The regional deposition of an inhaled aerosol of 1.0-micron diameter fluorescent microspheres (FMS) was used to produce high-resolution maps of regional ventilation. Five anesthetized, prone, mechanically ventilated pigs received two 10-min inhalations of pairs of different FMS labels, accompanied by intravenous injection of 15.0-micron radioactive microspheres. The lungs were air ... More