Estimation of internal exposure to uranium with uncertainty from urinalysis data using the InDEP computer code.

Area of Science:

• Occupational health
• Radiation dosimetry
• Epidemiological studies

Background:

• National Institute for Occupational Safety and Health (NIOSH) is studying mortality in workers exposed to uranium.
• Over 220,000 urine samples were analyzed for internal uranium exposure.
• Existing bioassay data analysis programs are time-consuming for large cohorts.

Purpose of the Study:

• To introduce the Internal Dose Evaluation Program (InDEP) for efficient internal radiation exposure assessment.
• To facilitate epidemiological studies of uranium- and plutonium-exposed cohorts.
• To describe the application of InDEP in a retrospective dose assessment.

Main Methods:

• Development of the Internal Dose Evaluation Program (InDEP) with batch processing capability.
• Analysis of bioassay data (urine samples) to derive intakes and organ doses.
• Utilizing least-squares regression and Bayesian methods for dose estimation with uncertainty.

Main Results:

• InDEP enables simultaneous evaluation of multiple subjects, significantly reducing assessment time.
• The program derives internal intakes and organ doses with uncertainty estimates.
• Application of InDEP informed exposure characteristic assumptions for a large cohort.

Conclusions:

• InDEP offers a novel solution for efficient internal dose assessment in large occupational cohorts.
• The batch processing feature of InDEP is crucial for epidemiological studies.
• This tool supports retrospective intake and organ dose assessments for radiation-exposed workers.