Irradiation with x-rays

, medical expert
Last reviewed: 12.03.2022

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Diagnostic studies using x-rays are still extremely common. In some cases, without this diagnostic method, the doctor simply will not be able to make a diagnosis. And, despite the fact that X-ray equipment and techniques are constantly being improved, however, some harm from the procedure is still present. So how negatively does X-ray exposure affect the human body? How to minimize the adverse impact and how often is it allowed to repeat the diagnosis? [1]

The unit of measurement of the dose of ionizing radiation is Sievert (Sv, Sv), which reflects the amount of energy that is absorbed by 1 kg of biological tissue and is equal in effect to the absorbed dose of γ-radiation in 1 Gray.

  • There are 1 thousand mSv in 1 Sv.
  • 1 mSv is 1000 µSv.
  • 1 Sievert is conditionally equal to 100 Roentgens.

What is the radiation exposure for x-rays?

X-rays are a stream of electromagnetic oscillations having a length that is in the range between ultraviolet and γ-rays. This wave variety has a specific effect on the human body.

X-ray is an ionizing radiation with high penetrating properties. It can indeed be dangerous to humans, but the degree of this danger depends on the dose received.

When passing through the tissue structures of the body, X-rays ionize them, make changes at the molecular and atomic level. The consequences of such an “intervention” can be both somatic diseases in the patient himself and genetic disorders in the next generation.

One or another organ or tissue structure reacts differently to x-rays. The most sensitive to radiation exposure is the red bone marrow. This is followed by bone tissue, thyroid gland, mammary glands, lungs, ovaries and other organs.

Fluorography can be called a kind of express X-ray diagnostics, which is used to detect pathologies of the respiratory system. It is worth noting that the exposure of fluorography is much less than when taking an image using an old analog device, but using a modern digital x-ray procedure is even safer.

Both fluorography and conventional x-rays can be prescribed for both adults and children - if there are clear indications, complaints, clinical symptoms or injuries, to clarify the diagnosis and determine treatment tactics.

Based on the results of such studies, the doctor is able to assess structural changes in tissues, identify anatomical changes, and developmental defects.

The frequency of x-rays is determined only by the doctor, who must always balance the risks of exposure with the likely harm from a misdiagnosis or the threat of missing some serious disease - for example, respiratory pathology or mediastinal disorders.

What is the radiation dose for x-rays?

The degree of absorbed radiation during each x-ray examination is not always the same. First of all, it depends on the type of diagnostics, as well as on the “age” of the X-ray equipment, on the working load volume.

The more modern and newer the device, the less harmful radiation it produces. We can safely say that the latest generations of X-ray technology are completely safe for the human body.

Nevertheless, we present the most average doses that a patient receives during diagnosis. At the same time, you need to pay attention to the fact that the indications for digital and conventional X-ray devices differ significantly.

  • The indicators of a digital fluorograph are from 0.03 to 0.06 mSv (the latest digital equipment produces radiation at a dose of 0.002 mSv, and this is 10 times less than older models).
  • Film fluorography indicators are from 0.15 to 0.25 mSv (the most outdated fluorographs give radiation from 0.6 to 0.8 mSv).
  • Indicators of the X-ray apparatus in the study of the chest from 0.15 to 0.4 mSv.
  • Indicators for digital dental X-ray (dental radiography) from 0.015 to 0.03 mSv (regular non-digital X-ray - from 0.1 to 0.3 mSv).

The specified parameters are applicable for one x-ray image. If the patient is diagnosed in several projections, then the dosage of radiation, respectively, increases.

Permissible radiation dose for x-rays

On average, a patient receives the following dose of radiation:

  • with computed tomography of the pelvic and abdominal organs - 10 mSv
  • with computed tomography of the head - 2 mSv
  • with computed tomography of chest organs - 7 mSv
  • with chest x-ray - 0.1 mSv
  • with X-ray of the spinal column - 1.5 mSv
  • with dental x-ray - 0.005 mSv

For comparison: the average annual natural exposure per inhabitant of the planet is 2.2 μSv, and one hour spent in an airplane flight is equal to 10 μSv.

