[en] Pulmonary ventilation scans using ¹²⁷Xe were compared with scans using ¹³³Xe in the diagonsis of pulmonary embolism. A perfusion scan using sup(99m)Tc-microspheres and ventilation scans with each of the xenon isotopes were performed on 44 patients referred for lung scanning to confirm or exclude a suspected clinical diagnosis of pulmonary embolism. No significant difference was found in the frequency of diagnosis of pulmonary embolism when comparing each of the ventilation scans with the corresponding perfusion scan. For reasons discussed, ¹²⁷Xe may be more useful than ¹³³Xe for pulmonary ventilation scanning. (orig.)