Radiation exposure in X-rays

Diagnostic studies using X-rays are still extremely common. In some cases, a doctor simply cannot make a diagnosis without this diagnostic method. And, despite the fact that X-ray equipment and methods are constantly being improved, some harm from the procedure is still present. So how negatively does radiation during X-rays affect the human body? How can adverse effects be minimized and how often is it allowed to repeat the diagnosis? [ 1 ]

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

• 1 Sv is 1 thousand mSv.
• 1 mSv is 1 thousand µSv.
• 1 Sievert is conventionally equal to 100 Roentgens.

What is the radiation exposure during an x-ray?

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

X-rays are 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, making changes at the molecular and atomic level. The consequences of such "intervention" can be both somatic diseases in the patient himself and genetic disorders in the next generation.

Each organ or tissue structure reacts differently to X-rays. The most sensitive to radiation is the red bone marrow. Then come bone tissue, the 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 organs. It is worth noting that the radiation of fluorography is much less than when taking a picture using an old analog device, but the use of a modern digital X-ray procedure is even safer.

Both fluorography and conventional X-rays can be prescribed to 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 physician, who must always weigh the risks of radiation against the potential harm from an incorrect diagnosis or the risk of missing a serious disease - for example, respiratory pathology or a disorder of the mediastinal organs.

What is the radiation dose for an x-ray?

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 new the device, the less harmful radiation it produces. It is safe to say that the latest generations of X-ray equipment are completely safe for the human body.

However, let us present the most average dose rates that a patient receives during diagnostics. It should be noted that the readings for digital and conventional X-ray machines differ significantly.

• Digital fluorograph readings range from 0.03 to 0.06 mSv (the latest digital equipment produces radiation at a dose of 0.002 mSv, which is 10 times less than older models).
• Film fluorography indicators range from 0.15 to 0.25 mSv (the most outdated fluorographs produce radiation from 0.6 to 0.8 mSv).
• X-ray machine readings for chest examination range from 0.15 to 0.4 mSv.
• The indicators for digital dental X-rays (dental radiography) are from 0.015 to 0.03 mSv (conventional non-digital dental X-rays are from 0.1 to 0.3 mSv).

The parameters specified are applicable for one X-ray image. If the patient undergoes diagnostics in several projections, the radiation dosage increases accordingly.

Acceptable radiation dose for x-rays

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

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

For comparison: the average annual natural radiation exposure per inhabitant of the planet is 2.2 µSv, and one hour spent flying on an airplane is equivalent to 10 µSv.

If fluoroscopy (visualization of an image on a monitor) is performed instead of radiography, the emitted radiation is significantly lower, but the total indicator may be higher, which is due to the duration of the diagnostic session. In particular, a 15-minute examination of the chest organs is accompanied by radiation in the amount of 2-3.5 mSv, examination 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 being examined).

If radionuclide diagnostics is carried out using radiopharmaceuticals, the total exposure dose may be 2-5 mSv.

X-ray exposure norm per year

The average annual amount of radiation received from natural sources per person is on average 3 mSv (from 1 to 10 mSv). The permissible amount of exposure received from preventive X-ray examinations is estimated by specialists at 1 mSv, however, many doctors believe that this figure does not correspond to reality and requires correction upwards.

It is important to understand that the specified value is applicable only to preventive X-ray procedures. As for therapeutic diagnostic studies, there is practically no standard here: X-rays are taken as many times as necessary to establish 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 permissible for patients who require systematic X-ray monitoring to receive 100 mSv per year, in particular, patients with oncology, precancerous conditions, congenital defects, and severe injuries.
• It is permissible to receive 20 mSv per year for patients who require thorough diagnostic studies for somatic non-oncopathologies in order to determine the correct treatment tactics and clarify the nuances of the disease.

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

Lethal dose of radiation in roentgens

There is no risk of receiving a lethal dose of radiation during an X-ray examination. This is only possible during man-made accidents or during prolonged stays in a radioactive storage area.

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

The dose of rays received by the body over 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 radiation to the period of exposure, and is designated as Roentgens per hour, Sieverts per hour, or Grays per hour.

