Assessment of the nuclear medicine personnel occupational exposure to radioiodine

Abstract Purpose To physically and cytogenetically screen medical personnel of XXX who are occupationally exposed to 131I. Materials and Methods The exposure was monitored by whole-body and finger ring dosimeters. The thyroid iodine intake was measured by a whole-body spectrometer equipped with two semiconductor gamma radiation detectors. A cytokinesis-block micronucleus assay and the premature chromosome condensation technique were used to assess the aberration score. Cytogenetic analyses were carried out on a group of 29 workers and were compared to 32 controls (healthy donors), matched for gender and age. Results On average, the exposed group showed a significantly higher frequency of genetic damage and a higher proliferation index compared to the control group. Smoking status, age and duration of exposure influenced the observed effects in both groups. No differences in measured biomarkers were observed after stratification of the exposed group into two subgroups based on the measured 131I activity below and above 6 Bq. Conclusion The findings suggest that radiation protection principles based on whole-body and finger ring dosimetry, supported by activity measurements with a whole-body spectrometer, may be insufficient to monitor the absorbed dose estimation of the nuclear medicine staff who are occupationally exposed to 131I. Furthermore, their future health risks are influenced by confounders. Direct assessments comparing physical and biological dose estimations on the larger group are needed to accurately monitor occupational radiation exposure.