Six-year follow-up of an acute 241Am inhalation intake

A 38-y-old Caucasian male who suffered an acute accidental inhalation intake of 6.3 kBq of 241Am was monitored over 2,135 d using periodic in vivo measurements of the activity in the lungs, liver, and skeleton. Lung clearance was described by a two-compartment exponential model with half-times of 110 d and 10,000 d. The observed uptake of 241Am in the liver (72 Bq) and skeleton (170 Bq) was significantly greater than predicted by the ICRP models for liver (5 Bq) and skeleton (8 Bq). The half-time in the liver was approximately 850 d. Estimates of skeletal activity based on head, wrist, and knee counts generally agreed within 25% over the course of the monitoring period. The half-time in the skeleton was approximately 20,000 d.