Deterministic And Stochastic Effects

Deterministic Effects

Deterministic effects are characterised by:

• A threshold dose below which no effect is seen
• Worsening of the effect as dose increases over the threshold
• Always occurring once the threshold dose is reached
• Different effects, tissues and people have different threshold doses for deterministic effects

All early effects, and most normal tissue late effects are deterministic.

Stochastic Effects

Stochastic effects account for the remaining late effects:

• They have no threshold dose
• They increase in likelihood as dose increase
• Their severity is not dose related
• There is no dose above which stochastic effects are certain to occur

Stochastic effects include radiation carcinogenesis and hereditary effects.