If we consider dangerous absorbed amounts of radiation, 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 is 7-10 Gray, then severe radiation sickness with 100% mortality develops. At a dose of 10-15 Gray, a person dies within an average of 20 days. If a radiation dose exceeds 15 Gray, then a fatal outcome is observed within 1-5 days.

Symptoms of X-ray Exposure

A single X-ray irradiation should not be accompanied by any side symptoms. The probability of such pathological signs increases only with prolonged or too frequent examination. 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:
  • reproductive dysfunction;
  • 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.

Radiation exposure during dental x-ray

X-ray diagnostics of teeth is accompanied by a minor radiation load, but it allows the doctor to determine the treatment tactics and identify serious pathologies:

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

Most often in dentistry, targeted X-rays are used - that is, obtaining an image of 1-3 teeth located next to each other. Today, diagnostics are performed using a computer device - a visiograph, and the radiation during the procedure is no more than 1-3 μSv. If an old film device is used, the radiation intensity increases approximately 10 times.

After the visiograph, the orthopantomograph, which produces a flat, expanded image of the entire dental mechanism, is the most widely used. The radiation load during such a study is 35 μSv.

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

Radiation exposure during chest x-ray

Radiation constantly affects people, and small doses of it do not cause harm to health. It is impossible to completely isolate oneself from radiation, since it affects 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 permissible indicator. During fluoroscopy, which is accompanied by a deliberately higher radiation load, the radiation is estimated at 1.4 mSv per minute of examination.

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

Radiation exposure in digital x-ray

The introduction of a digital ionizing radiation detector into modern X-ray machines has made it possible to display images directly on the monitor screen, without quality errors. At the same time, the degree of radiation that a patient receives during diagnostics has decreased. Today, digital X-rays are an improved alternative to X-ray equipment. Its efficiency is more than 10% higher when compared to the analog version of the image: the image is clearer. The only drawback is the relatively high cost of the equipment.

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

Radiation Dose for Spinal X-ray

An X-ray of the spinal column allows you to evaluate its structure, condition and, to some extent, functionality. Thanks to the image, 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 are determined. It is also possible to evaluate the structural features of the bone vertebral tissue, the thickness and density of the cortex, detect manifestations of osteoporosis, tumors, destructive-dystrophic processes, metabolic disorders.

To make the diagnostic image more objective, the X-ray is performed in two projections:

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

It is possible to simultaneously examine the entire spinal column or its sections:

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

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

When performing a computed tomography scan of the spinal column, the load increases to 6 mSv.

Radiation Dose for Chest X-Ray

Chest X-ray is probably the most frequently prescribed. The examination can be represented by fluorography, analog or digital radiography. The average radiation dose is about 0.1 mSv, but this figure may vary in one direction or another depending on the type of device and its age.

For preventive purposes, specialists recommend using fluorography (even better - the digital version). If you need to examine the chest organs well, it is better to resort to radiography.

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

It is not recommended to take more than 1-2 images per day (the exception is computed tomography, where a series of images 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 radiation load received.

Radiation exposure during x-ray of the stomach

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

During fluoroscopy, a specialist can observe an image of an organ in real time on a special monitor. The device takes a series of pictures demonstrating the dynamics of the contrast agent transport.

Despite the fairly significant radiation load – about 6 mSv – doctors note that patients should not be afraid of radiation. This dose is diagnostically justified and does not have a detrimental effect on human health.

Radiation Dose for Colon X-Ray

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

Otherwise, colon fluoroscopy is called irrigoscopy. During the procedure, the patient is given a series of images after a contrast agent with barium is introduced into the intestine. The diagnostic method allows detecting intestinal development defects, tumor processes, fistulas, chronic inflammatory pathologies, and diverticulitis.

As with other examinations, the doctor decides whether to send the patient for an X-ray of the intestine or to prescribe a colonoscopy. Colonoscopy, unlike X-rays, does not have a radiation load. This is an endoscopic procedure during which the doctor examines the inner surface of the intestine using an endoscope. Both the first and second diagnostic methods have their advantages and disadvantages. However, the choice is decided based on the indications and on an individual basis.

