Friday, December 8, 2023

Linear no-threshold model in radiation safety

The most conservative theory of radiation is the "linear no-threshold" (LNT) model. According to this model, there is no safe threshold for exposure to ionizing radiation, and any amount of radiation, no matter how small, has the potential to cause harm. The LNT model assumes a linear relationship between radiation dose and the risk of adverse health effects, extending this linear relationship down to zero dose.

In other words, the LNT model suggests that the risk of radiation-induced health effects, such as cancer, increases linearly with increasing radiation dose, and there is no level of radiation exposure considered completely without risk.

Deterministic vs Stochastic effects

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