Quality assurance system and verification method for afterloading radiotherapy

Abstract

This invention discloses a quality assurance system and verification method for afterloading radiotherapy. The system includes: an afterloading quality assurance verification phantom: used to simulate the actual application environment of afterloading radiotherapy under controlled conditions, comprising a pelvic simulation phantom and a measurement adaptation module for adapting different types of applicator devices and multiple types of dose measurement units; multiple types of dose measurement units: set at predetermined measurement positions within the afterloading quality assurance verification phantom, used to acquire different types of dose and time-related measurement data under the same geometric conditions; QA analysis software: used to generate a QA scheme for quality assurance that can be executed by the afterloading radiotherapy device, and to analyze the measurement data obtained by the multiple types of dose measurement units; and an afterloading radiotherapy device: connected to the applicator device adapted in the afterloading quality assurance verification phantom for executing the QA scheme.

Description

Technical Field

[0001] This invention relates to the field of quality assurance and quality control technology for radiotherapy equipment, and in particular to a quality assurance system and verification method for afterloading radiotherapy. Background Technology

[0002] HDR brachytherapy, due to its steep dose gradient and highly localized treatment location, is widely used in the treatment of gynecological tumors such as cervical cancer. With the widespread adoption of CT-based 3D planning and personalized dwell time optimization algorithms, quality assurance (QA) for HDR brachytherapy has evolved from early focus on equipment calibration and single-point checks to system-level verification that focuses on image scanning, source channel reconstruction, treatment plan calculation, actual source positioning, and dose delivery consistency. Current common QA techniques in the industry include point dose measurement based on thermoluminescent dosimeters, two-dimensional dose distribution verification based on film, and detector methods for monitoring the source delivery process. However, overall, it still primarily involves item-by-item verification, and a standardized, end-to-end, integrated QA system is still immature.

[0003] Prior art document CN115068842B: This patent proposes a method for verifying brachytherapy plans after loading. It primarily constructs a simulation structure through 3D modeling or 3D printing, places thermoluminescent dosimeters at predetermined locations, and measures and compares the dose at each residence point in the treatment plan. The scheme focuses on using TLDs to verify the accuracy of brachytherapy plan dose calculations, providing high-precision point dose data. However, its verification primarily focuses on point dose values ​​at discrete locations, with limited coverage of source positioning accuracy, positioning repeatability, and consistency of two-dimensional or spatial dose distribution. Furthermore, it does not establish an end-to-end QA system covering the entire process from image scanning to source channel reconstruction, plan design, and plan execution.

[0004] Prior art document CN215084351U discloses a device for verifying spatial radiation dose in afterloading brachytherapy. Its structural feature is the use of a cylindrical or channel-like structure to place film and measure the cumulative dose generated by the afterloading source at different paths or spatial locations. This approach utilizes the spatial resolution advantage of film to achieve intuitive verification of radiation dose distribution, making it suitable for checking source path or spatial dose characteristics. However, this device primarily focuses on film dose measurement itself, failing to integrate with other measurement methods or combine treatment planning data with software analysis to achieve system-level, standardized end-to-end QA.

[0005] Although quality assurance (QA) techniques for brachytherapy have been widely used in dose measurement and equipment calibration, from an overall development perspective, existing technologies still mainly employ itemized and localized verification methods, which are difficult to fully reflect the comprehensive performance of the treatment system under actual clinical operation, and especially difficult to systematically evaluate the consistency between the treatment plan and the actual dose delivery.

[0006] First, current QA methods for afterloading radiotherapy mainly rely on single measurement methods, such as using thermoluminescent dosimeters or small detectors for point dose verification, or using film for two-dimensional dose distribution measurement. While these methods have advantages in their respective measurement dimensions, due to the limited dimensions of measurement information, they cannot simultaneously cover absolute dose values, spatial distribution patterns, and temporal control characteristics, which may lead to the masking of some geometric or time-related errors.

