OPTICAL TOMOGRAPHY OF POLYMER GELS FOR 3D DOSIMETRY

用于 3D 剂量测定的聚合物凝胶光学断层扫描

• 批准号: 2108047
• 负责人: MAREK J MARYANSKI
• 金额: $ 38.51万
• 依托单位: MGS RESEARCH, INC.
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1997-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2108047
• 关键词: biomedical equipment development; gel; image processing; personal computers; polymers; radiation dosage; tomography

This project aims to develop a novel, tissue-equivalent gel-dosimeter of ionizing radiation, which is capable of producing highly-resolved and accurate data on three dimensional dose distributions using optical tomographic densitometry. The dose-response mechanism relies on the production of Rayleigh scattering micro-particles in the gel at the site of radiation absorption, where acrylic comonomers dispersed in the gel are polymerized. Absorption and scattering of collimated light passing through the optically turbid medium produces a net attenuation of light intensity that can be measured and is directly related to the dose. Measurements of the projections of the optical density into different directions can be used to reconstruct the distribution of radiation doses within the gel. Doses of the order of 1 Gy can be measured with a spatial resolution <1mm. In Phase 1, basic optical properties of the gel have been investigated and a prototype optical scanner using a single laser beam and scanning photodiode was constructed and used successfully to create accurate 2D dose maps. The goals of Phase 2 are to reengineer the optical tomography apparatus in order to perform 3D scanning in reasonable times, to further develop the reconstruction and image analysis software of the scanner, and to further evaluate and develop formulations of polymer gel optimized for their optical properties. The latter will require studies designed to better understand the factors that affect the optical density - dose response of polymer gels. There are significant advantages to the use of this simpler optical method of reading the dose distribution stored by the gel compared to MR imaging, which is the only alternative. The polymer gel - optical scanner system will find widespread use in radiation therapy practice, for 3D measurements in homogeneous and anthropomorphic phantoms, confirmation of computerized treatment planning and in quality assurance procedures. PROPOSED COMMERCIAL APPLICATION: Acceptance testing of approximately 125 new high energy X-ray machines requires the measurement of between 6 and 12 dose distributions, using about 1,200 gels. Quality assurance procedures for the existing 2,500 linear accelerators could require 10,000 polymer-gels. Brachytherapy and experimental applications could account for 2,000 more gels. At $300 per gel, initial annual sales of gels in excess of $3 Million are anticipated. Scanner sales (25 per year at $60,000 each) would add $l.5 Million to this.

本项目旨在开发一种新型的、组织等效的凝胶剂量计， 电离辐射，能够产生高分辨率和 使用光学成像技术的三维剂量分布的精确数据 断层摄影密度测定法 剂量反应机制依赖于 在现场凝胶中产生瑞利散射微粒 辐射吸收，其中分散在凝胶中的丙烯酸共聚单体是 聚合的 准直光通过时的吸收和散射 产生光的净衰减 强度可以测量，并与剂量直接相关。 测量光密度投影到不同的 方向可用于重建辐射剂量的分布 在凝胶中。 1戈伊量级的剂量可以用空间剂量计测量。 分辨率<1 mm。 在阶段1中，凝胶的基本光学性质具有 已经进行了研究，使用单激光器的原型光学扫描仪 光束和扫描光电二极管的构造和使用成功， 创建精确的2D剂量图。 第二阶段的目标是重新设计 光学层析成像设备，以合理地执行3D扫描， 次，进一步开发重建和图像分析软件 并进一步评估和开发 聚合物凝胶优化其光学性能。 后者将 需要进行研究，以更好地了解影响 聚合物凝胶的光密度-剂量响应。 存在显著 使用这种更简单的阅读剂量的光学方法的优点 与MR成像相比，凝胶存储的分布是唯一的 替代. 聚合物凝胶光学扫描系统会发现 在放射治疗实践中广泛使用， 同质和拟人化的幻影，确认计算机化的 治疗计划和质量保证程序。 拟议商业应用：约125个的验收测试 新的高能X射线机需要测量6到 12个剂量分布，使用约1，200个凝胶。 质量保证 现有的2,500个直线加速器的程序可能需要10000个 聚合物凝胶。 近距离放射治疗和实验应用可以解释 两千多个凝胶 每支凝胶售价300美元， 预计将超过300万美元。 扫描仪销售（25台/年， 每个人60，000美元）将增加150万美元。