Radiation- invisible, inaudible, has no taste, color and smell, and therefore terrible. Word " radiation» Causes paranoia, horror, or an incomprehensible state that strongly resembles anxiety. With direct exposure to radiation, radiation sickness can develop (at this point, anxiety develops into panic, because no one knows what it is and how to deal with it). It turns out that radiation is deadly ... but not always, sometimes even useful.

So what is it? What do they eat it with, this radiation, how to survive a meeting with it and where to call if it accidentally sticks on the street?

What is radioactivity and radiation?

Radioactivity- instability of the nuclei of some atoms, manifested in their ability to spontaneous transformations (decay), accompanied by the emission of ionizing radiation or radiation. In the following, we will only talk about the radiation that is associated with radioactivity.

Radiation, or ionizing radiation- these are particles and gamma quanta, the energy of which is large enough to create ions of different signs when exposed to a substance. Radiation cannot be caused by chemical reactions.

What is the radiation?

There are several types of radiation.

• alpha particles: relatively heavy, positively charged particles that are helium nuclei.
• beta particles are just electrons.
• Gamma radiation has the same electromagnetic nature as visible light, but has a much greater penetrating power.
• Neutrons- electrically neutral particles, appear mainly in the immediate vicinity of a working nuclear reactor, where access, of course, is regulated.
• x-ray radiation similar to gamma rays, but lower in energy. By the way, our Sun is one of the natural sources of X-rays, but the earth's atmosphere provides reliable protection from it.

Ultraviolet radiation and laser radiation in our consideration are not radiation.

Charged particles interact very strongly with matter, therefore, on the one hand, even one alpha particle, when it enters a living organism, can destroy or damage a lot of cells, but, on the other hand, for the same reason, sufficient protection against alpha and beta -radiation is any, even a very thin layer of solid or liquid matter - for example, ordinary clothing (unless, of course, the source of radiation is outside).

should be distinguished radioactivity and radiation. Radiation sources - radioactive substances or nuclear installations (reactors, accelerators, X-ray equipment, etc.) - can exist for a considerable time, and radiation exists only until it is absorbed in any substance.

What can be the effect of radiation on a person?

The effect of radiation on a person is called irradiation. The basis of this effect is the transfer of radiation energy to the cells of the body.
Irradiation can cause metabolic disorders, infectious complications, leukemia and malignant tumors, radiation infertility, radiation cataract, radiation burn, radiation sickness. The effects of irradiation have a stronger effect on dividing cells, and therefore irradiation is much more dangerous for children than for adults.

As for the frequently mentioned genetic(i.e., inherited) mutations as a result of human exposure, these have never been found. Even among the 78,000 children of those Japanese who survived the atomic bombing of Hiroshima and Nagasaki, no increase in the number of cases of hereditary diseases was ascertained ( the book "Life after Chernobyl" by Swedish scientists S. Kullander and B. Larson).

It should be remembered that much more REAL damage to people's health is caused by emissions from the chemical and steel industries, not to mention the fact that science still does not know the mechanism of malignant degeneration of tissues from external influences.

How can radiation enter the body?

The human body reacts to radiation, not to its source.
Those sources of radiation, which are radioactive substances, can enter the body with food and water (through the intestines), through the lungs (during breathing) and, to a small extent, through the skin, as well as in medical radioisotope diagnostics. In this case, we talk about internal learning.
In addition, a person may be exposed to external radiation from a source of radiation that is outside their body.
Internal exposure is much more dangerous than external exposure.

Is radiation transmitted as a disease?

Radiation is created by radioactive substances or specially designed equipment. The radiation itself, acting on the body, does not form radioactive substances in it, and does not turn it into a new source of radiation. Thus, a person does not become radioactive after an X-ray or fluorographic examination. By the way, an x-ray (film) also does not carry radioactivity.

An exception is a situation in which radioactive preparations are intentionally introduced into the body (for example, during a radioisotope examination of the thyroid gland), and a person becomes a source of radiation for a short time. However, preparations of this kind are specially chosen so as to quickly lose their radioactivity due to decay, and the intensity of the radiation falls off quickly.

Of course you can " get dirty» body or clothing with radioactive liquid, powder or dust. Then some of this radioactive "dirt" - along with ordinary dirt - can be transferred by contact to another person. Unlike a disease that, when transmitted from person to person, reproduces its harmful power (and can even lead to an epidemic), the transmission of dirt leads to its rapid dilution to safe limits.

What is the unit of measure for radioactivity?

measure radioactivity serves activity. measured in becquerels (Bq), which corresponds to 1 decay per second. The content of activity in a substance is often estimated per unit weight of the substance (Bq/kg) or volume (Bq/m3).
There is also such a unit of activity as Curie (Key). This is a huge one: 1 Ki = 37000000000 (37*10^9) Bq.
The activity of a radioactive source characterizes its power. So, in the source of activity 1 Curie occurs 37000000000 disintegrations per second.

As mentioned above, during these decays, the source emits ionizing radiation. The measure of the ionization effect of this radiation on matter is exposure dose. Often measured in x-rays (R). Since 1 Roentgen is a rather large value, in practice it is more convenient to use a millionth ( mcr) or thousandth ( mr) fractions of Roentgen.
The action of common household dosimeters is based on the measurement of ionization over a certain time, that is, the exposure dose rate. The unit of measurement of the exposure dose rate is micro-roentgen/hour .

Dose rate multiplied by time is called dose. The dose rate and the dose are related in the same way as the speed of the car and the distance traveled by this car (path).
To assess the impact on the human body, the concepts equivalent dose and equivalent dose rate. measured, respectively, in Sievertach (Sv) and Sieverts/hour (Sv/h). In everyday life, one can assume that 1 Sievert = 100 Roentgen. It is necessary to indicate which organ, part or whole body received a given dose.

It can be shown that the above-mentioned point source with an activity of 1 Curie (for definiteness, we consider a source of caesium-137) at a distance of 1 meter from itself creates an exposure dose rate of approximately 0.3 Roentgen / hour, and at a distance of 10 meters - approximately 0.003 Roentgen / hour. Decrease in dose rate with increasing distance always occurs from the source and is due to the laws of radiation propagation.

Now the typical error of the media reporting: “ Today, a radioactive source of 10 thousand roentgens was discovered on such and such a street at a rate of 20».
First, the dose is measured in Roentgens, and the characteristic of the source is its activity. A source of so many X-rays is the same as a bag of potatoes weighing so many minutes.
Therefore, in any case, we can only talk about the dose rate from the source. And not just the dose rate, but indicating at what distance from the source this dose rate was measured.

