LET dependence of yield ratios of radiation-induced intra- and interchromosomal aberrations in human lymphocytes.
OBJECTIVE
To investigate the LET dependence of various yield ratios of intra- and interchromosomal aberrations in order to quantify proximity effects for illegitimate rejoining of chromosome breaks.


METHODS
Calculations are based on 13 human lymphocyte data sets obtained from in vitro irradiation experiments with various radiation qualities covering an LET range of 0.5 to 150keV/microm. A total of 93000 first-division metaphases was analysed for all categories of chromosome-type aberrations.


RESULTS
No dose dependence was found for the various yield ratios of chromosomal aberrations. No LET dependence became apparent for the yield ratio of inter- to intrachromosomal exchange-type aberrations (dicentrics/centric rings = F value). However, a clear LET dependence was found for the yield ratio of intra-arm intrachanges to inter-arm intrachanges (interstitial deletions/centric rings = G ratio) and for the yield ratio of intra-arm intrachanges to interchromosomal exchanges (interstitial deletions/dicentrics = H ratio).


CONCLUSIONS
Measurements of intrachanges are informative for interpretation and quantification of proximity effects in the formation of radiation-induced chromosome aberrations. In particular, yield ratios for intra-arm intrachanges are likely to have a high potential as an indicator of high-LET radiations.
GSF, National Research Center for Environment and Health, Institute of Radiobiology, Neuherberg, Germany.
M
M
Bauchinger
E
E
Schmid
D000512:Alpha Particles / Q000009:adverse effects; D002869:Chromosome Aberrations / Q000235:genetics; D019457:Chromosome Breakage / Q000235:genetics; D002875:Chromosomes / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects; D006801:Humans; D018499:Linear Energy Transfer / Q000235:genetics*; D008214:Lymphocytes / Q000528:radiation effects*; D009502:Neutrons / Q000009:adverse effects; D011522:Protons / Q000009:adverse effects; D014965:X-Rays / Q000009:adverse effects
D011522:Protons