How to prepare
PET/CT scanning is a relatively comfortable, noninvasive procedure. To prepare, you should not eat or drink anything (besides water) for at least six hours before your scan. Once at the hospital, you will be given a sugar solution containing a small amount of radioactive material (called a radioisotope) through an IV. The most common radioisotope used in PET/CT scanning is FDG (fluorodeoxyglucose). There are no harmful effects associated with the radioisotopes used in PET/CT scanning.
If you have diabetes
If you have diabetes, you should let the Mission technologist performing your scan know. People with diabetes do not have to worry about FDG affecting their blood sugar levels. (It would take one million doses of FDG to equal the glucose in just one teaspoon of sugar.) However, if your blood sugar is abnormally low or high during the scan, it could interfere with the accuracy of your results.
The procedure
Once you have received the IV, you will need to sit quietly to allow the radioisotope to circulate throughout your body. After about an hour, you will be asked to empty your bladder, then you will be taken to the scanning room. An attendant will help you onto the scanning table, where you will need to lie as still as possible once the scan begins. Like most diagnostic imaging technologies, the PET/CT machine consists of a scanning table that moves slowly through a short tunnel. When the PET/CT scanner was invented, it was designed to be more spacious than other imaging devices. However, if at any point in the test you begin to feel claustrophobic (frightened by small, enclosed spaces), you should let the technologist know. He or she may administer a mild sedative to help you relax.
Immediately before the scan begins, you will be given an enhancing agent through another IV. This second injection is necessary to produce the CT portion of the scan, while the earlier injection of the radioisotope assists in the PET imaging. After receiving the enhancing agent, you may experience a warm sensation, nausea, shortness of breath, itching or sneezing-all of which are normal; however, you should still tell the attendant if you experience these or any other side effects. You will be able to communicate with the attending Mission PET/CT technologist at all times throughout the procedure, though you should try to lie as still and quietly as possible. The actual scan should take around 30-45 minutes to complete.
Follow up
Once the test is complete, you will be able to go home and resume your normal daily activities. You will need to drink plenty of fluids to flush your body of the remaining radioisotope. Your physician will let you know when you can expect the results of your scan.
