RADIATION BIOLOGY OF SIMULATED RADON-DAUGHTER ALPHAS

本计划项目介绍、汇集和链接了五个项目 旨在用LET研究α粒子的生物效应 模拟氡子体所发射的辐射。个人 每个项目都从不同的角度处理这一中心主题。 辐射在单个细胞中最早可观察到的生物效应 是染色体畸变的产生， 将对颗粒进行详细研究。这个项目的特点是 试图量化精确已知数量的阿尔法效应， 穿过单个细胞的粒子。这一点尤其重要，因为 大多数有风险的细胞可能只会被一个阿尔法穿过， 粒子 由于氡对人体的危害具有随机迟发效应 关于致癌作用，实验研究直接集中在致癌 转化和突变或DNA调节，这可能是早期的 参与致癌过程的步骤。各种各样的细胞和 在这一领域提出了分子研究。 致癌转化的测定是一种强有力的工具， 用于涉及可能的超加性的语用研究 α粒子与石棉、烟草烟雾冷凝物和 各种化学物质，以及调节影响的研究，如 激素和维甲酸。机制研究的目的是确定 并描述导致诱导的分子变化， 恶性肿瘤 氡子体发射的α粒子覆盖了 当它们到达肺中的关键细胞时， 具有约90至250 keV/（μ）m的LET值。阿尔法粒子与此 LET值的范围将在放射学研究中心生成 加速器设施。

This Program Project presents, brings together, and links five projects designed to investigate the biological effects of alpha particles with LETs simulating those emitted by the daughter products of radon. The individual projects each address this central theme from different points of view. The earliest observable biological effect of radiation in individual cells is the production of chromosome aberrations, and their production by alpha particles will be studied in detail. The special feature of this project is the attempt to quantitate the effect of precisely known numbers of alpha particles traversing single cells. This is particularly important, as it is likely that most cells at risk will be traversed by no more than one alpha particle. Since the hazard of radon in the human involves the stochastic late effects of carcinogenesis, the experimental studies focus directly on oncogenic transformation and on mutations or DNA modulations, which may be early steps involved in the carcinogenic process. A variety of cellular and molecular studies are proposed in this area. Assays for oncogenic transformation represent a powerful tool and will be used for pragmatic studies involving the possible supra-additive interaction of alpha particles with asbestos, tobacco-smoke condensate, and a variety of chemicals, as well as the study of modulating influences, such as hormones and retinoids. Mechanistic studies will be designed to identify and characterize the molecular changes that lead to the induction of malignancy. The alpha particles emitted by the radon daughters cover a range of energies, and by the time they reach the critical cells in the lung, they have LET values from about 90 to 250 keV/(mu)m. Alpha particles with this range of LET values will be generated at the Radiological Research Accelerator Facility.