[Ventilation scintigraphy with 127Xenon gas--efficient use for emergency diagnosis of pulmonary embolism].

In a retrospective study all lung scans performed in 1982 were compared to those during 1983. In 1982, ventilation scans using 133Xe were performed first, followed by 6-view perfusion scans using 99mTc-MAA. In 251 patients, 149 (59%) had normal perfusion scans and the ventilation study was thus superfluous. In 95 patients (24%) the ventilation/perfusion defects matched. Only 43 patients (17%) had evidence of pulmonary embolism. In 1983, perfusion scans were performed first, and only patients with abnormality on the perfusion scan had a ventilation study using 127Xe. Of the 359 perfusion scans performed, 240 (67%) ruled out pulmonary embolism. Of the remaining 119 (33%), a ventilation study was performed immediately after the perfusion scan in the position showing a perfusion defect. A finding consistent with pulmonary embolism was observed in 58 patients (16%). In conclusion, the use of 127Xe in clinical practice represents a financial, technical and diagnostic advantage, as well as a reduction in radiation dose to patients and personnel.