Clinical outcome analysis was carried out in 175 of 206 consecutive patients referred for a lung scan with clinical suspicion of pulmonary embolism (PE). The follow-up time period ranged from 4 to 18 months. High-quality ventilation images corresponding to the six standard perfusion images were obtained using Technegas as a ventilatory agent. Lung scan reports showed that 22% of the patients had a high, 14% indeterminate, 18% low and 9% very low probability for PE and 37% were normal lung scans. These reports usually supported the referring clinicians' provisional diagnosis and were confirmed by the clinical outcome analysis of these patients giving an apparent sensitivity for the lung scan of 96% and specificity 93%. A strategy for lung scanning in PE is proposed.