title: Controlled deposition of tantalum powder in a cast of the human airways: applications for aerosol bronchography.
abstract: A hollow latex cast of the human larynx and tracheobronchial tree extending to 2 mm diameter airways "inhaled" tantalum powder (mass median aero-dynamic diameter equals 9.2 mum, omicron-g equals 1.41) at 8 liters/min. Tantalum deposited within the cast as predicted by preliminary deposition  calculations. These calculations predicted deposition surface densities among greater than 2 mm diam. airways to have a range of similar to 2:1, and also predicted less than 5% alveolar deposition. A deposition surface density of 8 mg/cm-2 provided good bronchographic visualization. Single rice grains located within some airways were distinctly outlined. The small amount of tantalum needed to outline the airways be a simulated voluntary inhalation indicates that tantalum may be suitable for use as a bronchographic contrast medium when administered under strictly controlled exposure conditions.
mesh_terms: D000336:Aerosols; D001980:Bronchi; D001995:Bronchography; D003287:Contrast Media; D007830:Larynx; D008961:Models, Structural; D013635:Tantalum; D014132:Trachea
chemical_list: D000336:Aerosols; D003287:Contrast Media; D013635:Tantalum