Is a PET-CT scan radioactive?

Before the scan, a small dose of FDG radiotracer is injected into a vein. Its temporary radioactivity allows the PET camera to map glucose use. The CT portion uses X-rays to show anatomy. The amount and type of exposure are selected by the imaging team for the examination, and the tracer decays and is passed out of the body over time.

Tell the team if you are pregnant, might be pregnant, breastfeeding, have diabetes, or have had difficulty with injections. These details can change preparation or timing. The test is different from radiotherapy: it is an imaging examination, not a treatment intended to destroy cancer cells.

Follow the centre's instructions about eating, drinking and medicines. After the injection, resting quietly helps the tracer distribute. Unless your team says otherwise, drinking fluids and urinating regularly help clear it. Ask before close contact with a baby or pregnant person if your centre has given specific precautions.

Read about [FDG Radiotracer](/materials/fdg-radiotracer/) and the examination in [PET-CT Scan](/treatments/diagnostics-and-staging/pet-ct-scan/). A [PET-CT Scanner](/technology/pet-ct-scanner/) combines the two imaging methods.

Tell staff immediately about pain, swelling or burning at the injection site, trouble breathing, faintness, or a rapidly spreading rash. Once home, seek urgent medical help for breathing difficulty, throat swelling or collapse. For less urgent concerns, call the imaging department and describe when the symptom began.

How should I adjust food, insulin or other medicines? What contact precautions apply to my household? When can I resume normal activities? Why is this scan preferred for my clinical question?