Inactivation of Synchronized Chinese Hamster V79 Cells with Charged-Particle Track Segments

BIRD, R. P., ROHRIG, N., COLVETT, R. D., GEARD, C. R., AND MARINO, S. A., Inactivation of Synchronized Chinese Hamster V79 Cells with Charged-Particle Track Segments. Radiat. Res. 82, 277-289 (1980). Synchronized Chinese hamster V79 cells were irradiated with protons, deuterons, and helium-3 ions in a series of cell inactivation experiments. The charged particles were accelerated at the Radiological Research Accelerator Facility at Brookhaven National Laboratory and provided a range of LET values from 10 to 170 keV/C/m. Two parts of the cell cycle were irradiated to determine clonogenic survival, the G,/S transition and late-S phase, both obtained by hydroxyurea-induced synchrony. The difference in radiation sensitivity between these two synchronized cell populations decreased with increased values of LET, but a 10-fold difference persisted with the highest LET values. The inactivation cross sections calculated from initial slopes of the survival curves increased to plateau values of about 19 and 38 C/m2 for the late-S and G,/S cells, respectively. In contrast, the respective cross sections of cell nuclei were measured and had mean values of 222 and 165 /Lm2.