A Cs-137 afterloading device. Preliminary results of cell kinetic effects of low dose-rate irradiation in an experimental tumour.

A Cs-137 afterloading technique is described which can be used in experimental tumours. Preliminary results, obtained with the human cervical carcinoma ME-180 xenografted to nude athymic mice, demonstrated that 20 Gy of low dose-rate irradiation induced an important redistribution of cells over cell cycle. The proportion of cells in G2-phase increased from 14.4% to 44.2% at 140 hours after irradiation. This method allows an accurate calculation of the dose-rate distribution in the tumour. Investigations of the cell kinetic effects of low dose-rate irradiation, at different dose-rates and different total doses, are therefore facilitated by the technique.