It is being proven that 100msv radiation was directly linked with cancer comes from data from Chernobyl, so 50msv I'd still being concerned this is like having 500k X-ray scan at one take, the greter rist doesn't come from the high dose itself, if comes from a time factor, the question needs to be, in how much time you get 50msv? It you tell me in one day I'll very concerned, this is a very high dose for rapidly changing organs like the bone marrow to absorb in one take (causing caners like leukemia ...)