PET stands for Positron Emission Tomography. The scan is used primarily in neurology, cardiology, and oncology. Radiation exposure is about same as 2 chest x-rays.
You lay on a table and are scanned like an MRI or CT procedure. The scan gives a color, three dimensional image of cell metabolism. The body uses glucose (sugar) for energy. They inject a isotope into you and it binds with glucose molecules. Cancer cells, by definition, are rapidly dividing cells (high metabolism). The scan then shows what cells are using the most glucose and have high metabolic rates. Very hard for cancer cells to hide from this scan.
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