X-rays play one of the most important roles in the study and practical use of atomic phenomena. Thanks to their research, many discoveries were made and methods for analyzing substances were developed, which are used in various fields. Here we will consider one of the types of X-rays - characteristic X-rays.
X-ray radiation is a high-frequency change in the state of an electromagnetic field propagating in space at a speed of about 300,000 km / s, that is, electromagnetic waves. On the scale of the range of electromagnetic radiation, X-rays are located in the wavelength range from approximately 10 -8 to 5∙10 -12 meters, which is several orders of magnitude shorter than optical waves. This corresponds to frequencies from 3∙10 16 to 6∙10 19 Hz and energies from 10 eV to 250 keV, or 1.6∙10 -18 to 4∙10 -14 J. It should be noted that the boundaries of the frequency ranges of electromagnetic radiation are rather conventional due to their overlap.
Is the interaction of accelerated charged particles (high-energy electrons) with electric and magnetic fields and with atoms of matter.
X-ray photons are characterized by high energies and high penetrating and ionizing power, especially for hard X-rays with wavelengths less than 1 nanometer (10 -9 m).
X-rays interact with matter, ionizing its atoms, in the processes of the photoelectric effect (photoabsorption) and incoherent (Compton) scattering. In photoabsorption, an X-ray photon, being absorbed by an electron of an atom, transfers energy to it. If its value exceeds the binding energy of an electron in an atom, then it leaves the atom. Compton scattering is characteristic of harder (energetic) X-ray photons. Part of the energy of the absorbed photon is spent on ionization; in this case, at a certain angle to the direction of the primary photon, a secondary one is emitted, with a lower frequency.
To obtain rays, glass vacuum bottles with electrodes located inside are used. The potential difference across the electrodes needs to be very high - up to hundreds of kilovolts. On a tungsten cathode heated by current, thermionic emission occurs, that is, electrons are emitted from it, which, accelerated by the potential difference, bombard the anode. As a result of their interaction with the atoms of the anode (sometimes called the anticathode), X-ray photons are born.
Depending on what process leads to the birth of a photon, there are such types of X-ray radiation as bremsstrahlung and characteristic.
Electrons can, meeting with the anode, slow down, that is, lose energy in the electric fields of its atoms. This energy is emitted in the form of X-ray photons. Such radiation is called bremsstrahlung.
It is clear that the braking conditions will differ for individual electrons. This means that different amounts of their kinetic energy are converted into X-rays. As a result, bremsstrahlung includes photons of different frequencies and, accordingly, wavelengths. Therefore, its spectrum is continuous (continuous). Sometimes for this reason it is also called "white" X-rays.
The energy of the bremsstrahlung photon cannot exceed the kinetic energy of the electron that generates it, so that the maximum frequency (and the smallest wavelength) of bremsstrahlung corresponds to the largest value of the kinetic energy of electrons incident on the anode. The latter depends on the potential difference applied to the electrodes.
There is another type of X-ray that comes from a different process. This radiation is called characteristic, and we will dwell on it in more detail.
Having reached the anticathode, a fast electron can penetrate inside the atom and knock out any electron from one of the lower orbitals, that is, transfer to it energy sufficient to overcome the potential barrier. However, if there are higher energy levels occupied by electrons in the atom, the vacated place will not remain empty.
It must be remembered that the electronic structure of the atom, like any energy system, seeks to minimize energy. The vacancy formed as a result of the knockout is filled with an electron from one of the higher levels. Its energy is higher, and, occupying a lower level, it radiates a surplus in the form of a quantum of characteristic X-ray radiation.
The electronic structure of an atom is a discrete set of possible energy states of electrons. Therefore, X-ray photons emitted during the replacement of electron vacancies can also have only strictly defined energy values, reflecting the level difference. As a result, the characteristic X-ray radiation has a spectrum not of a continuous, but of a line type. Such a spectrum makes it possible to characterize the substance of the anode - hence the name of these rays. It is precisely because of the spectral differences that it is clear what is meant by bremsstrahlung and characteristic X-rays.
