Prevention of radiation pneumonitis from inhaled cerium-144 by lung lavage in beagle dogs.

Abstract

This study was performed to evaluate bronchopulmonary lavage and chelation therapy as a treatment method to prevent the development of radiation pneumonitis after inhalation of a radioactive aerosol. Twelve beagle dogs were exposed to an aerosol of cerium-144 in fused clay particles resulting in initial lung burdens from 47 to 64 muCi of 144-Ce per kg of body weight. Eight of the dogs were treated with a series of 10 bronchopulmonary lavages and 10 intravenous injections of calcium diethylenetriamine pentaacetate acid during the first 56 days after exposure to remove the deposited 144-Ce; the remaing 4 exposed dogs receiged no treatment. An additional 4 dogs were exposed to stable cerium and were given the course of treatment as an additional control group. Three of the 4 untreated dogs and 2 of the 8 treated dogs died 171 to 246 days after exposure with radiation pneumonitis or pulmonary fibrosis, or both. All but one of the remaining dogs were alive and apparently in good clincial health 550 dyas after exposure; the one dog had radiographic indications of pulmonary fibrosis by 365 days after exposure. The relative distribution of 144-Ce in the lungs and other major organs was similar in the treated and untreated dogs that died.