Retention of ¹³³Ba in the Trachea of Rabbits, Dogs, and Monkeys Following Local Administration As¹³³BaSO₄ Particles

Abstract

The retention of ¹³³Ba in the trachea from intratracheally administered ¹³³BaSO₄ particles was determined in rabbits, dogs, and monkeys. A significant retention of Ba in the trachea was observed with two peaks in these three animal species 1 week after administration. The first peak in the cranial region of the trachea corresponded to the approximate position of the tracheostomy and the second peak in the caudal trachea corresponded to the approximate position of the tip of the cannula. The amount of ¹³³Ba retained 1 week after injection in the caudal region of trachea, which indicated the physiological retention of particles in the airway wall, was 0.145, 0.044, and 0.043% of the initial injection dose for rabbits, dogs, and monkeys, respectively. These retention rates were much lower than those measured in a previous rat study. If experimental conditions of anesthesia and relative injection dose (e.g., the amount of ¹³³BaSO₄ per surface area of the tracheal lumen) did not affect particle retention, the present results may suggest that the extent to which particle retention occurred in airway walls is different among the animal species.