 | PET/CT
Positron Emission Tomography/Computed Tomography To schedule an appointment, call 202-466-2033
What is a PET scan?
How does PET/CT work?
What is FDG?
How is PET/CT used?
Is PET/CT safe?
What will happen when I arrive for my appointment?
What happens during the PET/CT study?
Are there potential side effects to a PET/CT scan?
How will I learn about the results of my scan?
What preparation is required?
Where does WRA perform PET scans?
What is a PET scan?
PET (Positron Emission Tomography) and CT (Computed Tomography) studies are both standard imaging tools that physicians use to pinpoint disease states in the body. A PET scan demonstrates biological function of the body while the CT scan provides information about the body's anatomy. Alone, each imaging test has particular benefits and limitations but when both scans – PET and CT – are performed on the same scanner and at the same time, the combined image provides complementary information which enables physicians to more accurately diagnose and identify cancer, heart disease and brain disorders.
How does PET/CT work?
When disease occurs, the biochemistry of the body’s tissue and cells change. In some diseases, like cancer, the metabolic activity of the malignant cells increases, thus requiring higher glucose uptake and utilization. When the small amount of FDG (radioactive glucose analog) is injected into the patient, it travels through the body and accumulates in cells which then emit signals that are captured by the PET/CT scanner and then transformed into images of biological function.
What is FDG?
A radiopharmaceutical is a radioactive drug. The most commonly used PET/CT radiopharmaceutical is FDG, which is a radioactive form of glucose (sugar). Radiopharmaceuticals are produced by physicists and chemists. Fluorodeoxyglucose is a commonly abbreviated to FDG. To begin the PET/CT procedure, a small amount of glucose is injected into your bloodstream. There is no danger to you from this injection. FDG has a half-life of approximately 110 minutes, so it is quickly expelled from your body. FDG must pass multiple quality control measures before it is used for any patient injection.
How is PET/CT used?
PET/CT is used to diagnose and stage patients with cancer, as well as patients with certain brain and heart disorders. In cancer, PET/CT can: distinguish benign from malignant tumors, stage cancer by showing metastases anywhere in your body, prove whether or not treatment therapies are working (chemotherapy/radiation). In the brain, PET/CT can: diagnose Alzheimer’s disease for early intervention, locate tumors in the brain and distinguish tumor from scar tissue, locate the focus of seizures for some patients with epilepsy, more accurately assess tumor and other sites in the brain for delicate surgery.
Is PET/CT safe?
The risks associated with a PET/CT scan are very minimal. The quantity of radiation is kept to a minimum and the FDG degrades quickly so that no detectable radioactivity is present after several hours. In addition to the radioactive decomposition, the remaining FDG is eliminated from the body through urine. Family members are not at risk for exposure since greater than 90% of the radioactivity has left the body or decomposed before the patient has left the center.
What will happen when I arrive for my appointment?
The nurse will take a medical history and any prior PET/CT exams will be reviewed. Your blood sugar level will be checked. The technologist will then administer the imaging tracer (FDG) using an injection. A one-hour resting period will be required before the scanning begins. This resting period is necessary for the FDG to be distributed throughout the body.
What happens during the PET/CT study?
You will be positioned on the scan table. The table will be moved into a large opening in the PET/CT scanner. You will be asked to lie still while the scanner acquires the images. The time of the scan varies but typically ranges from 20-30 minutes.
Are there potential side effects to a PET/CT scan?
No, there are no side effects to having a PET/CT scan performed. It is a completely painless and non-invasive study. At WRA, our radiologists have extensive experience performing PET/CT studies every day. If any questions should arise after your procedure, you should contact your referring physician or the radiologist who performed the procedure.
How will I learn about the results of my scan?
After the radioactive tracer is processed by the organ being studied and the scanner records the information, the images are interpreted by a WRA board-certified radiologist with special training in PET/CT. Your scan results will be sent to your physician generally within 24-48 hours of your study.
What preparation is required?
Although the actual PET/CT scan lasts just 30 minutes, there are additional on-site pre-scan preparations that are required. We advise allotting three hours for the entire appointment which includes the injection of a radioisotope and a one-hour rest period to allow the injection to be absorbed throughout the entire body. We need to know in advance if the patient is diabetic, pregnant or breast feeding. Patients must fast for at least six hours prior to the exam. During that time, patients may drink water only and take any prescribed medications. It is also important that PET/CT patients restrict any exercise 24-hours prior to the study. This means avoiding the treadmill, formal exercise, exerted walking, etc. All patients receive a preliminary low-dose CT scan which is used primarily for anatomic localization.
Where does WRA perform PET/CT scans?
PET/CT scans are performed in Washington, D.C. at 2021 K Street, NW, Suite T-120. You may call 202-466-2033 to schedule an appointment.
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