Patient Info by Procedure
PET/CT
PET/CT combines the functional information from a positron emission tomography (PET) exam with the anatomical information from a computed
tomography (CT) exam into one single exam. A PET scan detects changes in cellular function – how your cells are utilizing nutrients like sugar and
oxygen. Since these functional changes take place before physical changes occur, PET can provide information that enables your physician to make an early diagnosis.
A CT scan uses a combination of X-rays and computers to give the radiologist a non-invasive way to see inside your body. One advantage of CT is its ability to rapidly acquire two-dimensional pictures of your anatomy. Using a computer these 2-D images can be presented in 3-D for in-depth clinical evaluation. The PET exam pinpoints metabolic activity in
cells and the CT exam provides an anatomical reference. When these two scans are fused together, your physician can view metabolic changes in the proper anatomical context of your body.
Why do I need this exam?
Your PET/CT exam results may have a major impact on your physician's diagnosis of a potential health problem – and, should a disease be detected, how a treatment plan is developed and managed. A PET/CT exam not only helps your physician diagnose a problem, it also helps predict the likely outcome of various therapeutic alternatives, pinpoint the best approach to treatment, and monitor your progress. If you're not responding as well as expected, you can be switched to a more effective therapy immediately.
What should I expect when I arrive?
When you arrive, we will take a review of your history and any past exams. For the PET portion of the exam you'll receive a radiopharmaceutical injection. This is a radioactive tracer that must pass multiple quality control measures before it is used for any patient injection. PET radiopharmaceuticals lose their radioactivity very quickly (2 minutes to 2 hours) and only very small amounts are injected. In all cases, little or no radioactivity will remain in your body 10 minutes to 6 hours after injection. For most studies, you'll have to wait for the radiopharmaceutical to distribute itself – typically 30 minutes to an hour. During this time you will be asked to relax.
What will the scan be like?
You will lie on a comfortable padded table. The table will move slowly through the tube-shaped PET/CT scanner as it acquires the information needed to generate diagnostic images. You will be asked to lie very still during the scan because movement can interfere with the results. For the CT scan you will be asked to hold your breath for a few seconds to minimize body movements. During the scan, you might hear a humming noise but you will not feel anything unusual. You may feel the table move while images are being taken at certain locations on your body. The technologist will monitor you during the exam. The specific details of your upcoming exam will be explained fully by the technologist or your physician. How long will all this take? The PET/CT scan should last between 30 and 45 minutes. The exam procedure can vary depending on what we are looking for and what we discover along the way. Plan to spend two to three hours with us.
What happens after the exam?
You may leave us as soon as the exam is complete. Unless you've received special instructions, you will be able to eat and drink immediately – drinking lots of fluids soon after the exam will help remove any of the radiopharmaceutical that may still be in your system. In the meantime, we'll begin preparing the results for review by our diagnosticians, and then by your physician, who will tell you what we've learned. Safety of PET/CT exams Be assured that PET/CT exams are a safe and effective diagnostic procedure. The radiopharmaceuticals used in PET don't remain in your system long, so there's no reason to avoid interacting with other people once you've left. To be extra safe, wait for a few hours before getting too close to an infant or anyone who's pregnant.
What should I do to prepare for the exam?
Wear comfortable clothes and leave valuables at home.
Take any prescribed medication on the day of the exam unless instructed otherwise by your physician.
Depending on the type of exam, you will be instructed not to eat or drink anything except for water for 4 to 6 hours prior to the study. This is due to the fact that results of the test are affected by your blood sugar.
It is important to be well hydrated for the test, so drink water the day before and the day of your exam. You may drink water up until your appointment time.
DO NOT perform any heavy lifting or exercise the day before your exam and especially not on the day of your exam.
If you are a diabetic, please notify our staff so that we may give you special instructions.
Please bring prior examinations, such as CT's and MRI's with you on the day of your study.
How much time should I allow?
Your examination time will vary depending on the type of study performed. Most patients should plan on spending approximately three hours with us.
What can I expect?
When you arrive, a specially trained technologist will discuss your PET/CT scan procedure with you and answer any questions you still might have. When you are ready for the study you will have your blood sugar tested. You will receive an injection of radiopharmaceutical. You will not experience any side effects to this material. You will then be asked to rest in a special quiet area for 30 minutes to 1 hour while the radiopharmaceutical distributes itself in your body.
During your PET/CT Scan you will lie on a comfortable table that passes slowly through the scanner as it acquires the information needed to generate diagnostic images. It is very important that you lie quietly and remain still during your scan. Scanning typically takes between 30 minutes and 1 hour.
After the scan is complete you may resume your normal activity and eating habits.