System and method for dynamic verification of radiotherapy plan

Abstract

The invention provides a system and a method for dynamic verification of radiotherapy plans, and the system comprises a three-dimensional electric platform, a three-dimensional electric reference mark support, a control unit and a software control module, and the three-dimensional electric platform is provided with a universal clamp which is used for bearing and fixing a dose measurement device. The three-dimensional electric reference mark support is independently installed on one side of the three-dimensional electric platform and used for fixing a reference mark visible to X rays, and the control unit is electrically connected with the three-dimensional electric platform and the three-dimensional electric reference mark support and used for controlling the reference mark according to the mode selected by the software control module and a motion trail instruction sent by the software control module. The software control module is used for driving the three-dimensional electric platform and the three-dimensional electric reference mark bracket to move independently or cooperatively, and comprises a motion management module for generating a motion track instruction, a mode control module for providing switching of a dose verification mode and a system performance test mode, and a dose analysis module for analyzing by adopting a Gamma algorithm. The real physiological movement of the patient can be simulated, the composite error is separated, and the adaptability is high.

Description

Technical Field

[0001] This invention relates to the field of radiotherapy technology, and more specifically to a system and method for dynamic verification of radiotherapy plans. Background Technology

[0002] Radiation therapy is one of the core methods of cancer treatment. Its core objective is to precisely deliver radiation doses to the tumor target area while maximizing the protection of surrounding healthy tissues. For tumors in the chest, abdomen, and other areas affected by respiratory movement, image-guided radiotherapy and real-time tracking technologies (such as Accuray's Synchrony® system) have been widely used in clinical practice to compensate for dose deviations caused by target displacement.

[0003] However, the dose verification process before radiotherapy planning still faces many bottlenecks. In the existing technology, the respiratory motion platform provided by Chinese invention patent application number CN201610553058.8 can only achieve two-dimensional vertical and horizontal motion, lacking three-dimensional motion simulation capabilities and a corresponding software analysis module, thus failing to complete dose closed-loop verification. The dynamic optimization system proposed by Chinese invention patent application number CN202110209202.7 focuses only on software algorithms, lacking a corresponding hardware execution platform, making it impossible to verify the optimization results in real motion scenarios. The dynamic verification method provided by Chinese invention patent application number CN202510953131.X relies on single-film measurement, with a fixed verification mode, and cannot separate dose error from equipment tracking error.

[0004] Furthermore, the static validation methods widely used in the industry, which involve placing the dosimeter or phantom statically for irradiation, completely ignore the actual impact of the patient's physiological movements, such as respiration, on dose distribution. During dynamic treatment, the radiation beam, target area, and organs are all in dynamic change, and static validation results cannot accurately reflect the dose deposition during treatment, potentially leading to misjudgments of the safety and effectiveness of the treatment plan. At the same time, existing dynamic validation equipment generally has poor compatibility, making it difficult to integrate with various dose measurement tools and radiotherapy equipment, increasing the cost of clinical application.

[0005] Therefore, there is an urgent need in this field for a dynamic verification technology that can simulate the real physiological movements of patients, separate complex errors, coordinate hardware and software, and is highly adaptable, in order to solve the above-mentioned deficiencies. Summary of the Invention

[0006] To address the technical problems in existing dose verification processes before radiotherapy planning, such as the inability to simulate real patient physiological movements, the inability to separate dose errors from equipment tracking errors, and the lack of coordination and compatibility between hardware and software, this invention provides a system and method for dynamic verification of radiotherapy plans. This system can not only accurately simulate real patient physiological movements to verify the accuracy of dynamic dose distribution, but also be specifically used to evaluate the performance accuracy of the respiratory motion management subsystem of radiotherapy equipment, achieving precise error localization and providing comprehensive and reliable quality control assurance for clinical radiotherapy.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A system for dynamic verification of radiotherapy plans includes a three-dimensional motorized platform, a three-dimensional motorized reference marker support, a control unit, and a software control module;

[0009] The three-dimensional electric platform is used to simulate the complete three-dimensional motion trajectory of the tumor target area and has a repeatability accuracy better than 1 mm. The three-dimensional electric platform is equipped with a universal clamp, which is used to support and fix at least one dose measurement device.

[0010] The three-dimensional electric reference marker bracket is installed on one side of the three-dimensional electric platform and is independent of the three-dimensional electric platform. The three-dimensional electric reference marker bracket is used to fix the X-ray visible reference marker to simulate the independent movement of the marker point in the body.

