Evaluation of Effective Dose Coefficient with Variation of Absorption Fraction in Gastrointestinal System for Ingestion of Radiocesium

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The purpose of this study is to identify the significance of the change in the intestinal absorption rate values the (ƒ₁ value) to the change of ingestion dose coefficient following an acute intake of ¹³⁴Cs and ¹³⁷Cs. This study also attempted to provide a simple calculation method of ingestion dose coefficients given a specific value of ƒ₁ and age groups by using linear regression models. In the range of 0-1, 10 different values of ƒ₁ for 1-year, 5-year-old, and the adult group were chosen and used in a separate calculation by using, a biokinetic compartment model, DCAL. It was found that the lower values of ƒ₁ lead to a significant decrease of the committed effective dose coefficient for an adult. Oppositely for children, the decrease of the coefficient was not as significant. This study also suggests that the significance of dose coefficient change due to the variation of ƒ₁ substantially depends on the biological half-life of the radionuclide, the fraction of absorbed energy and the mass of organs and tissues in human body.