JOURNAL OF NUCLEAR MEDICINE 7:77-87, 1966 Lung Scanning Following Radioaerosol Inhalation

The pulmonary distribution of inhaled radioactive particles and their clear arice from the lung were studied exhaustively during the last 20 years to eval uate potential radiation hazards ( 1). Airborne particles smaller than 1-2 @ are known to be distributed evenly throughout the entire respiratory tract, includ ing the terminal bronchioles and alveoli. Soluble aerosols, such as sodium peni cellin, are rapidly absorbed into the blood (2). Insoluble plutonium oxide par tides are more slowly removed by the ciliary escalator mechanism and by phagocytosis with subsequent transposition to the hilar lymph nodes (1). Visualization of the bronchial tree radiographically requires the intratra cheal instillation of several grams of radiopaque material. The procedure is known to be hazardous in patients with impaired pulmonary function. Fur thermore, bronchography does not permit visualization of the small branches near the lung periphery. Thus, a need exists for a method to determine airway patency in obstructive bronchopulmonary disease when bronchography is con traindicated. This report describes the development of a safe radioaerosol inhalation pro cedure and lung scanning technique using commercially available radiophar maceutical agents in minute quantities and standard respirator-nebulizer equip ment. The results of basic studies in dogs and preliminary applications in pa tients with obstructive bronchopulmonary disease are presented. Radiation ex posures to the lungs and contamination of the examining room and personnel can be maintained within permissible limits