Does the limiting F value at very low doses depend systematically on linear energy transfer?
The debate on the validity of the ratios of radiation-induced yields of chromosome aberrations, in particular the F value (dicentrics/ring chromosomes), as a chromosomal fingerprint of radiation quality is still in progress. From a recent analysis of their experimental data, Sasaki et al. (Radiat. Res. 150, 253-258, 1998) noted that despite a considerable variability in the data, the limiting F value at the lowest doses, or the F(0) value, obviously decreased with increasing LET, indicating that the LET could be a factor that determines the F value. We have reassessed here our own 13 cytogenetic data sets that cover a range of dose-averaged LET of 0.5 to 150 keV/microm in terms of this F(0)-value approach, but we could not confirm such a dependence on LET at very low doses. The validity of the F value as a biomarker therefore remains questionable. For a final evaluation, scoring of a far greater number of cells at low doses would be necessary to reduce the large error ranges of F values.
Schmid
E
E
GSF, National Research Center for Environment and Health, Institute of Radiobiology, 85764 Neuherberg, Germany.
Braselmann
H
H
Bauchinger
M
M
D002478:Cells, Cultured; D002869:Chromosome Aberrations; D018499:Linear Energy Transfer; D008214:Lymphocytes / Q000528:radiation effects / Q000648:ultrastructure; D011829:Radiation Dosage