A case of wound intake of plutonium isotopes and 241Am in a human: application and improvement of the NCRP wound model.

Plutonium isotopes (239Pu and 238Pu, and 241Am) with a total activity of 269 kBq were accidentally deposited in a puncture wound of the right index finger of a nuclear worker at the Mayak Production Association. Tissues surrounding the wound site contaminated with radionuclides were excised 4.5 h after the injury. Residual contamination within the wound amounted to 0.05% of the initial contamination. The 10-d therapy with CaNa3-diethylene triamine pentaacetate acid (CaNa3-DTPA) was performed in parallel with in vivo measurements of the wound site and daily urine bioassays. The wound intake of radionuclides was consistent with two forms of radioactive materials detected within the wound site, i.e., soluble compounds and a large fragment, which was completely removed by excision. On day 9 after the injury, the clearance rate from the wound site was 1.8 times higher than the rate predicted by the National Council on Radiation Protection and Measurements (NCRP) model for soluble compounds of plutonium and americium. The NCRP model parameters of transfer rates from the colloid and intermediate state (CIS) into soluble, and particles, aggregates and bound state (PABS) compartments were modified to eliminate any difference. As a result, a difference between the observed wound site radionuclide content and the value predicted by the modified wound model did not exceed 14% up to 9 days after the injury. For a longer period from 7 to 24 months, the value predicted by the modified model was consistent with results of the corresponding in vivo measurements. The treatment reduced the effective dose (50 years) from internal exposure by at least 480 times. The dose estimated (without accounting for a contribution of exposure dose to the regional lymph nodes draining the wound site) did not exceed 11 mSv.