Evaluation of Tritium: Relative Biological Effectiveness and Cancer Mortality

氚的评估：相对生物有效性和癌症死亡率

• 批准号: 7874091
• 负责人: DAVID B RICHARDSON
• 金额: $ 7.06万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7874091
• 关键词: Evaluation; Tritium; Relative; Biological; Effectiveness

DESCRIPTION (provided by applicant): X-rays and gamma radiation are well-established carcinogens with substantial evidence of carcinogenicity in humans from epidemiological research. In contrast, there is very little epidemiological research on the human health effects of beta radiation. Even less is understood about the effects of chronic exposure to beta-emitters, such as tritium, a low- energy radioisotope of hydrogen that is produced through nuclear fuel production. Radiation protection standards assign a relative biological effectiveness (RBE) of 1 for beta-emitters compared to gamma-emitters. However, a recent scientific review concluded that the RBE of tritium needs reevaluation. The goal of this proposed study is twofold. First, we propose to estimate the RBE of tritium based on data from the existing literature. The ultimate goal is to apply an accurate RBE for tritium to examine the relationship between chronic, low-dose tritium exposure and cancer among a cohort of nuclear production workers at the Savannah River Site (SRS), the nation's only large- scale tritium production facility. Second, we propose to utilize the information regarding the RBE of tritium to reevaluate the cancer mortality associated with other forms of radiation exposure in conjunction with tritium at the SRS facility. Worker information, including annual tritium and gamma radiation dose, is enumerated for 18,883 workers employed from 1951-1999. Using this data, we propose to establish the distribution of the RBE of tritium with gamma as our reference form of radiation. Recognizing that quantification of a dose-response function for the tritium component of SRS workers will be highly imprecise due to the low magnitudes of tritium doses, we will employ Markov Chain Monte Carlo estimation, a technique that will allow us to establish an a priori distribution based on data from laboratory studies and to test how well an epidemiologic dataset - the SRS cohort data -- fits that distribution. Finally, we will use these estimates to provide more accurate evaluation of the relationship between chronic, low-dose radiation exposure and cancer outcomes. Radiation exposure exists in settings outside of the nuclear fuels industry. Other occupational groups, and the general population, also experience chronic, low-dose radiation exposures. Therefore, the results of the proposed research are relevant for a broad range of occupational and environmental exposures. PUBLIC HEALTH RELEVANCE: There is very little epidemiological evidence concerning the effects of protracted exposures to tritium and its relative biological effectiveness compared to gamma- emitters. The USDOE Savannah River Site is unique in that it was involved in tritium production for nuclear weapons. The goal of this project is to evaluate the association between cancer and estimated tritium dose in this cohort. In addition, we will use Markov Chain Monte Carlo methods to combine current information on the RBE for tritium with our epidemiological data in order to estimate a (posterior) distribution of the RBE for tritium.

描述（由申请人提供）：从流行病学研究中，X射线和伽马辐射是完善的致癌物，具有大量证据。相反，关于β辐射的人类健康影响的流行病学研究很少。关于长期暴露于β发射体的影响，例如Tritium，这是通过核燃料生产产生的低能氢发射异位素的影响。与伽马发射器相比，辐射保护标准为β发射体的相对生物学有效性（RBE）为1。但是，最近的科学综述得出的结论是，trib的rbe需要重新评估。这项拟议的研究的目标是双重的。首先，我们建议根据现有文献的数据估算trib的RBE。最终的目标是将精确的RBE应用于Tritium，以检查萨凡纳河（SRS）（SRS）的核生产工人队列中慢性，低剂量trip暴露与癌症之间的关系，这是该国唯一的大型大型tri症生产设施。其次，我们建议利用有关Tritium RBE的信息来重新评估与其他形式的辐射暴露相关的癌症死亡率与SRS设施的Tritium结合使用。 1951 - 1999年从雇用的18883名工人列举了包括年度Tritium和Gamma辐射剂量在内的工人信息。使用这些数据，我们建议将Tritium of Tritium的分布与伽马作为我们的参考辐射形式。 Recognizing that quantification of a dose-response function for the tritium component of SRS workers will be highly imprecise due to the low magnitudes of tritium doses, we will employ Markov Chain Monte Carlo estimation, a technique that will allow us to establish an a priori distribution based on data from laboratory studies and to test how well an epidemiologic dataset - the SRS cohort data -- fits that distribution.最后，我们将使用这些估计值对慢性，低剂量辐射暴露与癌症结局之间的关系进行更准确的评估。在核燃料行业以外的环境中存在辐射暴露。其他职业群体和普通人群也经历了慢性低剂量辐射暴露。因此，拟议研究的结果与广泛的职业和环境暴露有关。 公共卫生相关性：与γ发射器相比，关于tra虫暴露及其相对生物学有效性的影响的流行病学证据很少。 USDOE Savannah河的独特之处在于它参与了核武器的trium生产。该项目的目的是评估该队列中癌症与估计的tri剂量之间的关联。此外，我们还将使用马尔可夫链蒙特卡洛方法将RBE上的当前信息与我们的流行病学数据相结合，以估算tritium的RBE的A（后验）分布。