[0007] Secondly, existing QA methods generally focus on the independent verification of equipment performance or individual functional modules, such as source drive accuracy, residence time control, or dose output stability, while rarely verifying the overall consistency of multiple links such as image acquisition, applicator reconstruction, dose calculation, planned transmission, and actual source positioning in a joint working state. This can easily lead to situations where each subsystem is qualified individually, but the overall treatment process still has deviations.

[0008] Secondly, at the software and data processing level, existing QA processes often rely on various fragmented software tools or manual processing steps to complete data reading, registration, and analysis, lacking a unified data management and automated evaluation mechanism. This fragmented approach not only reduces the repeatability and efficiency of QA but also increases the risk of human error, hindering the formation of standardized and auditable QA results.

[0009] Furthermore, given that cervical cancer and other gynecological tumors are the main application scenarios for afterloading radiotherapy, most existing phantoms or devices still have a general structural design and have not been fully optimized in combination with the geometric features of commonly used gynecological tumor afterloading applicators and human organs at the treatment site. This makes it difficult to realistically simulate clinical treatment scenarios while ensuring repeatable positioning, thus limiting the representativeness of QA results for actual clinical applications.

[0010] In summary, the existing afterloading radiotherapy QA system is inadequate in terms of standardization and system integration, and lacks a comprehensive solution that can organically combine the individual performance verification of multiple devices with end-to-end system performance verification. Summary of the Invention

[0011] To address the aforementioned technical problems, this invention provides a technical solution for ensuring the performance of equipment and the end-to-end system performance of afterloading radiotherapy systems. The solution mainly comprises an integrated afterloading quality assurance verification phantom and QA software. The solution's functions include developing a quality assurance execution plan, measuring the results of the verification plan execution, and analyzing and evaluating the verification results. Through collaborative work with afterloading radiotherapy planning software and afterloading radiotherapy equipment, this solution can achieve both standardized, item-by-item performance verification of the equipment and end-to-end equipment system performance verification.

[0012] To achieve the above objectives, the present invention provides a quality assurance system for afterloading radiotherapy, comprising: an afterloading quality assurance verification phantom: used to simulate the actual application environment of afterloading radiotherapy under controlled conditions, including a pelvic simulation phantom and a measurement adaptation module for adapting to different types of application devices and multiple types of dose measurement units; multiple types of dose measurement units: set at predetermined measurement positions within the afterloading quality assurance verification phantom, used to acquire different types of dose and time-related measurement data under the same geometric conditions; QA analysis software: used to generate a QA scheme for quality assurance that can be executed by the afterloading radiotherapy device, and to analyze the measurement data obtained by the multiple types of dose measurement units; and an afterloading radiotherapy device: used to connect to the application device adapted in the afterloading quality assurance verification phantom to execute the QA scheme.

[0013] Furthermore, the system also includes a brachytherapy planning system (TPS) for generating customized QA plans that can be executed by brachytherapy equipment based on image scan results.

[0014] Furthermore, the QA analysis software includes the following modules: a QA program management and generation module for generating and managing QA programs for quality assurance purposes; a multi-type measurement data management module for identifying, storing, and associating multi-type measurement data obtained during the execution of QA programs; a data analysis module for comparing and analyzing the obtained multi-type measurement data; and a result synthesis and report output module for outputting the analysis results of the QA analysis software.

[0015] Furthermore, the QA scheme management and generation module also imports and stores customized QA schemes generated by the afterloading treatment planning system (TPS).

[0016] Furthermore, the post-installation quality assurance verification model also includes a base for limiting and fixing the pelvic simulation model, and the base is provided with positioning marks for position reset.

[0017] Furthermore, the pelvic simulation model has metal balls embedded inside as image positioning markers inside the model, and the positions of the metal balls and the corresponding positions of the positioning markers have a fixed positional relationship.

[0018] Furthermore, the measurement adaptation module includes an interface structure and a fixing module for adapting to different types of source devices, as well as a measurement unit mounting structure for fixing the multi-type dose measurement units at predetermined measurement positions. The interface structure and fixing module provide clear geometric constraints for fixing the source devices, thereby providing stable and repeatable physical channel conditions for the movement and residence of the radiation source.

