What to know about a whole-body PET-CT scan

The scan uses a small amount of FDG radiotracer, which tends to collect in tissues using more glucose. The PET images show this activity, while CT images provide detailed information about body structures. Activity can also occur with inflammation or infection, so a bright area is not automatically cancer.

A whole-body examination may help assess the original site, look for spread, guide staging, or monitor a known condition. Learn about the [PET-CT Scanner](/technology/pet-ct-scanner/) and [FDG Radiotracer](/materials/fdg-radiotracer/).

Follow the imaging centre's instructions about fasting, drinking water, medicines and arrival time. Tell the team if you have diabetes, might be pregnant, are breastfeeding, or have difficulty lying still. Wear comfortable clothing and expect a quiet resting period after the tracer is given before imaging begins.

During the scan, remain still while the table moves through the scanner. The appointment may take several hours because preparation and tracer uptake are part of the process. Results are interpreted with your symptoms, examination and other tests.

Contact the imaging team if you develop a rash, breathing difficulty, faintness or marked discomfort after the appointment. Ask when and how results will be explained, especially if the scan was arranged for unexplained symptoms or a suspected condition. Seek urgent help for severe breathing trouble or loss of consciousness.

Ask what the scan is intended to answer, whether you need to fast, which medicines to take, and when normal activities can resume. Ask how findings will be combined with biopsy, blood tests or earlier images, and what happens if an area shows increased tracer activity.