Further, the following considerations can be made. 10,000 roentgens per hour is a fairly large value. With a dosimeter in hand, it can hardly be measured, since when approaching the source, the dosimeter will first show both 100 Roentgen/hour and 1000 Roentgen/hour! It is very difficult to assume that the dosimetrist will continue to approach the source. Since dosimeters measure the dose rate in micro Roentgen/hour, it can be assumed that in this case we are talking about 10 thousand micro Roentgen/hour = 10 milliRoentgen/hour = 0.01 Roentgen/hour. Such sources, although they do not pose a mortal danger, are less common on the street than hundred-ruble bills, and this can be a topic for an informational message. Moreover, the mention of the "norm 20" can be understood as a conditional upper limit of the usual dosimeter readings in the city, i.e. 20 micro-roentgen/hour.

Therefore, the correct message, apparently, should look like this: “Today, a radioactive source was discovered on such and such a street, close to which the dosimeter shows 10 thousand microroentgens per hour, while the average value of the radiation background in our city does not exceed 20 microroentgens per hour ".

What are isotopes?

There are more than 100 chemical elements in the periodic table. Almost each of them is represented by a mixture of stable and radioactive atoms who are called isotopes this element. About 2000 isotopes are known, of which about 300 are stable.
For example, the first element of the periodic table - hydrogen - has the following isotopes:
hydrogen H-1 (stable)
deuterium H-2 (stable)
tritium H-3 (radioactive, half-life 12 years)

Radioactive isotopes are commonly referred to as radionuclides .

What is a half-life?

The number of radioactive nuclei of the same type is constantly decreasing in time due to their decay.
The decay rate is usually characterized by the half-life: this is the time during which the number of radioactive nuclei of a certain type will decrease by 2 times.
Absolutely wrong is the following interpretation of the concept of "half-life": " if a radioactive substance has a half-life of 1 hour, this means that after 1 hour its first half will decay, and after another 1 hour - the second half, and this substance will completely disappear (decay)«.

For a radionuclide with a half-life of 1 hour, this means that after 1 hour its amount will become 2 times less than the original, after 2 hours - 4 times, after 3 hours - 8 times, etc., but will never completely disappear. In the same proportion, the radiation emitted by this substance will also decrease. Therefore, it is possible to predict the radiation situation for the future, if you know which and in what quantity of radioactive substances create radiation in a given place at a given time.

Everyone has it radionuclide- mine half life, it can be both fractions of a second and billions of years. It is important that the half-life of a given radionuclide is constant, and it's impossible to change it.
The nuclei formed during radioactive decay, in turn, can also be radioactive. So, for example, radioactive radon-222 owes its origin to radioactive uranium-238.

Sometimes there are statements that radioactive waste in storage facilities will completely decay in 300 years. This is not true. It's just that this time will be approximately 10 half-lives of cesium-137, one of the most common man-made radionuclides, and over 300 years its radioactivity in waste will decrease by almost 1000 times, but, unfortunately, will not disappear.

What is radioactive around us?

The following diagram will help to assess the impact on a person of certain sources of radiation (according to A.G. Zelenkov, 1990).

By origin, radioactivity is divided into natural (natural) and man-made.

a) Natural radioactivity
Natural radioactivity has existed for billions of years, it is present literally everywhere. Ionizing radiation existed on Earth long before the origin of life on it and were present in space before the appearance of the Earth itself. Radioactive materials have been part of the Earth since its birth. Any person is slightly radioactive: in the tissues of the human body, potassium-40 and rubidium-87 are one of the main sources of natural radiation, and there is no way to get rid of them.

Consider that a modern person spends up to 80% of his time indoors - at home or at work, where he receives the main dose of radiation: although buildings protect from radiation from the outside, the building materials from which they are built contain natural radioactivity. Radon and its decay products make a significant contribution to human exposure.

b) Radon
The main source of this radioactive inert gas is the earth's crust. Penetrating through cracks and crevices in the foundation, floor and walls, radon lingers in the premises. Another source of indoor radon is the building materials themselves (concrete, brick, etc.) containing natural radionuclides, which are a source of radon. Radon can also enter homes with water (especially if it is supplied from artesian wells), when natural gas is burned, etc.
Radon is 7.5 times heavier than air. As a result, the concentration of radon in the upper floors of multi-storey buildings is usually lower than on the first floor.
A person receives the bulk of the dose of radiation from radon while in a closed, unventilated room; regular ventilation can reduce the concentration of radon by several times.
Long-term exposure to radon and its products in the human body greatly increases the risk of lung cancer.
The following chart will help you compare the radiation power of various radon sources.

c) Man-made radioactivity
Technogenic radioactivity arises as a result of human activity.
Conscious economic activity, during which the redistribution and concentration of natural radionuclides occurs, leads to noticeable changes in the natural radiation background. This includes the extraction and combustion of coal, oil, gas, and other fossil fuels, the use of phosphate fertilizers, the extraction and processing of ores.
So, for example, studies of oil fields in Russia show a significant excess of the permissible levels of radioactivity, an increase in radiation levels in the area of ​​wells caused by the deposition of radium-226, thorium-232 and potassium-40 salts on equipment and adjacent soil. Especially contaminated are operating and exhausted pipes, which often have to be classified as radioactive waste.
Such a mode of transport as civil aviation exposes its passengers to increased exposure to cosmic radiation.
And, of course, nuclear weapons tests, nuclear energy and industry enterprises make their contribution.

Of course, accidental (uncontrolled) spread of radioactive sources is also possible: accidents, losses, theft, spraying, etc. Such situations are, fortunately, VERY RARE. In addition, their danger should not be exaggerated.
For comparison, the contribution of Chernobyl to the total collective dose of radiation that Russians and Ukrainians living in contaminated territories will receive in the next 50 years will be only 2%, while 60% of the dose will be determined by natural radioactivity.

What do commonly encountered radioactive items look like?

According to the MosNPO Radon, more than 70 percent of all cases of radioactive contamination detected in Moscow occur in residential areas with intensive new construction and green areas of the capital. It was in the latter in the 1950s and 1960s that household waste dumps were located, where low-level industrial waste, which were then considered relatively safe, was also dumped.

In addition, the individual objects shown below can be carriers of radioactivity:

	A switch with a glow-in-the-dark toggle switch, the tip of which is painted with a permanent light composition based on radium salts. Dose rate when measuring "point-blank" - about 2 milliroentgen / hour

Is the computer a source of radiation?

The only parts of a computer that can be referred to as radiation are the monitors on cathode ray tubes(CRT); displays of other types (liquid crystal, plasma, etc.) are not affected.
Monitors, along with conventional CRT televisions, can be considered as a weak source of X-ray radiation that occurs on the inner surface of the CRT screen glass. However, due to the large thickness of the same glass, it also absorbs a significant part of the radiation. So far, no effect of X-ray radiation from monitors on CRT on health has been found, however, all modern CRTs are produced with a conditionally safe level of X-ray radiation.