Sometimes the excess energy is not emitted by the atom, but is spent on knocking out the third electron. This process - the so-called Auger effect - is more likely to occur when the electron binding energy does not exceed 1 keV. The energy of the released Auger electron depends on the structure of the energy levels of the atom, so the spectra of such electrons are also discrete.
Narrow characteristic lines are present in the X-ray spectral pattern along with a continuous bremsstrahlung spectrum. If we represent the spectrum as a plot of intensity versus wavelength (frequency), we will see sharp peaks at the locations of the lines. Their position depends on the anode material. These maxima are present at any potential difference - if there are X-rays, there are always peaks too. With increasing voltage at the electrodes of the tube, the intensity of both continuous and characteristic X-ray radiation increases, but the location of the peaks and the ratio of their intensities does not change.
The peaks in the X-ray spectra have the same shape regardless of the material of the anti-cathode irradiated by electrons, but for different materials they are located at different frequencies, uniting in series according to the proximity of the frequency values. Between the series themselves, the difference in frequencies is much more significant. The shape of the maxima does not depend in any way on whether the anode material represents a pure chemical element or whether it is a complex substance. In the latter case, the characteristic X-ray spectra of its constituent elements are simply superimposed on each other.
With an increase in the atomic number of a chemical element, all lines of its X-ray spectrum are shifted towards increasing frequency. The spectrum retains its form.
The phenomenon of spectral shift of characteristic lines was experimentally discovered by the English physicist Henry Moseley in 1913. This allowed him to associate the frequencies of the maxima of the spectrum with the ordinal numbers of the chemical elements. Thus, the wavelength of the characteristic X-ray radiation, as it turned out, can be clearly correlated with a specific element. In general, Moseley's law can be written as follows: √f = (Z - S n)/n√R, where f is the frequency, Z is the element's ordinal number, S n is the screening constant, n is the principal quantum number, and R is the constant Rydberg. This relationship is linear and appears on the Moseley diagram as a series of straight lines for each value of n.
The values of n correspond to individual series of characteristic X-ray peaks. Moseley's law allows one to determine the serial number of a chemical element irradiated by hard electrons from the measured wavelengths (they are uniquely related to the frequencies) of the X-ray spectrum maxima.
Structure electron shells chemical elements are identical. This is indicated by the monotonicity of the shift change in the characteristic spectrum of X-rays. The frequency shift reflects not structural, but energy differences between electron shells, unique for each element.
There are small deviations from the strict linear relationship expressed by Moseley's law. They are connected, firstly, with the peculiarities of the filling order of the electron shells in some elements, and, secondly, with the relativistic effects of the motion of electrons in heavy atoms. In addition, when the number of neutrons in the nucleus changes (the so-called isotopic shift), the position of the lines can change slightly. This effect made it possible to study the atomic structure in detail.
The significance of Moseley's law is extremely great. Its consistent application to the elements of Mendeleev's periodic system established the pattern of increasing the serial number according to each small shift in the characteristic maxima. This contributed to the clarification of the question of the physical meaning of the ordinal number of elements. The Z value is not just a number: it is the positive electric charge of the nucleus, which is the sum of the unit positive charges of the particles that make up it. The correct placement of elements in the table and the presence of empty positions in it (then they still existed) received powerful confirmation. The validity of the periodic law was proved.
Moseley's law, in addition, became the basis on which a whole area of experimental research arose - X-ray spectrometry.
Let us briefly recall how the electronic structure is arranged. It consists of shells, denoted by the letters K, L, M, N, O, P, Q, or numbers from 1 to 7. Electrons within the shell are characterized by the same main quantum number n, which determines the possible energy values. In outer shells, the energy of electrons is higher, and the ionization potential for outer electrons is correspondingly lower.
The shell includes one or more sublevels: s, p, d, f, g, h, i. In each shell, the number of sublevels increases by one compared to the previous one. The number of electrons in each sublevel and in each shell cannot exceed a certain value. They are characterized, in addition to the main quantum number, by the same value of the orbital electron cloud that determines the shape. Sublevels are labeled with the shell they belong to, such as 2s, 4d, and so on.
