Models of the Tracheobronchial Airways of the Dog Lung

Abstract Two models of the geometry of the tracheobronchial (TB) region of the dog have been developed based upon lung cast data of two beagle dogs (Raabe et al., 1976). These models consist of lengths, diameters, and branching angles of the TB airways. Because the data were incomplete, a method was developed to estimate these parameters for the missing airways based upon relationships between parent airway diameter and daughter airway diameters. Compared to the model of the complete TB region for one dog, the cast data account for only 8% of the total number of TB airways, 42% of the surface area, and 84% of the volume. Single-path models, in which one path represents the entire TB region, were then constructed based upon the two completed models and assumptions about air flow rates in their airways. The airway dimensions in the sequential segments of the single-path models were calculated using the subset of complete model airways that had the average time of flight from the trachea to the terminal bronchioles. The simpler single-path models were developed to be used with dosimetry simulation models for the investigation of particle deposition or gas uptake in the dog.