When radiation is good for you

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477705/ and http://a-place-to-stand.blogspot.com/2010/03/radiation-damage-lnt-or-hormesis-prof.html explain how radiation in small doses stimulate your immune system, and prevent cancer from taking hold. Hard to argue with the multiple studies and hard numbers.