For monitors, the Swedish National Standards are now generally accepted by all manufacturers. "MPR II", "TCO-92", -95, -99. These standards, in particular, regulate electric and magnetic fields from monitors.
As for the term "low radiation", this is not a standard, but just a declaration by the manufacturer that he has done something only known to him in order to reduce radiation. The less common term "low emission" has a similar meaning.

The norms in force in Russia are set out in the document "Hygienic requirements for personal electronic computers and organization of work" (SanPiN SanPiN 2.2.2 / 2.4.1340-03), the full text is located at, and a short excerpt about the permissible values ​​​​of all types emissions from video monitors - here.

When fulfilling orders for radiation monitoring of offices of a number of organizations in Moscow, LRC-1 employees conducted a dosimetric examination of about 50 CRT monitors of various brands, with a screen diagonal size of 14 to 21 inches. In all cases, the dose rate at a distance of 5 cm from the monitors did not exceed 30 μR/h, i.e. with a threefold margin was within the allowable rate (100 microR/h).

What is normal background radiation?

On Earth, there are populated areas with an increased radiation background. These are, for example, the highland cities of Bogota, Lhasa, Quito, where the level of cosmic radiation is about 5 times higher than at sea level.

These are also sandy zones with a high concentration of minerals containing phosphates mixed with uranium and thorium - in India (Kerala state) and Brazil (Espirito Santo state). It is possible to mention the site of the outlet of waters with a high concentration of radium in Iran (the city of Romser). Although in some of these areas the absorbed dose rate is 1000 times higher than the average over the Earth's surface, the survey of the population did not reveal any shifts in the patterns of morbidity and mortality.

In addition, even for a particular area there is no "normal background" as a constant characteristic, it cannot be obtained as a result of a small number of measurements.
In any place, even for undeveloped territories where “no human foot has set foot”, the radiation background changes from point to point, as well as at each specific point over time. These background fluctuations can be quite significant. In habitable places, the factors of the activity of enterprises, the work of transport, etc. are additionally superimposed. For example, at airfields, due to high-quality concrete pavement with crushed granite, the background is usually higher than in the surrounding area.

Measurements of the radiation background in the city of Moscow allow you to indicate the TYPICAL value of the background on the street (open area) - 8 - 12 microR/h, in room - 15 - 20 microR/h.

What are the standards for radioactivity?

With regard to radioactivity, there are a lot of rules - literally everything is normalized. In all cases, a distinction is made between the population and the staff, i.e. persons whose work is related to radioactivity (workers of nuclear power plants, nuclear industry, etc.). Outside of their production, personnel refers to the population. For personnel and industrial premises, their own standards are established.

Further, we will only talk about the norms for the population - that part of them that is directly related to ordinary life, based on the Federal Law "On Radiation Safety of the Population" No. 3-FZ dated 05.12.96 and "Radiation Safety Standards (NRB-99). Sanitary rules SP 2.6.1.1292-03.

The main task of radiation monitoring (measurements of radiation or radioactivity) is to determine the compliance of the radiation parameters of the object under study (dose rate in the room, the content of radionuclides in building materials, etc.) with the established standards.

a) air, food and water
For inhaled air, water and food, the content of both man-made and natural radioactive substances is normalized.
In addition to NRB-99, "Hygienic requirements for the quality and safety of food raw materials and food products (SanPiN 2.3.2.560-96)" are applied.

b) building materials
The content of radioactive substances from the families of uranium and thorium, as well as potassium-40 (in accordance with NRB-99) is regulated.
Specific effective activity (Aeff) of natural radionuclides in building materials used for newly constructed residential and public buildings (class 1),
Aeff \u003d ARa + 1.31ATh + 0.085 Ak should not exceed 370 Bq / kg,
where АRa and АTh are the specific activities of radium-226 and thorium-232, which are in equilibrium with other members of the uranium and thorium families, Ak is the specific activity of K-40 (Bq/kg).
GOST 30108-94 “Construction materials and products. Determination of specific effective activity of natural radionuclides” and GOST R 50801-95 “Wood raw materials, timber, semi-finished products and products from wood and wood materials. Permissible specific activity of radionuclides, sampling and methods for measuring the specific activity of radionuclides”.
Note that according to GOST 30108-94, the result of determining the specific effective activity in the controlled material and establishing the class of the material is taken as the value of Aeff m:
Aeff m = Aeff + DAeff, where DAeff is the error in determining Aeff.

c) premises
The total content of radon and thoron in indoor air is normalized:
for new buildings - no more than 100 Bq/m3, for those already in operation - no more than 200 Bq/m3.
In the city of Moscow, MGSN 2.02-97 "Permissible levels of ionizing radiation and radon in building sites" are applied.

d) medical diagnostics
No dose limits are set for patients, but there is a requirement for minimum sufficient levels of exposure to obtain diagnostic information.

e) computer equipment
The exposure dose rate of X-ray radiation at a distance of 5 cm from any point of the video monitor or personal computer should not exceed 100 μR/hour. The norm is contained in the document "Hygienic requirements for personal electronic computers and organization of work" (SanPiN 2.2.2 / 2.4.1340-03).

How to protect yourself from radiation?

From the source of radiation are protected by time, distance and matter.

• by time- due to the fact that the shorter the time spent near the radiation source, the lower the radiation dose received from it.
• Distance- due to the fact that the radiation decreases with distance from the compact source (in proportion to the square of the distance). If at a distance of 1 meter from the radiation source the dosimeter records 1000 μR/hour, then at a distance of 5 meters the readings will drop to approximately 40 μR/hour.
• Substance- it is necessary to strive to have as much substance as possible between you and the source of radiation: the more it is and the denser it is, the greater part of the radiation it will absorb.

Concerning main source irradiation in rooms radon and its decay products, then regular airing allows to significantly reduce their contribution to the dose load.
In addition, if we are talking about building or finishing your own housing, which will probably last more than one generation, you should try to buy radiation-safe building materials - since their range is now extremely rich.

Does alcohol help with radiation?

Alcohol ingested shortly before exposure can, to some extent, mitigate the effects of exposure. However, its protective effect is inferior to modern anti-radiation drugs.

When to think about radiation?

Always think. But in everyday life, it is extremely unlikely to encounter a source of radiation that poses an immediate threat to health. For example, in Moscow and the region, less than 50 such cases are recorded per year, and in most cases - thanks to the constant systematic work of professional dosimetrists (employees of the MosNPO Radon and the Central State Sanitary and Epidemiological Service of Moscow) in places where sources of radiation and local radioactive contamination are most likely to be detected (landfills pits, scrap yards).
Nevertheless, it is in everyday life that one should sometimes remember about radioactivity. This is useful to do:

• when buying an apartment, house, land,
• when planning construction and finishing works,
• when choosing and purchasing building and finishing materials for an apartment or house
• when choosing materials for landscaping the area around the house (soil of bulk lawns, bulk coatings for tennis courts, paving slabs and paving stones, etc.)

