Abstract: The present invention is directed a ventilation system used in the diagnostic imaging of a patient's pulmonary function, and more particularly, is directed to a disposable radioactive inhalation adaptor to be used in conjunction with standard ventilation apparatus. More specifically, the invention involves a hand-held ventilation system which delivers oxygen as well as the appropriate dose of Xenon-133 gas to the patient without contaminating the area. The claimed ventilation system is particularly designed for use with patients who cannot breathe on their own or who cannot cooperate with the standard respiratory diagnostic imaging apparatus.