A Comparative Study of Post-irradiation Growth Kinetics of Spheroids and Monolayers

Abstract

Post-irradiation growth kinetics of γ-irradiated spheroid and monolayer cells in exponential growth phase was investigated by means of dose–response curves based on cell counts after specified time intervals following irradiation. A mathematical model of cell-growth after irradiation was fitted to these curves. The model parameters (related to division delay and growth of non-surviving cells) obtained from this analysis consistently indicate increasing resistance to sub-lethal damage of cells cultured as multicellular spheroids under conditions of increasing three-dimensional contact. In contrast, no indication of an increased radiation-resistance was found with cells cultured on a substratum under a variety of conditions.