body position over time during dynamic positioning calibration. When the patient moves slightly during treatment (e.g., pressure decreases or increases in a certain part of the body), the pressure sensor matrix can capture the distribution change, thereby inferring the positional shift. For example, if a significant change in pressure is detected in the patient's shoulder or hip area, it can be determined that the patient may have slipped or changed posture.

[0044] Accelerometer: Positioned appropriately to capture minute acceleration changes in the patient's body, with an accuracy of ±0.001 g and a sampling rate of up to 2 kHz. This high-precision accelerometer can detect subtle vibrations or displacement trends occurring in the patient, including displacement along the Z-axis (vertical direction). Its data can reflect whether the patient has experienced sudden movement or positional changes due to respiration, etc.

[0045] Inertial Measurement Unit (IMU): Fixedly mounted on the patient's body surface (e.g., a chest / abdomen patch) or treatment bed. The IMU integrates a three-axis accelerometer and a three-axis gyroscope, providing three-dimensional acceleration and angular velocity information of the patient's position. Compared to a single accelerometer, the IMU can monitor changes in the patient's posture angle, such as slight turning or tilting. This is very helpful in correcting optical monitoring blind spots (such as when the patient's back area is obstructed, preventing the optical system from capturing the image).

[0046] FPGA Control Unit: A high-speed field-programmable gate array controller (FPGA) is used to process and aggregate the sensor data and control the linear accelerator for compensation adjustments. The FPGA connects to the linear accelerator's control system via a high-speed EtherCAT communication interface, with a communication latency of <2 ms. During operation, the FPGA receives pressure distribution data from the pressure sensing matrix, attitude / acceleration data from the accelerometer and IMU in real time, and fuses this data using a built-in algorithm. When a patient's positional shift or attitude change is detected to exceed a preset threshold, the FPGA generates a dynamic correction command within approximately 5 milliseconds. This command is sent to the linear accelerator control system via EtherCAT, causing the accelerator to immediately perform positioning compensation, including adjusting the position of the treatment gantry or the beam direction to realign with the patient's tumor target area. In this embodiment, the dynamic calibration command can also drive the automatic positioning motor in the positioning laser lamp detector to fine-tune the laser lamp's pointing angle Δθ (e.g., adjusting by 0.02° each time) to maintain laser alignment with the isocenter. Through this closed-loop control, automatic compensation for changes in patient position during radiotherapy is achieved, significantly improving the accuracy of beam alignment and reducing the risk of dose deviation caused by minor patient movements. According to clinical test data, the target dose coverage can be improved by about 18% after the introduction of this dynamic calibration function.

[0047] Furthermore, this system integrates a non-contact vital sign monitoring module to acquire physiological parameters such as body surface temperature without increasing the patient's burden, enabling real-time monitoring of the patient's condition. This module includes a flexible graphene temperature sensing layer and a multi-parameter fusion algorithm unit. Flexible graphene temperature sensing layer: This is an ultra-thin flexible sensing layer (approximately 0.3 mm thick) covering the surface of the multifunctional radiotherapy fixation plate. The material has high thermal conductivity and high infrared emissivity (ε≈0.95). This flexible graphene temperature sensing layer is equivalent to a high-resolution body surface thermal imaging sensor, in which a thermopile sensor array is embedded to collect patient body surface temperature data. The thermopile array contains multiple miniature temperature sensing units (64 channels in this embodiment), each channel corresponding to a temperature sensing unit of approximately 5 mm × 5 mm. The entire array can respond to changes in body surface temperature within 0.2 seconds, with a temperature resolution accuracy of approximately ±0.05℃. When the patient lies on the multifunctional radiotherapy fixation plate, the flexible graphene temperature sensing layer can measure the skin temperature of different parts of the body in a non-contact manner (through infrared sensing), generating a body surface temperature distribution map. Compared to traditional contact thermometers or sensors, this solution does not irritate the skin or cause discomfort, meeting the requirements of non-invasive monitoring. In addition, due to the flexibility of graphene material, the sensing layer adheres closely to the surface of the multifunctional radiotherapy fixation plate, without affecting patient comfort or interfering with radiation therapy.

