Modeling Plutonium Decorporation in a Female Nuclear Worker Treated with Ca-DTPA after Inhalation Intake.

Area of Science:

• Radiological Sciences
• Occupational Health
• Biokinetics Modeling

Background:

• Bioassay data from a former female nuclear worker exposed to plutonium-americium mixture is unique.
• Chelation therapy using calcium-diethylenetriaminepentaacetic acid (Ca-DTPA) enhances plutonium and americium excretion, complicating dose assessment.
• Current practices often exclude chelation-affected data from internal dose assessments.

Purpose of the Study:

• To model plutonium biokinetics in a female nuclear worker, explicitly including data affected by chelation therapy.
• To assess internal radiation dose by incorporating a novel chelation model into biokinetic analysis.
• To evaluate the effectiveness of chelation treatment in reducing internal radiation dose.

Main Methods:

• Biokinetic modeling of plutonium (Pu) and americium (Am) using bioassay data (urine, feces) from a female nuclear worker.
• Application of a newly developed chelation model to incorporate Ca-DTPA treatment effects.
• Utilized Markov Chain Monte Carlo (MCMC) method for model parameter uncertainty analysis.

Main Results:

• Accurate modeling of plutonium biokinetics and dose assessment was achieved, with a goodness-of-fit (χ2/nData ≈ 1).
• Estimated worker's 239Pu intake at 12 Bq.
• Calculated committed effective dose to the whole body (1.2 mSv) and equivalent doses to bone surfaces (37.8 mSv), liver (9.1 mSv), and lungs (0.8 mSv).

Conclusions:

• The study successfully modeled chelation-affected bioassay data in a female, providing a more comprehensive dose assessment.
• Demonstrated the significant impact of chelation therapy on plutonium biokinetics and internal dose reduction.
• Highlights the importance of including chelation data in future internal dose assessments for exposed workers.