Age-specific uncertainty of the 131I ingestion dose conversion factor

Area of Science:

• Environmental Science
• Nuclear Chemistry
• Radiological Health

Background:

• Nuclear material production leads to environmental releases of radionuclides.
• Radioactive iodine-131 (131I) is a common fission by-product released from nuclear facilities.
• Physiological variations across age groups impact iodine biokinetics.

Purpose of the Study:

• To establish age-specific dose conversion factor uncertainty for accurate internal dose assessment of 131I.
• To analyze the distribution characteristics of the 131I dose conversion factor across different age groups.

Main Methods:

• Determined the log-normal distribution of the 131I dose conversion factor.
• Identified key parameters influencing dose conversion factor uncertainty: thyroid mass and iodine uptake fraction.
• Investigated the correlation between thyroid mass and iodine uptake fraction.

Main Results:

• The 131I dose conversion factor exhibits log-normal distribution with age-specific characteristics.
• Thyroid mass and iodine uptake fraction are critical parameters for dose conversion factor determination across all ages.
• A significant correlation exists between thyroid mass and iodine uptake fraction, impacting dose conversion factor uncertainty.

Conclusions:

• Accurate internal dose assessment for radioiodine exposure necessitates age-specific dose conversion factors.
• Understanding the correlation between thyroid mass and iodine uptake fraction enhances the precision of dose estimates.
• Improved dose estimates for oral 131I intake can be achieved by considering age-specific factors and their input parameters.