¹³¹I dose coefficients for a reference population using age-specific models.

Area of Science:

• Radiological Physics and Dosimetry
• Internal Dosimetry
• Radiation Protection

Background:

• Accurate internal dose assessment for the public requires age-specific dose coefficients.
• Iodine-131 (¹³¹I) is a significant radionuclide in radiological assessments, necessitating precise biokinetic modeling.

Purpose of the Study:

• To estimate age-specific dose coefficients for ¹³¹I exposure in the general public.
• To calculate total nuclear disintegrations and S values for various source and target regions.
• To determine committed tissue equivalent doses and dose coefficients for different age groups.

Main Methods:

• Utilized age-specific biokinetic models for iodine and 10 paediatric reference computational phantoms.
• Performed Monte Carlo transport simulations using FLUKA code.
• Estimated total nuclear disintegrations (ã(r_S,τ)), S values, committed tissue equivalent doses (H_T(τ)), and dose coefficients (e(τ)).

Main Results:

• Thyroid source ã(r_S,τ) values increase with age; S values decrease with age due to increased target mass.
• Committed tissue equivalent doses (H_T(τ)) generally decrease with age.
• Ingestion dose coefficients are 63% higher than inhalation; thyroid contributes 96-99% to dose coefficients.

Conclusions:

• Estimated dose coefficients for ¹³¹I are lower than previous ICRP reference values.
• Derived values can improve internal dose estimations for public exposure scenarios involving ¹³¹I.
• Interpolation of dose coefficients allows accurate dose evaluation for ¹³¹I therapy or emergencies.