Korean-specific internal dosimetry data for radioiodine bioassay and evaluation of the dosimetric impact

Abstract

Our earlier works focused on exploring the Korean iodine biokinetic model and calculating Korean-specific S values and dose coefficients. Building on this foundation, this study extended our efforts to establish an extensive dosimetry dataset for Korean-specific iodine bioassay. We calculated bioassay functions (e.g., thyroid retention and urinary excretion functions), dose-per-content-functions, and content for the specified doses based on the Korean biokinetic model and dose coefficients previously developed. Also, this study provides a comprehensive understanding of the practical impact of using Korean-specific dosimetry data. Compared to the ICRP reference data, the thyroid retention functions for Koreans were significantly lower (for I-131, peaks at 18% vs. 27%). The physical half-lives of radioiodine played a significant role in the differences of dose-per-content-function. For long-lived iodine isotopes such as I-125, the dose-per-content-functions were comparable to ICRP data, whereas for short-lived iodine isotopes such as I-131, the higher values were observed in the Korean data, indicating a greater dose estimation for a given iodine activity measured in the thyroid. Although we revealed the differences between Korean and ICRP reference data, the comprehensive understanding of Korean data suggests that using the Korean-specific data should be considered only when high doses are predicted.