REGIONAL PULMONARY FUNCTION STUDIED WITH XENON133*

Abstract

A chemically inert radioactive gas within the lung is detected by means of externally placed scintillation counters. Indices of relative ventilation and perfusion for 6 different regions of the lung are calculated from external counting rates after a single breath of air-Xe mixture, after rebreathing the mixture, and after intravenous injection of dissolved Xe133. These indices are independent of the volume of lung within the counting field. Findings in 21 seated normal subjects indicate a) somewhat greater ventilation and much greater perfusion in the lower than in the upper portion of the lung; b) slightly more uniform inspired air distribution on deep inspiration than during quite breathing; c) greater ventilation of the middle and lower portions of the lung on the left than on the right; and d) greater perfusion of the lower portion of the lung on the right than on the left. Forty patients with various cardiac or pulmonary disorders have been studied, and 4 illustrative cases are presented. The method is compared with the O15 technique of West and co-workers (J. Clin. Invest. 40:1, 1961).