The Evaluation of Genotoxic Risks in Medical Personnel Occupationally Exposed to Ultrasound: The Alkaline Comet Assay Study

The use of ultrasound devices in medical diagnosis has experienced a phenomenal growth in recent years. Therefore it has become important to check its genetic harmlessness, especially in occupationally exposed medical personnel. In the present study, the alkaline comet assay was selected as a sensitive biomarker of exposure to evaluate the levels of primary DNA damage in peripheral blood leukocytes of ultrasound-exposed and corresponding control subjects. Exposed and control groups comprised of 30 subjects of similar age and smoking habits. The venous blood samples were processed by standard comet assay procedure: they were embedded into agarose microgels, subjected to lysis, denaturation and electrophoresis in alkaline conditions. The extent of DNA migration in leukocytes was assessed by measuring of comet tail length and tail moment. A total of 100 randomly captured comets from each slide were examined using an epifluorescent microscope connected through a black and white camera to an computerising image analysis system. The results obtained indicate potentially genotoxic effects of daily occupational exposure to ultrasound with significant increased values of comet tail length and tail moment measured in leukocytes of the exposed subjects compared to control. Within exposed group significant inter-individual differences in DNA damage were assessed, indicating different genome sensitivity. It was also observed that smoking habits influenced the levels of primary DNA damage in some control and exposed subjects. In spite of their limitations, results of present comet assay study indicate that individuals occupationally exposed to ultrasound may experience an increased genotoxic risk and strongly emphasize the need for more research into the nature and extent of the biological consequences to medical personnel working with ultrasound.