Neatorama had this link to a Wired story from all the way back in 1997: In 1978, a Russian nuclear scientist named Anatoli Bugorski was working on a piece of broken equipment in a particle accelerator and his head was inside the accelerator when it fired accidentally.

He says he saw a flash of blinding light “brighter than a thousand suns” as the particle beam passed through his head. Instruments indicate that the radiation in the proton beam was about 200,000 rads. A lethal dose of radiation is in the realm of 500-600 rads. Everyone, including Bugorski himself, assumed he was a dead man. He was transported to a hospital, not to be treated, but to be observed by doctors studying radiation poisoning as he died. As with most victims of radiation poisoning, his skin swelled and peeled away as if burned…but he did not die. He survived, although the radiation continued to destroy nerves inside his head for two YEARS following the accident, freezing all the muscles on one side of his face. As of the writing of the Wired story in 1997, he only suffered from occasional small seizures, and from tinnitus. He went on to complete his Ph.D. and continued to work in the Soviet nuclear program for years afterward, though he is now retired.