[0019] Furthermore, the measurement unit mounting structure includes placement boxes respectively disposed on the upper and lower sides of the interface structure and the fixing module, the placement boxes being used to accommodate the multi-type dose measurement units.

[0020] Furthermore, the types of application devices include: radiotherapy guides, implantation needles, and application devices; and the multi-type dose measurement unit includes at least one dose measurement device selected from dose measurement films, thermoluminescent dosimeters, ionization chambers, and radiation detectors.

[0021] The technical solution of the present invention also provides a quality assurance verification method for afterloading radiotherapy, which uses the quality assurance system for afterloading radiotherapy as described above. The method includes the following steps: generating a quality assurance QA plan executable by the afterloading radiotherapy equipment using QA analysis software or an afterloading treatment planning system (TPS); executing the QA plan by the afterloading radiotherapy equipment to perform non-clinical treatment irradiation under verification phantom conditions and acquiring measurement data through multiple types of dose measurement units; analyzing the acquired measurement data by the QA analysis software and outputting an analysis result report. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the quality assurance system for afterloading radiotherapy according to the present invention;

[0024] Figure 2 This is an overall structural diagram of the integrated aftermarket quality assurance verification module;

[0025] Figure 3 This is an overall structural diagram of the fixation module of the present invention when using the radiotherapy guide plate, implantation needle, and applicator respectively;

[0026] Figure 4This is a boom diagram of the measurement adapter module when using the applicator in this invention;

[0027] Figure 5 This is a BOM diagram of the measurement adapter module when using a radiotherapy guide plate according to the present invention;

[0028] Figure 6 This is a diagram of the measurement adapter module when using a radiotherapy guide plate according to the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The technical solution of this invention mainly includes the following key points:

[0031] (1) Design of an end-to-end quality assurance system for afterloading radiotherapy systems

[0032] The integrated afterloading quality assurance verification phantom, multi-type dose measurement units, treatment planning system, afterloading radiotherapy equipment, and QA analysis software are designed as a complete system to form an end-to-end quality assurance system.

[0033] (2) Integrated aftermarket quality assurance verification module

[0034] A tissue simulation phantom was designed for convenient fixation and positioning during imaging scans. It can be configured with different adapter structures to be selected and combined according to different applicators and measurement methods. This allows for the acquisition of different types of QA validation data under unified geometric conditions, enabling comprehensive and complete multi-item testing and validation. The validation phantom is used to simulate afterloading therapy application scenarios and is compatible with applicators, implantation needles, or implantation guidance structures to ensure consistency between QA measurement conditions and actual treatment conditions.

[0035] (3) Analysis of multi-type measurement data based on standardized verification phantoms

[0036] The software unifies the management of executable QA protocols and corresponding multi-type measurement results, and performs quality assurance verification analysis on multiple items, including radiation source positioning accuracy, positioning repeatability error, residence time control error, treatment plan dose calculation error, etc., to generate a complete end-to-end test verification report.

[0037] like Figure 1As shown, the technical solution of this invention achieves comprehensive analysis of the generation, execution, and measurement results of quality assurance treatment plans through the collaborative work of an integrated afterloading quality assurance verification phantom, QA analysis software, afterloading treatment planning system (TPS), and afterloading radiotherapy equipment. Specifically, the integrated afterloading quality assurance verification phantom is used to simulate the actual application environment of afterloading radiotherapy under controlled conditions and acquire measurement data; the QA analysis software is used to generate a series of executable equipment single-item performance verification quality assurance execution plans and analyze the measurement results; based on the simulation phantom, it is compatible with the installation of corresponding applicators, insertion needles, or templates for afterloading equipment, and after scanning images, the afterloading treatment planning system (TPS) generates an executable end-to-end system performance verification plan for the afterloading machine; the QA analysis software can automatically analyze the results of each single performance verification and the end-to-end system performance verification results by combining the equipment execution plan and the corresponding measurement results.