[0011] The control unit is electrically connected to the three-dimensional electric platform and the three-dimensional electric reference mark support, and is used to drive the three-dimensional electric platform and the three-dimensional electric reference mark support to move independently or collaboratively according to the mode selected by the software control module and the motion trajectory command sent.

[0012] The software control module runs on a computer device and includes a motion management module, a mode control module, and a dose analysis module. The motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images or support user-defined motion parameters to generate motion trajectory instructions. The mode control module provides switching between two predefined working modes: dose verification mode and system performance test mode. In dose verification mode, the three-dimensional electric platform is driven to move along the trajectory while the three-dimensional electric reference marker support remains stationary. In system performance test mode, the three-dimensional electric reference marker support is driven to move along the trajectory while the three-dimensional electric platform remains stationary. The dose analysis module integrates a pencil beam dose calculation algorithm to predict the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions. It receives the measured dose data from the dose measurement device, uses a Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, and automatically generates a visual verification report including Gamma pass rate, dose deviation distribution histogram, and position deviation distribution histogram.

[0013] Furthermore, the reference marker is a metal sphere.

[0014] Furthermore, the motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images to generate motion trajectory instructions, including:

[0015] (1) Respiratory phase division and image preprocessing

[0016] Input: Patient's 4D-CT image sequence, which typically contains 10 respiratory phases, corresponding to 0%-90% of the respiratory cycle, with one phase taken at 10% intervals;

[0017] Preprocessing: Gaussian filtering was used to remove noise from CT images, and the lung parenchyma region was segmented using the HU value thresholding method to exclude interference from non-target tissues, including bone and air.

[0018] Phase-time normalization: Let the total duration of the respiratory cycle be... , No. The time percentage of each phase is:

[0019]

[0020] in, For the first The duration of each phase satisfies ;

[0021] (2) Automatic extraction of target center coordinates

[0022] The Demons deformation registration algorithm was used to register the 0% temporal CT images with the other nine temporal CT images, obtaining the deformation field for each temporal phase. , Physical coordinates of the CT image;

[0023] The tumor target region at the reference time phase is delineated manually or automatically, and the coordinates of the target center are calculated. ;

[0024] According to the deformation field Calculate the first Target center coordinates at each time phase ;

[0025] Ten time phases Arranged in chronological order, sampling points are supplemented using cubic Hermite interpolation to obtain continuous three-dimensional motion trajectories:

[0026]

[0027] in, It is a time variable; , , These are the interpolation coefficients;

[0028] The coordinate data of the three-dimensional motion trajectory are stored in a CSV file in chronological order to generate a four-dimensional time-position sequence file. The time-position sequence file is then converted and encoded to obtain the motion trajectory instructions.

[0029] Furthermore, the dose analysis module predicts the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions, including:

[0030] (1) Calculation of static dose contribution matrix

[0031] Input: Beam parameters exported from the radiotherapy planning system, phantom / patient CT density map, wherein the beam parameters include beam energy, angle, collimator position, subfield shape and weight;

[0032] The dose contribution matrix under static conditions is calculated using the pencil-beam convolution algorithm. ,in Numbering Ziye, total Wild-looking; Number the grid points for dose calculation; Indicates the first The individual against the first The static dose contribution of each grid point;

[0033] (2) Dynamic dose contribution correction

[0034] Based on motion trajectory Calculate each time step Grid point position offset That is, the displacement of the target area / phantom at that time step;

[0035] For each subfield Correct its time step Dose contribution:

[0036]

[0037] in, Number the offset grid points, by original coordinates minus This is obtained through bilinear interpolation. ; As time step weights, Consistent with the sampling frequency of the motion trajectory ensures that the total dose is equivalent to the static plan;

[0038] (3) Dynamic dose superposition and fuzzy effect correction

[0039] By summing the dose contributions of all subfields at all time steps, the dynamic expected dose distribution is obtained:

[0040]

[0041] Correcting motion-induced dose ambiguity: using Gaussian convolution kernels The convolution process is performed using the following formula:

[0042]

[0043] in, It is a three-dimensional high-period function. is the standard deviation in the Gaussian convolution kernel.

