Mickey

YES, I see showing "light evidence" (presumably higher SUV)in a PETscan 4 months after treatment for BOT as VERY COMMON. Remember all a PETscan does is measure sugar uptake, not cancer. Since the normal cells in your mouth, especially near the base of tongue suck up sugar big time when trying to recover from TX, on a PETscan, it looks exactly the same. For that reason, my CCC will only do post TX Petscans at least six months after TX. At the 3 month mark, they do an MRI instead.
While you can get a copy of your Petscan, it will just scare you unnecessarily in my opinion but if you remain calm about it, then you could underline the parts you want to ask your ENT about.
The scan schedule they put you on seems normal to me.
Don't get me wrong, PETscans are great before TX since the cells haven't been damaged by TX, so they can highlight the abnormal sugar uptake by the cancer. PETscans really help the RO plot out the radiation field. But once you've had TX, they are not reliable for at least six months.
Trust me, I know just how worrisome these scans are. Even after 13 scans over these 5 years, I worry worry worry about each one. I just try not to let it get out of control.
Oh, and PETscans are also wonderful in spotting lymph node cancer, and have been a major factor in eliminating unnecessary neck dissections. But it strikes me as strange how many doctors just don't get it about early PETscans for base of tongue cancer.
Charm