What is Positron Emission Tomography-Computed Tomography?
The word tomography means producing an image of the inside of a solid object. In medicine, it means producing an image of the inside of the human body.
When elementary particles known as positrons and a specialized computer are used to create the images, it’s called Positron Emission Tomography – Computed Tomography, or more commonly a PET/CT scan.
In the past, PET Scans and CT Scans were done separately. Modern machines use both strategies to create more accurate, more helpful images.
The images of the body’s organs and tissues help your doctor evaluate organ and tissue function and identify cellular-level changes to the body.
All PET-CT Scans require the use of a tracer. Depending on the part of the body your doctor is studying and the condition (s)he suspects you may have, the tracer might be inhaled, swallowed, or injected. You can read more about the most common tracers we use during PET/CT scan further on in this article.
Why do I need a PET/CTA Scan?
This type of scan is used in nearly all medical specialties to diagnose, treat, and monitor a huge variety of conditions. Here at our cardiovascular specialty clinic, the most common reason we perform PET/CT Scans are heart problems.
A cardiologist may want to know if there is tissue damage in your heart. Healthy heart tissue absorbs tracer more quickly than damaged tissue.
If your doctor’s concern is cancer, then the doctor actually looking for cells that absorb the tracer too quickly.
Different tracers can also be used to watch blood flowing through your arteries and veins. This is helpful to cardiologists and vascular specialists who might believe you have plaque inside your arteries.
What are the Risks of a PET/CT Scan?
Although it requires the use of a large, loud machine, the PET/CT Scan itself is completely non-invasive and painless.
Before visiting the scanner, though, you’ll need to have a tracer introduced to your bloodstream. Depending on the tracer and the part of the body your heart or vein specialist wants to study, you might be able to inhale or swallow the tracer. Others need to be injected directly into the bloodstream.
Tracers used during a PET/CT scan vary, but they all contain radioactive tracers. The American College of Radiology Imaging Network considers the procedure to be low-risk; a patient is not exposed to a dangerous amount of radioactivity during a single scan. Both your doctor and your insurance company will work hard to ensure you don’t receive too many tests with radioactive tracers.
You may have heard that people undergoing radiation therapy need to avoid pregnant women and small children because of the radiation their bodies carry around with them after treatment. This is true, but remember that radiation therapy, like for cancer, is very different from having a test done a radioactive tracer. You will not be given enough radioactive tracer to harm your health.
Which Tracers Will Be Used During my PET/CT Scan?
The FDG Tracer requires the most intense preparation of any tracer we use here at FHCC. The day that a patient needs a PET/CT Scan with FDG, they cannot eat or drink anything at all. Some patients may not even be able to brush their teeth. But we use FDG because it’s an excellent way to watch the speed at which cells absorb glucose.
Ammonia is a very useful tracer. It can help your cardiovascular specialist watch blood flow through your heart. The day you receive a PET/CT scan with an ammonia tracer, you’ll need to avoid caffeine. It’s worth noting that a caffeine-free product is not the same as a decaffeinated product. You should also remember that chocolate contains some caffeine. You’ll also need to avoid food and tobacco for about four hours before your exam.