The sublevel contains which are set, in addition to the main and orbital, by one more quantum number - magnetic, which determines the projection of the electron's orbital momentum onto the direction of the magnetic field. One orbital can have no more than two electrons, differing in the value of the fourth quantum number - spin.
Let us consider in more detail how characteristic X-ray radiation arises. Since the origin of this type of electromagnetic emission is associated with phenomena occurring inside the atom, it is most convenient to describe it precisely in the approximation of electronic configurations.
So, the cause of this radiation is the formation of electron vacancies in the inner shells, due to the penetration of high-energy electrons deep into the atom. The probability that a hard electron will interact increases with the density of the electron clouds. Therefore, collisions are most likely within densely packed inner shells, such as the lowest K-shell. Here the atom is ionized, and a vacancy is formed in the 1s shell.
This vacancy is filled by an electron from the shell with a higher energy, the excess of which is carried away by the X-ray photon. This electron can "fall" from the second shell L, from the third shell M and so on. This is how the characteristic series is formed, in this example, the K-series. An indication of where the electron filling the vacancy comes from is given in the form of a Greek index when designating the series. "Alpha" means that it comes from the L-shell, "beta" - from the M-shell. At present, there is a tendency to replace the Greek letter indices with the Latin ones adopted to designate shells.
The intensity of the alpha line in the series is always the highest, which means that the probability of filling a vacancy from a neighboring shell is the highest.
Now we can answer the question, what is the maximum energy of the characteristic x-ray quantum. It is determined by the difference in the energy values of the levels between which the electron transition occurs, according to the formula E \u003d E n 2 - E n 1, where E n 2 and E n 1 are the energies of the electronic states between which the transition occurred. The highest value of this parameter is given by K-series transitions from the highest possible levels of atoms of heavy elements. But the intensity of these lines (peak heights) is the smallest, since they are the least likely.
If, due to insufficient voltage on the electrodes, a hard electron cannot reach the K-level, it forms a vacancy at the L-level, and a less energetic L-series with longer wavelengths is formed. Subsequent series are born in a similar way.
In addition, when a vacancy is filled, a new vacancy appears in the overlying shell as a result of an electronic transition. This creates the conditions for generating the next series. Electronic vacancies move higher from level to level, and the atom emits a cascade of characteristic spectral series, while remaining ionized.
Atomic X-ray spectra of characteristic X-ray radiation are characterized by a fine structure, which is expressed, as in optical spectra, in line splitting.
The fine structure is due to the fact that the energy level - the electron shell - is a set of closely spaced components - subshells. To characterize the subshells, one more, internal quantum number j is introduced, which reflects the interaction of the intrinsic and orbital magnetic moments of the electron.
Due to the influence of the spin-orbit interaction, the energy structure of the atom becomes more complicated, and as a result, the characteristic X-ray radiation has a spectrum that is characterized by split lines with very closely spaced elements.
Fine structure elements are usually denoted by additional digital indices.
The characteristic X-ray radiation has a feature that is reflected only in the fine structure of the spectrum. The transition of an electron to the lowest energy level does not occur from the lower subshell of the overlying level. Such an event has a negligible probability.
This radiation, due to its features described by Moseley's law, underlies various X-ray spectral methods for the analysis of substances. When analyzing the X-ray spectrum, either diffraction of radiation by crystals (wave-dispersive method) or detectors sensitive to the energy of absorbed X-ray photons (energy-dispersive method) are used. Most electron microscopes are equipped with some form of X-ray spectrometry attachment.
Wave-dispersive spectrometry is characterized by especially high accuracy. With the help of special filters, the most intense peaks in the spectrum are selected, thanks to which it is possible to obtain almost monochromatic radiation with a precisely known frequency. The anode material is chosen very carefully to ensure that a monochromatic beam of the desired frequency is obtained. Its diffraction on the crystal lattice of the studied substance makes it possible to study the structure of the lattice with great accuracy. This method is also used in the study of DNA and other complex molecules.
