Radiation sickness

Radiation disease - a disease caused by the action of ionizing radiation (see ionizing Radiation). Clinic of radiation sickness depends on the conditions of exposure: exposure (see) can be external - full body or the greater part of it - and internal, when a radioactive substance (see Isotopes) through the respiratory tract or the digestive tract get inside the organism are accumulated in it and thus create pockets of constant exposure of the body. So, radioactive strontium accumulates in the bones, radioactive cesium - in muscles and other tissues, radioactive yttrium in the liver, radioactive iodine in the thyroid gland, radioactive phosphorus in the bone marrow.
In the basis of the pathogenesis of radiation sickness are violations of the functions of all organs and systems, but the most important value for the development of different clinical syndromes, is a Central nervous system and hemodynamics, the defeat of the gastrointestinal tract; suppression of physiological regeneration of tissues and toxemia.
There are acute radiation sickness (acute radiation syndrome)arising from a one-time intensive (several hundred rad) irradiation, fulminant form resulting from irradiation in doses of the order of several thousand rads., and chronic, growing by prolonged exposure of the body in small doses.

Radiation sickness is a complex clinical syndrome that develops under the influence of ionizing radiation.
The first descriptions of radiation sickness among the professional radiation damages of roentgenologists and radiologists, as well as in people exposed to radiation for therapeutic purposes. In what became known health problems in working with radiation sources. After application (1945) nuclear weapons and nuclear weapons tests there were mass radiation damage. In addition, watched the defeat of individuals in accidents, mainly at work on nuclear reactors.
Development of radiation sickness is the final stage in the chain of processes, starting with the interaction of radiation with tissues, cells and fluid in the complex system of the entire organism (see Radiobiology).
Peculiarities of the action of certain types of radiation are determined mainly by the difference in penetration, the number of ionization per unit volume of the tissue and the mean free path of a particle. The development of changes at the molecular level and the formation of chemically active compounds leads to intensive exchange transformations. The appearance of blood products pathological exchange under the effect of high doses of irradiation is the basis of radiation toxemia. Of great importance violations of physiological processes of regeneration of a number of tissues, and change the functions of the nervous and endocrine systems, which forms the clinical syndrome of radiation sickness.
Proven greater sensitivity to the action of radiation hematopoietic tissue, spermatogenic epithelium, epithelium of the skin, intestine. Especially great is the damaging effects of radiation on the system in a state of active organogenesis and differentiation (the nervous system of the embryo, fetal bone, and so on). Radiation effect on the organs and systems depends on the level of radiation doses and dose distribution in time. In the whole organism, especially during irradiation in small doses, great importance of individual reactivity, initial functional state of the nervous and endocrine systems, as well as congenital or acquired deficiency of other bodies.
The course of radiation sickness is divided into three periods: the formation, recovery and remote consequences or outcomes (D. Baisogalos and A. K. Guskova). Depending on the nature of impact (one-time large or long repeated in relatively small doses, local or total exposure) there are acute and chronic radiation disease of varying severity dominated local or General changes. The formation of the disease occurs normally in the period of contact with radiation sources and in the near term after its termination. The recovery period is from 2 to 5 years after the termination of exposure (or ate significantly reduce its intensity).