What is a PET scan?
A PET scan (short for positron emission tomography) is a special imaging test that helps doctors see how your organs and tissues are working. It uses a small amount of a safe, radioactive substance to show changes in your body that might not show up on other scans. Doctors often use PET scans to look for cancer, heart problems or brain conditions.
Who is a candidate for PET scan?
A PET scan may be recommended if:
- Your doctor is checking for cancer or seeing if it has spread
- You have a known condition and need to see how it’s responding to treatment
- You have heart disease and your doctor wants to check blood flow
- You’re being tested for brain issues like seizures, memory loss or tumors
PET scans are usually ordered when doctors need more detailed information than other scans can provide.
What to expect during a PET scan
Before the test, you’ll get a small injection of a radioactive tracer. It travels through your body and helps certain areas show up clearly on the scan.
- You’ll wait quietly for about 30–60 minutes while the tracer moves through your body
- Then, you’ll lie on a table that slides into a large machine
- You’ll need to stay very still during the scan, which usually takes about 30 minutes
- The test doesn’t hurt, but the machine may feel a little tight or noisy
You might be asked to avoid eating for several hours before the scan.
What are the risks for a PET scan?
PET scans are considered safe for most people. The amount of radiation used is very small and leaves your body quickly.
However:
- People who are pregnant or breastfeeding should tell their doctor before getting a PET scan
- There’s a small chance of allergic reaction to the tracer, but this is rare
- Staying still for the scan may be uncomfortable for some people
What does recovery from a PET scan entail?
Most people can go back to normal activities right after a PET scan. The radioactive tracer will leave your body naturally, usually within a day.
After the scan:
- Drink plenty of water to help flush out the tracer
- You may need to wait for your doctor to go over the results
- If the scan was done to guide treatment, your care plan may change based on the results