Again I realize this response comes long after your post, but it may be of help to someone.

Yes I had "the mask" created and was secured to the table for IMRT treatment.

I really don't know what was the worst: the confinement; the popsicle stuck into my mouth; the horrendous noises; or knowing I was literally being "fried" by the rads.

Nonetheless they messed up by not taking into consideration the metal fillings in my teeth. The radiation was not localized and reflected throughout my mouth.

It was the worst part of everything I went through.