PET/CT Scans FAQ
How Does a PET/CT Scan Work?
The scanner is a camera that produces powerful images of the human body and allows your physician to see what is happening inside your body. The scanner picks up glucose signals, ingested or injected, as it journeys through the body to the organs targeted for examination. A computer then converts the signals into pictures that reveal medical diagnostic information.
What Are The Benefits of a PET/CT Scan?
- Provides answers as to whether a tumor is malignant or benign.
- Safe, noninvasive diagnostic procedure.
- Detailed diagnostic information.
- Shorter time for definitive diagnosis.
- Earlier detection of disease with fewer invasive diagnostic procedures.
- Precise staging of the disease.
- More effective tracking of the results of chemotherapy and radiotherapy.
- Can result in less intensive surgery and/or avoidance of some surgeries.
- Identification of distant tumors.
- Distinguishes between scar tissue and tumor recurrence.
- Contributes to lowering overall health care costs.
What Should I Do Prior to the PET/CT Scan?
- Tell your doctor and technologist if you are diabetic.
- Tell your doctor if you are pregnant, think you might be pregnant or if you are a nursing mother.
- Wear comfortable clothing in layers.
- You may wear your hearing aid, glasses and dentures to the PET/CT center but leave valuables at home.
- Take any prescribed medications on the day of your test unless instructed differently by your doctor.
- Do not eat for at least four hours before your scan.
- Drink 24–30 ounces of water during the two hours before the scan. Black decaffeinated coffee (no cream, no sugar) is acceptable along with the water.
- Avoid all beverages except water and black decaffeinated coffee for at least four hours before your scan.
Can I Eat or Drink Before my Scan?
Typically, you will be asked to not eat or drink anything except water for at least four hours before your scan.
How Long Will the Scan Last?
You can expect to be in the PET/CT center for 1-1/2 to 3 hours. The actual scan takes much less time.
How Do I Prepare For the Scan?
Different tests require different preparations. You may be asked to drink an oral contrast agent which may be diluted barium or diluted IV contrast. The oral contrast must be ingested approximately 90 minutes (1-1/2 hours) prior to the time you are scanned. The oral contrast allows the Radiologist to distinguish your normal intestines from abnormalities in the abdomen and pelvis.
Some Exams Require Injection of IV Contrast Material
Other tests may require you to only drink clear liquids 4 hours prior to your exam or have some lab work done. Some exams require the injection of IV contrast material, a radioactive glucose called FDG, administered by a technician through a small IV.
This Allows Radiologist to See Your Organs & Soft Tissue
This allows the Radiologist to see your organs and soft tissue with more clarity. This contrast material may cause a warm sensation in your body; it will only last momentarily and will not cause any pain. There is no danger from this injection as glucose is a common substance in the body and the dosage is a minimal exposure to radiation.
You Will Have a One Hour Wait
Once the glucose is introduced into your system, you then wait approximately one hour while it distributes itself through your body. During this hour please try to remain still and calm, as too much movement can affect the quality of your exam. You will then be asked to lie on a table that passes slowly through the PET/CT scanner.
What Will the Test be Like?
The CT machine looks like a large square doughnut and only covers the area that is being examined. Before entering the scanning room you will be asked to remove anything that is metallic. Once the technologist positions you on the table the scan will begin. During the exam you will be in the room alone; however, your technologist will be able to see and hear you throughout the whole procedure. Each CT room has pictorial “skylights” above the scanner to help you stay relaxed and comfortable.
How Will I Feel After the Test?
There are no side effects from the oral glucose or injected radioactive glucose. You will be able to return to normal activities after your scan.
How Will my Physician Get the Results?
After your scan is completed, a Radiologist will study the exam by looking at the images on a computer using the Picture Archiving & Communication System (PACS). The Radiologist will issue a report and a copy of that report will be sent to your physician. Your physician’s office will then contact you with the results. Films of the exam can also be produced and sent to your physician.