[0048] Multi-parameter fusion algorithm unit: This unit comprehensively analyzes surface temperature data from the flexible graphene temperature sensing layer and displacement data from the pressure sensor matrix and accelerometer to assess the patient's vital signs and stability during treatment. In this embodiment, the fusion algorithm utilizes an LSTM (Long Short-Term Memory) neural network model to learn and judge multimodal data over a period of time. This enables the system to provide timely warnings of abnormal situations: for example, if the patient shows signs of fever (temperature in certain areas of the body surface continues to rise and exceeds 38.5°C) or moves unconsciously (pressure / accelerometer data indicates a positional shift exceeding 1.5 mm), the algorithm will output a warning signal. When the detected abnormality in the patient's temperature or position reaches a preset safety threshold, the system can even automatically trigger a treatment pause signal to remind medical staff to check the patient's condition and take appropriate action. This multi-parameter closed-loop monitoring improves the safety of the radiotherapy process. For example, patients may experience discomfort or stress responses from maintaining a fixed position for a long time; by monitoring temperature and subtle changes in movement, accidents can be detected in advance and prevented. In this invention, the graphene temperature sensing layer is combined with a pressure / accelerometer to achieve true non-contact vital sign monitoring, reducing the skin allergy reaction rate to below 0.3%.

[0049] Furthermore, the intelligent temperature control heating system is responsible for heating the multifunctional radiotherapy fixation plate to a comfortable body temperature range and maintaining a constant temperature, preventing patient discomfort due to the plate being too cold, while also ensuring temperature stability to prevent overheating risks. This system includes a PID temperature control module and a safety protection unit. PID temperature control module: Employs a proportional-integral-derivative (PID) control algorithm for closed-loop control of the heating process. The PID controller adjusts the power supply to the heating layer by acquiring real-time temperature feedback (from the temperature-sensitive layer of the multifunctional radiotherapy fixation plate or an independent temperature sensor, such as an NTC thermistor), thereby stabilizing the temperature of the multifunctional radiotherapy fixation plate near the set value (e.g., 37±0.5℃). In this embodiment, the PID algorithm parameters are adaptively adjustable; for example, initial settings of Kp=0.8, Ki=0.01, and Kd=0.2 can achieve a heating rate of approximately 5℃ / second. The heating strategy consists of three phases: First, the initial rapid heating phase, where the PID controller drives the heating layer at maximum power output to quickly raise the temperature of the multifunctional radiotherapy fixation plate from room temperature to near the target value (e.g., 35°C); then, the steady-state isothermal phase, where the controller dynamically adjusts the power output within a small range (e.g., the rated range of 20–150 W) to precisely maintain the temperature at around 37°C (with allowable fluctuations of ±0.5°C); after treatment, the cooling phase begins, where heating is stopped and the cooling fan is activated to help cool the multifunctional radiotherapy fixation plate (typical cooling rate of approximately 3°C / min) so that it does not overheat when used by the next patient.

[0050] Safety Protection Unit: To prevent overheating risks caused by heating system malfunctions or control failures, the system is designed with redundant safety protection mechanisms. On one hand, high-response-speed overheat sensors (such as NTC thermistors with a response time of <0.05 seconds) and control switches (such as solid-state relays with a withstand current of 20 A) are integrated into the hardware. If temperature monitoring detects that the temperature of the multi-functional radiotherapy fixation plate exceeds the safety threshold, the safety unit will cut off the power supply to the heating layer to prevent further heating. On the other hand, temperature anomaly detection logic is also set in the software. If the PID module fails to control the temperature within the normal range within the expected time, the system will alarm and stop heating. Through dual protection, the temperature of the multi-functional radiotherapy fixation plate is ensured to always remain within a safe range (e.g., between 30 and 42°C). In addition, the color indicator of the temperature-sensitive layer (changing from purple to green) provides a clear indication of temperature compliance, allowing operators to confirm that the multi-functional radiotherapy fixation plate has reached the appropriate temperature.

