Dependence of cell survival on instantaneous dose rate of a linear accelerator.

Abstract

With the development of flattening filter-free linear accelerators for radiotherapy, the instantaneous dose rate has increased by approximately a factor 4. This leads to the question of whether there may be a radiobiological consequence. The present study investigates the radiobiological effect of this high instantaneous dose rate on two cell lines. A Varian Trilogy TX linear accelerator was used to directly compare the effect of three different dose rates (5.01, 9.99 and 29.91 Gy/min, with instantaneous dose rates in the pulse of 56.5, 112.8 and 338 Gy/s) on clonogenic survival. V79 and FaDu(DD) cells were irradiated with doses in a range from 1 to 10 Gy in order to obtain dose response curves. For both cell lines, there is not observed any effect of the instantaneous dose rate on cell survival.