What is Positron Emission Tomography (or PET)?
PET scanning uses radioactive isotopes (radiopharmaceuticals) to create a powerful diagnostic tool for cancer, heart disease and a variety of neurological disorders like Alzheimer's disease. Similar to conventional nuclear medicine, the exam requires the injection of a radiopharmaceutical, which circulates throughout the body and localizes in cancer sites or other disease processes. The primary radiopharmaceutical, or tracer, used in PET is a radioactive sugar called FDG. Cancer cells use this sugar at an aggressive rate. PET uses a scanner to detect radioactivity and generate a whole body image demonstrating cancer sites, heart disease or neurological disorders.

What is the advantage of combined PET and CT?
With a combination PET/CT scanner, the concept is similar to weather radar. PET provides the radar that identifies a tumor, while the CT scan provides the anatomic map that helps identify the precise location of the disease.

Most cancer patients will have CT and PET scans ordered at the same time. CMC provides these services in one visit and on one scanner, all in about 30 minutes.

How do patients prepare for the exam?
The standard preparation is to have no food for four hours prior to the exam. Drinking at least two glasses of water two hours prior to the exam is also requested. Diabetic patients and those needing a cardiac exam will have additional instructions. To obtain accurate results on a PET scan, diabetic patients will need to work closely with the PET staff to regulate blood sugar levels.

How is the exam performed?
A PET/CT scan takes 30 to 45 minutes. The total time in the department is about two hours considering there is a one-hour wait after the isotope injection. After the injection, patients relax for a 60-minute uptake period. Physicians frequently order a mild sedative or diuretic (aids to empty bladder) for this period. Both of these medications can improve the quality of the scan.

After the uptake period, patients lie on the scanner table in a comfortable position and move as little as possible for 30 to 45 minutes. There are no side affects from the isotope injection or the scan itself. The affects of the diuretic or sedative will be explained prior to the procedure.

When are results available?
Physicians provide exam results. The radiologist interprets the PET scans the day they are performed. Some cases may require comparison to other exams, resulting in a slight delay. CMC provides results directly to physicians as soon as the radiologist verifies the report accuracy.