Stochastic vs Deterministic Effects

Two kinds

Deterministic effects, now often called tissue reactions, happen only after a dose passes a threshold. Above that threshold the effect is expected to appear, and a higher dose makes it more severe. Examples are skin erythema, epilation, cataracts, sterility, and the acute radiation syndromes. Stochastic effects are random. They have no threshold, so any dose carries some risk, and a higher dose raises the chance the effect occurs, not its severity. Cancer, including leukemia, and hereditary genetic effects are stochastic.