What do “stochastic” and “deterministic” mean?
In this context, stochastic and deterministic refer to the nature of the response of the body to low and high levels of radiation respectively. The term “stochastic” implies that an increase in radiation exposure results in an increase in the PROBABILITY of an effect occurring, i.e. the induction of a cancer. There are two other features of stochastic processes that apply in the context of radiation. First, there is no threshold with stochastic processes. That is, even an infinitesimal amount of radiation exposure carries with it an infinitesimal probability (risk) of cancer induction at a later stage. Secondly, doubling the radiation dose results in a doubling of the probability. The term “deterministic” implies that an increase in radiation dose results in an increase in the CONSEQUENCE, for example increased severity of skin burns after contact with a powerful radiation source. This should be contrasted with stochastic effects, where it is the probability of occurrence that increase
