I can totally empathize sympathize and understand what you are saying...I wish I had a magical solution to your problem as mine is the same...I am extremely fortunate at this point have not had to have radiation treatments but yet I know that I would react the same as you have...despite being told to take deep breaths or thinking about something else I give you credit for even deciding to go through with the treatments and now that you are more familiar with what is going to happen you may be a little more relaxed. I can immagine how intimidating being constricted would be. For music if you have an mp3 or anything like that they have small speakers that can attach...or a portable cd player can hook up to these portable speakers...or a boom box
The other thing that helps me is detatching myself from myself it sounds wierd but that is the only way I actually went through with my surgery the hour and a half trip to hospital...I would find one thing and just focus on it like something in the room or for me it was stone necklace (kinda spiritual)focused on the smoothness, the feel of it in my hands...Please let us know how you make out. I will keep you in my thoughts as I may need the same support some day and if there is something that works for you you have to know you are not alone and it may work for others as well...Take care sweetie and for tonight try a long hot bath some candles and soothing music...just try to relax...

Thinking of you

Dianne