It should still be noted that radiation is far from the main reason for constant concern. According to the scale of relative danger of various types of anthropogenic impact on humans developed in the USA, radiation is at 26 th place, and the first two places are occupied by heavy metals and chemical toxicants.

Ionizing radiation or radiation is harmful to health, everyone knows this. But what diseases occur under the influence of radiation, what dose can be safe for a person, and what can kill him?

Radiation is an invisible danger

Safe radiation dose

Where does a person receive doses of radiation? Do not forget about natural radiation. At different points on the planet, the background radiation can differ significantly. So, on the mountain peaks, the radiation is higher, because there the protective properties of the atmosphere are lower. Increased radiation can also be in places where there is a lot of dust and sand with thorium and uranium in the air.

What dose of radiation can be safe, maximum permissible, and the body will not suffer? It should not exceed 0.3-0.5 µSv per hour. But if you stay in this room for a short time, then the human body transfers radiation with a power of 10 μS per hour without harm to health, this is the maximum permissible level of radiation.

Dangerous dose of radiation

If the maximum permissible level of radiation is exceeded, changes occur in the body of the victim. How does radiation affect a person, what can be in the body under its influence? The table below shows the doses of radiation and their effects on humans.

Radiation dose (per year)	Impact on a person
0.05 mSv	Permissible level of radiation, which should be near nuclear facilities.
0.3 - 0.6 mSv	Emit artificial sources of radiation (medical devices)
3 mSv	Natural sources radiate, norm
3 - 5 mSv	Received by miners at uranium mines
10 mSv	The maximum permissible level of radiation received by miners during the extraction of uranium
20 mSv	Maximum allowable level of penetrating radiation for people working with radiation
50 mSv	This is the permissible (lowest) level of exposure, after which oncological diseases already occur.
1 Sv (1000 mSv)	The consequences are not so serious. If the exposure is short, the body may react with a malaise that does not threaten human life. But after a few years, there is a chance of getting cancer.
2-10 Sv	Short-term exposure will lead to the development of radiation sickness, this is not a lethal dose, but the consequences can be serious: there may be a fatal outcome
10 Sv	Damaging radiation. This is a lethal dose that the human body cannot tolerate. Illness and death within a few weeks.

Diseases that appear due to radiation

There are chemical elements (plutonium, radium, uranium, etc.) that are capable of spontaneous transformations. They are accompanied by a stream of radiation. It was first discovered in radium, so it was called radioactive decay, and the radiation was radioactive. Another name for it is penetrating radiation.

The genetic consequences of penetrating radiation are poorly understood

Mutations

Scientists know that radiation causes mutations. Damaging radiation causes changes. But while the genetic implications of penetrating radiation mutations are poorly understood. The fact is that mutations make themselves felt only after generations, and it will take many hundreds of years for mutations to manifest themselves. And it is not clear whether their occurrence is due to radiation or whether mutations are caused by other reasons.

Also, the difficulty lies in the fact that most children with anomalies do not have time to be born, women have a spontaneous abortion, a child with abnormalities may not be born. Mutations are dominant (immediately make themselves felt), and recessive, which appear only if the father and mother of the child have the same mutant gene. Then mutations may not appear for several generations, or they may not affect the life of a person and his descendants at all.

After the tragedy in Hiroshima and Nagasaki, 27,000 children were studied. Their parents themselves felt the effects of significant doses of radiation. They found only two mutations in the body. And the same number of children whose father and mother were exposed to less severe radiation did not have a mutation at all. However, this still doesn't say anything. The study of the effect of radiation on humans, mutations began not so long ago, and perhaps other “surprises” await us.

Radiation sickness

It occurs either with a single strong exposure or with constant exposure to relatively small doses. The damaging radiation is dangerous for human life. This is the most common disease associated with penetrating radiation.

Leukemia

Leukemia is caused by penetrating radiation

Statistics show that penetrating radiation often becomes the cause of leukemia. Back in the 40s of the last century, they noticed that radiologists often died after leukemia, the body could not withstand the radiation. Later, the influence of penetrating radiation on the development of leukemia was confirmed by observations of the inhabitants of Hiroshima and Nagasaki.

This time there was no talk about the exact doses of radiation, they took approximate figures, focusing on the epicenter of the explosion and the symptoms of acute radiation injury. Only 5 years after the bombing, cases of leukemia began to be recorded. Examined 109 thousand people who survived the bombing:

• The group of irradiated (dose over 1 Gy) from 1950 to 1971 - 58 cases, which is 7 times more than the figure expected by scientists.
• The group of exposed (dose less than 1 Gy) - 64 people fell ill, although it was expected that 71.

In subsequent years, the number of cases decreased. The consequences in the form of leukemia are dangerous for people who have experienced radiation before the age of 15 years. Illness after penetrating radiation does not immediately make itself felt. Most often, 4-10 years pass after the damaging radiation has dealt its blow. There is no consensus on how much radiation causes such consequences, everyone gives different allowable doses (50, 100, 200 r). The pathogenesis of radiation leukemia is also not fully understood yet, but scientists are working in that direction and offer their theories.

Other cancers

Penetrating radiation affects the occurrence of cancer

Scientists are studying the effects of radiation on humans, including trying to understand whether penetrating radiation affects the occurrence of cancer. But it is impossible to talk about exact information, because scientists cannot conduct experiments on people. Experiments are being conducted with animals, but they cannot be used to judge how damaging radiation affects the human body. For the information to be reliable, it is important to comply with the following conditions.

• You need to know the amount of absorbed dose.
• It is necessary that the radiation evenly hit either the whole body or a specific organ.
• Examine the experimental group regularly, and do this for decades.
• There must be another "control" group of people so that the level of the disease can be compared.
• Both groups must include a huge number of people.

It is impossible to conduct such an experiment, so scientists have to study the consequences associated with exposure to penetrating radiation after accidental exposure. So far, the data obtained is inaccurate. So, scientists believe that there is no acceptable dose of penetrating radiation, any dose increases the risk of developing cancer and can cause this disease. Most often, people after penetrating radiation appear:

1. Leukemia is number one.
2. Mammary cancer. 10 out of 1000 women develop this condition.
3. Thyroid cancer. After irradiation, 10 out of 1000 people develop a disease. It is now curable, the mortality rate is very low.
4. The result of exposure is lung cancer. Information that penetrating radiation affects the frequency of occurrence of this disease, on the human body, appeared not only according to data collected after the bombing of Japan, but also after a survey of miners of uranium mines in Canada, the USA and Czechoslovakia.

The word "radiation" is more often understood as ionizing radiation associated with radioactive decay. At the same time, a person experiences the action of non-ionizing types of radiation: electromagnetic and ultraviolet.

