Dosimetry of Brachytherapy Sources In Millimeter Range

毫米范围近距离放射治疗源的剂量测定

• 批准号: 6527115
• 负责人: RAVINDER NATH
• 金额: $ 28.61万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6527115
• 关键词: biomedical equipment development; iodine; iridium; linear energy transfer; mathematical model; medical implant science; palladium; phosphorus; radiation therapy dosage; radionuclide implant; radionuclide therapy; radionuclides; restenosis; single photon emission computed tomography; statistics /biometry; strontium; technology /technique development; yttrium

DESCRIPTION (provided by applicant): Recently, radiotherapy has been shown to be an effective treatment for the prevention of restenosis following angioplasty. In catheter-based systems for intravascular brachytherapy (IVB) a radioactive source is placed in the lumen at a short distance from the target, typically 1 to 3 mm. Both gamma and beta emitters are currently in use for IVB. All sources produce dose distributions with a steep dose gradient in the target volume with dimensions of a few millimeters. However, high energy photon emitters (e.g. (192)Ir), low energy photon emitters (e.g. (103)Pd) or beta emitters (e.g. ((90)Sr/(90)Y) have very different dosimetric and physical characteristics in terms of depth dose penetration, attenuation effects and shielding requirements. IVB delivery devices based on (192)Ir and (90Sr/90Y) have become commercially available and one based on (103)Pd is under development. There is now a critical need to obtain dosimetry parameters for these systems for the determination of dose distributions in the target and surrounding volumes. There is a need to modify the dose calculation formalism of the AAPM Task Group No. 43, which is suited to point-like interstitial brachytherapy sources. We propose a calculation formalism based on cylindrical coordinates, which is better suited to the geometry of catheter-based P/B sources. Also, there is a critical need to validate the manufacturers' dosimetry data by independent investigations using both dosimetry measurements and calculations. We propose to use two independent dosimetry methods (radiochromic film and thermoluminescent [TL} sheet dosimetry) and Monte Carlo calculations (ITS, MCNP and EGS4 codes) to intercompare various results and obtain an accurate set of dosimetry parameters for IVB systems. Our hypothesis is that successful implementation of the various IYB systems requires a better understanding of dosimetry issues at millimeter distances. The principal objective is to determine the dosimetry parameters in the immediate vicinity (within mm) of the various radionuclides (both photon emitters and beta emitters) and to examine critically the dosimetry issues of importance in the clinical implementation of IVB for prevention of restenosis following angioplasty. The goals of the project are to develop tools for the optimization of dose distributions produced within a target volume and uniformity of dose along and around a blood vessel.

描述（申请人提供）：最近，放疗已显示为 成为预防再狭窄的有效治疗方法 血管成形术。在基于导管内血管内近距离放射治疗（IVB）的系统中 放射性源位于距目标短距离的管腔中， 通常1至3毫米。伽马和β发射器目前都用于IVB。 所有来源都会在目标中产生剂量分布，并具有陡峭的剂量梯度 尺寸为几毫米。但是，高能量光子 发射器（例如（192）ir），低能光子发射器（例如（103）PD）或beta 发射器（例如（（90）sr/（90）y）具有非常不同的剂量和物理 深度剂量渗透，衰减效果和 屏蔽要求。基于（192）IR和（90SR/90Y）的IVB交付设备 已成为商业上可用的，一个基于（103）PD不在 发展。现在有至关重要的需要获得剂量计参数 这些系统用于确定目标中的剂量分布 周围的体积。需要修改剂量计算形式主义 AAPM任务组的第43号 近距离放射治疗来源。我们提出了基于圆柱形的计算形式主义 坐标，更适合基于导管的P/B的几何形状 来源。此外，迫切需要验证制造商的 通过使用两种剂量测量的独立研究，剂量测定数据 和计算。我们建议使用两种独立的剂量法 （放射性薄膜和热发光[TL}片剂量法）和蒙特卡洛 计算（ITS，MCNP和EGS4代码）以对抗各种结果，并且 获得IVB系统的一组准确的剂量测定参数。我们的假设 是否成功实施各种IYB系统需要更好 了解毫米距离的剂量学问题。校长 目的是确定附近附近的剂量测定参数 （在毫米内）各种放射性核素（光子发射器和β都 发射器）并批判性地检查了重要性的剂量学问题 IVB的临床实施以预防再狭窄 血管成形术。该项目的目标是开发优化工具 在目标体积和剂量均匀性内产生的剂量分布的 沿着血管和周围。