A fused PET/CT is still the "gold standard" but you want the radiologist administering and reading the scan to have seen a lot of head and neck scans. The risk of false positives is greater when the experience of the "reader" is less, they may be over-cautious and incorrectly interpret inflammation or healing as cancer.

Even with top person, the rate of false positives can be about 5-7% (per our ENT and also, the radiologist) -- however the risk of false negatives is quite small.

The radioactive labelled glucose of the PET shows areas of high cellular activity (cancer is glucose-hungry, thus takes it up strongly, but so do areas of normal cell growth such as healing wounds) -- the CT component allows the radiologist to examine the "hot spot's" physical appearance. Experienced radiologists can Usually separate cancer from benign processes, but sometimes there are areas that cannot be identified. The doctor may then order a biopsy, if practicable, or another scan such as an MRI.

Gail