Effect of Gamma Radiation on Gastric Emptying Time in the Dog

¹ From the Naval Medical Research Institute, National Naval Medical Center, Bethesda, Maryland

The effect of gamma radiation on gastric emptying time was studied in 13 dogs using a barium meal, roentgenographic technique. Radiation doses of 300 and 600 r produced no notable effect on gastric emptying time at 2 or 3 days after irradiation or at 7 or 8 days after 300 r. A marked delay in gastric emptying time was observed 3 days after 1300 r, associated with other acute gastrointestinal manifestations of severe radiation injury. Gastrointestinal symptoms were much less pronounced on the 2nd day after 1300 r and at this time gastric emptying time was normal. The lack of effect of radiation doses in the lethal range on gastric emptying of the dog was in marked contrast to the rat in which species significant delay in gastric emptying is produced by doses in the sublethal range. These findings are in accord with the fact that dogs show minimal gastrointestinal signs and symptoms in the lethal range of radiation dosage.