Comparison of nitrogen-13 and xenon-133 for ventilation studies

Due to the solubility of Xenon-133 in blood and tissue, errors are introduced in the determination of regional pulmonary ventilation. We investigated these errors by comparing the results from ventilation measurements with Xenon-133 and Nitrogen-13 in 5 normal subjects and 7 patients with pneumonectomy. In the normal subjects we found in the upper lung fields no significant difference in the uptake rate of both gases, but in the middle and lower lung fields the uptake rate for Xenon-133 was increased by 25% (p<0.05), compared with Nitrogen-13. Also in the pneumonectomy patients we found in the intact hemithorax an increase of the uptake rate for Xenon-133 of 25% over the whole region (p<0.005). At the pneumonectomized hemithorax the uptake of Xenon-133 was 8.5 +- 1.3% of the total measurement, with an uptake rate of 0.72 +- 0.07 min -1. A correction method has been developed to compensate for this effect. (Author)