What is a PET scan?
A PET (positron emission tomography) scan is a test that can help a healthcare provider diagnose cancer, heart disease, and some brain diseases. It takes digital pictures that may show abnormal cells in your body. The test is painless, usually has no side effects, and takes about 2 hours. Because of the special equipment needed, you'll get a PET scan in the hospital or an outpatient testing center.
A PET scan measures important body functions like blood flow and oxygen to give your healthcare provider information about how well your body is working. It can also find some problems earlier than computed tomography (CT) or magnetic resonance imaging (MRI) tests.
What should I do before my PET scan?
Before you arrive for your PET scan, take the following steps:
* Talk to your healthcare provider if you're breast-feeding, think you might be pregnant, or have diabetes. Let him know of any medicines you're taking, including supplements or over-the-counter medicines, and any allergies you have. Give this information to the technologist, too.
* Don't exercise for 24 hours before the test.
* Don't eat or drink anything for several hours before the test. The testing center will give you specific instructions on eating and drinking.
* You can take any medicines that you usually take, but take them only with water. If you have diabetes, talk to your healthcare provider to get special instructions.
* Wear comfortable clothes without metal snaps, zippers or buttons because metal may interfere with the PET scan. Leave your jewelry, including watches, at home.
* Bring any previous PET scans or other test films that you had done at other facilities with you.
* Let the technologist know if you feel uncomfortable in closed-in spaces.
What happens during the PET scan?
When you arrive at the test center, you may have to change into a hospital gown and take off any clothing or jewelry that might interfere with the test. You'll have an I.V. placed in your arm and you'll be given a substance called a radiotracer through the I.V. that helps the machine take special pictures of your body. You'll feel a slight pin prick when the I.V. is placed and you may have a cool feeling moving up your arm when you're given the radiotracer. These feelings will go away in a few minutes. Tell the technologist right away if you feel anything unusual; for example, if you have any breathing problems.
You'll then wait quietly for about 45 minutes for the radiotracer to travel through your body. The technologist will dim the lights, ask anyone with you to wait in the waiting room, and encourage you to relax or take a nap.
After about 45 minutes, a technologist will take you to the PET scanner, which is a large machine with a round, donut-shaped opening in the middle. A table will move you into the opening. You'll be asked to lie on the table on your back, usually with your arms over your head, and remain still while pictures are taken.
You might be asked to hold your breath during some pictures, and the table will move. You can ask the technologist to tell you when the table will move so you're not surprised. The PET scanner will make some whirring and clicking sounds, and some machines are louder than others. The technician will be in a control room right next to you. You can talk to her through an intercom during the test, and she can see you through a glass window or on a video camera. Let her know right away if you have any discomfort. Some testing centers have CD players so you can enjoy some music. The scan will take about 45 minutes.
What should I do after the PET scan?
Once the test is over, be sure to drink plenty of water throughout the day, unless your healthcare provider tells you otherwise. The technologist may give you additional instructions to follow after the test. Unless your healthcare provider tells you differently, you can drive and return to your daily activities right away.
A radiologist with special training will read the scan and send the results to your healthcare provider in 2 to 3 days. He'll go over the results and answer your questions.