title: Use of radioactive gases in studies of regional lung function.
mesh_terms: D006801:Humans; D009587:Nitrogen Isotopes; D011868:Radioisotopes; D011877:Radionuclide Imaging; D014692:Ventilation-Perfusion Ratio; D014978:Xenon
chemical_list: D009587:Nitrogen Isotopes; D011868:Radioisotopes; D014978:Xenon