The Characteristics of Bronchial Clearance in the Miniature Donkey

Abstract

Clearance of monodisperse ferric oxide particles fagged with copper Cu 64 or gold Au 198 has been studied in five miniature donkeys. Loss of radioactivity from the lung in the first few hours after inhalation has been demonstrated to represent clearance of particles via the bronchial tree. Bronchial clearance when measured from the upper or lower lung or over the neck occurs exponentially with half periods of 8 to 35 minutes. The rates and magnitudes of bronchial clearance of individual donkeys are very reproducible although there are substantial individual differences with respect to the amount of lung deposition for a given particle size and the rate of bronchial clearance.