Radiation Dose for Sinus X-rays

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

The radiation load when taking a picture is about 1 mSv. The recommended frequency of diagnostics is up to 2-3 times a year.

Depending on the indications, the doctor may prescribe magnetic resonance imaging or ultrasound instead of x-ray.

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

Radiation Dose for Hip X-Ray

X-rays of the hip joint are prescribed to detect diseases and conditions affecting either the joint itself or the tissues adjacent to it:

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

The effective dose during an X-ray of the hip joint is on average 1.47 mSv. To protect the patient from residual radiation during the procedure, special lead aprons and pads are used. In some X-ray rooms, it is possible to adjust the irradiated field, precisely targeting the area being examined, without affecting other parts of the body.

Typically, a hip joint image is taken in two projections: direct (anterior-posterior) and lateral.

X-ray irradiation during pregnancy

During pregnancy, it is possible to undergo an X-ray examination, but only if certain conditions are met:

• avoid radiation in the first trimester;
• use only digital X-rays, which have a minimal radiation load;
• Cover the areas not being examined and the abdomen with special lead pads that block scattered radiation.

If you follow these rules, the likelihood of harm to the future child becomes negligible. The results of one study showed that prenatal radiation in low doses can increase the risk of cancer in children. In addition, it is important to understand that such diagnostics are prescribed to pregnant and lactating women only if there are indications. In this case, the procedure is not performed for preventive purposes. Preference is given to alternative diagnostic options - for example, ultrasound examination.

To avoid complications, a pregnant or breastfeeding woman must inform her doctor about her condition. Depending on this, the doctor may cancel, postpone or replace the diagnostic procedure to reduce possible risks.

Most epidemiological studies of paternal preconception diagnostic radiation exposure have found no association with childhood cancer risk.[ 4 ],[ 5 ]

X-ray radiation dose to a child

X-rays can be administered to children of all ages, provided there are indications. The main benefit of this type of examination is that the diagnostic accuracy justifies the risks associated with radiation exposure. However, there are certain conditions. It is difficult to determine whether a significant reduction in diagnostic medical radiation exposure will result in a reduction in overall childhood cancer rates or specific forms of childhood cancer. [ 6 ]

Thus, to reduce the likelihood of harm to children's health, X-rays are performed using the lowest radiation dose that allows for acceptable image quality.

The X-ray method allows:

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

Preventive use of X-rays is permitted only from the age of 14.

Consequences of X-ray exposure

The most common and formidable complication affecting the organs of hematopoiesis is blood diseases. A person may develop:

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

Other possible pathologies include:

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

The harm of X-ray radiation appears only with intensive and prolonged exposure. Usually, medical equipment 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 exposure to X-rays in their usual use can increase the risk of long-term 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 capable of accumulating and forming radioactive substances, much less emitting them later.

How to remove radiation after an x-ray?

After a regular X-ray or fluorography procedure, X-rays do not accumulate in the tissues, so there is no need to remove anything from the body. However, if a person has undergone scintigraphy, during which special drugs containing radioactive substances were introduced into the body, then some preventive measures should still be taken:

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

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

Where is there more radiation: CT or X-ray?

CT is a study that lasts several minutes and takes a series of images sequentially, reflecting the layer-by-layer state of tissues. This procedure provides the doctor with detailed information about the skeletal system, blood vessels, soft tissues, so it is more informative than a regular X-ray.

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

Where is there more radiation: X-ray or fluorography?

Radiography and fluorography have different radiation loads. Thus, during fluorography, the patient's body is exposed to radiation, but not in such a large dose as during film (analog) radiography. But digital X-ray is safer than fluorography, and the more modern the diagnostic equipment, the less load it gives to the body.

In general, the fluorographic method is used mainly for preventive and routine examinations - for example, when it is necessary to determine the probability of developing malignant and tuberculous processes in patients. Such a procedure, in the absence of individual contraindications, can be safely repeated annually. However, this diagnostic method is still less informative, unlike X-rays, which are carried out only according to indications due to the high radiation load. Therefore, when choosing the most suitable type of diagnostics, it is important to consider a number of factors, including the probable radiation exposure during X-rays. If possible, it is better to choose a digital device: it is both safe and informative.