How long does a PET-CT scan take to work for cancer of unknown primary?

The appointment includes checks before the scan, an injection of a tracer, a quiet waiting period while it travels through the body, and the scan itself. The combined images show body structure and areas of increased activity. For cancer of unknown primary, this may help doctors look for where a cancer began or identify areas that need further testing. The scan cannot by itself confirm every diagnosis, and it does not remove or destroy a tumour.

A radiologist and the clinical team usually need time to assess the images alongside your symptoms, examination and any biopsy results. The time until you hear the result depends on the service and how urgently the team needs it.

Follow the imaging department's instructions about eating, drinking, medicines and activity. Tell the team if you have diabetes, might be pregnant, are breastfeeding, or have difficulty lying still. Wear comfortable clothing and plan to remain at the department for the full appointment rather than arranging a tight schedule. After the scan, follow the department's advice about fluids, activity and contact with others.

Ask how and when the result will be shared, and whether another test such as a biopsy is expected. Keep a note of new symptoms and bring a list of medicines to your appointment.

Contact the imaging department promptly if you develop a reaction after the tracer, such as marked rash, swelling or breathing difficulty; seek urgent medical help for severe breathing trouble or collapse. Contact your cancer team sooner if pain, weakness, confusion, bleeding or other symptoms worsen while you are waiting for results. These symptoms need assessment on their own and should not be interpreted as proof of a particular cancer site.

Ask what the scan is intended to clarify, whether you need to fast, when the report is likely to be available, and what may happen if it does not identify a primary site. You can also ask which symptoms should prompt a call before the results appointment.