Radiation induced cancer risk reduction as a function of dose protraction: interspecies comparison

电离辐射（IR）会对生物体造成损害。不同总剂量和IR的健康影响 IR 传递的剂量率必须通过基于整个生物体的统计分析来确定 终点例如患癌症的风险增加或寿命缩短的风险增加。的 如果延长时间，为了达到相同的最终生物效应，可以增加总剂量的因素被称为 剂量和剂量率有效性因子（DDREF）。整个区域累积的长期辐射 美国人口众多，受到政府制定的监管政策的管辖。这些政策 依赖国家和国际机构使用 DDREF 评估 IR 潜在危险的工作 值作为考虑长期红外暴露的关键输入因素之一。最终，政府 职业和公共红外暴露（大部分是长期暴露）的监管限制以及 X 射线的建议 基于医疗诊断程序（主要是低总剂量）都取决于当前接受的 DDREF 值。 使用关于急性和长期暴露的计算工具和动物数据，我们发现 DDREF 此时使用的估计是不合适的（Haley et al. 2015），但剂量率有效性因子（DREF） 可以使用大量的动物数据进行评估。在这个项目中，我们建议使用种间比较来 细化 (1) 外束 DREF 值和 (2) 放射性核素剂量/质量/给药途径剂量率 特定类型的辐射诱发癌症（以及因内部原因导致的寿命缩短）的有效性因素（DREF） 发射器）。鉴于一些国际机构正在寻求改变这一事实，这一点尤其重要 DDREF 的价值观——ICRP 专门向我们小组发送的一封信，支持这项工作的重要性 附在申请表上。

Ionizing radiation (IR) causes damage to living organisms. The health effects of IR for different total doses and dose rates at which IR was delivered have to be defined by statistical analyses based on whole organism endpoints such as an increase in the risk for development of cancer or an increased risk of life shortening. The factor by which a total dose could be increased, if protracted, for the same final biological effect, is known as dose and dose-rate effectiveness factor (DDREF). The cumulative protracted radiation received by the entire population of USA is very large and falls under regulatory policies that are government defined. These policies rely on the work of national and international agencies evaluating potential dangers of IR using the DDREF value as one of the key input factors for consideration of protracted IR exposures. Ultimately, government regulated limits for occupational and public IR exposures (mostly protracted) and recommendations for X-ray based medical diagnostic procedures (mostly low total doses) all depend on currently accepted DDREF value. Using computational tools and animal data on acute and protracted exposures we found that the DDREF estimate used at this time is inappropriate (Haley et al. 2015) but that dose-rate effectiveness factor (DREF) can be evaluated using extensive animal data. In this project we propose to use interspecies comparisons to refine (1) external beam DREF values and (2) radionuclide dose/quality/route of administration dose rate effectiveness factors (DREF) for specific types of radiation induced cancers (and life shortening from internal emitters). This is especially important in light of the fact that several international bodies are looking to change values for DDREF– a letter from ICRP sent specifically to our group supporting the importance of this work is attached to the application.