[Radionuclide study of ventilation and perfusion in different sections of the lungs]

At present in the practice of radionuclide methods of investigation of the ventilation and blood flow one mistakes either a regional ventilated volume or the rate of indicator clearance from a given region for regional alveolar ventilation. The regional ventilation-perfusion ratio is obtained by dividing corresponding values expressed not in absolute but in relative units that causes erroneous results. A method proposed in this paper makes it possible to calculate regional distributions of ventilation, perfusion and their ratio as won as the values of mean time and the passage of an indicator through the alveolar-bronchial space and the vascular bed of the lungs strictly in accordance with the conditions of the clinical physiology of respiration. Measurements were taken according to an established method using either a gamma-chamber or a radiographic unit with autonomous detectors. To study the regional blood flow, 133Xe and 99mTc-MAA can be used. An assumption of preserving the persistence of the general ventilation-perfusion ratio for the lungs with any regional disturbances of this ratio should be attributed to the most serious allowances of this method.