Maureen,
My understanding is that it is not the ENT typically who orders the follow up scans but the radiation oncologist. After my radiation treatments, the radiation oncologist wanted to see me 1 month after treatment ended, then 3 months (at which time I had a CT scan), at 6 months (another CT scan), at 9 months and approx. 12 months (another scan). I saw the ENT surgeon every 6 weeks following the end of radiation treatment.
I would contact your radiation oncologist and make sure that he/she is comfortable with the monitoring schedule and that you and your husband are as well. As Gary noted above, every doc seems to have a different approach to imaging, some prefer MRI's, some CT scans, some PET/CT scans, some x-rays.
Best, Sheldon