Measurement of Iodine-131 in Airborne Nuclear Medicine Facility and its Assessment of Internal Occupation Radiation Dose

The increasing use of the radiopharmaceutical Iodine-131 (I-131) in nuclear medicine facilities has significant implications regarding the potential for internal radiation received by workers through inhalation from I-131 contamination in the airborne. Unlike measuring external radiation which can be used with detectors that are widely available on the market, measuring internal radiation is a challenge due to the lack of measuring equipment and the limitations and complexity of the assessment. This study aims to estimate the internal dose of radiation workers by measuring I-131 concentrations in nuclear medicine facilities. Air samples were collected using a Negretti Automation Large Volume Air Sampler [Model NR 2030] fitted with a honeycomb polyurethane filter. The process of air sampling was conducted within various areas of the facility, including the hot lab, injection room, patient isolation room, administration room, pre-injection waiting room, post-injection waiting room, and SPECT-CT radiation room. The activity of I-131 gas from the sample was measured using a GSB Gamma Spectrometer. The measurement results show that the highest activity of I-131 is in the isolation room, with a value of 67.29 ± 3.99 Bq/m³. Meanwhile, several measurement locations such as the pre-injection room, post-injection room, examination room and admission room in several days found no concentration of I-131 in the air of these rooms. Based on these estimations, the group of professions who have the highest risk of being contaminated with I-131 through inhalation are nurses, radiologists and cleaning staff with the estimated range of doses received respectively being 4.1×10^-3 - 61×10^-3 µSv, 6.70×10^-3 – 121×10^-3 µSv and 5.95×10^-3 - 182×10^-3 µSv.