One of the features of the characteristic X-ray radiation is also taken into account in gamma spectrometry. This is the high intensity of the characteristic peaks. Gamma spectrometers use lead shielding against external background radiation that interferes with measurements. But lead, absorbing gamma quanta, experiences internal ionization, as a result of which it actively emits in the X-ray range. Additional cadmium shielding is used to absorb the intense peaks of the characteristic x-ray radiation from lead. It, in turn, is ionized and also emits X-rays. To neutralize the characteristic peaks of cadmium, a third shielding layer is used - copper, the X-ray maxima of which lie outside the operating frequency range of the gamma spectrometer.
Spectrometry uses both bremsstrahlung and characteristic X-rays. Thus, in the analysis of substances, the absorption spectra of continuous X-rays by various substances are studied.
The discovery and merit in the study of the basic properties of X-rays rightfully belongs to the German scientist Wilhelm Conrad Roentgen. The amazing properties of X-rays discovered by him immediately received a huge response in the scientific world. Although then, back in 1895, the scientist could hardly imagine what benefit, and sometimes harm, X-rays can bring.
Let's find out in this article how this type of radiation affects human health.
The first question that interested the researcher was what is X-ray radiation? A number of experiments made it possible to verify that this is electromagnetic radiation with a wavelength of 10 -8 cm, which occupies an intermediate position between ultraviolet and gamma radiation.
All these aspects of the destructive effects of the mysterious X-rays do not at all exclude surprisingly extensive aspects of their application. Where is X-rays used?
The most important applications of X-rays have become possible due to the very short wavelengths of the entire range of these waves and their unique properties.
Since we are interested in the impact of X-rays on people who encounter them only during a medical examination or treatment, then we will only consider this area of application of X-rays.
Despite the special significance of his discovery, Roentgen did not take out a patent for its use, making it an invaluable gift for all mankind. Already in the First World War, X-ray units began to be used, which made it possible to quickly and accurately diagnose the wounded. Now we can distinguish two main areas of application of x-rays in medicine:
X-ray diagnostics is used in various options:
Let's take a look at the difference between these methods.
All of the above diagnostic methods are based on the ability of X-rays to illuminate photographic film and on their different permeability to tissues and the bone skeleton.
The ability of X-rays to have a biological effect on tissues is used in medicine for the treatment of tumors. The ionizing effect of this radiation is most actively manifested in the effect on rapidly dividing cells, which are the cells of malignant tumors.
However, you should also be aware of side effects that inevitably accompany radiotherapy. The fact is that cells of the hematopoietic, endocrine, and immune systems are also rapidly dividing. A negative impact on them gives rise to signs of radiation sickness.
Shortly after the remarkable discovery of X-rays, it was discovered that X-rays had an effect on humans.
These data were obtained in experiments on experimental animals, however, geneticists suggest that similar effects may apply to the human body.
The study of the effects of X-ray exposure has led to the development of international standards for acceptable radiation doses.
After visiting the X-ray room, many patients are worried - how will the received dose of radiation affect their health?
The dose of general irradiation of the body depends on the nature of the procedure. For convenience, we will compare the received dose with natural exposure, which accompanies a person throughout his life.
These radiation doses meet acceptable standards, but if the patient feels anxious before the X-ray, he has the right to ask for a special protective apron.
Each person has to undergo X-ray examination repeatedly. But there is a rule - this diagnostic method cannot be prescribed to pregnant women. The developing embryo is extremely vulnerable. X-rays can cause chromosome abnormalities and, as a result, the birth of children with malformations. The most vulnerable in this regard is the gestational age of up to 16 weeks. Moreover, the most dangerous for the future baby is an x-ray of the spine, pelvic and abdominal regions.
Knowing about the detrimental effect of x-rays on pregnancy, doctors avoid using it in every possible way during this crucial period in a woman's life.
However, there are side sources of X-rays:
Expectant mothers should be aware of the danger posed by them.
For nursing mothers, radiodiagnosis is not dangerous.
To avoid even the minimal effects of X-ray exposure, some simple steps can be taken:
But, no medical procedures or special measures are required to remove radiation after an x-ray!
Despite the undoubtedly serious consequences of exposure to X-rays, one should not overestimate their danger during medical examinations - they are carried out only in certain areas of the body and very quickly. The benefits of them many times exceed the risk of this procedure for the human body.
