Korean-specific iodine S values for use in internal dosimetry

Area of Science:

• Medical Physics
• Radiological Dosimetry
• Nuclear Medicine

Background:

• International Commission Radiological Protection (ICRP) phantoms may not accurately represent Korean anatomy, potentially biasing internal dosimetry.
• Anatomical variations necessitate the development of region-specific dosimetric data for accurate radiation dose assessment.

Purpose of the Study:

• To generate a comprehensive dataset of S values for key iodine radioisotopes tailored to the Korean population.
• To improve the accuracy of internal dosimetry and radiation protection for Koreans undergoing radioiodine therapy or exposure.

Main Methods:

• Monte Carlo simulations were employed to calculate S values.
• Mesh-type Reference Korean Phantoms (MRKPs) were developed in a high-fidelity mesh format for simulation.
• S values were computed for five iodine radioisotopes: I-125, I-129, I-131, I-133, and I-134.

Main Results:

• Significant discrepancies were found between Korean and ICRP phantom-derived S values, with ratios ranging from 0.16 to 6.2.
• The majority of S value ratios (Korean/ICRP) were below 1, indicating lower absorbed doses in Korean phantoms for certain iodine isotopes.
• The interquartile range for S value ratios was 0.47-1.28, with a mean of 0.96 and a median of 0.69.

Conclusions:

• The developed Korean S values are crucial for precise internal dosimetry in the Korean population.
• This study highlights the importance of using anatomically relevant phantoms in radiation dosimetry.
• The findings will enhance the safety and effectiveness of radiation protection measures involving iodine radioisotopes for Koreans.