I had two concussions. So the head ones I guess were needed. With the abdominal ones at the time I actually thought I needed them. I'm not too worried about the radiation from the scans as the increase in risk is not too much considering a six month stay on the space station is 80mSv and the maximum dose over a lifetime for an astronaut is 1S. Also I eat pretty healthy, rarely drink, haven't smoked or used chewing tobacco for awhile so I feel that takes me out of a predisposition to get it in a way I guess. I just hate to not know what's going on with my body. I just recently had blood work, urinalysis, ultrasound and chest xray for pain that's persisted in my back for near two months and the doctors say they don't know and the only route now is ct scan or mri which I don't care for either one. It's just my mind spirals and I'm very inquisitive so I need to know. Thanks for all the replies.