Removal of inhaled 241Am oxide particles of various sizes from beagle dogs using lung lavage and chelation treatment

The combined treatments of lung lavage and chelation therapy were evaluated for the removal of inhaled 241AmO2 aerosols in Beagle dogs. Groups 1 to 3 were exposed to monodisperse particles of 241AmO2 of 0.75, 1.5 and 3.0 μm aerodynamic diameter (AD) respectively; a fourth group was exposed to polydisperse particles of 241AmO2 with an activity median aerodynamic diameter (AMAD) of 1.8 μm. Treatment consisted of 5 lung lavages of the right and left lungs. Treated dogs were also given 18 intravenous injections of DTPA. The dogs were sacrificed 64 days after inhalation exposure. The amount of 241Am removed from lung in the lavage fluid for Groups 1 to 4 represented 41, 46, 42 and 33 % of the initial lung burden, respectively. The amount of 241Am excreted in the urine from the treated dogs in excess of that excreted by the untreated dogs for Groups 1 to 4 was 20, 19, 8 and 26 %, respectively. More 241Am was excreted in the urine from dogs that inhaled smaller particle sized aerosols. As a result of the removal of 241Am activity, the 64-day cumulative absorbed radiation doses to lung, liver and skeleton were reduced by 50, 90 and 85 %, respectively. (author)