If not radiography is performed, but fluoroscopy (visualization of the image on the monitor), then the emitted radiation is much smaller, but the total figure may be greater, due to the duration of the diagnostic session. In particular, a 15-minute study of the chest organs is accompanied by irradiation in the amount of 2-3.5 mSv, a study of the digestive system - 2-6 mSv. During computed tomography, doses of 1-11 mSv are used (which depends on the date of manufacture of the X-ray machine and the organ under study).

If radionuclide diagnostics is carried out using radiopreparations, then the total exposure dose can be 2-5 mSv.

X-ray exposure per year

The average annual amount of exposure received from natural sources per person is on average 3 mSv (from 1 to 10 mSv). The allowable amount of load received from preventive X-ray studies is estimated by experts at 1 mSv, however, many doctors believe that this figure is not true and needs to be corrected upwards.

It is important to understand that the indicated value applies only to preventive X-ray procedures. As for therapeutic diagnostic studies, there is practically no norm here: X-rays are taken as many times as necessary to make a correct diagnosis and prescribe effective treatment. That is, this number is not limited. There are practical recommendations for different categories of sick people:

  • It is acceptable to receive 100 mSv per year for patients who need systematic X-ray monitoring - in particular, patients with oncology, precancerous conditions, congenital malformations, and severe injuries.
  • It is acceptable to receive 20 mSv per year for patients who need thorough diagnostic studies for somatic neo-oncopathologies in order to determine the correct treatment tactics and clarify the nuances of the disease.

Despite this, without indications, computed tomography, radiography, and scintigraphy should not be performed.

Lethal dose of radiation in roentgens

There is no danger of receiving a lethal dose of radiation during an x-ray examination. This is possible only during man-made accidents, or during a long stay in the area of storage of radioactive substances.

It is believed that the lethal amount of X-ray exposure is from 6-7 Sv/h and above. However, not only such a high dose is dangerous: regular exposure to a smaller amount of radiation can also lead to problems - for example, provoke cell mutation.

The dose of rays received by the body for a certain period of time (for example, per hour) is called the dose rate. This indicator is calculated as the ratio of the amount of exposure to the period of exposure, and is denoted by Roentgens per hour, Sievert per hour or Gray per hour.

If we consider dangerous absorbed amounts of radiation, then it is generally accepted that the development of radiation sickness starts at a dose of 1 Gray, if it is received in a short period of time (no more than 96 hours). If the dose was 7-10 Gray, then severe radiation sickness develops with one hundred percent mortality. At a dose of 10-15 Gray, human death occurs within an average of 20 days. If a radiation dose exceeding 15 Gray is received, then a lethal outcome is observed within 1-5 days.

Symptoms of X-Ray Exposure

A single X-ray exposure should not be accompanied by any side symptoms. The likelihood of the appearance of such pathological signs increases only with prolonged or too frequent research. Theoretically, the following symptomatic series can be distinguished:

  • Short term effects:
    • headache;
    • dizziness, nausea, vomiting;
    • diarrhea;
    • general weakness;
    • skin reactions;
    • sore throat;
    • decrease in the number of blood cells (due to suppression of bone marrow function).
  • Long term effects:
    • violation of reproductive function;
    • decreased hormonal activity of the thyroid gland;
    • cataract.

It is important to understand that the appearance of any symptoms after an x-ray is an exception to the rule. This is observed extremely rarely and in exceptional cases.

Irradiation during x-ray of the tooth

X-ray diagnostics of teeth is accompanied by a slight radiation exposure, however, it provides an opportunity for the doctor to determine the tactics of treatment and identify serious pathologies:

  • determine the depth of carious lesions, periodontitis, pulpitis;
  • find hidden cavities;
  • control the quality of the procedure performed - in particular, during the treatment of root canals, etc.

Most often in dentistry, targeted x-rays are used - that is, obtaining an image of 1-3 teeth located nearby. To date, diagnostics are performed using a computer device - a visiograph, and the exposure during the procedure is no more than 1-3 μSv. If an old film apparatus is used, then the irradiation intensity increases by about 10 times.

After the visiograph, the orthopantomograph is the leader in terms of the prevalence of use, performing a flat unfolded image of the entire dentoalveolar mechanism. The exposure load in this study is 35 μSv.

