It's not that bad but I'm not claustrophobic. If you are try to close your eyes and try not think about it. The mask making isn't scary - you lay down like you would for regular treatment - and they place the material over your face it stretches to fit you then dries - it's holey - like a strainer - they will cut out holes for your eyes and mouth after - I kept my eyes closed through all my treatments - just listened to the cd of the day. Being locked into place isn't fun but it's meant to keep you still so he radiation hits the right place.

You'll be okay try not to worry... Good luck