​Following external irradiation

An acute exposure to high doses of ionizing radiation can lead to cell death and thus impaired functioning of tissues and organs.

• A localized irradiation that only affects part of the body will have functional effects on the skin and underlying organs. Skin lesions result in radiation burns, which can evolve into chronic radiation dermatitis later.
  Exposure of the eye’s lens to ionizing radiation can cause opacities that lead to cataracts. While it occurs rapidly after an acute irradiation level of several grays, the delay to onset can reach several years following prolonged exposure to lower doses.
• A “global” irradiation can be life-threatening if an individual receives an elevated dose, due to impairment of a large number of cells, particularly in radiosensitive tissues such as bone marrow. It is manifested clinically by acute radiation syndrome (ARS). The severity of this syndrome depends on the received dose and its distribution, the type of radiation, and its exposure duration. The effects of ARS are seen as the impairment of the hematopoietic, gastrointestinal and neurovascular systems (in descending order of radiosensitivity). Lung damage can be associated to this.

Deterministic effects caused by a homogeneous irradiation

After an internal contamination

These effects are inadvertently observed in humans since they occur after a significant radiological incorporation of radionuclide activity. Tissues and organs of retention are at a higher risk of developing these effects, as are the body’s paths of entry (e.g. the lungs and the gastrointestinal tract).