An evaluation of protracted low dose rate irradiation from an acute dose survival curve

A method of transformation from an acute survival curve to a protracted low dose rate survival curve based on the concept of the dose equivalent sublethal damage advanced by Oliver is introduced. The transformation was done by solving a differential equation which was formulated between the slope of both survival curves and which was able to be applied to the situation where the dose rate might change with time, e.g., in using short-life radioisotope or the complexity of the recovery of sub-lethal damage. The effects of the short-life radioisotopes (radon seeds and radiogold grains) in radiotherapy were estimated by using this method and applying it to Lajtha-Oliver's model; our data are compared with the data obtained by Orton.