[en] Public and governmental concern about the cancer risks associated with indoor exposure to alpha particle-emitting radon progeny is growing. Such concern arises from the exposure-dependent elevation in cancer risk seen in underground miners, most notably uranium miners. Risk estimates for the general population are derived from extrapolations of risk estimates for the uranium miners. The ability to compare data from the numerous retrospective population studies, animal model experiments, and in vitro experiments is based upon dose-conversion factors that indicate equivalent detrimental endpoints due to certain exposure levels. Recently, efforts to use cytotoxic endpoints such as cell survival, micronucleus formation, and mitotic delay as biologic dosimeters have been compared in vivo and in vitro to obtain dose conversion ratios. While these efforts are successful in cumulative exposure levels of 75-1000 working level months (WLM), such biological dosimeters are insensitive to the cumulative exposure levels found in indoor environments (1-50 WLM). More sensitive indicators of radiation damage/effect are needed to improve dose conversion factors and to better understand how alpha-emitters such as radon cause cancer