[0044] Furthermore, the dose analysis module uses a Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, including:

[0045] (1) Data preprocessing and registration

[0046] Input: Measured dose map exported from the dose measurement device and the calculated dynamic expected dose map ;

[0047] Mesh unification: Using nearest neighbor interpolation method to unify the mesh. and Convert to the same resolution;

[0048] Spatial registration: Using the motion trajectory of the three-dimensional electric platform as a reference, the positional deviation of the measured dose map is corrected to ensure that the spatial coordinates of the two are aligned;

[0049] (2) Calculation of Gamma value

[0050] For each grid point Calculate two core difference metrics:

[0051] Dose difference :

[0052] Location differences :

[0053]

[0054] The consistency index of each grid point is calculated using the three-dimensional Gamma formula:

[0055]

[0056] in, This serves as a reference threshold for dose difference. This is a reference threshold for location differences.

[0057] Furthermore, the pass / fail criterion for the Gamma analysis algorithm is a Gamma pass rate ≥ 95%. ≤1, valid grid points are defined as ≥5% , This represents the maximum expected dose; when the Gamma pass rate is below 95%, it is automatically flagged. The high deviation area is identified, and a deviation heatmap is output.

[0058] The present invention also provides a method for dynamic verification of radiotherapy plans, wherein the method employs the aforementioned system for dynamic verification of radiotherapy plans, and the method includes the following steps:

[0059] S1. Acquire 4D-CT images of the target patient, and generate motion trajectory instructions by extracting or customizing motion parameters through the motion management module;

[0060] S2. Select either the dose verification mode or the system performance test mode based on the verification requirements;

[0061] S3. The radiotherapy equipment starts irradiation. The control unit drives the three-dimensional electric platform and / or the three-dimensional electric reference marker support to perform synchronous movement according to the selected mode and the motion trajectory command.

[0062] S4. The dose measurement device records the measured dose data in real time and transmits it to the dose analysis module in the software control module;

[0063] S5. The dose analysis module compares the measured dose data with the predicted dynamic expected dose distribution using Gamma analysis, and generates a visual verification report including Gamma pass rate and dose deviation distribution histogram, thus completing the verification.

[0064] Compared with the prior art, the system and method for dynamic verification of radiotherapy plans provided by the present invention have the following beneficial effects:

[0065] 1. Precise error separation facilitates quality control and investigation: Through the system performance test mode, using the static platform as the gold standard for dose measurement, the verification deviation can be directly attributed to the tracking, algorithm, or execution error of the radiotherapy equipment itself, solving the industry pain point that existing technologies cannot locate the source of error.

[0066] 2. Full-scenario coverage and comprehensive functions: One system simultaneously meets the two core quality control requirements of dynamic dose verification and equipment performance testing, without the need for additional configuration of multiple devices, reducing the equipment investment and operational complexity of clinical quality control.

[0067] 3. High versatility and wide adaptability: Through universal fixtures and modular design, it can be compatible with a variety of dose measurement devices and radiotherapy equipment, and adapt to the radiotherapy verification needs of different diseases such as lung cancer and abdominal tumors. Its adaptability far exceeds that of existing single-function equipment.

[0068] 4. Verification results are authentic and reliable: Based on the patient's 4D-CT images, personalized motion trajectories are extracted to accurately reproduce the three-dimensional motion of the tumor. The verification process closely matches clinical practice and avoids the distortion of results caused by static verification and simplified motion simulation.

[0069] 5. High degree of automation, improving work efficiency: The software and hardware work together to automate the entire process from trajectory generation to report output, reducing manual intervention, reducing operational errors, and shortening the verification cycle to meet the needs of clinical batch radiotherapy plan verification. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the hardware execution layer structure in the system for dynamic verification of radiotherapy plans provided by the present invention.

[0071] Figure 2 This is a schematic diagram of the dose verification mode provided by the present invention.

[0072] Figure 3 This is a schematic diagram of the system performance testing mode provided by the present invention.

[0073] Figure 4 This is a schematic diagram of the software control and data analysis process provided by the present invention. Detailed Implementation

[0074] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0075] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0076] Please refer to Figures 1 to 4 As shown, the present invention provides a system for dynamic verification of radiotherapy plans, including a three-dimensional electric platform, a three-dimensional electric reference marker support, a control unit, and a software control module;

[0077] The three-dimensional electric platform is used to simulate the complete three-dimensional motion trajectory of the tumor target area with a repeatability accuracy better than 1 mm. The three-dimensional electric platform is built based on the existing high-precision open-source XYZ positioning system and is equipped with a stepper motor drive. The specific structural composition of the three-dimensional electric platform is well known to those skilled in the art. The three-dimensional electric platform is equipped with a universal fixture for supporting and fixing at least one dose measurement device. The dose measurement device can be implemented using various existing dose measurement devices such as ionization chambers, films, OSL dosimeters, and ArcCheck phantoms.

