CET PET scan: what patients should know

The wording is not universally used. Your referral may mean a PET-CT examination or PET imaging paired with a contrast-enhanced CT. The booking team can tell you which tracer and CT technique are planned.

PET detects patterns of activity after a small amount of radiotracer is given, while CT maps structures inside the body. A clinician interprets both image sets together. The scan can help locate active disease, assess its distribution, guide a biopsy site, or check how cancer has responded to treatment. Uptake is not specific to cancer: inflammation, infection, normal organs and healing tissue can also appear active. Results therefore need to be read alongside symptoms, examination findings and other tests.

Follow the imaging centre's instructions about food, drinks, medicines and physical activity. Tell the team before arrival if you have diabetes, could be pregnant, are breastfeeding, have kidney problems, previously reacted to contrast, or cannot lie flat. Bring your medicine list and earlier scans if requested. After the tracer injection, you will usually rest quietly before imaging; movement and talking can affect where tracer collects. Plan extra time because preparation and uptake occur before the scanner images are taken.

Tell staff immediately if you develop breathing difficulty, throat tightness, facial swelling, widespread hives, severe dizziness or feel faint during or soon after an injection. After leaving, seek urgent medical care for the same symptoms. Contact the imaging centre if an injection site becomes increasingly painful, swollen or red. For ordinary questions about hydration, contact with children or breastfeeding after the tracer, use the personalised instructions supplied by the nuclear medicine team.

Ask what “CET PET” means on your referral, whether the CT will use intravenous contrast, and what clinical question the scan is intended to answer. Also clarify whether medicines need adjusting, when you may eat, how results will be communicated, and whether another test or tissue sample could still be needed after imaging.