Simulation study on iodine thyroid blocking in Koreans with high dietary iodine consumption

This study conducted a simulation of iodine thyroid blocking in the Korean population, which typically has a high dietary iodine intake, using the Korean biokinetic model. We evaluated the thyroid protective effects of stable iodine administration and produced thyroid retention functions and dose coefficients for Koreans. Our findings highlight notable differences between the Korean model and the International Commission on Radiological Protection (ICRP) reference model. The faster recovery from the thyroid blocking, due to higher blood iodide concentrations, resulted in lower protective effects (66 % versus 86 % for 100 mg of stable iodine administered 24 h before iodine exposure) compared to the ICRP model. Additionally, the Korean model demonstrated higher thyroid retention functions, particularly when stable iodine was administered within 24 h before or 2 h after exposure, with delayed secondary peaks. Thyroid dose coefficients were also higher in the Korean model, with values up to 1.5 times greater, due to both lower protective effects and higher S values in Korean anatomical models. While this study offers valuable insights into the thyroid blocking effect in Koreans, this study does not undermine the validity of thyroid protection guidelines in Korea, which should be based on broader assessments, including pathological and risk-benefit analyses.