Investigation of the Lung Function Using Inert Radioactive Gases

In previous experiments using MAA (macroaggregated albumins), a scintillation camera and a computer we demonstrated the influence of diminished ventilation on perfusion in parts of the lung, With this device it was possible to observe the passage of MAA through the right heart and to all parts of the lung. Using 133Xe instead of MAA we have been able to measure in addition rapid respiratory movements. Thus the authors obtained for both lungs and for any part of the lung: (1) ''Dynamic'' functions: FVC (forced vital capacity), wash out-curves; (2) ''Static'' volumes: VC (vital capacity), TLC (total lung capacity), FRC (functional residual capacity), RV (residual volume); and (3) VA/Q ratio. Simultaneously with the nuclear measurements we recorded the static and dynamic lung volumes. This device enabled us to calibrate the count-rates with spirometrically measured volumes. For determination of FRC we used a whole body plethysmograph. Further pulmonary function tests including Raw airway resistance by body plethysmography, arterial blood gases, shunt calculations, and right heart-catheterization were correlated with the nuclear data. In a first series we studied normal persons and compared our results with those previously reported. In a second series we studied selected patients with various lung diseases: defined bronchial and vascular obstruction, restrictive disorders and cystic lesions. (author)