Dynamic imaging of the respiratory cycle with 81mKr

To define the regional ventilation of the human lung, subjects were monitored with a gamma camera, while breathing air labeled with radioactive 81mKr which is being continuously eluted from a generator. The information observed is displayed as a reiterated multiframe moving picture. This is accomplished by storing the information from multiple breaths, selecting acceptable cycles (determined by the duration of inspiration and expiration and the amplitude to extremes of the cycles), and normalizing the usable information and converting the summed data into sequential frames, which are repeatedly shown on a video screen from computer memory.