Positron Emission Tomography (PET)
What is PET/CT?
PET/CT is a safe and highly effective exam that combines the functional information from a Positron Emission Tomography (PET) exam with the anatomical information from a Computed Tomography (CT) exam into a single study.
How does it work?
A PET exam detects changes in how the body's cells are utilizing compounds such as sugar and oxygen. The CT scan uses X-rays to produce images of the body anatomy. Both methods use computers to reconstruct information into three dimensional "slices" that provides a high resolution, non-invasive look inside of the body. The PET and CT images are fused together to create a set of images that are reviewed by a radiologist.
Why do I need this exam?
Your PET/CT exam may help your doctor to diagnose a potential health problem. If a disease is detected, a PET/CT exam helps the healthcare team develop and manage a treatment plan.
A PET/CT exam also helps doctors evaluate the status of disease progression, and helps predict the outcome of various therapeutic alternatives. It will assist in deciding the best approach to treatment and aide in monitoring the response to therapy. If it is shown that a course of treatment is not effective, then another course of action may be taken.
Pre-exam instructions for a PET/CT
To schedule your PET/CT exam, please call us at (707) 525-4040.
Please do not eat for at least 4 hours prior to your study. You may drink water up to 2 hours before your exam.
A diet free of carbohydrates is necessary the day prior to the exam through the completion of the scan. If there is too much sugar in the system at the time of the exam, the procedure may have to be rescheduled for another time. Dietary sugar competes with the FDG injection, which could result in a low quality exam. You may eat high-protein foods such as meats and fish, as well as vegetables, and salads. Avoid foods such as pasta, bread, potatoes, fruit, or sugar. Do not drink alcohol or caffeinated beverages for 24 hours before your scheduled exam. The FDG dose you will receive is prepared specifically for you through a sophisticated and costly procedure. Please inform us as soon as possible if you should need to cancel for any reason.
Take all of your medications as usual. Diabetic patients will be scheduled so that the exam will not interfere with regular meal and medication schedules.
Also, please avoid exercise on the day before or the day of your exam.
You should wear comfortable, loose-fitting clothes without metal buttons, snaps, or zippers. You may be asked to change into a gown if necessary. You will also be asked to remove jewelry or other metal objects before the exam begins.
We ask that you arrive at our facility about fifteen minutes prior to your scheduled time so you can complete the registration process. Be sure to bring a copy of your insurance information with you. We may request that you bring films or reports with you from previous tests at other facilities. Please be prepared to provide information regarding your medical history.
On the day of the exam
When you arrive, you will be taken to a comfortable private room where your medical history will be reviewed. A licensed Nuclear Medicine technologist will check your blood sugar level and start a temporary intravenous line. You will be given an injection of a compound called FDG, which is a basic sugar that is labeled with a radioactive isotope, fluorine-18. After the injection, there is a waiting period of about one hour to allow the material to diffuse through the body and attach to target areas. During this time, you will be given a warm blanket and asked to remain still and rest quietly. The use of cell phones, music players, and reading materials are not recommended to avoid proper distribution of the injected material.
After the waiting period, you will be positioned on a padded scanning table. The table will be moved through the tube-shaped PET/CT scanner as it acquires the information needed to generate the diagnostic images. You will be asked to remain still during the exam because motion can interfere with the results. During the scan, you may hear some soft machine noise, but you will not feel anything unusual. You will feel the table move as it positions your body into the area to be imaged. The technologist will monitor you during the exam.
The scanning portion of the PET/CT is usually between 30 and 60 minutes. The total time for the entire procedure is typically between 90 to two hours.
After your exam
You may leave as soon as the exam is completed. Unless you have received special instructions, you will be able to eat and drink immediately following the procedure. It is advised that you drink plenty of fluids for the rest of the day to help clear the residual radioactive material from your urinary system. Otherwise, you may return to your normal diet and routine activities. We would also recommend that you limit time near any woman who might be pregnant for the first few hours following your test.
Your scan will be evaluated by our Diagnostic Radiologists with a report sent promptly to your referring physician, who will be able to review the results with you.
PET/CT side-effects
The FDG is a radioactive pharmaceutical that must pass multiple quality control measures before it is used for any patient injection. It has a short half-life of less than 2 hours. Most of the radioactive component has left your system within 6 to 8 hours following the injection.
You should not experience any unusual sensations or side-affects from this exam.