DNA damage is a proven biomarker of radiation effects. Cytogenetic techniques commonly employed to detect DNA strand breaks include chromosomal aberrations, micronucleus and comet assays in field and laboratory circumstances. In recent times, flow cytometry (FCM) has been widely used to quantify DNA damage as it offers the analysis of a large number of nuclei within minutes providing statistically reliable results in a short period of time. Ideally, all cells in an organism contain the same amount of DNA. DNA damage results from the breakage and rearrangement of chromosomes and interference with the normal segregation of chromosomes during cell division. Double-strand breaks are the most prominent DNA lesions caused by ionizing radiation and other damage resulting from exposure to genotoxic agents that give rise to cells with abnormally high or low DNA content. This variability can be detected as an increase in the coefficient of variation (CV) of cells in the G0/G1 phase measured by flow cytometry. Alternatively, appearance of aneuploid cell populations as a result of mitotic machi...