I would like to add to what Gary said in that "false negatives" for fused PET/CT scans are very uncommon -- that is, a situation where there IS cancer but the scan fails to find it. Comparative studies have quoted figures from essentially "none" to 2-3%. So if you get a "clear" scan read by someone who knows what he or she is doing, you can breathe a bit easier.

Rate of false positives may also reflect experience and hence, confidence, of the radiologist in distinguishing cancer from hightened uptake by inflammation, infection or healing tissues.

Of course the PET/CT is only part of a proper diagnostic workup, as Gary notes.

Gail