[0051] In summary, the structural design of this multifunctional radiotherapy positioning system enables it to ensure positioning accuracy while also considering patient comfort and safety. The multifunctional radiotherapy fixation base plate, positioning laser lamp detector, sensors, and heating control unit together form an organic whole, providing a reliable guarantee for precise radiotherapy.

[0052] This system also provides corresponding multifunctional radiotherapy positioning methods, covering the entire process from pre-treatment preparation to monitoring and calibration during treatment. The following sections, in conjunction with the functions of each component of this system, detail the implementation steps S1 to S8 of this method: Multifunctional radiotherapy fixation base plate installation and fixation S1: Before the first treatment each day, place the multifunctional radiotherapy fixation base plate on the treatment bed of the linear accelerator, and at the same time check whether the interface (positioning post and positioning hole) between the multifunctional radiotherapy fixation base plate and the positioning frame is properly matched to maintain the repeatability and positioning accuracy of the installation of the multifunctional radiotherapy fixation base plate.

[0053] Isocenter Alignment (S2): After installing the multi-functional radiotherapy fixation base plate, adjust the positioning frame to a horizontal reference position: observe the electronic level on the positioning frame and adjust it to zero level. Then turn on the positioning laser light in the linear accelerator room, so that the laser projects intersecting rays at the center of the multi-functional radiotherapy fixation base plate. By rotating or fine-tuning the screws on the positioning frame, finely adjust the position and orientation of the positioning laser light detector to ensure that the laser light detector mounted on the positioning frame is precisely aligned with the mechanical isocenter of the linear accelerator. When the crosshairs on the positioning laser light detector completely coincide with the rays projected by the laser light, and the electronic level reading remains zero, it indicates that the installation and positioning of the multi-functional radiotherapy fixation base plate and the positioning laser light detector relative to the isocenter of the linear accelerator have been completed.

[0054] Morning Check-up S3: Before the formal start of daily treatment, the morning quality control (QA) check-up process is executed. First, the measurement function of the positioning laser lamp detector is activated. The laser sensor inside the detector captures the minute deviations of the light beam generated by the positioning laser lamp relative to its own crosshair markers and outputs the corresponding deviation detection signal. The data acquisition unit records these signals and converts them into quantitative laser deviation data (e.g., the laser's horizontal / vertical deviation angle). Simultaneously, the linear accelerator's image guidance system is activated to acquire the day's CBCT images or field verification images: because titanium alloy metal markers are embedded inside the positioning laser lamp detector, these markers will appear as bright spots in the acquired images. The CBCT images are analyzed using image processing algorithms to identify the actual position coordinates of each metal marker and compare them with their theoretical expected positions, calculating the linear accelerator isocenter offset Δd (as mentioned in the previous section, Δd is calculated from the coordinate difference of the markers). This series of checks simultaneously verifies the laser positioning accuracy and the consistency of the gantry isocenter, achieving sub-millimeter level accuracy. For example, the laser sensor of the positioning laser light detector in this embodiment has an accuracy of less than 0.05 mm, and the position recognition error of the titanium alloy marker in CBCT is also at the level of 0.1 mm, thus ensuring the reliability of the measurement results.

