Growth Kinetics of C3H10T1/2 Cells Exposed to Low-LET Radiation

SummaryGrowth curves and size of the colonies of C3H10T1/2 cells exposed to low-LET radiation (31 MeV protons) were determined after 0, 1, 3, 5, and 7 Gy. The data show that: cell density at confluence was 3·3 × 104 cells/cm2; the initial division delay was very small; in the first 15 h the increase in the cell number was essentially the same at all doses; at 100 h the colony size distribution was very large, ranging from 0 to 7 generations, even within the control population. The temporal dependence of the growth properties of surviving and non-surviving cells was represented by the equation N = N0(Fe(a(t − dD)) + (1 − F)ea/bD(1 − e−bD(t − dD))) where F is the surving fraction, t the time of sampling, a the growth rate, d the division delay per unit dose, b the rate per unit of dose at which the non-surviving cells lose their ability to divide. The resulting values were: a = 0·029 ± 0·002 h−1; b = 0·0041 ± 0·0009 h−1 Gy−1 and d = 1 ± 0·8 h Gy−1. It was found that growth curves are affected by non-survivi...