[0078] The three-dimensional electric reference marker bracket is installed on one side of the three-dimensional electric platform and is independent of the three-dimensional electric platform. The three-dimensional electric reference marker bracket is used to fix the reference marker visible to X-rays to simulate the independent movement of the marker point in the body and provide a dedicated marker source for equipment performance testing.

[0079] The control unit has a built-in microprocessor and is electrically connected to the three-dimensional electric platform and the three-dimensional electric reference mark support. The control unit is used to drive the three-dimensional electric platform and the three-dimensional electric reference mark support to move independently or in concert according to the mode selected by the software control module and the motion trajectory command sent, with control accuracy down to the micrometer level.

[0080] The software control module runs on a computer device and includes a motion management module, a mode control module, and a dose analysis module. The motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images or support user-defined motion parameters to generate motion trajectory instructions. The trajectory sampling frequency is not less than 10Hz to ensure the continuity of motion simulation. The mode control module is used to provide switching between two predefined working modes: dose verification mode and system performance test mode. In dose verification mode, the three-dimensional electric platform is driven to move along the trajectory while the three-dimensional electric reference marker support remains stationary. In system performance test mode, the three-dimensional electric reference marker support is driven to move along the trajectory while the three-dimensional electric platform remains stationary. The dose analysis module integrates a pencil beam dose calculation algorithm to predict the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions. It receives the measured dose data from the dose measurement device, uses a Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, and automatically generates a visual verification report including Gamma pass rate, dose deviation distribution histogram, and position deviation distribution histogram.

[0081] In a specific implementation, the reference marker is a metal ball, specifically a tungsten alloy metal ball with a diameter of 2mm, which can effectively simulate the independent movement of the marked point in the body.

[0082] The core algorithms of this system include motion trajectory generation algorithm, dynamic dose prediction algorithm and Gamma analysis algorithm. The three work together to achieve a closed loop of "motion simulation-dose prediction-result verification". The algorithm design strictly follows the radiotherapy quality control industry standards (such as AAPM TG218 and TG226 reports). The specific technical details are as follows.

[0083] In a specific implementation, the motion trajectory generation algorithm is used to accurately extract the tumor motion trajectory from the patient's 4D-CT images, or supports user-defined motion parameters. The core objective is to reproduce the three-dimensional dynamic displacement of the tumor during human respiration. Specifically, the motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images to generate motion trajectory instructions, including:

[0084] (1) Respiratory phase division and image preprocessing

[0085] Input: Patient's 4D-CT image sequence, which typically contains 10 respiratory phases, corresponding to 0%-90% of the respiratory cycle, with one phase taken at 10% intervals;

[0086] Preprocessing: Gaussian filtering is used ( ) Remove noise from CT images and segment the lung parenchyma region using the HU value threshold method (-200~2000HU) to exclude interference from non-target tissues such as bone and air;

[0087] Phase-time normalization: Let the total duration of the respiratory cycle be... (Clinical routine value is 3-5 seconds), the first Each phase ( The time allocation for ) is as follows:

[0088]

[0089] in, For the first The duration of each phase satisfies ;

[0090] (2) Automatic extraction of target center coordinates

[0091] The Demons deformation registration algorithm (a non-rigid registration based on B-spline interpolation) was used to register the CT images of the remaining nine time phases, with the 0% phase (end-tidal) as the reference image, to obtain the deformation field of each phase. , Physical coordinates of the CT image (unit: mm);

[0092] Manually or automatically delineate the tumor target volume (GTV / CTV) at the reference time phase and calculate the target center coordinates. ;

[0093] According to the deformation field Calculate the first Target center coordinates at each time phase ;

[0094] Ten time phases Arranged in chronological order, sampling points were supplemented using cubic Hermite interpolation (sampling frequency 10Hz, i.e., one point every 100ms) to obtain a continuous three-dimensional motion trajectory:

[0095]

[0096] in, It is a time variable; , , These are the interpolation coefficients, derived from adjacent time phases. It is obtained by fitting the motion velocity (calculated by the time phase coordinate difference / time difference);

[0097] The coordinate data of the three-dimensional motion trajectory are combined into four-dimensional data points according to the timestamp and three-dimensional coordinates and arranged in chronological order. The data points are stored in a CSV file to obtain a four-dimensional time-position sequence file. The time-position sequence file is then subjected to data conversion and control encoding (including spatial registration, kinematic constraint processing and control protocol encapsulation) to obtain motion trajectory instructions. The motion trajectory instructions are loaded into the motion management module of the software control module during implementation and verification.

