ABSTRACT
The health effects of radiation are normally divided into two categories – ‘stochastic effects’ and ‘deterministic effects’. Stochastic effects, of which radiation-induced cancer is a prime example, are defined as effects where the probability of occurrence increases with radiation exposure dose but the severity of the effect is independent of the exposure dose. The human data on the induction of cancer by ionising radiation come essentially from the Life Span Study of Japanese atomic bomb survivors. Cancer is a disease of old age with a peak incidence at around 75 years of age and yet there are cancers occurring in children and in young adults. The radiation model developed can offer some insight into this phenomenon. Cancer in young adults is frequently associated with a family history of early cancers which suggests that a genetic predisposition could be involved.