[0038] like Figure 2 As shown, the integrated aftermarket quality assurance verification module of the present invention can be divided into the following major modules:

[0039] ① A base with positioning marks (to limit and fix the mold body; the cross positioning marks are used for overall position reset during image scanning).

[0040] ② Measurement adapter module (different adapter structures can be selected according to different applicators and measurement methods: it can be adapted to different applicators / insertion needles / individualized insertion guides and other applicator methods, as well as one or more measurement components such as thermoluminescence, film, and ionization chamber)

[0041] ③ Pelvic cavity simulation phantom (with surface positioning marks and internal tissue simulation structure: using materials of different densities to simulate human bone tissue, soft tissue, cavities, etc.)

[0042] The verification phantom device is used to simulate the actual application environment related to afterloading radiotherapy under controlled conditions, providing a stable physical basis for the execution and measurement of quality assurance treatment plans; the multimodal dose measurement unit is set in the verification phantom device to acquire different types of dose and time-related measurement data under uniform geometric conditions; the afterloading radiotherapy device is connected to the source device in the verification phantom device and performs predetermined radiation source positioning and residence operations in the verification phantom device.

[0043] Through the coordinated operation of the aforementioned hardware systems, this invention is able to acquire basic measurement data for quality assurance analysis under execution conditions consistent with the actual brachytherapy process.

[0044] The measurement adapter module is used to simulate the geometry or anatomy related to afterloading radiotherapy in order to reproduce the spatial relationship between the radiation source, applicator and dose measurement unit during afterloading radiotherapy under non-clinical conditions.

[0045] See Figure 3 (a)-(b) show the overall structural diagram of the fixation module when using the radiotherapy guide, implantation needle, and applicator, respectively. Figures 4-6 The BOM diagram of the corresponding measurement adapter module is shown. The relevant labels in the diagram are explained below:

[0046] 41-Film / thermoluminescent dosimeter / radiation detector placement box; 42-Receiving box; 43-Applicator fixation module part 1; 44-Applicator fixation module part 2; 45-Applicator fixation module part 3; 46-Applicator; 53-Fixation module adapted to radiotherapy guide plate; 54-Radiation guide plate; 55-Insertion needle and uterine cannula; 63-Fixation module adapted to insertion needle; 64-Insertion needle.

[0047] The measurement adapter module of the present invention has the following characteristics:

[0048] (1) The structure has a certain spatial shape and internal structure that is compatible with multiple source application methods. Its structure is configured to provide clear geometric constraints for the fixation of the source application device or the insertion needle, and to provide stable and repeatable physical channel conditions for the movement and residence of the radioactive source, thereby ensuring the comparability between different schemes of measurement.

[0049] (2) It has a repeatable positioning structure to ensure that the positional relationship of the verification phantom device relative to the afterloading radiotherapy device remains consistent during multiple measurements or multiple executions; the verification phantom device also includes a measurement unit mounting structure (film / thermoluminescent dosimeter / radiation detector placement box) for mounting multiple types of dose measurement units to ensure that the measurement units are stably fixed at predetermined positions; in addition, the verification phantom device also includes an interface structure (or fixing module) adapted to the applicator or implantation needle to achieve a reliable connection between the applicator or implantation needle and the verification phantom device. Furthermore, the phantom device has embedded metal spheres as internal image positioning markers, and the positions of the metal spheres and the internal positions corresponding to the cross marks on the phantom surface have a fixed corresponding positional relationship.

[0050] Through the above structural design, the verification phantom device can provide a repeatable and controllable physical environment for ensuring the quality of afterloading radiotherapy.

[0051] Multiple dose measurement units are installed in the verification phantom device to acquire different types of dose and time-related measurement information under the same geometric conditions.

[0052] The multi-type dose measurement unit includes at least one dose measurement device, which can be selected from one or more of dose measurement film, thermoluminescent dosimeter, ionization chamber, or radiation detector. By configuring different types of measurement devices, the multi-modal dose measurement unit can acquire point dose information, two-dimensional or multi-dimensional dose distribution information, and measurement information related to the residence time and movement characteristics of the radiation source.

