Using Xenon-133 and a scintillation camera to evaluate pulmonary function.

tion has been given to evaluating pulmonary disease using radioisotopic techniques. The majority of the radioactive preparations used for these studies can be divided into two general categories : colloidal aggregates of albumin and radioactive gases. Macro aggregates labeled with 1311or 99@'Tchave been used extensivelyfor determining regional pulmonary per fusion and, as such, are useful for evaluating patients with suspected pulmonary emboli (1—5) . The dis tribution of these macroaggregates in the lung is usually determined by conventional rectilinear scan ning although the scintillation camera has also been used effectively (4,5). To obtain information on ventilation and diffusion one of the radioactive gases—oxygen, carbon dioxide, krypton or xenon—must be used. The half-lives of gamma-emitting oxygen and carbon radioisotopes are extremely short so that the cyclotron used for their production must be very close to the pul monary-function laboratory (6—9). Thus because of their universal availability, the noble gases are being used more extensively, and, of these gases, †̃33Xe has the best physical characteristics (5, 10—13). In this paper we report our preliminary experience using an Anger scintillation camera to record pul monary uptake and clearance of †̃33Xe in patients referred to our service for pulmonary-function evalu ation. The radioactive xenon was administered either by inhalation or intravenous injection.