I agree with all the very informed posters here ( you did not need to ask the question of me as you can see). Gary has made a very important point, a PET this soon after treqtment is going to light up things just from the healing process (increased metabolism in the area) after the treatments and the diagnostic value of it is highly questionable. I didn't get my first PET until 3 years out from treatment. Before then it was all MRI's and CT's. The surgery will tell you much. Likely the nodes will be full of scar tissues that were malignant before, and after radiation will be cancer free. This is of course assuming that with the IMRT radiation they also painted the areas of known mets (the neck nodes) with a lesser dose of radiation than they gave the primary.