Biokinetic model analysis with DTPA administration for a case of accidental inhalation of actinides in Japan.

This article focuses on the evaluation of Ca/Zn-diethylenetriaminepentaacetic acid (DTPA) therapy efficacy following accidental inhalation of plutonium isotopes and americium-241 (^241Am) by workers at a Japan Atomic Energy Agency (JAEA) facility in 2017. Using a biokinetic model based on the European Coordinated Network on Radiation Dosimetry (CONRAD) approach, the study analyzed urinary excretion data to characterize the absorption types and particle size (activity median aerodynamic diameter, AMAD) of inhaled ^241Am and to simulate the enhanced excretion due to DTPA administration. The model, incorporating reactions in blood, interstitium, and lymph compartments, qualitatively reproduced long-term urinary excretion trends observed in the most exposed worker, supporting its utility in assessing decorporation treatment efficacy. Limitations include empirical determination of reaction rates and assumptions regarding tissue parameters, indicating the need for further refinement before quantitative application.