I have to have regular MRIs because of a bone condition ( not cancer related ) I am extremely claustrophobic too , I absolutely hate them . Last time the Consultant agreed Lorazepam, it really did help , may be worth asking about for future scans . When you have sedation the technicians have to interact with you a lot more to make sure you are ok which I found helped me too .
I also react to the contrast for CT scan , I’ve been told I shouldn’t have it again.
Sounds like a very stressful day for you ,I hope it goes better than you think x