Uses of an FDG PET scan

FDG PET scans can help locate active tissue, assess spread, guide treatment planning, and compare disease activity over time. The scan is a decision-support tool, so its findings are combined with examination, laboratory results, pathology, and other imaging.

FDG follows glucose use. Many cancers use glucose actively, but infection, inflammation, healing tissue, and some normal organs can also take up FDG. Clinicians may order the scan to investigate an unclear finding, look for disease in other parts of the body, select a biopsy target, plan radiotherapy, or assess whether treatment is changing activity.

It can also help investigate selected non-cancer questions, including some neurological and cardiac assessments. A result that looks active is not automatically cancer, and a less active result must be interpreted in context.

Follow instructions about fasting, fluids, medicines, exercise, and arrival time. Tell the team about diabetes, pregnancy or possible pregnancy, breastfeeding, infection, recent procedures, and medicines. Rest quietly after the injection and keep still during imaging. Ask when you may eat, drive, work, or return to your usual routine.

Seek urgent care for severe breathing difficulty, fainting, chest pressure, a new seizure, sudden weakness, or sudden confusion. Contact the imaging service before the appointment if you cannot fast, have unstable glucose, feel acutely unwell, or may be pregnant so the plan can be reviewed.

Ask which clinical question the scan addresses, whether CT contrast is needed, what preparation applies to your medicines, and what other results will be reviewed with the report.