Hun, I would tell him that he's going to have a little poke and then he will go to sleep for a bit and have nice dreams while they check out some things inside him... I would try your best not to worry (or try to hide it really well) because he
will sense your anticipation!
I'd explain to him that he can't eat or drink anything because it would make his tummy upset and he can't throw up while he's sleeping... These are the things I told Aaralyn and she was really ok with every thing, until she saw the big ct scan machine, and then the nurse did a horrible job of getting the iv in her, but anyway, you'll have a great staff and they will help make you feel better about things too.
Have a nice special treat ready for Joseph when he wakes up and expect him to be very wobbly and out of it for a while. Aaralyn thought she could walk about an hour after she came out of her anestesia and her knees buckled

poor thing.
It will all be ok, just trying to give you a pretty good idea of what it will be like so you'll be prepared. Bring tissues in your purse

but Joseph will be totally fine through it