[0053] The multi-type dose measurement units are fixed in predetermined measurement positions through the measurement unit mounting structure in the verification phantom device, for example, in the aforementioned 41-film / thermoluminescent dosimeter / radiation detector placement box, thereby ensuring that various measurement data are acquired based on consistent spatial reference conditions during multiple quality assurance measurements.

[0054] The QA analysis software of this invention is used to uniformly organize, control, and analyze the QA process of afterloading radiotherapy systems, and is the core software unit for realizing end-to-end quality assurance processes. It performs at least the following functions:

[0055] (1) Generate a quality assurance (QA) protocol for afterloading radiotherapy equipment;

[0056] (2) Manage QA programs and their corresponding execution and measurement data;

[0057] (3) Analyze the results of multiple types of measurements;

[0058] (4) Output quality assurance results for evaluating the performance of the afterloading radiotherapy system.

[0059] By setting up QA analysis software, this invention can organically integrate the verification phantom, multimodal measurement unit, treatment planning system and afterloading radiotherapy device to form a complete end-to-end quality assurance closed loop.

[0060] The QA analysis software of this invention includes the following modules:

[0061] 1. QA Solution Management and Generation Module

[0062] The QA protocol management and generation module is used to generate and manage QA protocols for quality assurance purposes. In a specific implementation, the QA protocol management and generation module is configured as follows:

[0063] (1) Generate at least one executable QA solution based on the preset quality assurance objectives;

[0064] (2) Number, classify and store the generated QA solutions;

[0065] (3) Export the QA protocol into a protocol format that can be recognized by the afterloading therapy device;

[0066] (4) Import and store the individualized QA scheme designed by the radiotherapy planning system.

[0067] The QA protocol is used to drive the afterloading radiotherapy device to perform non-clinical treatment irradiation under validation phantom conditions in order to obtain measurement data for quality assurance analysis.

[0068] 2. Multi-type measurement data management module

[0069] The multimodal measurement data management module is used for unified management of measurement data obtained during QA execution. The multimodal measurement data management module is configured to manage at least the following data types:

[0070] (1) Data reading from dosimetry film;

[0071] (2) Measurement data from the thermoluminescent dosimeter;

[0072] (3) Dosage measurement data from the ionization chamber;

[0073] (4) Measurement data obtained by the radiation detector.

[0074] In a specific implementation, the multi-type measurement data management module can identify, store, and associate data from different sources and different measurement batches to ensure the traceability of data in subsequent analysis processes.

[0075] 3. Data Analysis Module

[0076] This module enables the comparison and analysis of data obtained from different measurement methods and batches under a unified reference condition, thereby improving the accuracy and comparability of quality assurance results.

[0077] The analysis module is configured to perform at least the following analysis operations:

[0078] (1) Analyze the point dose measurement results;

[0079] (2) Analyze two-dimensional or multi-dimensional dose distribution;

[0080] (3) Analyze the data related to the source residence time;

[0081] (4) Analyze the accuracy and repeatability of the source positioning;

[0082] (5) Conduct a consistency comparison analysis of the measurement results of the same QA solution in multiple executions;

[0083] (6) Compare and analyze the measurement results with the preset or expected results calculated by the radiotherapy planning system;

[0084] Based on the above analysis, the QA analysis software can reflect the actual operational characteristics of the afterloading radiotherapy system during the QA execution process from two dimensions: dose and time.

[0085] 4. Results Synthesis and Report Output Module

[0086] The Results Synthesis and Report Output module is used to summarize and output the analysis results of various functional modules of the QA analysis software.

[0087] The beneficial technical effects of the technical solution of the present invention are as follows:

[0088] (1) This invention integrates the verification phantom device, multimodal dose measurement unit, QA analysis software, treatment planning system and afterloading radiotherapy device at the system level, and realizes end-to-end quality assurance verification for the entire process of afterloading radiotherapy.

