Hmmm. I did not to mean to imply that radiation builds up by itself. What I meant was that the radiation in the body stays there.
I just don't think that's correct. In order for there to be radiation, there has to be an unstable particle within the body. This can happen through inhalation, ingestion or through a lesion of the skin, but "radiation" doesn't really stay in the body, it's an energy wave that may damage tissue as it passes through (typically by burning in high doses or by DNA mutations at lower levels) but the skin is sufficiently thick to block most smaller radioactive particles. If what you say was true we should avoid the elderly like the plague because they would be virtually lethal from all of the sunlight they had absorbed in their lifetimes. Unless I'm still missing what you're saying. How does the radiation stay there, say from an X-ray?