Synthesis of, and animal experiments with, N-isopropyl-p-123I-iodo-amphetamine (IMP) and 18F-3-deoxy-3-fluoro-D-glucose (3-FDG) as tracers in brain and heart diagnostic studies.

For the investigation of brain functions 18F-3-deoxy-3-fluoro-D-glucose (3-FDG) and N-isopropyl-p-123I-iodo-amphetamine (IMP) were synthesized and the course of radioactivity measured in several organs of mice. The results can be summarized as follows: IMP is rapidly extracted from the blood and reaches a value of less than 1% g within the first 15 min; 123I-radioactivity in the lungs shows a maximum of 76%/g as soon as half a minute after injection and decreases with a concomitant increase in the liver and brain; The maximum 123I-uptake in the brain of 11%/g is reached after 30 min and levels off at a constant value of 10%/g; 30 min after injection the brain/blood ratio for IMP is about 14; The time course of 3-FDG in the brain has a maximum of 4.8%/g as soon as 5 min after injection and decreases to a constant value of 3%/g within 1 hr; and Accumulation of 18F- radioactivity in the heart reaches a maximum of 14%/g after 1 hr and is eliminated with a half-life of 300 min. Comparative clinical studies with 3-FDG and 3-0-11C-methyl-D-glucose (CMG) have shown that 3-FDG can be considered as a CMG-analogue and thus can be used for the in-vivo determination of local glucose perfusion and transport rates.