The main sources of radiation are:

• natural radioactive substances around and inside us - 73%;
• medical procedures (radioscopy and others) - 13%;
• cosmic radiation - 14%.

Of course, there are technogenic sources of pollution that appeared as a result of major accidents. These are the most dangerous events for mankind, because, as in a nuclear explosion, iodine (J-131), cesium (Cs-137) and strontium (mainly Sr-90) can be released in this case. Weapons-grade plutonium (Pu-241) and its decay products are no less dangerous.

Also, do not forget that for the last 40 years the Earth's atmosphere has been very heavily polluted by radioactive products of atomic and hydrogen bombs. Of course, at the moment, radioactive fallout falls only in connection with natural disasters, such as volcanic eruptions. But, on the other hand, during the fission of a nuclear charge at the time of the explosion, a radioactive isotope of carbon-14 is formed with a half-life of 5,730 years. The explosions changed the equilibrium content of carbon-14 in the atmosphere by 2.6%. At present, the average effective equivalent dose rate due to explosion products is about 1 mrem/year, which is equal to about 1% of the dose rate due to natural background radiation.

mos-rep.ru

Energy is another reason for the serious accumulation of radionuclides in the human and animal body. The coal used to operate the CHP plant contains naturally occurring radioactive elements such as potassium-40, uranium-238 and thorium-232. The annual dose in the area of ​​coal-fired CHP is 0.5–5 mrem/year. By the way, nuclear power plants are characterized by significantly lower emissions.

Almost all inhabitants of the Earth undergo medical procedures using sources of ionizing radiation. But this is a more complex issue, to which we will return a little later.

What units is radiation measured in?

Various units are used to measure the amount of radiation energy. In medicine, the main one is the sievert - the effective equivalent dose received in one procedure by the whole organism. It is in sieverts per unit time that the level of background radiation is measured. The becquerel is a unit of measure for the radioactivity of water, soil, and so on per unit volume.

See the table for other units of measurement.

Term	Units		Unit ratio	Definition
	In the SI system	In the old system
Activity	Becquerel, Bq		1 Ci = 3.7 × 10 10 Bq	Number of radioactive decays per unit time
Dose rate	Sievert per hour, Sv/h	X-ray per hour, R/h	1 µR/h = 0.01 µSv/h	Radiation level per unit of time
Absorbed dose		radian, rad	1 rad = 0.01 Gy	The amount of ionizing radiation energy transferred to a specific object
Effective dose	Sievert, Sv		1 rem = 0.01 Sv	Radiation dose, taking into account the different sensitivity of organs to radiation

Consequences of irradiation

The effect of radiation on a person is called irradiation. Its main manifestation is acute radiation sickness, which has various degrees of severity. Radiation sickness can manifest itself when irradiated with a dose equal to 1 sievert. A dose of 0.2 Sv increases the risk of cancer, and a dose of 3 Sv threatens the life of the irradiated person.

Radiation sickness manifests itself in the form of the following symptoms: loss of strength, diarrhea, nausea and vomiting; dry, hacking cough; cardiac disorders.

In addition, radiation causes radiation burns. Very large doses lead to the death of the skin, up to muscle and bone damage, which is treated much worse than chemical or thermal burns. Along with burns, metabolic disorders, infectious complications, radiation infertility, radiation cataracts may appear.

The consequences of irradiation can manifest themselves after a long time - this is the so-called stochastic effect. It is expressed in the fact that among exposed people the frequency of certain oncological diseases may increase. Theoretically, genetic effects are also possible, but even among the 78,000 Japanese children who survived the atomic bombing of Hiroshima and Nagasaki, they did not find an increase in the number of cases of hereditary diseases. And this is despite the fact that the effects of irradiation have a stronger effect on dividing cells, so radiation is much more dangerous for children than for adults.

Short-term exposure to low doses, used for examination and treatment of certain diseases, gives rise to an interesting effect called hormesis. This is the stimulation of any system of the body by external influences that have a force insufficient for the manifestation of harmful factors. This effect allows the body to mobilize forces.

Statistically, radiation can increase the level of oncology, but it is very difficult to identify the direct effect of radiation, separating it from the action of chemically harmful substances, viruses, and others. It is known that after the bombing of Hiroshima, the first effects in the form of an increase in the incidence began to appear only after 10 years or more. Cancer of the thyroid, breast and certain parts of the body is directly related to radiation.

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The natural radiation background is about 0.1–0.2 µSv/h. It is believed that a constant background level above 1.2 μSv / h is dangerous for humans (it is necessary to distinguish between an instantly absorbed radiation dose and a constant background dose). Is it a lot? For comparison: the level of radiation at a distance of 20 km from the Japanese nuclear power plant "Fukushima-1" at the time of the accident exceeded the norm by 1,600 times. The maximum recorded radiation level at this distance is 161 µSv/h. After the explosion, the radiation level reached several thousand microsieverts per hour.

During a 2–3-hour flight over an ecologically clean area, a person receives exposure to 20–30 μSv. The same dose of radiation threatens if a person takes 10-15 pictures in one day with a modern x-ray machine - a visiograph. A couple of hours in front of a cathode ray monitor or TV gives the same dose of radiation as one such picture. The annual dose from smoking one cigarette a day is 2.7 mSv. One fluorography - 0.6 mSv, one radiography - 1.3 mSv, one fluoroscopy - 5 mSv. Radiation from concrete walls - up to 3 mSv per year.

When irradiating the whole body and for the first group of critical organs (heart, lungs, brain, pancreas, and others), regulatory documents set the maximum dose value at 50,000 μSv (5 rem) per year.

Acute radiation sickness develops at a single exposure dose of 1,000,000 μSv (25,000 digital fluorography, 1,000 spinal radiographs in one day). Large doses have an even stronger effect:

• 750,000 µSv - short-term insignificant change in blood composition;
• 1,000,000 µSv - mild degree of radiation sickness;
• 4,500,000 µSv - severe radiation sickness (50% of those exposed die);
• about 7,000,000 µSv - death.

Are x-rays dangerous?

Most often, we encounter radiation during medical research. However, the doses that we receive in the process are so small that we should not be afraid of them. The irradiation time with an old X-ray machine is 0.5–1.2 seconds. And with a modern visiograph, everything happens 10 times faster: in 0.05–0.3 seconds.

According to the medical requirements set forth in SanPiN 2.6.1.1192-03, during preventive medical radiological procedures, the radiation dose should not exceed 1,000 μSv per year. How much is in pictures? Quite a bit of:

• 500 sighting images (2–3 μSv) obtained with a radiovisiograph;
• 100 of the same images, but using a good X-ray film (10–15 µSv);
• 80 digital orthopantomograms (13–17 µSv);
• 40 film orthopantomograms (25–30 μSv);
• 20 computed tomograms (45–60 μSv).

