Radioiodine internal dose coefficients specific for Koreans

Area of Science:

• Nuclear Medicine
• Radiological Protection
• Biokinetics

Background:

• International Commission on Radiological Protection (ICRP) provides reference dose coefficients.
• Existing models may not accurately reflect Korean physiological and anatomical characteristics.
• Radioiodine isotopes are used in diagnostics and therapeutics, necessitating accurate dosimetry.

Purpose of the Study:

• To develop internal dose coefficients for radioiodine specific to the Korean population.
• To compare these Korean-specific coefficients with ICRP reference values.
• To investigate the impact of population-specific biokinetics and phantom design on dose assessment.

Main Methods:

• Incorporation of a Korean biokinetic model.
• Utilization of Korean S values (absorbed fraction per unit cumulated activity).
• Development of Korean reference phantoms for dose calculation.

Main Results:

• Significant differences in thyroid dose coefficients for longer-lived iodine isotopes (I-125, I-129) between Korean and ICRP values (ratios 0.30-0.55).
• Comparable thyroid dose coefficients for short-lived I-131 (ratios 0.95-0.98) due to offsetting factors.
• Substantial variations in non-thyroidal and effective dose coefficients due to anatomical and technical differences.

Conclusions:

• Korean-specific internal dose coefficients for radioiodine provide more precise dose assessments.
• The use of these tailored coefficients is particularly recommended for scenarios involving potentially high radiation doses.
• This study highlights the importance of population-specific dosimetry in radiological protection.