PET/CT

PET/CT combines the functional information from a Positron Emission Tomography (PET) exam with anatomical information from a Computed Tomography (CT) exam in 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.  The advantage of CT is its ability to take cross sectional images of your body. These are combined with the information from the PET scan to provide more anatomic details of the metabolic changes in your body.  The PET exam highlights 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 diagnosis, and course of treatment selected by your physician.

A PET/CT study not only helps your physician diagnose a problem, it also helps your physician predict the likely outcome of various therapeutic alternatives, select the best approach to treatment, and monitor your progress.  If you are not responding as well as expected, you may be switched to an alternative therapy. Ask your physician what he or she hopes to learn from your PET/CT exam.

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 will receive an injection of radioactive material similar to that which is used for bone scans and other nuclear medicine exams.  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 (two hours) and only very small amounts are injected.  In all cases, the majority of radioactivity will be eliminated from the body approximately 6 hours after injection.

For most studies, you will have to wait for the radiopharmaceutical to distribute itself — typically 30 minutes to an hour.  During this time you will be asked to relax. During the exam, you will lie very still on a comfortable table that will move slowly through the scanner as it acquires the information needed to generate diagnostic images.

How long will all this take?

The PET/CT scan should last between 20 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 hours with us.

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.

Safety of PET/CT exams

Be assured that PET/CT exams are a safe and effective diagnostic procedure. The radiopharmaceuticals used in PET do not 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 wear to my appointment?

You should wear loose comfortable clothing.  Avoid wearing clothes with metal/plastic button and zippers.  Women are encouraged to wear a bra without metal snaps/hooks or under wire.  If you do arrive wearing any of the above, you will be asked to change into a hospital gown.

Preparing for your PET/ CT exam:

Non-Diabetic Patient:

  • Nothing to eat from midnight on except for water.  Nothing to eat at least 6 hours prior to exam if scheduled in the afternoon.  You may take morning meds with water only, a few soda crackers if necessary.
  • Last meal should be high protein and low carbohydrate.  Avoid breads, pastas, cereals, grains, fruits, candy and other high carbohydrate / sugar foods.
  • May drink water.  You are encouraged to drink approximately 32 ounces of water about 1 to 2 hours prior to your exam.
  • No gum chewing the day of the exam
  • Avoid physical activity (ex:  heavy lifting, vigorous exercise etc.) for 24 hours prior to exam
  • Bring outside films and reports – PET/CT, CT or MRI if applicable.

Non- Insulin Dependant Diabetic Patients (If you are on oral diabetic medications):

*THE GOAL IS TO HAVE YOU ARRIVE WITH A STABLE BLOOD SUGAR LEVEL BELOW 200MG/DL*

  • You can eat light, low carbohydrate meal a minimum of 4 hours prior to scan.  Nothing to eat from this point on.  You may drink water.
  • You need to take Glucophage or other oral diabetic medication as usual
  • You need to bring your diabetic medications with to your appointment

Insulin Dependent Diabetic Patients:

*THE GOAL IS TO HAVE YOU ARRIVE WITH A STABLE  BLOOD SUGAR LEVEL BELOW 200MG/DL*

  • You can eat light, low carbohydrate meal a minimum of 4 hours prior to scan.  Nothing to eat from this point on.  You may drink water.
  • You need to take insulin injection with meal (minimum of 4 hours prior to injection time)
  • You need to bring your diabetic medications to your appointment

After the exam:

After the exam is completed, you will be able to go home and return to normal activities.  The scan will be read by a radiologist.  Test results will be mailed to you by your provider if they are normal. The ordering provider does not telephone you with normal test results. Abnormal test results will be reported to you by telephone by the ordering provider or their assistant, along with follow up instructions.

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