That is, if every day throughout the year we take one picture on a visiograph, add to this a couple of computed tomograms and the same number of orthopantomograms, then even in this case we will not go beyond the permitted doses.

Who should not be irradiated

However, there are people to whom even such types of exposure are strictly prohibited. According to the standards approved in Russia (SanPiN 2.6.1.1192-03), irradiation in the form of radiography can only be performed in the second half of pregnancy, except in cases where the issue of abortion or the need to provide emergency or emergency care must be resolved.

Paragraph 7.18 of the document reads: “X-ray examinations of pregnant women are carried out using all possible means and methods of protection so that the dose received by the fetus does not exceed 1 mSv in two months of undiagnosed pregnancy. If the fetus receives a dose exceeding 100 mSv, the doctor must warn the patient about the possible consequences and recommend terminating the pregnancy.”

Young people who will become parents in the future need to cover the abdominal area and genitals from radiation. X-ray radiation has the most negative effect on blood cells and germ cells. In children, in general, the entire body should be shielded, except for the area being examined, and studies should be carried out only when necessary and as directed by a doctor.

Sergey Nelyubin, Head of the Department of X-ray Diagnostics, RNCH named after I.I. B. V. Petrovsky, Candidate of Medical Sciences, Associate Professor

How to protect yourself

There are three main methods of X-ray protection: time protection, distance protection and shielding. That is, the less you are in the zone of action of X-rays and the farther you are from the radiation source, the lower the radiation dose.

Although the safe dose of radiation exposure is calculated for a year, it is still not worth doing several x-ray studies on the same day, for example, fluorography and. Well, each patient should have a radiation passport (it is invested in a medical card): the radiologist enters information about the dose received during each examination into it.

Radiography primarily affects the endocrine glands, the lungs. The same applies to small doses of radiation during accidents and releases of active substances. Therefore, as a preventive measure, doctors recommend breathing exercises. They will help cleanse the lungs and activate the reserves of the body.

To normalize the internal processes of the body and remove harmful substances, it is worth using more antioxidants: vitamins A, C, E (red wine, grapes). Sour cream, cottage cheese, milk, grain bread, bran, raw rice, prunes are useful.

In the event that food inspires certain concerns, you can use the recommendations for residents of the regions affected by the accident at the Chernobyl nuclear power plant.

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In real exposure due to an accident or in a contaminated area, quite a lot needs to be done. First you need to carry out decontamination: quickly and accurately remove clothes and shoes with radiation carriers, properly dispose of them, or at least remove radioactive dust from your belongings and surrounding surfaces. It is enough to wash the body and clothes (separately) under running water using detergents.

Before or after exposure to radiation, nutritional supplements and anti-radiation drugs are used. The most well-known drugs are high in iodine, which helps to effectively combat the negative effects of its radioactive isotope, which is localized in the thyroid gland. To block the accumulation of radioactive cesium and prevent secondary damage, "Potassium orotate" is used. Calcium supplements deactivate the radioactive strontium preparation by 90%. Dimethyl sulfide is shown to protect cellular structures.

By the way, the well-known activated carbon can neutralize the effect of radiation. And the benefits of drinking vodka immediately after exposure are not a myth at all. It really helps to remove radioactive isotopes from the body in the simplest cases.

Just do not forget: self-treatment should be carried out only if it is impossible to consult a doctor in a timely manner and only in the case of real, not fictitious exposure. X-ray diagnostics, watching TV or flying on an airplane do not affect the health of the average inhabitant of the Earth.

Radiation is the flow of particles formed during nuclear reactions or radioactive decay.. We all have heard about the danger of radioactive radiation for the human body and we know that it can cause a huge number of pathological conditions. But often most people do not know what exactly is the danger of radiation and how you can protect yourself from it. In this article, we examined what radiation is, what is its danger to humans, and what diseases it can cause.

What is radiation

The definition of this term is not very clear for a person who is not related to physics or, for example, medicine. The term "radiation" refers to the release of particles formed during nuclear reactions or radioactive decay. That is, this is the radiation that comes out of certain substances.

Radioactive particles have different ability to penetrate and pass through different substances. Some of them can pass through glass, the human body, concrete.

Based on the knowledge of the ability of specific radioactive waves to pass through materials, rules for protection against radiation are drawn up. For example, the walls of X-ray rooms are made of lead, through which radioactive radiation cannot pass.

Radiation happens:

• natural. It forms the natural radiation background to which we are all accustomed. The sun, soil, stones emit radiation. They are not dangerous to the human body.
• technogenic, that is, one that was created as a result of human activity. This includes the extraction of radioactive substances from the depths of the Earth, the use of nuclear fuels, reactors, etc.

How radiation enters the human body

Acute radiation sickness

This condition develops with a single massive irradiation of a person.. This condition is rare.

It can develop during some man-made accidents and disasters.

The degree of clinical manifestations depends on the amount of radiation that has affected the human body.

In this case, all organs and systems can be affected.

chronic radiation sickness

This condition develops with prolonged contact with radioactive substances.. Most often it develops in people who interact with them on duty.

In this case, the clinical picture can grow slowly, over many years. With prolonged and prolonged contact with radioactive sources of radiation, damage to the nervous, endocrine, and circulatory systems occurs. The kidneys also suffer, failures occur in all metabolic processes.

Chronic radiation sickness has several stages. It can proceed polymorphically, clinically manifested by the defeat of various organs and systems.

Oncological malignant pathologies

Scientists have proven that radiation can cause cancer. Most often, skin or thyroid cancer develops, and there are also frequent cases of leukemia - blood cancer in people suffering from acute radiation sickness.

According to statistics, the number of oncological pathologies after the accident at the Chernobyl nuclear power plant has increased tenfold in areas affected by radiation.

The use of radiation in medicine

Scientists have learned to use radiation for the benefit of mankind. A huge number of different diagnostic and therapeutic procedures are in one way or another associated with radioactive radiation. Thanks to thoughtful security protocols and state-of-the-art equipment such use of radiation is practically safe for the patient and for medical personnel but subject to all safety regulations.

Diagnostic medical techniques using radiation: radiography, computed tomography, fluorography.

Treatment methods include various types of radiation therapy that are used in the treatment of oncological pathologies.

The use of radiation methods of diagnosis and therapy should be carried out by qualified specialists. These procedures are prescribed to patients only according to indications.

Basic methods of protection against radiation

By learning how to use radioactive radiation in industry and medicine, scientists have taken care of the safety of people who may come into contact with these dangerous substances.

Only careful observance of the basics of personal prevention and protection against radiation can protect a person working in a dangerous radioactive zone from chronic radiation sickness.

The main methods of protection against radiation:

• Distance protection. Radioactive radiation has a certain wavelength, beyond which it does not operate. So in case of danger, you must immediately leave the danger zone.
• Shielding protection. The essence of this method is to use for the protection of substances that do not pass through themselves radioactive waves. For example, paper, a respirator, rubber gloves can protect against alpha radiation.
• Time protection. All radioactive substances have a half-life and decay time.
• Chemical protection. A person is given orally or injected with substances that can reduce the negative effects of radiation on the body.

