The Alkaline Comet Assay as a Biomarker of Primary Dna Damage in Peripheral Blood Leukocytes of Nuclear Medicine Personnel

The aim of this study was to assess whether occupational exposure to chronic low doses of ionizing radiation in nuclear medicine departments may lead to genotoxicity. The alkaline comet assay was selected as a biomarker of exposure to evaluate the levels of primary DNA damage in peripheral blood leukocytes of exposed and corresponding control subjects. Statistically significant differences were found between comet tail length and tail moment values measured in leukocytes from the exposed and control groups. Within exposed group significant inter-individual differences in DNA damage were assessed, indicating different genome sensitivity. In majority of exposed subjects the levels of DNA damage were in positive correlation with the duration of occupational exposure, while the influences of age and dosimeter readings could be excluded. However, the levels of primary DNA damage detected both in control and exposed subjects were significantly influenced by smoking. The present study indicates the possibility of genotoxic risks related to occupational exposure in nuclear medicine departments. Therefore, the exposed personnel should carefully apply the radiation protection procedures to minimize, as low as possible, radiation exposure to avoid possible genotoxic effects. According to results obtained, the alkaline comet assay could be usefully applied as a sensitive additional biomarker in the regular health screening of workers occupationally exposed to low doses of ionizing radiation. Introduction Ionizing radiation is an ubiquitous environmental physical agent whose DNA damaging effects are fairly well established. As a strong physical mutagen and a clastogenic agent, it causes the breakage of phosphodiester bonds in DNA, cross-linking as well as damage to nucleotide bases [1].