[0098] As a specific implementation, the motion management module is used to support user-defined motion parameters to generate motion trajectory instructions, including:

[0099] User inputs motion parameters (including respiratory rate) xyz direction motion amplitude , , (Motion waveform types) generate standardized trajectories. Commonly used motion waveforms include:

[0100] Sine wave (simulating regular breathing):

[0101] in, Let x be the initial bias in the x-direction. The formula is the same;

[0102] Multi-degree-of-freedom combined wave (simulating irregular breathing, superimposing second harmonics to simulate breathing irregularity): ;

[0103] Parameter range limitation: respiratory rate Breaths / minute (covering the adult's resting to exercise respiratory rate), range of motion mm (covering the range of tumor motion in 95% of clinical patients).

[0104] In a specific implementation, the dynamic dose prediction algorithm predicts the dose distribution of the target area and organs at risk (OAR) under dynamic conditions based on treatment plan data and motion trajectory. Its core function is to address the problem of "dose deposition position shift caused by motion." Specifically, the dose analysis module predicts the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions, including:

[0105] (1) Calculation of static dose contribution matrix

[0106] Input: Beam parameters exported from the radiotherapy planning system (TPS), phantom / patient CT density map, wherein the beam parameters include beam energy, angle, collimator position, subfield shape and weight;

[0107] The dose contribution matrix under static conditions (far motion) was calculated using the pencil-beam convolution (PBC) algorithm. ,in Numbering Ziye, total Wild-looking; Number the grid points for dose calculation (the default grid size is 2mm×2mm×2mm, but can be customized); Indicates the first The individual against the first Static dose contribution of each grid point (in Gy);

[0108] (2) Dynamic dose contribution correction

[0109] Based on motion trajectory Calculate each time step Grid point position offset That is, the displacement of the target area / phantom at that time step;

[0110] For each subfield Correct its time step Dose contribution:

[0111]

[0112] in, Number the offset grid points, by original coordinates minus This is obtained through bilinear interpolation. ; As time step weights, Consistent with the sampling frequency of the motion trajectory ensures that the total dose is equivalent to the static plan;

[0113] (3) Dynamic dose superposition and fuzzy effect correction

[0114] By summing the dose contributions of all subfields at all time steps, the dynamic expected dose distribution is obtained:

[0115]

[0116] Correcting dose ambiguity caused by motion: Because the radiation beam has a certain width (e.g., millimeters), dose diffusion occurs during motion. Gaussian convolution kernels are used to correct this. The convolution process is performed using the following formula:

[0117]

[0118] in, It is a three-dimensional high-period function. Set the standard deviation in the Gaussian convolution kernel. Matching clinical beam half-height.

[0119] In a specific implementation, the Gamma analysis algorithm is used to compare the "dynamic expected dose distribution" with the "measured dose data" to evaluate the consistency between dose and location. Specifically, the dose analysis module uses the Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, which includes:

[0120] (1) Data preprocessing and registration

[0121] Input: Measured dose map exported from a dose measurement device (such as ArcCheck) and the calculated dynamic expected dose map ;

[0122] Mesh unification: Using nearest neighbor interpolation method to unify the mesh. and Convert to the same resolution (default is 2mm×2mm×2mm);

[0123] Spatial registration: Using the motion trajectory of the three-dimensional electric platform as a reference, correct the positional deviation of the measured dose map (such as displacement caused by platform motion delay) to ensure that the spatial coordinates of the two are aligned;

[0124] (2) Calculation of Gamma value

[0125] For each grid point Calculate two core difference metrics:

[0126] Dose difference : (Relative dose difference, in %)

[0127] Location differences :

[0128] (3D distance deviation, unit mm);

[0129] The consistency index of each grid point is calculated using the three-dimensional Gamma formula:

[0130]

[0131] in, The reference threshold for dose difference is set (default 3%, customizable from 2% to 5%). The reference threshold for positional differences is 3mm by default, and can be customized from 2 to 5mm.

[0132] As a specific implementation method, the pass / fail criterion for the Gamma analysis algorithm is a Gamma pass rate ≥ 95%. ≤1, valid grid points are defined as ≥5% , This represents the maximum expected dose; when the Gamma pass rate is below 95%, it is automatically flagged. The high deviation area is identified, and a deviation heatmap is output.

[0133] As a specific implementation method, the Gamma pass rate statistics are as follows: Calculation The proportion of grid points with a value ≤1 to the total number of valid grid points (a valid grid point is defined as...). ≥5% , (This represents the expected maximum dose, excluding interference from low-dose regions).

