Final answer:
The uptake of FDG by tumors is primarily based on the higher glycolytic rates of cancer cells compared to normal cells. Increased glucose metabolism by tumors allows for the use of FDG as a tracer in PET scans, aiding in the detection of cancerous tissue.
Step-by-step explanation:
The Uptake of FDG by Tumors
The uptake of FDG (fluorodeoxyglucose) by tumors is based on the higher glycolytic rate of tumors relative to normal tissue. Tumors demonstrate increased glucose metabolism because they need to fuel rapid cell division and growth, which are hallmarks of cancer cells. This increased consumption of glucose makes FDG an excellent tracer for positron emission tomography (PET) scans, which are then able to highlight areas where cancerous tissue is likely to be found due to the high uptake of this glucose analog.
During a PET scan, FDG, which is a radioactively labeled glucose molecule, is injected into the patient's body. The 18F isotope emits positrons as it decays, and when these positrons encounter electrons, they annihilate each other, emitting two gamma rays. These gamma rays are detected by the PET scanner, creating detailed, three-dimensional images that show metabolic activity in various tissues. As such, areas with rapid glucose use—such as tumors—show up as brightly colored regions on the PET scan images, providing critical diagnostic information.