In 1895, the German physicist W. Roentgen discovered a new, previously unknown type of electromagnetic radiation, which was named X-ray in honor of its discoverer. W. Roentgen became the author of his discovery at the age of 50, holding the post of rector of the University of Würzburg and having a reputation as one of the best experimenters of his time. One of the first to find a technical application for Roentgen's discovery was the American Edison. He created a handy demonstration apparatus and already in May 1896 organized an X-ray exhibition in New York, where visitors could look at their own hand on a luminous screen. After Edison's assistant died from the severe burns he received from constant demonstrations, the inventor stopped further experiments with X-rays.
X-ray radiation began to be used in medicine due to its high penetrating power. Initially, X-rays were used to examine bone fractures and locate foreign bodies in the human body. Currently, there are several methods based on X-rays. But these methods have their drawbacks: radiation can cause deep damage to the skin. Appearing ulcers often turned into cancer. In many cases, fingers or hands had to be amputated. Fluoroscopy(synonymous with translucence) is one of the main methods of X-ray examination, which consists in obtaining a planar positive image of the object under study on a translucent (fluorescent) screen. During fluoroscopy, the subject is between a translucent screen and an x-ray tube. On modern X-ray translucent screens, the image appears at the moment the X-ray tube is turned on and disappears immediately after it is turned off. Fluoroscopy makes it possible to study the function of the organ - heart pulsation, respiratory movements of the ribs, lungs, diaphragm, peristalsis of the digestive tract, etc. Fluoroscopy is used in the treatment of diseases of the stomach, gastrointestinal tract, duodenum, diseases of the liver, gallbladder and biliary tract. At the same time, the medical probe and manipulators are inserted without tissue damage, and the actions during the operation are controlled by fluoroscopy and are visible on the monitor.
Radiography - method of X-ray diagnostics with the registration of a fixed image on a photosensitive material - special. photographic film (X-ray film) or photographic paper with subsequent photo processing; With digital radiography, the image is fixed in the computer's memory. It is performed on X-ray diagnostic devices - stationary, installed in specially equipped X-ray rooms, or mobile and portable - at the patient's bedside or in the operating room. On radiographs, the elements of the structures of various organs are displayed much more clearly than on a fluorescent screen. Radiography is performed in order to detect and prevent various diseases, its main goal is to help doctors of various specialties correctly and quickly make a diagnosis. An x-ray image captures the state of an organ or tissue only at the time of exposure. However, a single radiograph captures only anatomical changes at a certain moment, it gives the statics of the process; through a series of radiographs taken at certain intervals, it is possible to study the dynamics of the process, that is, functional changes. Tomography. The word tomography can be translated from Greek as slice image. This means that the purpose of tomography is to obtain a layered image of the internal structure of the object of study. Computed tomography is characterized by high resolution, which makes it possible to distinguish subtle changes in soft tissues. CT allows to detect such pathological processes that cannot be detected by other methods. In addition, the use of CT makes it possible to reduce the dose of X-ray radiation received by patients during the diagnostic process.
Fluorography- a diagnostic method that allows you to get an image of organs and tissues, was developed at the end of the 20th century, a year after X-rays were discovered. In the pictures you can see sclerosis, fibrosis, foreign objects, neoplasms, inflammations that have a developed degree, the presence of gases and infiltrate in the cavities, abscesses, cysts, and so on. Most often, a chest x-ray is performed, which allows to detect tuberculosis, a malignant tumor in the lungs or chest, and other pathologies.
X-ray therapy- This is a modern method with which the treatment of certain pathologies of the joints is performed. The main directions of treatment of orthopedic diseases by this method are: Chronic. Inflammatory processes of the joints (arthritis, polyarthritis); Degenerative (osteoarthritis, osteochondrosis, deforming spondylosis). The purpose of radiotherapy is the inhibition of the vital activity of cells of pathologically altered tissues or their complete destruction. In non-tumor diseases, X-ray therapy is aimed at suppressing the inflammatory reaction, inhibiting proliferative processes, reducing pain sensitivity and secretory activity of the glands. It should be borne in mind that the sex glands, hematopoietic organs, leukocytes, and malignant tumor cells are most sensitive to X-rays. The radiation dose in each case is determined individually.