It is also possible to perform maxillofacial CT: in this case, the exposure is estimated at 45-60 μSv.

Irradiation with X-ray of the lungs

Radiation constantly acts on people, and its small doses do not cause harm to health. It is impossible to completely isolate yourself from radiation, since it acts from the external environment: from the earth's crust, water, air, etc. For example, the natural radiation background is approximately 2 mSv per year.

During a chest X-ray, the patient receives only about 0.1 mSv, which not only does not exceed, but is much less than the allowable indicator. In the course of fluoroscopy, which is accompanied by a deliberately greater radiation exposure, exposure is estimated at 1.4 mSv per minute of examination.

The degree of radiation may vary, depending on the applicable x-ray equipment. More modern devices are much less dangerous. But even relatively old technology uses low-energy x-rays, and their impact is extremely short. Given this, even with repeated exposure, they are considered harmless to patients.

Irradiation with digital x-ray

The introduction of a digital ionizing radiation detector into modern X-ray machines made it possible to display an image directly on the monitor screen, without qualitative errors. At the same time, the degree of radiation received by the patient during the diagnosis also decreased. Today, digital X-ray is an improved alternative to X-ray technology. Its efficiency is more than 10% higher when compared with the analog version of the image: the picture is clearer. The only negative is the relatively high cost of the equipment.

The effective equivalent dose received during digital fluorography is, on average, an indicator of 0.04 mSv. This is many times less than any person receives from natural sources of ionizing radiation, and much less than the permissible degree of exposure when performing a preventive X-ray examination. [2], [3]

Radiation dose for x-ray of the spine

X-ray of the spinal column allows you to evaluate its structure, condition and, to some extent, functionality. Thanks to the picture, you can evaluate the shape of the spine, determine the presence of curvatures (physiological - lordosis and kyphosis, or pathological - scoliosis), fractures. The integrity of the vertebrae, arches and processes, their symmetry is determined. It is also possible to evaluate the structural features of the bone vertebral tissue, the thickness and density of the cortical layer, to detect manifestations of osteoporosis, tumors, destructive-dystrophic processes, and metabolic disorders.

To make the diagnostic picture more objective, x-rays are performed in two projections:

  • direct (the patient lies on his back);
  • lateral (oblique).

It is possible to simultaneously study the entire spinal column, or its departments:

  • cervical region;
  • thoracic;
  • lumbosacral or coccygeal region.

Depending on the scale of the study and the number of images, the radiation exposure will be determined. On average, its values are about 1.5 mSv.

During computed tomography of the spinal column, the load increases to 6 mSv.

Radiation dose for chest x-ray

A chest x-ray is probably the most commonly ordered. The study can be represented by fluorography, analog or digital radiography. The average radiation dose in this case is about 0.1 mSv, but this figure may differ in one direction or another depending on the type of device, its age.

For preventive purposes, experts recommend using fluorography (even more preferably, a digital version). If you need a good look at the organs of the chest, then it is better to resort to x-rays.

Doctors note that it is possible to protect organs that are not being examined with the help of a protective screen - a plate equipped with a lead layer. Such protection is most often worn on the stomach, neck, genitals, head. Young people and women of reproductive age should be protected from irradiation of the genital area and abdominal cavity. It is preferable for children to cover the entire body, except for the directly examined area.

It is not recommended to take more than 1-2 shots per day (the exception is computed tomography, where a series of shots is indispensable). It is also important for the patient to have a radiation book, where the radiologist regularly enters data on the date of the examination and the received radiation exposure.

Irradiation with X-ray of the stomach

X-ray of the stomach with contrast is a common method for diagnosing various pathologies and functional disorders of the digestive system. Plain X-ray may not always provide enough information to determine the diagnosis, because the stomach is a hollow organ. To assess its condition, shape, size, position, contrast fluoroscopy is necessary. This procedure requires the introduction of a contrast agent into the digestive tract - a suspension of barium sulfate.

During fluoroscopy, a specialist can observe the image of the organ in real time on a special monitor. At the same time, the device takes a series of images that demonstrate the dynamics of the transport of the contrast agent.