[0134] As a specific implementation, the visualization verification report includes Gamma pass rate, dose deviation distribution histogram, position deviation distribution histogram, three-dimensional coordinates and deviation values ​​of high deviation areas, and supports exporting DICOM format reports for clinical archiving.

[0135] The present invention also provides a method for dynamic verification of radiotherapy plans, wherein the method employs the aforementioned system for dynamic verification of radiotherapy plans, and the method includes the following steps:

[0136] S1. Obtain physiological motion information such as 4D-CT images of the target patient, and generate motion trajectory instructions by extracting or customizing motion parameters through the motion management module;

[0137] S2. Select either dose verification mode or system performance test mode based on verification requirements. Dose verification mode is used to evaluate the accuracy of radiotherapy plan dose, while system performance test mode is used to test the tracking accuracy of equipment.

[0138] S3. The radiotherapy equipment starts irradiation. The control unit drives the three-dimensional electric platform and / or the three-dimensional electric reference marker support to perform synchronous movement according to the selected mode and the motion trajectory command.

[0139] S4. The dose measurement device records the measured dose data in real time and transmits it to the dose analysis module in the software control module;

[0140] S5. The dose analysis module compares the measured dose data with the predicted dynamic expected dose distribution using Gamma analysis, and generates a visual verification report including Gamma pass rate and dose deviation distribution histogram, thus completing the verification.

[0141] For other specific limitations regarding the methods used for dynamic validation of radiotherapy plans, please refer to the description of the system used for dynamic validation of radiotherapy plans above, which will not be repeated here.

[0142] Therefore, those skilled in the art should understand that each functional module in the above-mentioned system for dynamic verification of radiotherapy plans can be implemented in whole or in part through software, hardware, or a combination thereof, and each of the above-mentioned functional modules can be embedded in the processor of the computer device in hardware form or independent of the processor, or stored in the memory of the computer device in software form, so that the processor can call and execute the operations corresponding to each of the above modules.

[0143] To better understand the system and method for dynamic verification of radiotherapy plans provided by this invention, preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. This embodiment uses radiotherapy verification for lung cancer patients as an example, employing an ArcCheck phantom as the dose measurement device and a linear accelerator equipped with a Synchrony® system as the radiotherapy equipment. The specific implementation steps are as follows:

[0144] 1) Device connection

[0145] Figure 1 As shown, a three-dimensional electric platform (driven by a stepper motor of model XY-Stage-8080 with a repeatability of ±0.5mm) is placed on the treatment bed of the radiotherapy equipment, and the ArcCheck phantom is fixed by a universal clamp; a three-dimensional electric reference mark bracket is installed on one side of the three-dimensional electric platform, and a tungsten alloy metal ball with a diameter of 2mm is fixed as a reference mark; the control unit is electrically connected to the three-dimensional electric platform and the three-dimensional electric reference mark bracket through an RS485 interface, and establishes communication with the computer software control module.

[0146] 2) Motion trajectory command generation

[0147] Import the 4D-CT image data of lung cancer patients into the motion control module. The motion management module automatically extracts the three-dimensional motion trajectory of the tumor during the inspiratory-expiratory cycle, generates a time-position sequence file to obtain the motion trajectory instructions, and sets the trajectory parameters as follows: motion range vertically 30mm, horizontally 15mm, and anteriorly 12mm, respiratory rate 12 breaths / minute. If the patient is undergoing respiratory gating therapy, the motion range can also be set according to the respiratory interval at the actual dose output.

[0148] 3) Dosage validation mode

[0149] In the selected dose verification mode, the software control module sends motion trajectory commands to the control unit, driving the three-dimensional motorized platform to move synchronously along the trajectory, while the three-dimensional motorized reference marker support remains stationary. The radiotherapy equipment is started, and irradiation is performed according to the preset treatment plan. The ArcCheck phantom moves with the platform and records dose data in real time. After irradiation, the dose analysis module calls the Gamma analysis algorithm (using the 3% / 3mm standard) to compare the measured dose data with the dynamic expected dose distribution, generating a verification report. If the Gamma pass rate is ≥95%, the radiotherapy plan dose verification is deemed successful.

[0150] 4) System performance testing

[0151] The selected system performance test mode is implemented. The control unit drives the three-dimensional motorized reference marker support to move along the same trajectory, while the three-dimensional motorized platform and ArcCheck phantom remain stationary. The radiotherapy equipment is started, and its Synchrony® system tracks the moving metal reference point and adjusts the beam direction. After irradiation, the dose analysis module analyzes the measured dose data. If the gamma pass rate is less than 95%, the tracking system of the radiotherapy equipment is deemed to have an error, requiring calibration of the equipment algorithm or mechanical precision.