[0089] (2) Standardized simulation verification models integrate multiple measurement methods under the same geometric conditions, enabling different types of measurement data to be obtained under unified physical conditions. This allows for the acquisition of multiple types of measurement information within the same quality assurance process, significantly improving the information dimensions covered by quality assurance analysis and overcoming the problem of limited information from a single measurement method.

[0090] (3) By introducing a quality assurance process centered on a unified QA execution plan, the quality assurance operation can follow an execution path that is highly consistent with the actual treatment. A unified QA execution plan that can be executed by afterloading therapy equipment is generated by QA analysis software, and after execution, the corresponding measurement results are imported, the results are automatically analyzed and verified, and an end-to-end test verification report is generated.

[0091] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A quality assurance system for afterloading radiotherapy, characterized in that, include: Afterloading quality assurance verification phantom: used to simulate the actual application environment of afterloading radiotherapy under controlled conditions, including a pelvic simulation phantom and a measurement adapter module for adapting to different types of source devices and multiple types of dose measurement units; Multi-type dose measurement unit: set at a predetermined measurement position within the post-loading quality assurance verification phantom, used to acquire different types of dose and time-related measurement data under the same geometric conditions; QA analysis software: used to generate executable QA protocols for quality assurance of afterloading radiotherapy equipment, and to analyze measurement data obtained from the multi-type dose measurement units; Afterloading radiotherapy equipment: used to connect to the application source device adapted in the afterloading quality assurance verification phantom to perform QA procedures.

2. The system according to claim 1, characterized in that, The system also includes a brachytherapy planning system (TPS) for generating customized QA plans that can be executed by brachytherapy equipment based on image scan results.

3. The system according to claim 2, characterized in that, The QA analysis software includes the following modules: QA Solution Management and Generation Module: Used to generate and manage QA solutions for quality assurance purposes; Multi-type measurement data management module: used to identify, store, and associate multi-type measurement data obtained during the execution of QA solutions; Data analysis module: used for comparative analysis of the acquired measurement data of various types; Results Synthesis and Report Output Module: Used to output the analysis results of the QA analysis software.

4. The system according to claim 3, characterized in that, The QA scheme management and generation module also imports and stores customized QA schemes generated by the afterloading treatment planning system (TPS).

5. The system according to any one of claims 1-4, characterized in that, The post-installed quality assurance verification model also includes a base for limiting and fixing the pelvic simulation model, and the base is provided with positioning marks for position reset.

6. The system according to claim 5, characterized in that, The pelvic simulation model has metal balls embedded inside as positioning markers for the internal image of the model. The positions of the metal balls and the corresponding positions of the positioning markers have a fixed positional relationship.

7. The system according to any one of claims 1-4, characterized in that, The measurement adaptation module includes an interface structure and a fixing module for adapting to different types of source devices, as well as a measurement unit mounting structure for fixing the multi-type dose measurement units at predetermined measurement positions. The interface structure and fixing module provide clear geometric constraints for fixing the source devices, thereby providing stable and repeatable physical channel conditions for the movement and residence of the radiation source.

8. The system according to claim 7, characterized in that, in, The measurement unit mounting structure includes placement boxes respectively disposed on the upper and lower sides of the interface structure and the fixing module, the placement boxes being used to accommodate the multi-type dose measurement units.

9. The system according to any one of claims 1-4, characterized in that, Application device types include: radiotherapy guides, implantation needles, and applicators; and The multi-type dose measurement unit includes at least one dose measurement device, which is selected from dose measurement film, thermoluminescent dosimeter, ionization chamber and radiation detector.

10. A quality assurance verification method for afterloading radiotherapy, characterized in that, Using the quality assurance system for afterloading radiotherapy as described in any one of claims 1-9, the method comprises the following steps: QA analysis software or afterloading treatment planning system (TPS) can be used to generate QA protocols for quality assurance that can be executed by afterloading radiotherapy equipment. QA protocols were implemented using afterloading radiotherapy equipment to perform non-clinical therapeutic irradiation under validation phantom conditions and to acquire measurement data through multiple types of dose measurement units. The acquired measurement data is analyzed using QA analysis software, and an analysis result report is generated.

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