Sounds like the preparation procedures vary somewhat by
location. Must be the posts I had read had me thinking one way and in reality it's another.
My experience was this - Laid on the table, they hold a small white towel over me as I slide down my sweat pants and pull up my shirt. Line up my tattoos, a little nudging here and there (odd feeling), cover the area with that white towel and they leave. Could feel the machine make some table adjustments after the CT scan. Then the whirring sound of the accelerator and zooming around me at a pretty good clip.
The towel is a nice modesty touch but not really needed after what the uro's do to you. I am at a teaching hospital too so it was often times more than one finger did the deed followed by discussion of what was felt. When I said to the RT techs I don't really need the towel, they chuckled and said the towel was for them, not me.