Comparative deterministic effects of inhaled, insoluble alpha- and beta-particle-emitting radionuclides in dogs

This report compares the deterministic effects from an alpha-particle-emitting radionuclide, (239)PuO(2), and a beta-particle emitter, (144)Ce in fused aluminosilicate particles (FAP). The studies were conducted in beagle dogs of both genders exposed by inhalation to aerosols of the radionuclides. The initial lung burdens of (239)Pu and (144)Ce were determined by whole-body counting of the (169)Yb added to the plutonium aerosol during its preparation or the (144)Ce and its progeny (144)Pr. In addition, organ retention data were obtained from parallel serial sacrifice studies with the same aerosols. After exposure, the dogs were observed for health effects over their lifetime. The deterministic effects observed for both of these relatively insoluble aerosols were lymphopenia, fibrosis, atrophy of the lung-associated lymph nodes, and radiation pneumonitis. Due to the longer half-life of plutonium, the lymphopenia was more prolonged and the clinical course of the radiation pneumonitis more chronic than that resulting from cerium. The greater tissue penetration of the beta-particle emissions from the cerium resulted in more uniform dose distribution over the lung and the atria of the heart than from the alpha-particle emissions from plutonium.