ALERT: A cyber incident at Optum/Change Healthcare may delay Luminis Health bill processing. Watch for fraud and verify any concerning messages with your provider's office. We are working to minimize disruptions.



Call (888) 909-9729

What Is a PET-CT Scan?

Our diagnostic imaging center uses PET-CT scans to diagnose heart disease, brain disorders and, most often, cancer. It can help doctors find cancer in the body, see if cancer has spread or check if a tumor is shrinking with treatment.

For cancer patients, a technologist injects a substance called a tracer. Cancer cells absorb more of this tracer than other cells do because cancer cells are more active and use more nutrients. For dementia or heart disease, doctors use a tracer with a substance that binds to the plaque that causes these diseases.

Next, a scanner detects the radioactivity in the body. In a PET scan image, cancer cells or other disease markers show up as brighter spots.

Today, almost all PET scans happen at the same time as a CT scan, which shows the structures of the body. This combination provides more context than a PET scan alone – showing doctors exactly where the cancer is within the body.

Why Choose Luminis Health Imaging for Your PET-CT Scan

We take every opportunity to make our PET-CT tests safer and more precise, and to provide a smoother process for you.

Through our Image Wisely pledge with the American College of Radiology, we make sure we use lower radiation options whenever possible. This means we only image the area your doctor wants to see, with the lowest dose option.

We know people living with cancer and other diseases have extra day-to-day stress. That's why we want to make testing as easy as we can. We offer extended daytime hours and easy online booking.

Another benefit of Luminis Health Imaging is that we keep all your test results in one place. If you're a Luminis Health patient, you and your health providers can access your scan results at any time through your MyChart account.

What To Expect at Your PET-CT Scan

Before your test, a technologist calls you to go over your instructions. This includes not eating or drinking for at least four hours before your scan. Your technologist also discusses when you should take your daily medications.


Besides fasting for four hours, you'll also need to avoid sweets and eat a low-carb diet the day before the exam. This makes cancer cells more likely to absorb the glucose in the tracer. Wondering what you should and shouldn't eat? We'll provide lists of recommended meal options. You're also free to call us with your questions anytime.


Finally, you'll need to avoid strenuous activities and exercise 24 hours before the appointment. Too much activity can affect metabolism and interfere with the test's accuracy. So save that long hike or bike ride for after your appointment.

For the test itself, a technologist injects the radioactive tracer and then you'll sit for an hour so the tracer can absorb. This is a great time to catch up on your reading or podcasts.


You'll feel the brief prick of the needle and may feel a little itchy for a few minutes as the tracer enters your body. The rest of the test is painless.


Next, you'll lie on a table that slides into the doughnut-shaped PET-CT scan. You'll need to lie still to get an accurate reading. This part can take 15 to 45 minutes, depending on the area your doctor needs to see. (As you can imagine, it takes longer to image a larger area).

After the test, your provider sets up an appointment to discuss the results. We know it's worrisome when you're thinking of your cancer status or a possible new diagnosis. Rest assured, whatever the result, your PET-CT scan helps your doctor work with you to create your best treatment plan.