
174 Statistical Computing in Nuclear Imaging
FDG and glucose makes it an excellent imaging agent. The glucose or FDG
is
transported out of the blood vessels though facilitated diffusion.
4
After this
glucose and FDG are phosphoryla ted. At this point, the physiological paths
differ. The phosphorylated glucose is further metabolized through glycolysis.
The phosphorylated FDG however is metabolized very slowly and in time scale
corresponding to imaging time it can be assumed that phosphorylated FDG
accumulates in the tissue (at least in most of organs). This remarkable prop-
erty of the FDG makes is an excellent marker for measuring the speed glucose
utilization ...