A positron emission tomography (PET) scan is an imaging test that uses a very small dose of a radioactive chemical, called a radiotracer, to help your provider check for diseases in your body. A PET scan detects changes in cellular function – specifically, how your cells are utilizing nutrients like sugar and oxygen. Since these functional changes take place before physical changes occur, a PET scan can provide information that enables your provider to make an early diagnosis.
A computed tomography (CT) scan shows detailed pictures of tissues and organs inside the body. It uses special X-ray equipment to take cross-sectional images of your body. Sometimes, a special dye called a contrast medium is given before the scan to provide better detail on the image.
PET/CT imaging combines the functional information from a PET scan with the anatomical information from a CT scan in one single exam. When these two scans are fused together, your provider can view metabolic changes in the proper anatomical context of your body. This provides more information and allows for a more precise diagnosis.
Today, almost all PET scans are performed on instruments that are combined PET and CT scanners. At Glencoe Regional Health, we partner with Shared Medical Services to bring this technology to our patients.
Common Uses
PET/CT scans are performed to:
- Detect cancer
- Determine whether a cancer has spread in the body
- Assess the effectiveness of a treatment plan, such as cancer therapy
- Determine if a cancer has returned after treatment
- Determine blood flow to the heart muscle
- Determine the effects of a heart attack, or myocardial infarction, on areas of the heart
- Identify areas of the heart muscle that would benefit from a procedure such as angioplasty or coronary artery bypass surgery (in combination with a myocardial perfusion scan)
- Evaluate brain abnormalities, such as tumors, memory disorders, seizures, and other central nervous system disorders
- Map normal human brain and heart function
What to Expect
When you arrive, we will review your history and any past exams. For the PET portion of the exam, you will receive an injection of radioactive material similar to what 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.
After your injection, you will be asked to wait in our injection suite for one hour while the radiopharmaceutical distributes. 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.
PET/CT scans last between 20 and 45 minutes. The exam can vary depending on what we are looking for and what we discover along the way. Plan to spend two to three hours with us.
Safety
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 is pregnant.
Appointments
If your provider orders a PET/CT scan, you’ll be provided with information about how to prepare for the appointment.