[0055] Data Transmission and Report Generation S4: The laser deviation data and isocenter deviation data collected during the morning check-up process will be automatically transmitted to an external terminal (such as the HIS or TPS computer in the radiotherapy department) via a wireless communication module. The system software will summarize this data and automatically generate a morning check-up report. This report will include at least: linear accelerator isocenter offset parameters (e.g., how many millimeters the offset is in the left-right and up-down directions), and positioning laser angle and position error parameters (e.g., how many degrees the laser's pointing angle deviates from the ISO center). In addition, the report can list whether the day's checks are within the allowable tolerance range, and will mark any deviations. Medical staff can then decide on subsequent actions: if the deviation exceeds the threshold, the machine needs to be recalibrated or adjusted before treatment; if it is within the allowable range, subsequent preparations can continue. Through wireless transmission and automatic reporting, the errors of previous manual recording and subjective judgment are eliminated, improving the efficiency and reliability of the QA process.

[0056] Treatment Preparation S5: Based on the morning check-up report, adjust the relevant parameters of the linear accelerator. For example, if the report shows a slight shift in isocenter, fine-tune the accelerator gantry position; if there is an angular error in laser positioning, correct the laser lamp settings or enable the dynamic calibration module to compensate during treatment. After confirming the machine is in good condition, begin patient placement on the bed. At this time, activate the intelligent temperature control heating system to control the heating layer of the multifunctional radiotherapy fixation plate, causing the temperature of the multifunctional radiotherapy fixation plate to rise rapidly and stabilize at a preset range of approximately 37°C. The PID control algorithm adjusts the output power, typically heating the multifunctional radiotherapy fixation plate to the target temperature of 37±0.5°C within less than 5 minutes. When the multifunctional radiotherapy fixation plate reaches the set temperature and the color of the temperature-sensitive layer changes from purple to green, the temperature is considered reached. After lying flat on the warm multifunctional radiotherapy fixation plate, the patient will feel significantly more comfortable, avoiding the discomfort of a traditional cold and hard bed board. Next, according to the treatment plan, use a thermoplastic film or other fixation device to fix the patient's position on the multifunctional radiotherapy fixation plate. During this process, the pressure sensor matrix within the multifunctional radiotherapy fixation plate begins operating in real time, recording the baseline pressure distribution between the patient's body and the plate. This data will serve as a reference for subsequent monitoring. Finally, before treatment, a non-contact monitoring module is activated to monitor the patient's surface temperature and condition, ensuring the patient is in a good state to tolerate the treatment.

[0057] Treatment Process Dynamic Monitoring S6: When radiotherapy officially begins, all monitoring modules of the system operate continuously, dynamically observing the patient's position and vital signs. First, the pressure sensor matrix continuously collects pressure distribution data of the patient's position at a high sampling rate. If the patient attempts to move or becomes displaced during treatment, these pressure sensor matrices immediately detect the change in pressure distribution relative to the initial state. For example, if the patient involuntarily shifts position due to relaxation or pain, the pressure readings of some sensing units will decrease, while the readings on the opposite side may increase. Simultaneously, the accelerometer and IMU also record the patient's linear acceleration changes and angular velocity data in real time, capturing potential subtle movement signs. The graphene temperature sensing layer also continuously monitors the patient's surface temperature, paying particular attention to any abnormal increases to prevent adverse reactions such as fever and excessive sweating. Under normal circumstances, these data should change smoothly within a safe range. All monitoring data are input into a multi-parameter fusion algorithm unit for intelligent analysis, and any abnormal trends will be immediately detected.

[0058] Dynamic Calibration S7: If a patient's position shift or posture change exceeds a preset threshold during treatment, the system will automatically trigger a dynamic calibration process. For example, in this embodiment, the threshold is set as follows: if the accelerometer detects a vertical (Z-axis) displacement of 0.3 mm, or if the pressure sensor matrix detects a significant change in pressure in a certain area (exceeding a preset change amount), it is considered a possible deviation in position. When either condition is met, the FPGA control unit will quickly calculate and generate corresponding dynamic correction instructions within 5 milliseconds. These instructions are sent to the linear accelerator control system via the EtherCAT bus. For example, if a slight slip of the patient is detected, causing the tumor target to shift downwards relative to the beam center by 0.3 mm, the FPGA will instruct the linear accelerator to adjust the treatment bed height by 0.3 mm, or change the beam emission angle to compensate. As another example, when a slight rotation of the patient's posture is detected, the system can drive the positioning motor in the positioning laser light detector to fine-tune the laser light angle Δθ = 0.02°, ensuring that the laser remains aligned with the center of the patient's mark, and simultaneously adjust the direction of the accelerator beam to match this angular change. The entire dynamic calibration and adjustment process is completed automatically in a closed loop, with small adjustments each time and at a very fast speed, without disturbing the patient. Through continuous fine-tuning and correction, the patient is always kept in the correct position to receive irradiation, greatly improving the positioning accuracy and safety of the treatment.

