Iodine-131 S values for use in organ dose estimation of Korean patients in radioiodine therapy

In the present study, iodine-131 S values (rT ← thyroid) were calculated for 30 target organs and tissues using the most recently developed Korean reference computational phantoms. The calculated S values were then compared with those of the International Commission on Radiological Protection (ICRP) reference computational phantoms to investigate the dosimetric impact of the Korean S values against those of the ICRP reference phantoms. The results showed significant differences in the S values due to the different anatomical/morphological characteristics between the Korean and ICRP reference phantoms. Most target organs/tissues showed that the S values of the Korean reference phantoms are lower than those of the ICRP reference phantoms, by up to about 4 times (male spleen and female thymus). Exceptionally, three target organs/tissues (gonads, thyroid, and extrathoracic region) showed that the S values of the Korean reference phantoms are greater, by 1.5–3.7 times. We expect that the S values calculated in the present study will be beneficially used to estimate organ/tissue doses of Korean patients under radioiodine therapy.