Chromosome aberrations and their interpretation

The interaction of ionizing radiations with genetic material may be expressed in the metaphase at different levels. The influence of radiation on the spindle may induce genome mutations modifications of the chromosome distribution. Directly on the chromosomes, ionizing radiations may induce gene and chromosome mutations. Only the latter are detectable by a cytogenetical analysis: the numerical evaluation of these chromosomic mutations allows a determination of dose-effect relationships for high level irradiation but for the study of mutagenic effect at low doses, more recent techniques are necessary such as banding and sister chromatid exchanges (SCE). (G.C.)