Radioactivity is called spontaneous transformation of unstable varieties of a chemical element in an unstable kind of another element, which is accompanied by the emission of elementary particles or nuclear (ionizing radiation). Such transformations are called nuclei of radioactive transformations, and themselves nuclei, atoms and elements - radioactive.

Types of radiation

Radioactive elements can produce three types of radiation: alpha, beta and gamma radiation, which can lead to serious diseases, genetic disorders and loss of life. Ionizing radiation occurs and with it the excitation of atoms and molecules are the trigger processes leading to the process of radiation damage to biological structures - cells, tissues, organs, systems and whole organism

Thus, severe exposure to lead to death, can occur both in a single bulk irradiation, and in constant contact with a weakly radioactive objects at home (e.g., treated with radiation jewels).

The sources of radiation are the various nuclear-technical installations (such as nuclear reactors, X-ray equipment) and radioactive substances. Their effect on the human body for a long time can not be shown.

The absorbed dose of radiation is determined by the impact of different kinds of radiation on a living organism, it is measured in rads. In order to compare the possible effects of radiation on different body, introduced the concept of an equivalent dose of radiation, which is a unit of one rem, which is the roentgen equivalent (X-rays - is a measure of radiation).

Under natural conditions, the human body is exposed to constant influence of cosmic rays and radiation of natural radioactive elements present in water, soil and tissues of the body. The levels of natural radiation corresponds to 100 mrem per year, but in some areas reach up to 1,000 millirem per year. We also introduce the concept of the maximum permissible dose (PDD) of radiation to the whole body - it is equal to 5 beram year.

Most household dosimeters measure the ionization over time, in mikrorentgenah per hour. According to the results of these measurements, we can judge the absorbed energy in biological tissue in normal room rate should not exceed 20 micro-roentgen per hour.

Biological effects of ionizing radiation

Under the influence of ionizing radiation in a human body are formed with a material of high chemical activity - free atoms or radicals, which destroy the cells of the organism. Ionizing radiation can also have a direct impact on biological molecules.

Damage to cells is largely dependent on how rapidly they pass metabolism: the higher the level of metabolic processes, and the higher susceptibility of radioactive radiation. Most Affected cells are cells of the blood, intestinal epithelium (there are a lot of immune cells), germ cells, the epithelium of the skin, bags, lens, connective tissue, cartilage, bone, muscle, nerve tissue. Defeat some kinds of proteins of cells may cause cancer and genetic mutations transmitted through several generations.

Exposure can cause a variety of diseases: infection (decreased immunity), metabolic disorders Metabolism: The basis of life of all living things , Cancer, infertility, cataracts Cataracts - how to solve the problem completely?   and much more. Particularly acute radiation affects the growing organism, so it is very dangerous for children and adolescents. Exposure to small doses of radiation very difficult to detect, because their effect is manifested through the decades. Even small doses of radiation can cause permanent genetic changes that will be inherited, resulting in the birth of children with various genetic diseases (eg, Down syndrome), epilepsy Epilepsy - a sacred disease , Violation of intellectual and physical development.

Radiation sickness

Radiation sickness develops when exposed to radiation in excess of the permissible dose. Depending on the nature of the impact (single massive or long-term repeated low doses) are acute and chronic radiation syndrome.

Acute radiation sickness begins with a period of overall response (about two days) - nausea, vomiting, headache, fever, weakness, lethargy, drowsiness. Gradually, over several weeks picking up changes in some of the most affected body irradiation (latent period) for some calming common manifestations. After that comes the period of marked clinical manifestations (last two - three weeks) with deep lesions of the blood, intestinal tissue and immunosuppression Immunity - types and characteristics in children in adults . If the dose was significant, that without medical help patients die. Then gradually begin the recovery period, which can last from one to three years.

Chronic radiation sickness - a disease with multiple clinical manifestations, it develops with prolonged exposure to ionizing radiation in a relatively small, but doses exceeding the SDA. Specific manifestations of this disease are lesions of different organs, duration and undulating course.

Radiation has a long (sometimes for life) the impact on the human body.

Galina Romanenko

  Radioactive substances are characterized by ionizing radiation, which is enough energy to separate electrons from atoms (resulting in formation of ions) and breaking of chemical bonds. Ionizing radiation Radiation and its biological effect: gently infected!   can damage any type of human tissue, and in most cases, damage from ionizing radiation can not be restored. Moreover - any violation of the natural repair mechanism of the body leads to the formation of cancer cells.

The most common types of ionizing radiation - alpha and beta particles, or gamma and X-rays.

In general, the degree of damage to the body depends on the intensity and duration of irradiation. The health consequences of exposure to radiation can be subdivided into two main categories: stochastic and not stochastic.

Stochastic (random) effects of radiation

Stochastic effects of radiation are associated with long-term exposure at the lowest level of radiation (the name "stochastic" means the likelihood of something). The higher the level of radiation, the more likely health effects, but the level of radiation does not affect their appearance.

Most people think cancer is a key implications for human health due to exposure. Cancer - is uncontrolled cell growth. Normally, the body controls the mechanism of growth and development of cells and repair damaged tissue. As a result, damage at the cellular or molecular level, this mechanism is disturbed, leading to uncontrolled cell growth - cancer Breast cancer - the verdict? . That's why the ability of radiation to break chemical bonds in atoms and molecules makes it a powerful carcinogen.

In addition, a group of stochastic or random radiation effects include changes in DNA caused by radiation - the so-called cell mutation. In some cases, the body can not cope with the task of recovery of such formations, which leads to the appearance of new mutations. Mutations can be teratogenic or genetic. Teratogenic mutations caused by exposure of the fetus and affect only the people affected by irradiation. Genetic mutation is transmitted to future generations.

Not stochastic effects of radiation

Not stochastic health effects associated with exposure to high-intensity - the emission of intense radiation, the more serious health consequences. Short-term intense exposure are called acute irradiation.

Unlike cancer, the effects of short-term exposure usually occur fast enough. Among the most common effects of acute exposure - burns and so-called radiation sickness or radiation poisoning, which causes premature aging and often leads to death. The irradiation dose of considerable thickness death occurs within two months. The main symptoms of radiation sickness include nausea Nausea - there may be problems with the nervous system , Weakness, hair loss, skin burns, malfunctioning of various organs.

From some of the health effects are usually observed in acute irradiation, suffering and patients undergoing radiotherapy Radiotherapy in cancer treatment: irradiation aid .

What is the level of radiation is safe?

Pinpoint completely safe for humans, do not entail any consequences for the health of radiation exposure is possible. Some scientists believe that exposure to doses of low power, even good for health (this concept is known as hormesis). Nevertheless, a certain degree of accuracy, there are several levels of radiation intensity at which exposure is accompanied by certain health effects.