[Tissue reactions under chronic exposure to ionizing radiation].

The overview presents an outline of the radiobiological mechanisms governing the origin of tissue reactions manifested by a number of systems influencing the course and the outcomes of chronic exposure of man. The issues under consideration include the key mechanisms of tissue reactions and adaptation in response to a long-term and fractionated exposure to ionizing radiation. The response of the hemopoietic, of immune, of genital, of endocrine, of respiratory systems and of the skin to chronic radiation is described. The development of a new approach to threshold dose estimation for chronic exposure effects is discussed.