Define ionizing radiations, radiation safety, radiation exposure and harmful effects of radiations on humans.

Ionizing Radiation

Ionizing Radiations:

A type of high energy radiation that has enough energy to remove an electron (negative particle) from an atom or molecule, which causes it to ionize. Ionizing radiation can cause chemical changes in cells and damage DNA.

Types of ionizing radiations:

1. Alpha particles
2. Beta particles
3. Gamma rays
4. X-rays
5. Positrons

Radiation penetration:

The penetration is the quantity of radiation that passes through the item. The inverse of attenuation is penetration. The quantity of penetration is determined by the energy of individual photons as well as the object's atomic number, density, and thickness.

typed of radiations

Radiation safety:

Radiation safety is the state of protection of the present and future generations of people from the harmful effects of ionizing radiation on their health.

The need for protection against radiation appeared almost immediately after its discovery at the end of the 19th century.  Being initially the interest of a narrow circle of specialists, with the beginning of the atomic era and the widespread use of radiation sources in industry, energy and medicine, radiation safety has become an urgent problem for all mankind.

The system of radiation safety, being a complex and resource-intensive task, requires the participation of large international and national organizations for its development and implementation, the central place among which is occupied by the International Commission on Radiation Protection.

Radiation exposure:

Radiation exposure is not something new for mankind. The natural radiation background is still the main source of exposure for the vast majority of the population. Its main components are cosmic rays and radiation from radionuclides of terrestrial origin, ubiquitously contained in the earth's crust both of these components are unevenly distributed in the sphere of human habitation. Cosmic radiation is negligible on the surface of the earth, but is a problem in the civil aviation area. External exposure from natural radionuclides depends on the composition of soils and is significant in regions with a significant content monazite sand or radium-226. The greatest contribution to the total exposure from natural sources is made by internal exposure to radioactive gas radon, inhaled by a person together with air.

The use of ionizing radiation in medicine for the diagnosis and treatment of diseases has become widespread in developed countries and is the main source of techno genic exposure of the population. The most widely used diagnostic procedures are fluorography, radiography and, more recently, computed tomography. In some countries, exposure from these procedures is comparable to the effect of natural background radiation

A limited number of people come into contact with radiation sources in their professional activities. These are workers of the nuclear industry and energy, doctors and personnel of medical institutions working with radiation, radiographic control flaw detectors. Aircraft crews performing regular flights also fall into this category, since exposure from natural cosmic radiation is significant for them.

Harmful effects of radiations:

The biological effectiveness of ionizing radiation lies not in the amount of energy that is transferred to the tissue, but in damage to the most critical elements of the body's cells at the molecular level. A lethal dose of radiation, if converted into thermal energy, would cause the body to heat up by only thousandths of a degree. However, when such energy is transferred by ionizing radiation, the consequences for a living organism become catastrophic. The main harm is caused due to damage to DNA molecules in the cell nucleus. In some cases, the cell is completely restored, in some it dies, sometimes irreversible changes occur in the cell, but it remains viable

With intense irradiation, when a certain critical volume of cells dies, the functioning of the corresponding tissues or organs is disrupted. This effect of exposure to radiation is called a tissue reaction and manifests itself in a short time after irradiation. Depending on the dose of radiation and the organ in question, a variety of pathological conditions occur, for example: temporary infertility, erythema, clouding of the lens of the eye. In case of acute irradiation in high doses, when vital organs are seriously damaged, radiation sickness develops. .

The consequences of irradiation for the fetus and fetus in the womb are especially considered. Large doses of radiation can cause both the death of the embryo and damage to organs that were formed during exposure. One of these consequences is the development of mental retardation in children whose mothers were exposed to serious radiation during pregnancy.

The fate of irradiated but viable cells develops more complicated. In many cases, such a cell will be isolated or destroyed by the body's defense mechanisms. However, if this does not happen, then after a sometimes significant delay, uncontrolled division can begin, leading to the appearance of cancers such as leukemia or malignant tumors. The type and severity of such a disease, apparently, does not depend on irradiation. We can only say that the probability of developing cancer depends on the amount of radiation, that is, the higher the dose, the higher the likelihood of complications. If the radiation causes damage in the germ cell, then there is a risk of pathologies in the offspring. Although this hypothesis has not received direct evidence for humans, experiments on plants and animals have shown the fundamental possibility of such effects. Oncological and hereditary effects of exposure are probabilistic and are called stochastic effects. These effects are long-term consequences of irradiation, as they can manifest themselves 10-20 years after exposure to ionizing radiation on the body. It can also be said that these malignant diseases are not specific to radiation exposure, it only provokes their development.

Recent epidemiological studies indicate the likelihood of non-cancerous diseases occurring after exposure to high doses. Prominent among these are heart disease, strokes, indigestion, and respiratory disease. Specific mechanisms for the occurrence of such complications after irradiation remain unexplored.

Effective radiation dose:

In radiation safety, the most interesting is the quantitative assessment of the effects of radiation on humans. The basic diametric value - the absorbed dose is poorly suited for this purpose, since the risk of hereditary and oncological consequences depends, among other things, on the type of ionizing radiation and on the radio sensitivity of human organs and tissues.

Different types of radiation interact differently with matter. In the general case, this is due to the difference in the mechanism of energy transfer: neutrons and alpha particles on their way cause much more ionization acts than gamma quanta. Accordingly, the harm caused to biological cells will be different. On the other hand, even in relation to the same type of radiation, the reaction to it of various organs and tissues is different. At the same time, the gonads, hematopoietic organs, lungs, stomach and large intestine are the most susceptible to the occurrence of long-term effects of radiation.

To determine the dose received by a person, taking into account the above factors, a special value has been introduced - the effective dose. The effective dose takes into account both the type of radiation and the radio sensitivity of organs through the application of radiation weighting factors and tissue weighting factors. The effective dose is calculated using special anthropomorphic models (phantoms) and refers to a certain average "conventional person.

Protection against ionizing radiation:

We can protect ourselves from ionizing radiations to wear,

• Protective kit
• Lead apron
• Lead thyroid collar
• A lead thyroid collar offers additional radiation protection for the thyroid (a gland located in front of the neck) that is particularly sensitive to radiation
• Lead gloves
• Safety goggles
• By ALARA method (stands for As Low as Reasonably Achievable. It is a guiding principle in radiation protection used to eliminate radiation doses that have no direct benefit.
• Minimum time of exposure
• Maintain 6 feet distance from source