Glad I found this discussion. Hubbie is going in for more radiation 6 months after his last treatment. This time the Doctor feels he removed all the cancer after his radical neck dissection but would like to clean up any microscopic cells with the cyber knif. There is a 10 to 15% chance his carotid artery could rupture. I have been so nervous of this situation. He has been feeling real dizzy after sitting and then standing. I almost want to stay very close to the hospital for a while when he is going through this just incase there is an emergency.