MECHANISM: METABOLIC
TRAPPING-- IMAGING OF MALIGNANT TUMORS
This mechanism
involves IV injection of a radiolabeled sugar analog (but not a sugar!)
This analog may be trapped by cells for cell metabolism.
Tumors, with
their higher-than-normal metabolic rate, are able to take up and retain
more molecules per gram than normal tissue, resulting in an accumulation
of the radioisotope in the tumor.
Radiopharmaceutical: F-18 FDG
Particle size:
none- compound is soluble
Some liver
uptake; small percent uptake in tumor, but uptake documented in almost
every type of tumor
Imaging typically
begun 60-90 min post injection; imaging possible only for several hours
post injection due to short half-life of F-18 (110 min)
