Effects of PuO2 particles deposited in rat lung following intraperitoneal injection

From 0.2 to 2.0 percent of intraperitoneally injected 239PuO2 was found in the alveolar septa of rats at 1 to 2 years after injection, resulting in a cumulative radiation dose to the lung of up to 600 rads. Only one lung tumor was seen in 108 injected rats. It was concluded that sequestration and immobilization of large PuO2 particles in the alveolar septa results in nil or low lung tumor incidence as compared to the high lung tumor incidence seen when PuO2 is delivered to the lung as an aerosol. (U.S.)