What should you know about nuclear medicine PET-CT scan?

The PET part detects activity after the body takes up a radiotracer, while the CT part maps the location and shape of tissues. This combined view can help clinicians look for active areas, assess known cancer, plan treatment, or clarify findings from another test. An area of increased tracer uptake is not, by itself, proof of cancer; inflammation and other processes can also change uptake.

FDG is a commonly used radiotracer related to how cells use glucose. The scan does not replace the clinical assessment, imaging review, or tissue diagnosis when a biopsy is needed.

Follow the imaging team’s instructions about eating, drinking, medicines, and activity before the appointment. Tell them if you have diabetes, may be pregnant, are breastfeeding, or have difficulty lying still. After the tracer is given, you usually rest quietly before the scan so normal activity does not affect the images. During imaging, remain still while the table moves through the PET-CT scanner. Drinking fluids afterwards may help clear the tracer, according to your team’s advice.

Contact the imaging service promptly if you develop unexpected symptoms after the appointment, such as trouble breathing, facial swelling, widespread itching, or severe weakness. Seek urgent care for severe breathing difficulty, fainting, or sudden confusion. These symptoms are not expected from every scan and need prompt assessment.

Ask which tracer will be used, what area will be scanned, whether you need to change any medicines, when results should be discussed, and whether another test such as a biopsy may be needed.