[0152] 5) Measurement report output

[0153] The software control module automatically generates a comprehensive report containing information such as Gamma pass rate, dose deviation distribution histogram, position deviation distribution histogram, and error curves for both modes. Clinicians can use the report results to optimize radiotherapy plans and calibrate equipment, ensuring treatment safety and effectiveness.

[0154] Compared with the prior art, the system and method for dynamic verification of radiotherapy plans provided by the present invention have the following beneficial effects:

[0155] 1. Precise error separation facilitates quality control and investigation: Through the system performance test mode, using the static platform as the gold standard for dose measurement, the verification deviation can be directly attributed to the tracking, algorithm, or execution error of the radiotherapy equipment itself, solving the industry pain point that existing technologies cannot locate the source of error.

[0156] 2. Full-scenario coverage and comprehensive functions: One system simultaneously meets the two core quality control requirements of dynamic dose verification and equipment performance testing, without the need for additional configuration of multiple devices, reducing the equipment investment and operational complexity of clinical quality control.

[0157] 3. High versatility and wide adaptability: Through universal fixtures and modular design, it can be compatible with a variety of dose measurement devices and radiotherapy equipment, and adapt to the radiotherapy verification needs of different diseases such as lung cancer and abdominal tumors. Its adaptability far exceeds that of existing single-function equipment.

[0158] 4. Verification results are authentic and reliable: Based on the patient's 4D-CT images, personalized motion trajectories are extracted to accurately reproduce the three-dimensional motion of the tumor. The verification process closely matches clinical practice and avoids the distortion of results caused by static verification and simplified motion simulation.

[0159] 5. High degree of automation, improving work efficiency: The software and hardware work together to automate the entire process from trajectory generation to report output, reducing manual intervention, reducing operational errors, and shortening the verification cycle to meet the needs of clinical batch radiotherapy plan verification.

[0160] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A system for dynamic verification of radiotherapy plans, characterized in that, Includes a three-dimensional electric platform, a three-dimensional electric reference mark bracket, a control unit, and a software control module; The three-dimensional electric platform is used to simulate the complete three-dimensional motion trajectory of the tumor target area and has a repeatability accuracy better than 1 mm. The three-dimensional electric platform is equipped with a universal clamp, which is used to support and fix at least one dose measurement device. The three-dimensional electric reference marker bracket is installed on one side of the three-dimensional electric platform and is independent of the three-dimensional electric platform. The three-dimensional electric reference marker bracket is used to fix the X-ray visible reference marker to simulate the independent movement of the marker point in the body. The control unit is electrically connected to the three-dimensional electric platform and the three-dimensional electric reference mark support, and is used to drive the three-dimensional electric platform and the three-dimensional electric reference mark support to move independently or collaboratively according to the mode selected by the software control module and the motion trajectory command sent. The software control module runs on a computer device and includes a motion management module, a mode control module, and a dose analysis module. The motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images or support user-defined motion parameters to generate motion trajectory instructions. The mode control module provides switching between two predefined working modes: dose verification mode and system performance test mode. In dose verification mode, the three-dimensional electric platform is driven to move along the trajectory while the three-dimensional electric reference marker support remains stationary. In system performance test mode, the three-dimensional electric reference marker support is driven to move along the trajectory while the three-dimensional electric platform remains stationary. The dose analysis module integrates a pencil beam dose calculation algorithm to predict the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions. It receives the measured dose data from the dose measurement device, uses a Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, and automatically generates a visual verification report including Gamma pass rate, dose deviation distribution histogram, and position deviation distribution histogram.

2. The system for dynamic verification of radiotherapy plans according to claim 1, characterized in that, The reference marker is a metal sphere.

