Radioactivity distribution in human body during C15O2 and 15O2 continuous inhalation in PET studies

Radioactivity absorption received by humans during C15O2 and 15O2 steady-state inhalation using a PET scanner was measured. Relative concentration of radioisotope absorption was measured using the profile scanning mode of the scanner. The volume (ml) of each organ was measured using computed tomography (CT). The accumulation of radioactivity (MBq·sec) in each organ was estimated from the radioactivity concentration (MBq·sec/ml) and volume (ml) of each organ. The radioactivity concentration was obtained using a brain and body emission scanning mode. In the profile image, high uptake organs, namely, the heart, brain, liver, kidneys were observed for C15O2 inhalation and for 15O2 inhalation, the heart and lungs were studied. The accumulated radioactivity in each organ was 12.3 MBq·sec for the brain, 13.7 MBq·sec for the lungs, 2.4 MBq·sec for the heart, 1.8 MBq·sec for the liver for C15O2 (185 MBq/min) inhalation, and for 15O2 (555 MBq/min) inhalation, 11.8 MBq·sec for the brain, 84.8 MBq·sec for the lungs, 5.6 MBq·sec for the heart, 17.1 MBq·sec for the liver. (author)