What does a PET-CT scan treat?

A PET-CT combines a PET image of activity in the body with a CT image showing anatomy. A small amount of FDG radiotracer is used because many active cells take up glucose. The combined images can help a team look for a tumour, assess whether disease has spread, choose a biopsy site, or compare findings over time.

The test may be considered for conditions such as lymphoma or cancer of unknown primary, depending on the clinical question. Areas of increased activity are not automatically cancer; inflammation, infection and normal body processes can also affect the images. Results must be interpreted with symptoms, examination and other tests.

Follow the imaging department's instructions about eating, drinking, medicines and activity before the appointment. Tell the team if you have diabetes, are pregnant or may be pregnant, are breastfeeding, or have difficulty lying still. Wear comfortable clothing and allow time for preparation, the tracer to circulate and image-taking.

After the scan, follow the department's advice about fluids, activity and contact with others. Ask when and how the report will be shared; the scan itself does not replace a treatment plan.

Contact the imaging team promptly if you develop an unexpected reaction after the appointment, feel severely unwell, or cannot follow preparation instructions. Seek urgent help for breathing difficulty, facial swelling, fainting or severe weakness.

What question is this PET-CT intended to answer? Do I need to change food, medicines or diabetes care beforehand? When should I expect the report? Which result would change the next step?