The Nature of Radiation Injury

• The effect of X-rays on living tissues are always harmful, but the practical results of such exposure depend on the amount and characteristics of the radiation and on the nature of the tissues irradiated.

The nature of radiation injury

• X-ray produce changes within living cells when they are absorbed.

• The cells within the tissue are then in a state of high chemicals reactivity and the subsequent chemical reaction can initiate any one of three main biological effects.

The somatic Effect:

• This causes inflammation, slowing of cell growth or necrosis and death of tissue. It usually occurs relatively quickly after exposure to radiation (but occasionally is not appreciated for some time).

• It is rapidly growing tissues (the blood-forming organs, the gonads and the germinative layers of the skin) which are most susceptible to this effect. For the same reason embryos and malignant tumors are also particularly sensitive to X-rays .

The carcinogenetic Effect:

•  It is known that tissue which have been exposed to X-rays show a higher incidence of subsequent cancerous changes, although it may be many years before malignance develop .

• The genetic Effect. Exposure of the gonads to radiation is liable to produce both the somatic effect and the long-term genetic effect. The latter increases the mutation rate and may produce inherited abnormalities in subsequent generations.

• While theses effects may result from exposure to single large doses of radiation, they can also be caused by the relatively small amounts repeated over long periods.