People working with radioactive substances have protocols for protection and behavior in various situations. Usually, dosimeters are installed in the working rooms - devices for measuring background radiation.

Radiation is dangerous to humans. With an increase in its level above the permissible norm, various diseases and lesions of internal organs and systems develop. Against the background of radiation exposure, malignant oncological pathologies can develop. Radiation is also used in medicine. It is used to diagnose and treat many diseases.

After the accident at the Fukushima nuclear power plant, another wave of panic radiophobia swept the world. In the Far East, iodine disappeared from sale, and manufacturers and sellers of dosimeters not only sold out all the devices they had in stock, but also collected pre-orders for six months or a year in advance. But is radiation really that bad? If you wince every time you hear that word, this article is for you.

What is radiation? This is the name of various types of ionizing radiation, that is, one that is capable of tearing off electrons from the atoms of a substance. The three main types of ionizing radiation are usually denoted by the Greek letters alpha, beta and gamma. Alpha radiation is a stream of helium-4 nuclei (virtually all helium from balloons was once alpha radiation), beta radiation is a stream of fast electrons (less often positrons), and gamma is a stream of high-energy photons. Another type of radiation is the neutron flux. Ionizing radiation (with the exception of X-rays) is the result of nuclear reactions, so neither mobile phones nor microwave ovens are sources of it.

Loaded weapon

Of all the arts, the most important for us, as you know, is cinema, and of the types of radiation - gamma radiation. It has a very high penetrating power, and theoretically no barrier can completely protect against it. We are constantly exposed to gamma radiation, it comes to us through the thickness of the atmosphere from outer space, breaks through the soil layer and the walls of houses. The reverse side of such all-permeability is a relatively weak destructive effect: out of a large number of photons, only a small part will transfer their energy to the body. Soft (low-energy) gamma radiation (and X-rays) mainly interacts with matter, knocking out electrons from it due to the photoelectric effect, hard radiation is scattered by electrons, while the photon is not absorbed and retains a significant part of its energy, so the probability of destruction of molecules in such process is much less.

Beta radiation is close to gamma radiation in its effect - it also knocks electrons out of atoms. But with external irradiation, it is completely absorbed by the skin and tissues closest to the skin, without reaching the internal organs. However, this leads to the fact that the flow of fast electrons transfers significant energy to the irradiated tissues, which can lead to radiation burns or provoke, for example, cataracts.

Alpha radiation carries significant energy and high momentum, which allows it to knock electrons out of atoms and even the atoms themselves out of molecules. Therefore, the “destruction” caused by them is much greater - it is believed that, having transferred 1 J of energy to the body, alpha radiation will cause the same damage as 20 J in the case of gamma or beta radiation. Fortunately, the penetrating power of alpha particles is extremely small: they are absorbed by the topmost layer of the skin. But when ingested, alpha-active isotopes are extremely dangerous: remember the infamous tea with alpha-active polonium-210, which poisoned Alexander Litvinenko.

Neutral danger

But the first place in the danger rating is undoubtedly occupied by fast neutrons. The neutron has no electric charge and therefore interacts not with electrons, but with nuclei - only with a "direct hit". A stream of fast neutrons can pass through a layer of matter, on average, from 2 to 10 cm without interacting with it. Moreover, in the case of heavy elements, colliding with the nucleus, the neutron only deviates to the side, almost without losing energy. And when colliding with a hydrogen nucleus (proton), the neutron transfers about half of its energy to it, knocking the proton out of its place. It is this fast proton (or, to a lesser extent, the nucleus of another light element) that causes ionization in matter, acting like alpha radiation. As a result, neutron radiation, like gamma quanta, easily penetrates into the body, but is almost completely absorbed there, creating fast protons that cause great destruction. In addition, neutrons are the very radiation that causes induced radioactivity in irradiated substances, that is, it turns stable isotopes into radioactive ones. This is an extremely unpleasant effect: for example, after being in the focus of a radiation accident, alpha, beta, and gamma-active dust can be washed off vehicles, but it is impossible to get rid of neutron activation - the body itself radiates (by the way, it was based on this the damaging effect of a neutron bomb that activated the armor of tanks).

Dose and Power

When measuring and evaluating radiation, such a number of different concepts and units are used that it is not surprising for an ordinary person to get confused.
The exposure dose is proportional to the number of ions that gamma and x-ray radiation creates in a unit mass of air. It is usually measured in roentgens (R).
The absorbed dose shows the amount of radiation energy absorbed by a unit mass of a substance. Previously, it was measured in rads (rad), and now - in grays (Gy).
The equivalent dose additionally takes into account the difference in the destructive ability of different types of radiation. Previously, it was measured in "biological equivalents of the rad" - rems (rem), and now - in sieverts (Sv).
The effective dose also takes into account the different sensitivity of different organs to radiation: for example, irradiating the hand is much less dangerous than the back or chest. Previously measured in the same rem, now in sieverts.
The conversion of some units of measurement into others is not always correct, but on average it is generally accepted that an exposure dose of gamma radiation of 1 R will bring the same harm to the body as an equivalent dose of 1/114 Sv. Converting rad to grays and rems to sieverts is very simple: 1 Gy = 100 rad, 1 Sv = 100 rem. To convert the absorbed dose into an equivalent dose, the so-called. "radiation quality factor", equal to 1 for gamma and beta radiation, 20 for alpha radiation and 10 for fast neutrons. For example, 1 Gy of fast neutrons = 10 Sv = 1000 rem.
The natural equivalent dose rate (ERR) of external exposure is usually 0.06 - 0.10 µSv/h, but in some places it can be less than 0.02 µSv/h or more than 0.30 µSv/h. A level of more than 1.2 µSv/h in Russia is officially considered dangerous, although in the cabin of an aircraft during a flight the DER can exceed this value many times over. And the crew of the ISS is exposed to radiation with a power of approximately 40 μSv / h.

In nature, neutron radiation is very small. In fact, the risk of being exposed to it exists only in the event of a nuclear bombardment or a serious accident at a nuclear power plant with a meltdown and release into the environment of most of the reactor core (and even then only in the first seconds).

Gas discharge meters

Radiation can be detected and measured using a variety of sensors. The simplest of these are ionization chambers, proportional counters, and gas-discharge Geiger-Muller counters. They are a thin-walled metal tube with gas (or air), along the axis of which a wire is stretched - an electrode. A voltage is applied between the body and the wire and the current flowing is measured. The fundamental difference between the sensors is only in the magnitude of the applied voltage: at low voltages we have an ionization chamber, at high voltages - a gas-discharge counter, somewhere in the middle - a proportional counter.

