The effect occupational exposure to ionizing radiation on the DNA damage in peripheral blood leukocytes of nuclear medicine personnel.

Objectives: The aim of this study was estimation of DNA strand breaks in leukocytes of peripheral blood of staff in a nuclear medicine department.

Methods: The exposed group consisted of 46 volunteers and the control group consisted of 40 volunteers. Samples consisting of 1 ml whole blood were collected by venepuncture. DNA damage in leukocytes was detected by alkaline comet assay.

Results: There was no correlation between the effective dose measured by individual dosimeters and DNA damage and no differences between sexes. The mean level of damage to DNA in people exposed to ionizing radiation was significantly elevated compared with control individuals. The highest value for mean comet tail moment was noted in leukocytes of PET/CT and scintigraphy technicians (1.28 vs. 0.30 for control, p=0.013). The levels of DNA damage in leukocytes of workers in category B (effective dose may exceed 1 mSv/year) were significantly enhanced. The DNA migration of leukocytes in exposed smokers and nonsmokers was similar. In the control group the damage to DNA of leukocytes in smokers was markedly but not significantly higher compared with nonsmokers.

Conclusions: Occupational exposure to ionizing radiation leads to enhanced levels of reversible DNA damage in leukocytes of nuclear medicine employees. The level of DNA damage depends on the kind of work. Cigarette smoking is related to the increase in DNA damage in unexposed individuals but not in nuclear medicine workers. Radiation seems to be a stronger inducer of DNA damage than smoking. Although most of the DNA damage detected by comet assay is repaired, further improvement of radiation safety should be taken under consideration.