Theoretical and experimental tests of a chromosomal fingerprint for densely ionizing radiation based on F ratios calculated from stable and unstable chromosome aberrations

In the present study, F ratios for both stable chromosome aberrations, i.e. ratios of translocations to pericentric inversions, and unstable aberratio ns, i.e. dicentrics and centric rings, were measured using fluorescence in situ hybridization. F ratios for stable aberrations measured after exposure to low (2.89 Gy Co-60 gamma rays) and high-LET (0.25 Gy Fe-56 ions; 1.25 G y Fe-56 ions; 3.0 Gy C-12 ions) radiation were 6.5 +/- 1.5, 4.7 +/- 1.6, 9. 3 +/- 2.5 and 10.4 +/- 3.0, respectively. F ratios for unstable aberrations measured after low (2.89 Gy Co-60 gamma rays) and high-LET (0.25 Gy Fe-56 ions; 3.0 Gy C-12 ions) radiations were 6.5 +/- 1.6, 6.3 +/- 2.3 and 11.1 /- 3.7, respectively. No significant difference between the F ratios for lo w- and high-LET radiation was found. Further tests on the models for calcul ation of the F ratio proposed by Brenner and Sachs (Radiat. Res. 140, 134-1 42, 1994) showed that the F ratio may not be straightforward as a practical fingerprint for densely ionizing radiation. (C) 1999 by Radiation Research Society.