Radiotoxicity of incorporated [3H]thymidine Consequences for the interpretation of FLM data of irradiated cell populations

Abstract

Problems in the interpretation of FLM [fraction of labeled mitoses] data of externally irradiated cell populations are mainly due to the interference of radiation effects with radiotoxic effects originating from incorporated [3H]thymidine. These problems were investigated using [mouse fibroblast] L-929 cells flash labeled in vitro with [3H]thymidine (30 min, 0.3 .mu.Ci/ml, 40 Ci/mM) and irradiated with 2 Gy [gray] of 200 kV X-rays; the fractions of labelled mitoses and the index of labeled and of unlabeled mitoses were determined. The FLM is not an adequate parameter to quantify the early cell kinetic changes in irradiated cell populations.