3. The system for dynamic verification of radiotherapy plans according to claim 1, characterized in that, The motion management module is used to automatically extract the three-dimensional motion trajectory of the tumor from the patient's 4D-CT images to generate motion trajectory instructions, including: (1) Respiratory phase division and image preprocessing Input: Patient's 4D-CT image sequence, which typically contains 10 respiratory phases, corresponding to 0%-90% of the respiratory cycle, with one phase taken at 10% intervals; Preprocessing: Gaussian filtering was used to remove noise from CT images, and the lung parenchyma region was segmented using the HU value thresholding method to exclude interference from non-target tissues, including bone and air. Phase-time normalization: Let the total duration of the respiratory cycle be... , No. The time percentage of each phase is: ， in, For the first The duration of each phase satisfies ; (2) Automatic extraction of target center coordinates The Demons deformation registration algorithm was used to register the 0% temporal CT images with the other nine temporal CT images, obtaining the deformation field for each temporal phase. , Physical coordinates of the CT image; The tumor target region at the reference time phase is delineated manually or automatically, and the coordinates of the target center are calculated. ; According to the deformation field Calculate the first Target center coordinates at each time phase ; Ten time phases Arranged in chronological order, sampling points are supplemented using cubic Hermite interpolation to obtain continuous three-dimensional motion trajectories: ， in, It is a time variable; , , These are the interpolation coefficients; The coordinate data of the three-dimensional motion trajectory are stored in a CSV file in chronological order to generate a four-dimensional time-position sequence file. The time-position sequence file is then converted and encoded to obtain the motion trajectory instructions.

4. The system for dynamic verification of radiotherapy plans according to claim 3, characterized in that, The dose analysis module predicts the dynamic expected dose distribution based on treatment plan data and motion trajectory instructions, including: (1) Calculation of static dose contribution matrix Input: Beam parameters exported from the radiotherapy planning system, phantom / patient CT density map, wherein the beam parameters include beam energy, angle, collimator position, subfield shape and weight; The dose contribution matrix under static conditions is calculated using the pencil-beam convolution algorithm. ,in Numbering Ziye, total Wild-looking; Number the grid points for dose calculation; Indicates the first The individual against the first The static dose contribution of each grid point; (2) Dynamic dose contribution correction Based on motion trajectory Calculate each time step Grid point position offset That is, the displacement of the target area / phantom at that time step; For each subfield Correct its time step Dose contribution: ， in, Number the offset grid points, by original coordinates minus This is obtained through bilinear interpolation. ; As time step weights, Consistent with the sampling frequency of the motion trajectory ensures that the total dose is equivalent to the static plan; (3) Dynamic dose superposition and fuzzy effect correction By summing the dose contributions of all subfields at all time steps, the dynamic expected dose distribution is obtained: ， Correcting motion-induced dose ambiguity: using Gaussian convolution kernels The convolution process is performed using the following formula: ， in, It is a three-dimensional high-period function. is the standard deviation in the Gaussian convolution kernel.

5. The system for dynamic verification of radiotherapy plans according to claim 4, characterized in that, The dose analysis module uses a Gamma analysis algorithm to compare the dynamic expected dose distribution with the measured dose data, including: (1) Data preprocessing and registration Input: Measured dose map exported from the dose measurement device and the calculated dynamic expected dose map ; Mesh unification: Nearest neighbor interpolation method is used to unify the mesh. and Convert to the same resolution; Spatial registration: Using the motion trajectory of the three-dimensional electric platform as a reference, the positional deviation of the measured dose map is corrected to ensure that the spatial coordinates of the two are aligned; (2) Calculation of Gamma value For each grid point Calculate two core difference metrics: Dose difference : , Location differences : ， The consistency index of each grid point is calculated using the three-dimensional Gamma formula: ， in, This is a reference threshold for dose difference. This is a reference threshold for location differences.

6. The system for dynamic verification of radiotherapy plans according to claim 5, characterized in that, The pass / fail criterion for the Gamma analysis algorithm is a Gamma pass rate ≥ 95%. ≤1, valid grid points are defined as ≥5% , This represents the maximum expected dose; when the Gamma pass rate is below 95%, it is automatically flagged. The high deviation area is identified, and a deviation heatmap is output.

7. A method for dynamic verification of radiotherapy plans, characterized in that, The method employs the system for dynamic verification of radiotherapy plans as described in any one of claims 1 to 6, and the method includes the following steps: S1. Acquire 4D-CT images of the target patient, and generate motion trajectory instructions by extracting or customizing motion parameters through the motion management module; S2. Select either the dose verification mode or the system performance test mode based on the verification requirements; S3. The radiotherapy equipment starts irradiation. The control unit drives the three-dimensional electric platform and / or the three-dimensional electric reference marker support to perform synchronous movement according to the selected mode and the motion trajectory command. S4. The dose measurement device records the measured dose data in real time and transmits it to the dose analysis module in the software control module; S5. The dose analysis module compares the measured dose data with the predicted dynamic expected dose distribution using Gamma analysis, and generates a visual verification report including Gamma pass rate and dose deviation distribution histogram, thus completing the verification.

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