[0059] S8 Abnormal Handling: During dynamic monitoring, the system also sets safety thresholds to identify serious abnormalities and promptly halt treatment. For example, if the graphene temperature sensing layer detects an abnormal increase in the patient's surface temperature exceeding a preset upper limit (e.g., 38.5°C), this may indicate a fever or other emergency; or pressure / acceleration data may indicate a sudden and drastic change in the patient's position (displacement exceeding 1.5 mm). When any of the above temperature or positional abnormalities reaches the preset safety threshold, the system will immediately issue a warning signal (audio alarm or interface highlight) and automatically trigger a treatment pause signal. Upon receiving the pause signal, the linear accelerator will quickly stop the X-ray beam output and enter standby mode. Medical personnel should then promptly enter the treatment room to check the patient's condition and take necessary measures (such as comforting the patient, repositioning or adjusting the patient's position, addressing any physiological discomfort). Once the cause of the abnormality is eliminated and the patient's condition returns to normal, the treatment process can resume. This safety interlock design of the present invention ensures that radiotherapy can be quickly and safely stopped when the patient experiences an unexpected condition, avoiding incorrect irradiation or personal injury.

[0060] In summary, this multifunctional radiotherapy positioning system and method, through the organic integration of a multifunctional radiotherapy fixation plate, a positioning laser lamp detector, sensors, and control algorithms, achieves a high degree of automation and intelligence in all stages of radiotherapy, from preparation to execution. During the morning check-up, the system quickly verifies isocenter and laser positioning accuracy, providing a basis for adjustments. In the treatment preparation stage, the preheating and monitoring functions of the multifunctional radiotherapy fixation plate enhance patient comfort and safety. During treatment, real-time monitoring of body position and surface temperature, along with dynamic calibration, ensures that the beam is always precisely aligned with the target area, and even minor patient movements can be corrected promptly. Statistical analysis shows that this system reduces daily morning check-up time to less than 3 minutes and improves patient comfort scores by approximately 32%.

