Although I too am not an MD, I am a PET / nuclear medicine technologist. I have done PET/CT for years and although CANNOT give you medical advice, I can explain how the scan works and that may help you.
Simply put; CT measures (images) densities. Benign or malignant the same. PET images are based on metabolic activity. Or how it consumes the injection. Scar tissue has very little if any metabolic activity. Ergo it is not alive. Malignant tumors are highly metabolically active (alive) and consume the glucose (sugar) in the FDG F18. This is the compound FluoroDeoxyGlugose attached to the isotope Fluorine 18. F18 is a positron emitting isotope that is ejected from the nucleus and strikes an orbiting electron creating “pair production” which is two 511 KeV photons at exactly 180 degrees from each other. This consistency makes imaging predictable and reliable. (Sorry to bore you with the technical stuff). Bottom line, theoretically, only metabolically active molecules will light up with enough activity to be rated in SUV’s. (Standard Uptake Values.) the higher the consumption rate the higher the SUV. There are some exceptions; infection being just one of them. In everything, there is variation, thus the activity needs to be quantified to show the relative value (chance) of active malignancy.
These complications are what make it important for a Radiologist (MD) trained in PET to be reading these.
Hope this helps.
Remember, I am NOT an MD. I am NOT offering/giving medical advice. I in NO way am indicating what your scan means literally or implied. Consult your physician for medical advice please.