Aerosol lung inhalation scan with sup(99m)Tc-millimicrospheres

We performed basic and clinical evaluation of aerosol lung inhalation scan with sup(99m)Tc-millimicrospheres (milli MISA). The mean diameter of aerosol particles was increased when the flow rate of carrier O2 gas was increased. Ninety percent of the particle was less than 3μ in diameter when the flow rate of O2 gas was 6 1/min and this flow rate was adequate to routine study. In normal subjects, the amount of radioactivity deposited in the lung was proportional to the inhaled time and it was about 1% of the original activity in the nebulizer after 10 minutes tidal breating. Aerosol deposition in the lung was homogeneous and no central airway deposit was seen. But when the respiratory rate was increased, central airway deposit and decreased peripheral penetration was observed. We classified the findings of the aerosol inhalation images in COPD according to the Suzuki's, method. This criteria of aerosol scan was compared with the lung function tests and showed good correlation with FEV 1.0%. In pulmonary vascular disease, ventilation-perfusion mismatch was observed in all 8 cases. In lung cancer, aerosol inhalation scan was also useful for follow-up examination after radio-therapy. Excessive deposition of upper airways in these patients was correlated well with the bron-choscopic findings, and was thought to be due to narrowing of trachea and bronchi. We concluded that aerosol lung inhalation scan with sup(99m)Tc-milliMISA was easy to perform and was useful for routine examination. (author)