Scott, have your dad's doctors recommended amifostine? Generally with IMRT, the radiation can be so precisely focused that some, if not all, of the parotid glands can be saved. In my case, although I had a lot of radiation all around my neck and jaw, I have recovered probably 97% of pre-treatment saliva, without needing amifostine, which many people cannot tolerate. I would ask the radiation oncologist about this, because if you can spare your dad this drug, things will be easier for him. Search for amifostine on this site and you will understand my reservations.