Despite the fairly significant radiation exposure - about 6 mSv - doctors note that patients should not be afraid of exposure. This dose is diagnostically sound and does not adversely affect human health.

Radiation dose for x-ray of the intestine

The effective radiation dose during an x-ray of the large intestine is 6 mSv, and an x-ray of the upper gastrointestinal tract and small intestine is up to 8 mSv.

Otherwise, fluoroscopy of the large intestine is called irigoscopy. During the procedure, the patient is taken a series of pictures after the introduction of a contrast agent with barium into the intestine. The diagnostic method allows to detect defects in the development of the intestine, tumor processes, fistulas, chronic inflammatory pathologies, diverticulitis.

As with other studies, the doctor decides whether to send the patient for an intestinal fluoroscopy or to prescribe a colonoscopy. Colonoscopy, unlike x-rays, does not have radiation exposure. This is an endoscopic procedure in which the doctor examines the inside of the intestines with an endoscope. Both the first and second diagnostic methods have their advantages and disadvantages. However, the issue of choice is decided according to indications and on an individual basis.

Radiation dose for x-ray of the sinuses

X-rays of the sinuses are often prescribed for persistent headaches, facial injuries, persistent nasal congestion, purulent discharge and systematic nosebleeds. The study helps to diagnose pathologies such as neoplasms (benign or malignant), ethmoiditis, frontal sinusitis, sinusitis, damage to the bone walls.

Radiation exposure during imaging is about 1 mSv. The recommended frequency of diagnostics is up to 2-3 times a year.

According to indications, the doctor may prescribe magnetic resonance imaging or ultrasound instead of radiography.

If computed tomography of the sinuses is performed, then the radiation exposure rises to 6 mSv. However, it should be taken into account that CT allows the doctor to more carefully examine the affected lesion in a layered image, which will give an accurate picture of the pathological process and help make the correct diagnosis.

Radiation dose for x-ray of the hip joint

X-ray of the hip joint is prescribed to identify diseases and conditions affecting either the joint itself or adjacent tissues:

  • traumatic hip dislocation;
  • fracture of the femoral neck (a very common injury in old age);
  • hip dysplasia or congenital dislocation (diagnosed in children);
  • degenerative-dystrophic pathologies (deforming arthrosis, coxarthrosis);
  • placement of an artificial joint prosthesis (hip arthroplasty).

The effective dose during an x-ray of the hip joint is 1.47 mSv on average. To protect the patient from residual radiation during the procedure, special lead aprons and linings are used. Some x-ray rooms have the ability to adjust the irradiated field, precisely targeting the area under examination, without affecting the rest of the body.

As a standard, a picture of the hip joint is performed in two projections: direct (anterior-posterior) and lateral.

X-ray exposure during pregnancy

During pregnancy, an X-ray examination is possible, but subject to certain conditions:

  • avoid radiation in the first trimester;
  • use only digital x-rays that provide minimal radiation exposure;
  • cover unexplored areas and the abdomen with special lead pads that block scattered radiation.

If you follow these rules, then the likelihood of harm to an unborn child becomes scanty. One study found that low-dose prenatal exposure may increase the risk of cancer in children. [4]In addition, it is important to understand that such diagnostics are prescribed for pregnant and lactating women only if indicated. With a preventive purpose, the procedure in this case is not carried out. Preference is given to alternative diagnostic options - for example, ultrasound.

To avoid complications, a woman who is pregnant or breastfeeding should definitely inform the doctor about her situation. Depending on this, the doctor may cancel, postpone or replace the diagnostic procedure in order to reduce the likely risks. 

Most epidemiological studies of pre-conceived paternal diagnostic exposure have not found an association with childhood cancer risk. [5], [6]

X-ray dose of radiation to a child

X-rays can be prescribed to children regardless of age - of course, if there are indications for this. The main advantage of such a study is that the accuracy of the diagnosis justifies the risks associated with radiation exposure. However, there are certain conditions. It is difficult to ascertain whether significant reductions in diagnostic medical exposure are associated with reductions in rates of general childhood cancer or specific forms of childhood cancer. [7]

So, to reduce the likelihood of damage to children's health, X-rays are performed using the lowest irradiation dose, which allows obtaining an acceptable image quality.

