Estimating individual exposure to ¹³¹I for radiation workers at radioisotope production using air sampling and smartphone techniques

Indoor individual exposure at radioisotope production depends strongly on temporal concentration variation, contacting time and working location of radiation workers. To estimate personal exposure to indoor air polluted with ¹³¹I for the workers at radioisotope production, we had employed a low cost indoor model appropriate for their specific situation. In this model, time-microenvironment occupied by the workers was recorded by a smartphone sensitive motion software. Simultaneously, on the work days, indoor air in the three iodine production rooms was sampled by a portable air sampler coupled with activated carbon cartridges impregnated by TEDA. Then the low background gamma spectrometer was used to measure activity of the cartridges and the concentration of ¹³¹I in these rooms was calculated with the temporal resolution of one hour. By combining the hourly concentration with the high temporal resolution of activity patterns, we estimated the actual exposures for the group of workers producing radioisotopes in Nuclear Research Institute (Dalat) for the first four months of 2015. The highest daily average exposure was 410.2 Bq/m³ while the highest average exposure of the group was 147.2 Bq/m³. It showed an useful value for minimizing risks and estimating internal doses as well. This feasibility study may be applied for assessing personal exposure at radioisotope production, but also for many other indoor environments. (author)