Comparison of dose estimation from occupational exposure to 239Pu using different modelling approaches

Area of Science:

• Occupational Health
• Radiological Protection
• Biomonitoring

Background:

• Assigning plutonium (Pu) doses to Mayak workers involves complex bioassay interpretation.
• Existing methods include conventional International Commission on Radiological Protection (ICRP) models, individualized Bayesian fitting, and adapted ICRP models for the Mayak population.

Purpose of the Study:

• To evaluate and compare three distinct approaches for Pu dose reconstruction in Mayak workers.
• To identify the sources of discrepancies in dose estimates derived from different bioassay interpretation methods.

Main Methods:

• Utilized a dataset of 42 deceased former Mayak workers with available urine bioassay and post-mortem tissue data.
• Applied conventional ICRP models, individualized Bayesian statistical fitting, and adapted ICRP models for dose assignment.
• Compared the quantitative dose estimates obtained from each of the three approaches.

Main Results:

• All three tested approaches were found to be adequate for bioassay and tissue interpretation for Pu dose reconstruction.
• Significant discrepancies were observed in the quantitative dose estimates generated by the different methods.
• Discrepancies were largely attributed to variations in the interpretation of plutonium behavior within the lungs according to the ICRP lung model.

Conclusions:

• While multiple methods are adequate for Pu dose reconstruction, quantitative estimates vary considerably.
• The interpretation of plutonium lung dosimetry within ICRP models requires careful validation for Mayak worker populations.
• Further research into refining Pu lung dosimetry models is crucial for accurate occupational dose assessment.