Dose-effect relations for stochastic rates of injury formation in cells.

The dose dependencies of lesion formation and cell survival are obtained for the imparting energy stochastic in time. It is shown that for the second-order dependence of the number of lesions on the radiation field one obtains the linear-quadratic dose dependence in the high dose range. The appearance of the linear component is related to the fluctuations and correlations of the rate of imparted energy. Expressions are obtained for cell survival in the one-target model for pulsed and prolonged irradiations.