I've had them done twice, and they were not as bad as I expected. I can be claustrophobic. For one of them, they asked me if I wanted a cloth over my eyes and I said yes. That way I couldn't see that I was in such a small space in the tube. If you can't see you are in a small space, then it bothers you less. You can just imagine you are lying on a bed. I could never hold my breath as long as they expected me to, but they didn't complain. I just did the best I could with the breathing.