What can a PET scan detect?

The scan uses a small amount of FDG Radiotracer, which behaves like glucose and can collect in active tissues. The PET images are combined with CT images, so the care team can compare activity with the body's anatomy. Increased activity may occur in cancer, but it can also reflect inflammation, infection, healing, or normal activity in organs such as the brain and heart. A scan finding alone does not identify the cause or prove that cancer is present.

Clinicians may use the result to look for a primary tumour, assess lymph nodes or distant areas, guide a biopsy, or compare disease activity during treatment. Cancer of Unknown Primary and Lymphoma are examples of situations where PET-CT may help answer a wider diagnostic question.

Follow the imaging centre's instructions about eating, drinking, medicines, diabetes, exercise, and arrival time. Wear comfortable clothing and tell the team about pregnancy, breastfeeding, diabetes, recent illness, or difficulty staying still. During the appointment, the tracer is given, followed by a quiet waiting period and imaging while you lie still. Ask when and how the report will be shared, and discuss the result with the clinician who knows your symptoms and other tests.

Contact the imaging centre promptly if you cannot follow the preparation instructions or have a change in your health before the appointment. After the scan, seek urgent medical help for trouble breathing, facial swelling, fainting, or severe weakness. These symptoms are not expected from the scan and need assessment rather than interpretation of the images.

What question is this PET-CT scan intended to answer? Which areas will be assessed, and could inflammation affect the result? Do I need another test, such as a biopsy, before a diagnosis is made? When should I expect the report and who will explain it?