PET/CT Exam Preparations

Your preparations before the PET/CT exam are very important. Our staff will give you personalized instructions depending upon the nature of your test. In general, the guidelines are as follows:

• We ask that you not have food or beverage for six hours before your scheduled appointment.
• There is no need to discontinue medication that you are taking for this procedure.
• We encourage you to wear comfortable clothing like sweats. In many cases you can wear these in the machine but you may, however, be asked to change into a gown.

The Procedure

The science of PET revolves around a highly refined technology yielding full body, three dimensional images captured with the aid of a continuous circular ring of stationary detectors. This technique utilizes safe, short-lived radiopharmaceuticals (also called radioisotopes) attached or labeled onto substances that are found naturally in the human body like glucose (sugar).

Combination PET/CT scanning combines two unique procedures into one comprehensive exam. The CT portion of the exam provides a detailed analysis of the size, location and structure of abnormalities or tumors while the PET (Positron Emission Tomography) portion provides insight into what is happening on a cellular level within the abnormality.

One of our Nuclear Medicine technologists will meet you soon after you arrive. They will explain all of the events that are about to take place and the approximate time involved in each part of the exam. We will ask you questions pertaining to your overall health and the reason why your physician ordered a PET/CT scan. Your medical history and past imaging records will provide the radiologist who will interpret your study with very important information. Every attempt will be made by our staff to have all prior imaging studies available the day you come for the procedure.

After the technologist has taken your history, he or she will put a small intravenous needle in a vein in your arm. This will be the site used for the radioisotope injection. If you are a diabetic patient, we may also want to do a blood sugar reading. The technologist will then inject a small, safe amount of the radioisotope through the IV tube and remove the tube.

After you have had your injection, you will need to remain as still as possible. This period of your examination is called the “resting” phase. During rest, the tracer radioisotope quickly moves to its intended area. This takes 1 to 2 hours. Resting is very important. Even small amounts of activity can divert the tracer from its destination and attract it to the muscles involved in the activity. There is a recliner chair in a quiet area where you can relax during the resting part of the exam.

Once the tracer has had time to accumulate, the scanning phase will begin. The CT scan is performed first and takes just seconds to complete. This is followed by the PET scan which takes approximately 25 minutes. Your position and comfort are our priority. The table will move into the scanner for a period of three minutes during which time the camera or detector will be counting the tracer in that part of your body. Then the table will move again and the counts will resume until you have been completely scanned. Sometimes we will start the scan time over to focus on a particular area but there will be no need for further injections.

The next part of the exam requires the radiologist to review all the images from the scans. They will review each image briefly to make sure that all the information needed for the exam has been acquired.

After the Exam

You may resume your normal activity. If your prior studies are available for the radiologist to compare with your new procedure, your physician will receive a report within 24 hours of the exam. The actual results of your exam will be given to you by your doctor who will compare your test results against his or her own clinical findings to provide you with a clear picture of your overall health.