PET, or Positron Emission Tomography, is a procedure that produces powerful images of the body’s biological functions and is being used more and more frequently to determine the extent of malignant disease. Unlike conventional imaging such as x-rays, CT scans, and MRIs, PET does not show the body’s anatomy, but rather shows the chemical function or metabolism of an organ or tissue.
The patient receives an intravenous injection of FDG, a glucose analog labeled with radioactive fluorine, and is then asked to lie still for 45 minutes to an hour while the isotope distributes throughout the body, and is absorbed by the cells. Then, while lying on a table called a scanning bed, the patient will be moved slowly through a scanner while it detects the injected tracer. This scanner creates a three-dimensional image of areas of increased metabolism (cancers), which appear as “hot spots”. When the imaging procedure is complete, the results are sent to a computer where the images are reviewed by a specially trained physician. Your doctor will then receive a report and an image detailing the findings of your examination.
Most PET scans are completed in 2-4 hours depending on the procedure. There are no adverse reactions resulting from the scan, and there have been no reported allergies associated with the injection. The total radiation dose is less than that of a CT scan, or equal to about two chest x-rays. The majority of the radiation is eliminated from the body within 18 hours.
When preparing for a PET scan, your doctor may:
- Tell you not to eat anything after midnight the night prior to your scan.
- Ask if you are a diabetic.
- Suggest you wear comfortable clothing.
- Ask what medications you are taking, and inform you if a certain medication should not be taken on the day of the exam.
- Ask you to bring other studies such as previous CT or MRI scans, so that comparison can be made to the new PET.
And work at Sloan-Kettering Cancer Center also suggests PET “can be used to stratify patients for treatment and clinical trials.”
Most private medical insurance carriers will pay for this exam. Medicare also recently approved reimbursement for certain disease processes. Be sure to check with your carrier for updated information on coverage.