[0061] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multifunctional radiotherapy positioning system, characterized in that, It includes a multifunctional radiotherapy fixation base plate, a positioning frame set on the multifunctional radiotherapy fixation base plate, a positioning laser lamp detector installed on the positioning frame, a dynamic positioning calibration module, a non-contact monitoring module, and an intelligent temperature control heating system; The multifunctional radiotherapy fixation base plate is used for installation on the linear accelerator treatment bed; The multifunctional radiotherapy fixation base plate includes, from top to bottom, a photochromic layer, a pressure sensor matrix layer, a thermosensitive layer, a heating layer, an upper carbon fiber skin layer, a foam layer, and a lower carbon fiber skin layer. The positioning laser lamp detector includes a main body, crosshair marks on the surface of the main body, a laser sensor that works in conjunction with the crosshair marks, and metal markers distributed equicenterly inside the main body. The laser sensor detects the alignment deviation of the laser line formed by the positioning laser lamp relative to the crosshair marks and outputs a detection signal. The metal markers form identifiable marks in IGRT or CBCT images. The non-contact monitoring module includes a flexible graphene temperature sensing layer and a multi-parameter fusion algorithm unit electrically connected to the flexible graphene temperature sensing layer. The flexible graphene temperature sensing layer covers a multifunctional radiotherapy fixation base plate and is used to acquire patient surface temperature data. The multi-parameter fusion algorithm unit evaluates the patient surface temperature data, outputs a warning signal when an abnormal temperature is detected, and outputs a treatment pause signal when the abnormal temperature reaches a preset safety threshold. The dynamic positioning calibration module includes a pressure sensor matrix, an accelerometer, an inertial measurement unit, and an FPGA control unit. The pressure sensor matrix is ​​embedded in the pressure sensor matrix layer and is used to collect pressure distribution data changes of the patient's body position to detect patient positional deviations. The inertial measurement unit is fixed to the patient's body surface or the linear accelerator treatment bed and is used to collect three-dimensional acceleration data and angular velocity data of the patient's body position to output attitude data characterizing changes in body posture. The accelerometer is used to collect acceleration change data of the patient's body position and output displacement-related data. The corresponding terminals of the FPGA control unit are electrically connected to the corresponding terminals of the pressure sensor, accelerometer, and inertial measurement unit to receive pressure distribution data, displacement-related data, and attitude data and generate dynamic correction commands. The intelligent temperature control heating system is electrically connected to the heating layer and is used to adjust the temperature of the multifunctional radiotherapy fixation base plate and maintain it within a preset temperature range.

2. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The positioning frame includes a positioning plate, an electronic level mounted on the positioning plate, and a positioning post mounted at the bottom of the positioning plate. The electronic level is adjustable and mounted on the positioning plate via a fine-tuning screw, and the positioning laser light detector is located on the leveling reference of the electronic level. The multifunctional radiotherapy fixation base plate has positioning holes that are compatible with the positioning columns.

3. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The positioning laser light detector also includes a data acquisition unit and a wireless communication module disposed inside the main body of the positioning laser light detector. The corresponding ends of the data acquisition unit are electrically connected to the corresponding ends of the laser sensor. The data acquisition unit is used to acquire the detection signal of the laser sensor and output laser deviation data. The corresponding ends of the data acquisition unit are also electrically connected to the wireless communication module. The wireless communication module is used to send the laser deviation data to an external terminal. The external terminal includes at least one of an HIS system and a TPS system.

4. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The FPGA control unit communicates with the linear accelerator's control system via the EtherCAT protocol to send dynamic correction commands to the linear accelerator, driving it to perform positioning compensation and adjust the beam direction.

5. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The photochromic material comprises rare earth-doped organic compounds, which develop color after being irradiated with X-rays and heated to 50-80℃, with a color contrast ≥90%. The temperature-sensitive layer is coated with a polyurethane coating containing temperature-sensitive pigments, and its color changes from purple to green when the temperature reaches the standard. The heating layer is made of epoxy resin with carbon nanotube conductive filler, and the heating temperature control range is 30-42℃. The thickness of the upper carbon fiber skin layer is 1.5 mm, and the tensile strength is ≥3500 MPa. The foam layer is made of polyurethane closed-cell foam with a density of 40 kg / m³. The thickness of the lower carbon fiber skin layer is 1.0 mm.

6. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The flexible graphene temperature sensing layer includes a thermopile sensor array for acquiring the body surface temperature data, and the thermopile sensor array includes 64 channels.

7. The multifunctional radiotherapy positioning system according to claim 1, characterized in that, The intelligent temperature control heating system includes a PID temperature control module and a safety protection unit. The control output terminal of the PID temperature control module is electrically connected to the heating layer via the safety protection unit, and the temperature acquisition terminal of the PID temperature control module is electrically connected to the temperature-sensitive layer to adjust the heating power of the heating layer according to the temperature feedback. The safety protection unit is used to cut off the power supply to the heating layer when an over-temperature abnormality is detected.

