Hi Paulan, I don't like confined places and found the bone scan to be fine. When I had this a small square plate did come close to various parts of my body (legs, arms and chest) but it wasn't claustrophobic at all. It didn't come near my face when I had it. It's like when you stand up for a chest X-ray you have to stand next to a plate where they put the X-ray film. The rest of your body is not confined. I didn't find it uncomfortable and you can breathe normally. Re the panic attacks, they will tell you what they are doing every step of the way. Mention your concerns to the radiographer and maybe relaxation breathing will help.
Hope it goes ok for you.
Take care, Nadine