The inverse dose-rate effect for radon induced lung cancer: a modified approach for risk modelling.

One of the features of high LET alpha-ray exposure due to radon inhalation is the well-known inverse dose-rate effect. The longer a given dose is delivered to the lung, the higher is its carcinogenic effect. This introduces the problem of risk extrapolation from high levels of radon exposure typical for uranium miners, down to low levels of radon exposure typical for the general population. An analytical model is presented that accounts for dose-rate effects over the entire exposure range. In accordance with radiobiological considerations and microdosimetric implications, the model provides an adequate description of the inverse dose-rate effect in the higher dose range. At the same time, a linear slope at low exposures that is independent of the dose-rate of exposure is attained.