Improving the Safety and Quality of Eye Plaque Brachytherapy by Assembly with Intensity Modulated Loading

通过调强加载组装提高眼斑近距离治疗的安全性和质量

• 批准号: 10579754
• 负责人: Lei Xing
• 金额: $ 7.75万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579754
• 关键词: 3D Print; Address; Adult; Affect; Air; Biological Assay; Biological Models; Brachytherapy; Calibration; Clinical; Computer software; Data; Device Designs; Devices; Diameter; Distributional Activity; Dose; Ensure; Evaluation; External Beam Radiation Therapy; Eye; Eye Neoplasms; Geometry; Glues; Goals; Gold; Health; Human; Human Resources; Image; Individual; Intensity-Modulated Radiotherapy; Lesion; Libraries; Location; Malignant Childhood Neoplasm; Malignant Neoplasms; Measurement; Measures; Methodology; Methods; Modality; Modeling; Molds; Monte Carlo Method; Normal tissue morphology; Operative Surgical Procedures; Optics; Organ; Outcome; Patients; Pattern; Performance; Positioning Attribute; Process; Radiation therapy; Radioactive; Radioactivity; Recommendation; Reporting; Research Design; Retinoblastoma; Safety; Sclera; Secure; Shapes; Side; Signal Transduction; Software Tools; Source; Structure; Surface; Surgical sutures; System; Techniques; Testing; Thinness; Time; Toxic effect; Uncertainty; Uveal Melanoma; Vendor; Visual; base; clinical center; clinically significant; cost; cost effective; design; design and construction; detector; digital; experimental study; flexibility; image guided; implantation; improved; lens; malignant neoplasm of eye; novel; patient oriented; patient safety; personalized medicine; programs; prototype; public health relevance; quality assurance; theories; treatment optimization; treatment planning; trend; tumor

Project summary / Abstract Intraocular cancers are optimally treated with eye plaque brachytherapy (EPB), involving surgical implantation of a carrier (“plaque”) loaded with radioactive sources (called seeds) on the scleral surface over the tumor base. While it is critical to ensure the strength and exact positions of the radioactive seeds for accurate treatment, current quality assurance (QA) practice according to the AAPM Task Group (TG) report 129 only dictates the plaque assembly be visually inspected due to the lack of an effective and practical technique to measure the seed radioactivity distribution. Clinically, this often limits treatments to using uniform seed intensity, otherwise we have to assume the correct loading without verification. This is especially suboptimal for plaques preloaded by the vendor, as seeds with different activities cannot be distinguished visually. Therefore, unlike the common practice of employing intensity modulation in external beam radiation therapy, we cannot further optimize treatment by using differential seed strengths to provide more personalized dosing based on the tumor itself and the location of normal organs. To overcome this fundamental issue hindering EPB advancement and solve the problems of previous EPB QA designs, our goal is to develop a fast, accurate, and low-cost QA system to allow safe integration of differentially loaded EPB. We constructed a proof-of-concept system consisting of a flat scintillator sheet and a lens/camera system mounted together, aiming to quantitatively measure the discrepancy in radioactivity/dose distribution of the plaque assembly from the originally planned distribution through the gamma evaluation commonly used for the QA of intensity modulated radiotherapy. The radioluminescence signal generated by a loaded plaque near the scintillator will be collected by the camera and processed in real- time to verify correct loading of the seeds. The measurement and analysis only require a few minutes, significantly shorter than the time to assay the extra verification seeds the physicist already must perform as recommended by TG129. Our preliminary data are promising, while we hypothesize that the performance can be improved by using a hemispherical scintillator conformal the plaque inner surface to enhance the system sensitivity and identify each individual seed in the plaque. Our initial Monte Carlo (MC) simulation demonstrated the feasibility. Specific aims: Design and construct a novel, functional prototype QA system with associated software enabling us to offer seed loading modulation to patients with ocular tumors, and commission/evaluate/validate the system through extensive phantom experiments and MC simulation. Study design: Systematic MC simulations will be performed to optimize the design before building the improved device. Software tools will be developed to analyze the data and document the measurement results. Extensive phantom measurements will be performed to compare and tune the MC and optical system models. Factors affecting the QA uncertainties will be studied. Health relatedness: This proposal aims to address the unmet need of intensity modulated, personalized EPB delivery based on the lesion shape and critical structure sparing.

项目概要/摘要 眼内癌的最佳治疗方法是眼斑近距离放射治疗（EPB），包括手术植入 在肿瘤基底上方的巩膜表面上装载有放射源（称为种子）的载体（“斑块”）。 虽然确保放射性粒子的强度和准确位置对于精确治疗至关重要， 根据AAPM任务组（TG）报告129，当前的质量保证（QA）实践仅规定了 由于缺乏有效和实用的技术来测量 种子放射性分布在临床上，这通常限制治疗使用均匀的种子强度，否则 我们不得不在未经验证的情况下假设正确的装载量。这对于预加载的斑块尤其是次优的 由于不同活性的种子在视觉上无法区分，因此，与普通 在外部束放射治疗中采用强度调制的实践中，我们不能进一步优化 通过使用不同的种子强度来提供基于肿瘤本身的更个性化的给药， 正常器官的位置。要克服这个阻碍土压工程发展的根本问题， 我们的目标是开发一个快速，准确，低成本的QA系统， 差动加载EPB的安全集成。我们构建了一个概念验证系统， 闪烁体片和安装在一起的透镜/照相机系统，旨在定量测量差异 在从最初计划的分布到通过 伽马评价通常用于调强放疗的QA。放射性发光 由闪烁体附近的加载斑块产生的信号将由照相机收集并在真实的中处理。 时间来验证种子的正确装载。测量和分析只需要几分钟， 显著短于测定物理学家已经必须执行的额外验证种子的时间， 推荐TG 129我们的初步数据是有希望的，而我们假设，性能可以 通过使用与斑块内表面共形的半球形闪烁体来改进 灵敏度和识别斑块中的每个单独的种子。我们最初的蒙特卡罗（MC）模拟表明， 可行性。具体目标：设计并构建一个新颖的、功能完善的问答系统原型， 使我们能够为眼部肿瘤患者提供种子加载调制的软件，以及 通过广泛的体模实验和MC模拟调试/评估/验证系统。研究 设计：在构建改进的器械之前，将进行系统的MC模拟以优化设计。 将开发软件工具来分析数据和记录测量结果。广泛 将进行体模测量，以比较和调整MC和光学系统模型。因素 将研究影响QA不确定性的因素。健康相关性：该提案旨在解决未得到满足的问题。 需要基于病变形状和关键结构保留的强度调制、个性化EPB输送。