RADIOBIOLOGY OF LOW-ENERGY AND SHORT-LIVED ISOTOPES

低能短寿命同位素的放射生物学

• 批准号: 3197551
• 负责人: CLIFTON C LING
• 金额: $ 12.79万
• 依托单位: MEMORIAL HOSPITAL FOR CANCER & ALLIED DI
• 依托单位国家: 美国
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1992-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3197551
• 关键词: energy source; neoplasm /cancer radionuclide diagnosis; palladium; radiation dosage; radionuclide imaging /scanning; radionuclide implant; radionuclides; radiotracer; relative biological effectiveness; stable isotope; stable isotope diagnosis; tissue /cell culture

A new radiation modality, encapsulated Pd-103 seed sources, is now in clinical use in the treatment of human cancer and radiation. The physical characteristics of this isotope are attractive for its use in permanent implantation. In comparison with Au-198, the low photon energies of Pd-103 (about 21 keV) reduces unwanted radiation exposure. Compared to I-125 (t 1/2 of about 60 days), the 17 day half life of Pd-103 corresponds to a more rapid delivery of radiation dose, which may be more efficacious in controlling tumors with fast growth kinetics. It is likely that the use of Pd-103 will increase as clinical experience is accumulated. It is most probable that Pd-103 has higher radiobiological effectiveness (RBE) than Cs-137. Its RBE may also be greater than that of I-125, with values ranging from 1.0-2.0. No data exists on the RBE of Pd-103. We propose to measure the RBE of Pd-103 relative to Cs-137, for a number of dose rates and for a number of cell lines of different growth kinetics. The RBE of I-125 will be re-examined, in part for a direct comparison with Pd- 103, and in part motivated by the recent discovery of previous dosimetric errors. Permanent implants with short half life radionuclides (e.g. PD-103 or Au- 198) deliver radiation with decreasing dose rate. The radiobiological effect of such time-dose patterns is not well understood. We propose experiments to study the topic, which also have relevance to the radiobiology of radiolabelled immunotherapy. Biophysical models will be examined in comparison with experimental results.

一种新的辐射模式，封装的PD-103种子源，现在正在 在治疗人类癌症和放射方面的临床应用。体能 这种同位素的特性使其在永久使用中具有吸引力。 植入。与Au-198相比，Pd-103的低光子能量 (约21keV)减少不必要的辐射暴露。与I-125(t 约60天的1/2)，Pd-103的17天半衰期对应于更多 快速提供辐射剂量，这可能在以下方面更有效 以快速生长动力学控制肿瘤。很可能使用的是 随着临床经验的积累，PD-103的含量将会增加。 PD-103极有可能具有较高的放射生物学效应 (RBE)而不是Cs-137。它的RBE也可能大于I-125， 取值范围为1.0-2.0。没有关于PD-103的RBE的数据。我们 建议测量Pd-103相对于Cs-137的相对标准偏差， 剂量率和一些不同生长动力学的细胞系。这个 将重新检查I-125的RBE，部分原因是为了直接与PD进行比较- 103，部分原因是最近发现了以前的剂量学 错误。 具有短半衰期放射性核素的永久性植入物(例如，Pd-103或Au- 198)以降低剂量率的方式提供辐射。放射生物学 这种时间-剂量模式的影响还不是很清楚。我们建议 研究这个主题的实验，这也与 放射性标记免疫疗法的放射生物学。生物物理模型将是 并与实验结果进行了比较。