A simple and practical lawIN2P3
The proportionality proposed between dose and effects can be shown on a dose-effect diagram by a 'linear relationship with no threshold' - that is to say, a straight line going through the origin. The relationship apply to a single dose or for cumulative doses as well : the effect of a dose is not changed by any previous exposure - each dose absorbed can be viewed as independent of any others. The proportionality apply to all ranges ( not specified on the figure) of doses, even very low doses : the risk is never zero. This line, practical as it is for regulating radioprotection recommandations, is not a law of nature.