Deterministic effects (or tissue reactions) of ionizing radiation are related directly to the absorbed radiation dose and the severity of the effect increases as the dose increases.

Example: Cataracts

Mnemonic: DDD Deterministic severity Determined by Dose

Stochastic effects of ionizing radiation are chance events, with the probability of the effect increasing with dose, but the severity of the effect is independent of the dose received. Stochastic effects are assumed to have no threshold.

Example: Cancer

Mnemonic:

Stochastic Severity No

Probability So