For the discovery of X-rays, Roentgen was awarded the first Nobel Prize in Physics in 1901, and the Nobel Committee emphasized the practical importance of his discovery.
Thus, X-rays are invisible electromagnetic radiation with a wavelength of 105 - 102 nm. X-rays can penetrate some materials that are opaque to visible light. They are emitted during the deceleration of fast electrons in matter (continuous spectrum) and during transitions of electrons from the outer electron shells of the atom to the inner ones (linear spectrum). Sources of X-ray radiation are: X-ray tube, some radioactive isotopes, accelerators and accumulators of electrons (synchrotron radiation). Receivers - film, luminescent screens, nuclear radiation detectors. X-rays are used in X-ray diffraction analysis, medicine, flaw detection, X-ray spectral analysis, etc.
Modern medical diagnostics and treatment of certain diseases cannot be imagined without devices that use the properties of X-rays. The discovery of X-rays occurred more than 100 years ago, but even now work continues on the creation of new methods and apparatus to minimize the negative effect of radiation on the human body.
Under natural conditions, the flux of X-rays is rare and is emitted only by certain radioactive isotopes. X-rays or X-rays were only discovered in 1895 by the German scientist Wilhelm Röntgen. This discovery happened by chance, during an experiment to study the behavior of light rays under conditions approaching vacuum. The experiment involved a cathode gas discharge tube with reduced pressure and a fluorescent screen, which each time began to glow at the moment when the tube began to act.
Interested in a strange effect, Roentgen conducted a series of studies showing that the resulting radiation, invisible to the eye, is able to penetrate various obstacles: paper, wood, glass, some metals, and even through the human body. Despite the lack of understanding of the very nature of what is happening, whether such a phenomenon is caused by the generation of a stream of unknown particles or waves, the following pattern was noted - radiation easily passes through the soft tissues of the body, and much harder through solid living tissues and inanimate substances.
Roentgen was not the first to study this phenomenon. In the middle of the 19th century, Frenchman Antoine Mason and Englishman William Crookes studied similar possibilities. However, it was Roentgen who first invented the cathode tube and an indicator that could be used in medicine. He was the first to publish a scientific work, which brought him the title of the first Nobel laureate among physicists.
In 1901, a fruitful collaboration began between the three scientists, who became the founding fathers of radiology and radiology.
X-rays are component the total spectrum of electromagnetic radiation. The wavelength is between gamma and ultraviolet rays. X-rays have all the usual wave properties:
To artificially generate an X-ray flux, special devices are used - X-ray tubes. X-ray radiation arises from the contact of fast tungsten electrons with substances evaporating from a hot anode. Against the background of interaction, short-length electromagnetic waves arise, which are in the spectrum from 100 to 0.01 nm and in the energy range of 100-0.1 MeV. If the wavelength of the rays is less than 0.2 nm - this is hard radiation, if the wavelength is greater than the specified value, they are called soft x-rays.
It is significant that the kinetic energy arising from the contact of electrons and the anode substance is 99% converted into heat energy and only 1% is X-rays.
X-radiation is a superposition of two types of rays - bremsstrahlung and characteristic. They are generated in the handset simultaneously. Therefore, X-ray irradiation and the characteristic of each specific X-ray tube - the spectrum of its radiation, depends on these indicators, and represents their superposition.
Bremsstrahlung or continuous X-rays are the result of deceleration of electrons evaporating from a tungsten filament.
Characteristic or line X-rays are formed at the moment of rearrangement of the atoms of the substance of the anode of the X-ray tube. The wavelength of the characteristic rays directly depends on the atomic number of the chemical element used to make the anode of the tube.
The listed properties of X-rays allow them to be used in practice:
The property of x-rays on which imaging is based is the ability to either decompose or cause some substances to glow.
X-ray irradiation causes a fluorescent glow in cadmium and zinc sulfides - green, and in calcium tungstate - blue. This property is used in the technique of medical X-ray transillumination, and also increases the functionality of X-ray screens.
