The part of this line above 10 rem (0.1 Sv) certainly supports this idea, although doubling the dose does not double the effect like is commonly thought.
Doses between 50 and 100 rem (0.5 and 1 Sv) resulted in a 29% increase in cancers over doses between 0.5 and 10 rem (0.005 and 0.1 Sv) even though there was a 1000% increase in dose.