APPLICATION OF THE COMET ASSAY FOR MONITORING DNA-DAMAGE IN WORKERS EXPOSED TO CHRONIC LOW-DOSE IRRADIATION I - STRAND BREAKAGE

We examined a group of people professionally at risk of exposure to lo w doses of ionizing radiation (altogether 49 individuals). Age, use of therapeutic drugs, work-related exposure to hazardous agents, previou s exposures to diagnostic X-rays, such as patient and nuclear medical examination, were registered. For each individual, the occupational ra diation burden received over the past period of 5 years was taken from the official personal records based on film dosimetry controlled ever y month. A matched group of controls was chosen among the administrati ve employees (40 individuals). The mean age of the studied population at the time of blood sampling was 49 years (range 24-69), The individu als were divided into groups according to risk of exposure and sex. Th e alkaline comet assay was used to measure DNA breaks and alkali-labil e sites. We compared the mean tail moments, tail length and percentage of DNA in the tail. There was a significant difference between the co ntrol and hazard groups in DNA damage. Higher DNA damage was also foun d for men than for women in the control group. There was no relation o f DNA damage to age either in control or hazard group. Additionally, a nalysis of distributions of tail moment values pointed to a considerab le individual diversity even in the control group. Therefore, further investigations are necessary into the suitability of the comet assay a s a biological dosimetry method; the results obtained so far warrant s uch investigations. (C) 1998 Elsevier Science B.V. All rights reserved .