PET scan for cancer metastasis

PET shows tracer activity across the scanned body, while CT shows location and structure. The team looks for patterns that fit the known cancer, but infection, inflammation, injury, and treatment-related healing can mimic spread. Some metastases may be better assessed with another scan, depending on the organ and the clinical question.

A report may describe lymph nodes, bones, lungs, liver, or other regions. If the original cancer is not known, assessment may involve [Cancer of Unknown Primary](/conditions/cancer-of-unknown-primary/) or [Lymphoma](/conditions/lymphoma/) pathways.

Ask which findings are new, which are uncertain, and whether they match earlier imaging. Share information about recent infection, surgery, injury, and treatment. Your team may recommend targeted imaging, repeat imaging after an interval, or biopsy. The result can help plan care, but treatment choices also depend on tissue type, symptoms, and your overall health.

Get urgent assessment for sudden weakness, new confusion, seizures, loss of bladder or bowel control, severe back pain, or significant breathing difficulty. These symptoms may require rapid treatment independent of what the scan eventually shows.

Which sites are concerning, and what alternatives could explain them? Is tissue confirmation needed? Could the finding change my stage or treatment? What symptoms should make me seek urgent help?