The plutonium-238 sphere glows in the dark like a one-watt light bulb. Plutonium is toxic, radioactive and incredibly heavy: one kilogram of this substance fits in a cube with a side of 4 cm.

Ionization chambers and proportional counters make it possible to determine the energy that each particle has transferred to the gas. The Geiger-Muller counter only counts particles, but the readings from it are very easy to receive and process: the power of each pulse is sufficient to directly output it to a small speaker! An important problem of gas-discharge counters is the dependence of the counting rate on the radiation energy at the same radiation level. To align it, special filters are used that absorb part of the soft gamma and all beta radiation. To measure the flux density of beta and alpha particles, such filters are made removable. In addition, to increase the sensitivity to beta and alpha radiation, "end counters" are used: this is a disk with a bottom as one electrode and a second spiral wire electrode. The cover of end counters is made of a very thin (10–20 µm) plate of mica, through which soft beta radiation and even alpha particles easily pass.

Semiconductors and scintillators

Instead of an ionization chamber, a semiconductor sensor can be used. The simplest example is an ordinary diode to which a blocking voltage is applied: when an ionizing particle enters a p-n junction, it creates additional charge carriers, which lead to the appearance of a current pulse. To increase the sensitivity, so-called pin diodes are used, where there is a relatively thick layer of undoped semiconductor between the layers of p- and n-semiconductors. Such sensors are compact and allow to measure particle energy with high accuracy. But the volume of the sensitive area is small, and therefore the sensitivity is limited. In addition, they are much more expensive than gas-discharge ones.

Another principle is counting and measuring the brightness of flashes that occur in certain substances when particles of ionizing radiation are absorbed. These flashes cannot be seen with the naked eye, but special highly sensitive devices - photomultiplier tubes - are capable of this. They even allow you to measure the change in brightness over time, which characterizes the energy loss of each individual particle. Sensors based on this principle are called scintillator sensors.

Radiation Shield

For protection against gamma radiation, heavy elements such as lead are most effective. The larger the number of the element in the periodic table, the stronger the photoelectric effect manifests itself in it. The degree of protection also depends on the energy of the radiation particles. Even lead attenuates radiation from caesium-137 (662 keV) by only a factor of two for every 5 mm of its thickness. In the case of cobalt-60 (1173 and 1333 keV), more than a centimeter of lead is required for a twofold attenuation. Only for soft gamma radiation, such as the radiation of cobalt-57 (122 keV), a sufficiently thin layer of lead will be a serious protection: 1 mm will attenuate it by a factor of ten. So anti-radiation suits from films and computer games in reality protect only from soft gamma radiation.

Beta radiation is completely absorbed by the protection of a certain thickness. For example, the beta radiation of cesium-137 with a maximum energy of 514 keV (and an average of 174 keV) is completely absorbed by a layer of water 2 mm thick or only 0.6 mm of aluminum. But lead should not be used to protect against beta radiation: too rapid deceleration of beta electrons leads to the formation of x-rays. To completely absorb the radiation of strontium-90, you need less than 1.5 mm of lead, but it takes another centimeter to absorb the resulting X-ray radiation!

Folk remedies

There is a well-established myth about the "protective" effect of alcohol, but it has no scientific justification. Even if red wine contains natural antioxidants that could theoretically act as radioprotectors, their theoretical benefit is outweighed by the practical harm of ethanol, which damages cells and is a neurotoxic poison.
The extremely tenacious popular recommendation to drink iodine so as not to “get infected with radiation” is justified only for a 30-kilometer zone around a freshly exploded nuclear power plant. In this case, potassium iodide is used to "keep out" radioactive iodine-131 into the thyroid gland (half-life - 8 days). The tactic of the lesser evil is used: let the thyroid gland be “clogged” with ordinary rather than radioactive iodine. And the prospect of getting a dysfunction of the thyroid gland pales before cancer or even death. But outside the zone of infection, swallowing pills, drinking an alcoholic solution of iodine or smearing it on the neck from the front does not make any sense - it has no preventive value, but you can easily earn iodine poisoning and turn yourself into a lifelong patient of an endocrinologist.

It is easiest to protect yourself from external alpha radiation: a sheet of paper is enough for this. However, most alpha particles do not pass through the air even five centimeters, so protection may be required only in case of direct contact with a radioactive source. It is much more important to protect against the ingress of alpha-active isotopes into the body, for which a respirator mask is used, and ideally an airtight suit with an isolated breathing system.

Finally, hydrogen-rich substances are best protected from fast neutrons. For example, hydrocarbons, the best option is polyethylene. Experiencing collisions with hydrogen atoms, the neutron quickly loses energy, slows down and soon becomes unable to cause ionization. However, such neutrons can still activate, that is, transform into radioactive, many stable isotopes. Therefore, boron is often added to neutron shielding, which very strongly absorbs such slow (they are called thermal) neutrons. Alas, the thickness of polyethylene for reliable protection must be at least 10 cm. So it turns out to be slightly lighter than lead protection against gamma radiation.

radiation pills

The human body is more than three-quarters water, so the main action of ionizing radiation is radiolysis (decomposition of water). The resulting free radicals cause an avalanche cascade of pathological reactions with the appearance of secondary "fragments". In addition, radiation damages chemical bonds in nucleic acid molecules, causing disintegration and depolymerization of DNA and RNA. The most important enzymes containing a sulfhydryl group - SH (adenosine triphosphatase, succinoxidase, hexokinase, carboxylase, cholinesterase) are inactivated. At the same time, the processes of biosynthesis and energy metabolism are disrupted, proteolytic enzymes are released from the destroyed organelles into the cytoplasm, and self-digestion begins. In the risk group, first of all, there are germ cells, precursors of blood cells, cells of the gastrointestinal tract and lymphocytes, but neurons and muscle cells are quite resistant to ionizing radiation.

Preparations capable of protecting against the effects of radiation began to be actively developed in the middle of the 20th century. Only some aminothiols, such as cystamine, cysteamine, aminoethylisothiuronium, turned out to be more or less effective and suitable for mass use. In fact, they are donors - SH groups, exposing them to attack instead of "relatives".

Radiation around us

To face radiation "face to face", accidents are not necessary at all. Radioactive substances are widely used in everyday life. Potassium is naturally radioactive and is a very important element for all living things. Due to the small admixture of the K-40 isotope in natural potassium, dietary salt and potash fertilizers “phonite”. Some older lenses used thorium oxide glass. The same element is added to some modern electrodes for argon welding. Until the middle of the 20th century, devices with illumination based on radium were actively used (in our time, radium was replaced by a less dangerous tritium). Some smoke detectors use an alpha emitter based on americium-241 or highly enriched plutonium-239 (yes, the same one from which nuclear bombs are made). But do not worry - the harm to health from all these sources is much less than the harm from worrying about this.