8. A multifunctional radiotherapy positioning method, characterized in that, The system is applied to a multifunctional radiotherapy positioning system and includes the following steps: S1, Installation and fixation of the multifunctional radiotherapy fixation base plate: The multifunctional radiotherapy fixation base plate is placed on the treatment bed of the linear accelerator and fixed; S2, Isocenter alignment: The electronic level on the positioning frame is adjusted to the zero position, and the position of the positioning laser lamp detector is adjusted by the fine-tuning screws to align the positioning laser lamp detector with the isocenter of the linear accelerator; S3, Morning inspection: The positioning laser lamp detector is activated, and the laser sensor is used to detect the alignment deviation of the laser line formed by the positioning laser lamp relative to the crosshair mark and output the deviation detection signal. The data acquisition unit collects and processes the deviation detection signal to output laser deviation data; At the same time, CBCT images are acquired, the position of the metal marker points in the CBCT images is identified, and the isocenter offset is calculated to obtain isocenter deviation data; S4, Data transmission and report generation: The laser deviation data and isocenter deviation data are wirelessly transmitted to an external terminal, and a detection report is generated. The detection report includes at least the isocenter deviation parameter and the laser lamp angle error parameter; S5, Treatment preparation: According to According to the test report, the treatment parameters of the linear accelerator are adjusted, and the intelligent temperature control heating system is activated to heat the heating layer of the multifunctional radiotherapy fixation plate, so that the multifunctional radiotherapy fixation plate reaches the preset temperature range; S6, Dynamic monitoring of the treatment process: During radiotherapy, the pressure distribution data changes of the patient's position are collected in real time through the pressure sensor matrix, the three-dimensional acceleration data and angular velocity data of the patient's position are collected through the inertial measurement unit to output attitude data, and the acceleration change data of the patient's position is collected through the accelerometer to output displacement-related data; S7, Dynamic calibration: When the patient's position deviation or attitude change is detected to exceed the preset threshold, the FPGA control unit fuses the pressure distribution data, attitude data and displacement-related data and generates a dynamic correction command, which is sent to the linear accelerator control system to drive the linear accelerator to perform positioning compensation and adjust the beam direction; S8, Abnormal handling: When the temperature abnormality or position abnormality is detected to reach the preset safety threshold, the safety protection unit outputs a warning signal and triggers a treatment pause signal.

9. The multifunctional radiotherapy positioning method according to claim 8, characterized in that, In step S3, the metal marker is a titanium alloy marker, which appears as a high-density shadow in the CBCT image. The algorithm extracts the center coordinates of the marker by image segmentation and compares the actual position coordinates with the theoretical position coordinates to calculate the offset Δd. The offset Δd satisfies: Δd=√((xactual-xtheoretical)²+(yactual-ytheoretical)²).

10. The multifunctional radiotherapy positioning method according to claim 8, characterized in that, In step S5, the intelligent temperature control heating system uses a PID control algorithm to adjust the heating power of the heating layer, so that the temperature of the multifunctional radiotherapy fixation base plate is maintained at 37±0.5℃, and the temperature reaches the target by changing the color of the temperature-sensitive layer from purple to green. The intelligent temperature control heating system includes an initial heating stage, a steady-state temperature control stage, and a cooling stage. In the initial heating stage, the heating layer is driven to heat up to 35°C at maximum power. In the steady-state temperature control stage, the heating power is dynamically adjusted through a PID algorithm to keep the temperature stable. In the cooling stage, the heating is turned off and the fan is activated for heat dissipation. In step S7, when the accelerometer detects that the Z-axis displacement reaches 0.3 mm or the pressure sensor matrix detects that the pressure distribution has changed by a preset value, the FPGA control unit generates the dynamic correction command within 5 ms, and drives the positioning motor used to adjust the angle of the positioning laser lamp according to the dynamic correction command to adjust the angle error of the positioning laser lamp. The single adjustment angle Δθ is 0.02°, and the direction of the linear accelerator beam is corrected simultaneously.

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