PET scan for cancer

A small amount of radiotracer is given before the scan. PET detects where the tracer collects, and CT shows the body’s structure. Increased activity can occur in cancer, but infection, inflammation, healing, and normal organ function can also appear active. The report therefore describes findings that must be interpreted in context.

PET-CT may be used for selected staging questions, to look for disease in another body region, or to compare activity during care. Learn about the [FDG Radiotracer](/materials/fdg-radiotracer/) and [PET-CT Scan](/treatments/diagnostics-and-staging/pet-ct-scan/).

Follow preparation instructions and tell the team about diabetes, medicines, pregnancy or possible pregnancy, and recent illness or procedures. When results are available, ask what the scan shows, what remains uncertain, and whether biopsy or another scan is needed. A PET result is one part of a decision, not a stand-alone treatment plan.

Seek prompt medical advice for new breathing difficulty, severe pain, confusion, weakness, persistent fever, or rapidly worsening symptoms. The appropriate urgency follows the symptom and examination findings rather than the scan’s activity pattern.

What question is this PET-CT intended to answer? Which findings are definite and which need confirmation? Could infection or treatment explain activity? Would biopsy or another imaging test change the plan?