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

电离辐射（IR）对生物体造成损害。研究了不同总剂量的胰岛素抵抗对健康的影响， 必须通过基于整个生物体的统计分析来确定IR的剂量率 终点，如癌症发展风险增加或寿命缩短风险增加。的 如果延长时间，对于相同的最终生物学效应，总剂量可以增加的因子被称为 剂量率效应因子（DDREF）。整个地球所受到的长期累积辐射 美国人口众多，福尔斯受政府规定的监管政策的约束。这些政策 依靠国家和国际机构的工作，利用DDREF评估IR的潜在危险 价值作为考虑长期红外线照射的关键输入因素之一。最终，政府 职业和公共红外线照射的规定限值（大部分是长期的）和X射线的建议 基于放射治疗的医学诊断程序（大多数是低总剂量）都依赖于目前接受的DDREF值。 使用计算工具和动物急性和长期暴露数据，我们发现DDREF 此时使用的估计值不合适（Haley等人，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，我们建议使用物种间的比较， 细化（1）外部射束DREF值和（2）放射性核素剂量/质量/给药途径剂量率 特定类型辐射诱发癌症的有效性因子（DREF）（以及内部辐射导致的寿命缩短） 发射器）。这一点尤其重要，因为有几个国际机构正在寻求变革， DDREF的价值观-ICRP专门向我们小组发送了一封信，支持这项工作的重要性， 附在应用程序中。

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.