"A little radiation might be good for you" - Edward Teller.
BTW there's actually some truth to this. Low levels of above-normal-background radiation have actually been shown to lengthen the lives of experimental animals, possibly by inducing a greater production of protective enzymes in response. Also, conversely, "Preliminary studies have shown that animals raised in shielded environments with zero radiation had a higher incidence of cancer than lab animals raised in an environment with normal background radiation." (http://www-med.stanford.edu/shs/update/archives/aug98/qa.html)