Occupational Diseases / / May 22, 2016
Ionizing radiation is a special kind of radiant energy, exciting in the irradiated medium ionization.Sources of ionizing radiation are X-ray tubes, high-power, high-voltage and accelerators, but mostly radioactive substances - natural (uranium, thorium, radium) and artificial (isotopes).
Radioactivity - spontaneous process of disintegration of atomic nuclei, which occur as a result of radiation - electromagnetic and corpuscular.
main activities associated with sources of ionizing radiation: gamma testing of metals and products, working on X-ray machines in hospitals and in technical laboratories, the use of isotopes for the control of production processes, operation of industrial and scientific high-power high-voltage and accelerator facilities, the use ofnuclear reactors, the use of radioactive substances and radiation in hospitals for diagnostic and therapeutic purposes, mining of radioactive ores.
When working with radioactive substances, in addition to external radiation, may take place penetrati
Radioactivity trapped in the body carried by the blood to various tissues and organs, becoming in the last source of internal exposure.The rate of removal of radioactive substances from the body is different;quickly identify readily soluble substances.Long-lived isotopes are particularly dangerous since, once in the body, they may be affected during the entire life of a source of ionizing radiation.
the decay of radioactive nuclei emit radiation 4 types: A, B-, gamma rays and neutrons.
and rays - a stream of positively charged particles having large mass (nuclei of helium atoms).External radiation and particles little dangerous, as they penetrate the tissue deep, absorbed by the stratum corneum of the skin epithelium.Hit and emitters inside the body is very dangerous, because there is a direct exposure of the cells of high power energy.
B-rays - a stream of particles with a negative charge (electrons).B-rays are more penetrating than alpha rays, their run in the air, depending on the energy range from fractions of a centimeter to 10-15 meters, the water in the tissues -. From a fraction of a millimeter to 1 cm
U-rays area high frequency electromagnetic radiation.The properties are similar to X-rays, but have a shorter wavelength.
energy gamma-rays varies widely.Depending on the energy of gamma rays are divided into soft (0.1-0.2 MeV), medium stringency (0.2-1 MeV), hard (1.10 MeV) and superrigid (above 10 MeV).
This type of radiation is the most penetrating and most dangerous case of external irradiation.
Neutrons - particles with no charge.They have great penetrating power.Under the influence of neutron irradiation elements that make up the tissues (such as phosphorus, etc..), May be radioactive.
Ionizing radiation is complex functional and morphological changes in tissues and organs.Under its influence the water molecules, which is part of the tissues and organs decompose to form free radicals and atoms, which have a high oxidative capacity.water radiolysis products operate on active sulfhydryl groups (SH) protein structures and convert them into inactive - bisulfide.As a result of impaired activity of various enzymatic systems in charge of synthetic processes, there is suppression and distortion of the past.Ionizing radiation also acts directly on molecules of proteins and lipids, providing a denaturing effect.Ionizing radiation can cause in the body of the local (burns) and the general (radiation sickness) defeat.
maximum permissible dose
maximum permissible dose (PDD) for the whole body irradiation (direct work with sources of ionizing radiation) is set to 0.05 J / kg (5 rems) in a single year.In exceptional cases for obtaining a quarter dose of 0.03 J / kg or 3 rem (while maintaining the total radiation dose for at 0.05 J / kg, or 5 rem).Such an increase in the dose is not allowed for women under the age of 30 years (for them the maximum dose during the quarter 0,013 J / kg, or 1.3 rem).