The photochemical effect of X-rays on light-sensitive silver halide materials (illumination) makes it possible to carry out diagnostics - to take X-ray images. This property is also used in measuring the amount of the total dose that laboratory assistants receive in X-ray rooms. Wearable dosimeters have special sensitive tapes and indicators. The ionizing effect of X-ray radiation makes it possible to determine the qualitative characteristics of the obtained X-rays.
A single exposure to conventional X-rays increases the risk of cancer by only 0.001%.
The use of X-rays is acceptable in the following industries:
The main application of X-rays is in the medical field. Today, the section of medical radiology includes: radiodiagnostics, radiotherapy (X-ray therapy), radiosurgery. Medical universities produce highly specialized specialists - radiologists.
The high penetrating power and ionizing effect of X-rays can cause a change in the structure of the DNA of the cell, therefore it is dangerous for humans. The harm from X-ray radiation is directly proportional to the received radiation dose. Different organs respond to irradiation to varying degrees. The most susceptible include:
Uncontrolled use of X-ray radiation can cause reversible and irreversible pathologies.
Consequences of X-ray exposure:
Important! Unlike radioactive substances, X-rays do not accumulate in the tissues of the body, which means that there is no need to remove X-rays from the body. The harmful effect of X-rays ends when the medical device is turned off.
The use of X-rays in medicine is permissible not only for diagnostic (traumatology, dentistry), but also for therapeutic purposes:
Radiodiagnostics includes the following methods:
X-ray therapy refers to local treatment methods. Most often, the method is used to destroy cancer cells. Since the effect of exposure is comparable to surgical removal, this treatment method is often called radiosurgery.
Today, x-ray treatment is carried out in the following ways:
These methods are gentle, and their use is preferable to chemotherapy in some cases. Such popularity is due to the fact that the rays do not accumulate and do not require removal from the body, they have a selective effect, without affecting other cells and tissues.
This indicator of the norm of permissible annual exposure has its own name - a genetically significant equivalent dose (GED). There are no clear quantitative values for this indicator.
Today, the following average GZD standards are in effect:
X-ray radiation does not require excretion from the body, and is dangerous only in case of intense and prolonged exposure. Modern medical equipment uses low-energy radiation of short duration, so its use is considered relatively harmless.
Although scientists have only discovered the effect of X-rays since the 1890s, the use of X-rays in medicine for this natural force passed quickly. Today, for the benefit of mankind, X-ray electromagnetic radiation is used in medicine, academia and industry, as well as for the generation of electricity.
In addition, radiation has useful applications in areas such as agriculture, archeology, space, law enforcement, geology (including mining) and many other activities, even cars are being developed using the phenomenon of nuclear fission.
In healthcare settings, physicians and dentists use a variety of nuclear materials and procedures to diagnose, monitor, and treat a wide range of metabolic processes and diseases in the human body. As a result, medical procedures using rays have saved thousands of lives by identifying and treating conditions ranging from overactive thyroid to bone cancer.
The most common of these medical procedures involve the use of rays that can pass through our skin. When an image is taken, our bones and other structures seem to cast shadows because they are denser than our skin, and these shadows can be detected on film or on a monitor screen. The effect is similar to placing a pencil between a piece of paper and a light. The shadow from the pencil will be visible on the sheet of paper. The difference is that the rays are invisible, so a recording element is needed, something like photographic film. This allows doctors and dentists to evaluate the application of X-rays by seeing broken bones or dental problems.
The use of X-ray radiation in a targeted manner for medical purposes, not only to detect damage. When used specifically, it is intended to kill cancerous tissue, reduce the size of a tumor, or relieve pain. For example, radioactive iodine (specifically iodine-131) is often used to treat thyroid cancer, a condition that many people suffer from.
Devices that use this property are also connected to computers and scan, called: computed axial tomography or computed tomography.
These instruments provide doctors with a color image that shows outlines and details of internal organs. This helps physicians detect and identify tumors, abnormal size, or other physiological or functional organ problems.
In addition, hospitals and radiological centers perform millions of procedures annually. In such procedures, doctors fire slightly radioactive substances into the body of patients to look at certain internal organs, such as the pancreas, kidneys, thyroid, liver, or brain, to diagnose clinical conditions.
