Monitoring of Iodine-125 intakes in A group of workers producing labeled compounds

This paper describes the programme and results of thyroid monitoring of six individuals working in a radioiodination laboratory in Iran. In this laboratory, nearly 3.7 GBq of 125 I solution is handled once every 40 days for protein labelling. The thyroidal 125 I measurements have been carried out using a thyroid counter equipped with a thin-window 50 mm diameter by 50 mm thick NaI (Ti) detector connected to a multichannel analyzer. According to the results of periodical measurements, the mean values of thyroid 125 I uptakes by workers resulting from separate operations were from 0.41 to 3.4 KBq, with the corresponding mean estimated intakes from 1.15 to 24.07 KBq. The highest estimated intake occurred for the iodination workers of interest, was 106.68 KBq. The 125 I intakes by the workers as a fraction of activity used have been calculated to range from 0.3 x 10-6 to 6.5 x 10-6