Are bright orange spots on pet scan cancer?

Tricky. Not all cancers are bright on pet scans and not all bright activity in a pet scan is cancer. Inflammation/infection can also show bright activity. Pet scans are performed in conjugation with ct (pet/ct) and though pet is great for detecting metabolism, its specificity is not as great. Reading a pet requires care/skill. Normal activity is seen in the brain, heart, liver, spleen, kidneys, bladder.