Systems that provide a safe and efficient means for the delivery and/or disposal of xenon radioisotopes (typically Xe 133, but Xe 127 is also used). These systems usually include a xenon-delivery unit, a gas trap, carbon dioxide absorbers, and bacteria filters placed in the mouthpiece. Xenon-delivery systems are mostly used in pulmonary function studies; when xenon is inhaled, a gamma camera produces images of the lungs showing regional ventilation and displaying the distribution of air intake. Xenon-delivery systems are also used during xenon-enhanced computed tomography and dynamic single-photon-emission computed tomography (CT and SPECT respectively) studies. Typically cound in nuclear medicine departments.