X-ray method allows:

  • detect diseases of the internal organs and the skeletal system;
  • find hidden pathological processes - in particular, bone-infectious lesions, tumors, fluid accumulations;
  • monitor the quality of the surgical intervention and the dynamics of treatment.

Prophylactic use of x-rays is allowed only from the age of 14.

Consequences of X-ray exposure

The most frequent and formidable complication affecting the hematopoietic organs is blood diseases. A person may develop:

  • reversible disorders of the blood composition in response to small amounts of x-ray exposure;
  • leukemia - a decrease in the number of leukocytes with their structural changes, which entails general disorders in the body, a decrease in immune defense, etc.;
  • thrombocytopenia - a drop in the level of platelets - blood cells responsible for clotting processes;
  • hemolytic disorders - occur under the influence of large radiation doses and are manifested by the breakdown of hemoglobin and red blood cells;
  • erythrocytopenia - a decrease in the level of red blood cells, resulting in tissue oxygen deficiency (hypoxia).

Other possible pathologies include:

  • malignant processes;
  • premature start of age-related changes;
  • development of cataracts due to damage to the eye lens.

The harm of X-ray irradiation appears only with intense and prolonged exposure. Usually, medical technology involves the use of low-energy radiation of short duration, so periodic diagnostics can be considered relatively safe.

According to experts, a single episode of X-ray exposure in its usual use can increase the risk of late onset of malignant complications by only 0.001%. In addition, not many people know that, unlike radioactive exposure, the harmful effects of X-rays cease immediately after the X-ray device is turned off. The human body is not able to accumulate and form radioactive substances, and even more so, subsequently emit them.

How to remove radiation after x-ray?

After a conventional x-ray or fluorography procedure, x-rays do not accumulate in the tissues, so there is no need to remove anything from the body. If a person underwent scintigraphy, during which special preparations containing radioactive substances were introduced into the body, then some preventive measures should still be taken:

  • during the day drink plenty of pure water, green tea;
  • upon arrival home after the procedure, drink a glass of milk or a little dry red wine;
  • add freshly squeezed juices, honey, seaweed, beets and nuts, dairy products (sour cream, cottage cheese, kefir, etc.) to the diet.

Toward evening it is good to take a walk - for example, in the park, square, along the river bank. Such simple measures will speed up the removal of harmful substances from the body.

Where is the exposure more: CT or X-ray?

CT is a study that lasts several minutes and takes a series of images in sequence, reflecting the layered state of the tissues. This procedure provides the doctor with detailed information about the skeletal system, blood vessels, soft tissues, and therefore is more informative than a conventional x-ray.

However, with computed tomography, the device performs more images than with radiography, and the effective radiation dose is 2-10 mSv, which depends on the duration of the diagnostic session and on which organ is being examined. Therefore, when choosing one or another type of diagnostics, one should carefully weigh all the pros and cons, evaluate the possible damage to health and the positive effect of the information obtained during the study.

Where is more exposure: X-ray or fluorography?

Radiography and fluorography have different radiation exposure. So, during fluorography, the patient’s body, although exposed to radiation, is not in such a large dosage as during film (analogue) radiography. But digital X-ray is safer than fluorography, and the more modern the diagnostic device, the less it puts a burden on the body.

In general, the fluorographic method is used mainly for preventive and planned studies - for example, when it is necessary to determine the likelihood of developing malignant and tuberculous processes in patients. Such a procedure, in the absence of individual contraindications, is safe to repeat annually. However, this diagnostic method is still less informative, unlike X-ray, which is performed only according to indications due to the high radiation exposure. Therefore, when choosing the most appropriate type of diagnosis, it is important to take into account a number of factors, including the likely exposure to x-rays. If possible, it is better to choose a digital device: it is both safe and informative.

Translation Disclaimer: The original language of this article is Russian. For the convenience of users of the iLive portal who do not speak Russian, this article has been translated into the current language, but has not yet been verified by a native speaker who has the necessary qualifications for this. In this regard, we warn you that the translation of this article may be incorrect, may contain lexical, syntactic and grammatical errors.

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