The evaluation of long-term effects of ionizing radiation through measurement of current sister chromatid exchange (SCE) rates in radiology technologists, compared with previous SCE values.

Ionizing radiation is a strong physical mutagen, causing breakage of phosphodiester bonds in DNA at any stage of the mitotic cycle. Analysis of sister chromatid exchange (SCE) has come into use as a sensitive DNA-damage indicator. We investigated the SCE rates in radiology technologists who are occupationally and chronically exposed to ionizing radiation. The study included 39 radiology technologists and 35 sex- and age-matched healthy controls. There was a statistically significant difference in the SCE frequency between radiology technologists and controls (p<0.0001). Additionally, previous SCE data of 10 radiology technologists were compared with current results regarding radiation exposure time. There was statistically significant difference between previous and current SCE values (p=0.005). The significant increase in the frequency of SCE in radiology technologists emphasizes the importance of radiation-protection procedures in order to minimize radiation exposure and avoid possible genotoxic effects. Comparison of two studies that measured SCE values of radiology technologists after 8 years also suggests that the genotoxic effect is reversible. In conclusion, radiation is still an important mutagenic agent despite improvements in daily working hours and conditions.