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X-Rays - Properties, Uses, and Risks

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5 min read


X-rays are an imaging procedure used to look at the structures inside your body. Read this article to learn about X-rays.

Written by

Dr. Narmatha. A

Medically reviewed by

Dr. Muhammad Shoyab

Published At October 17, 2022
Reviewed AtOctober 17, 2022


An X-ray or X- radiation is high-energy electromagnetic radiation that produces images of the body. They can pass through the body structures onto the special plates, which produce “negative” type pictures. X-ray is referred to as Rontgen radiation, named after the scientist Wilhelm Conard Rontgen, who discovered it. The more solid structures of the body appear whiter in the film. The soft tissues in the body, such as skin, blood, and muscle, allow most of the X-rays to pass through and appear dark gray on the film or the screen. Hard tissues such as bone or tumors allow only a few of the X-rays to pass through and appear white on the film. The air present in the lungs appears black in the X-ray film.

Computed radiography is the digital replacement of conventional X-ray film radiography. It uses x-ray sensitive photo-stimulable phosphor plate (imaging plate) to create a digital image. It eliminates the use of conventional X-ray film. Digital radiography is another form of radiography that uses x-ray sensitive image plates to produce a digital radiographic image on a computer.

What Are the Properties of X-Rays?

X-rays are electromagnetic energy. They are produced by energy changes in electrons external to the nucleus, which moves from higher energy level to lower level causing excess energy to be released. X- rays have enough energy to break up molecules and thus damage living cells. They have a wavelength ranging from 10 picometers to 10 nanometers, and the frequencies range from 30 petahertz to 30 exahertz. The energies of X-ray range from 145eV to 124keV. The wavelengths of X-rays are shorter than UV rays and longer than those of gamma rays.

What Are the Uses of X-Ray?

X-rays are widely used in many fields such as medical, industrial, and research. Diagnostic medical X-rays are the most common way of exposure in your lifetime. X-ray is used to examine different parts of the body.

Bones and Teeth:


  • Lung infections and diseases such as pneumonia (an infection that inflames the air sacs of the lungs), lung cancer, pulmonary edema (collection of excessive fluid in the lungs), and tuberculosis.

  • Breast cancer.

  • Enlarged heart, a sign of congestive cardiac failure (a condition in which the heart fails to pump blood properly) is clearly shown on X-rays.

  • Blocked blood vessels (injecting contrast material may provide detailed images of your circulatory system).


  • Accidental swallowing of objects in children and adults can be viewed clearly with the help of X-rays.

  • Digestive tract problems (swallowing barium may reveal digestive tract problems).

  • Intestinal obstruction.

  • Free fluid in ascites (collection of fluid in the abdominal cavity).

  • Free air from visceral perforation (presence of a hole in the gastrointestinal tract).

  • Gallstones.

  • Kidney stones.

What Are the Factors to Be Considered Before Taking X-rays?

  • Pregnancy - Inform your technician if you are pregnant. Radiation exposure will cause birth defects to the fetus in the womb.

  • Breastfeeding - If you are breastfeeding women, you may be instructed not to feed for about 24 hours after the scan because the contrast material may pass through the breast milk.

  • Kidney Diseases - You should inform your doctor if you are having kidney failure or other kidney disorders.

How Is an X-Ray Taken?

  • The patient might be asked to remove any clothing or jewelry which might interfere with the imaging process and to wear the hospital gown.

  • The patient is positioned between the X-ray machine and cassette containing x-ray film or specialized plate. Other body parts not being imagined may be covered with a lead apron which prevents unnecessary radiation exposure.

  • Patients will be asked not to move during imaging which may affect the image quality. They may ask to hold their breath for a few seconds at varying times to produce clear images.

  • Once you are ready, the X-ray machine will produce a safe level of X-ray beam that will be targeted into the area to be examined. Depending on the parts of the body to be examined, X-rays will be taken at different angles.

  • A chest X-ray may be taken from front, back, sides, etc.. This procedure usually takes just a few minutes for simple X-rays and a longer time for an imaging technique that uses contrast material.

  • If the patient is a child, the caretaker or one of the parents may be allowed to stay in the room. They must wear a lead apron to prevent radiation exposure. If the child is not cooperative, they might use restraints or other techniques to hold them in place during imaging. It does not harm your child. It prevents your children from increased radiation exposure by repeating the process.

  • Once an X-ray is taken, the images will be displayed on the computer screen within minutes. The conventional X-ray technique requires developing the film to get the images. After your X-ray, you can continue your regular diet and activities.

Contrast Material:

Before some type of X-rays, you may be asked to swallow contrast material, or it may be injected into your vein through an intravenous (IV) line. Contrast materials are special dyes such as barium and iodine used to outline the body structures to be examined. After scanning with contrast, you may be asked to drink plenty of water to flush out the contrast materials from the body. However, contrast materials are not used with most X-rays.

What Are the Different Types of Medical X-Rays?

  1. Projectional Radiography: Projectional radiography is also called conventional radiography, which produces two-dimensional images of the structures by X-ray radiation. Plain radiography or roentgenography refers to projectional radiography, which does not use any advanced techniques such as computed tomography that produces three-dimensional (3D)images. Plain radiography produces single static images and does not use any contrast materials in imaging.

  2. Computed Tomography: Computed tomography (CT) is a specialized imaging technique used to examine different structures of the body. In a CT scan, the X-ray beam is projected to the targeted area. The scanner detects this and transfers it to the computer. The computer processes the information into two-dimensional images (slices), which will then be arranged into three-dimensional images on the screen.
  3. Fluoroscopy: Fluoroscopy is an imaging technique used to get moving images of the internal structures of the patient. In fluoroscopy, the patient is placed between the X-ray source and the fluorescent screen. X-ray beams passed through the body will be absorbed based on the type of tissue, which produces an image on the fluorescent screen.

What Are the Typical Values of X-Ray Doses Used in Medical Imaging?

Typical values of effective dose for various medical X-rays are:

  • Dental- Intraoral - 0.008/mSv (millisievert).

  • Dental- Orthopantomogram - 0.014/mSv.

  • Chest radiography - 0.025/mSv.

  • Limbs and joints - 0.07/mSv.

  • Head (+eye,+jaw,etc.,) - 0.07/mSv.

  • Cervical spine - 0.2/mSv.

  • CT pelvimetry - 0.32/mSv.

  • Screening mammography - 0.4/mSv.

  • Pelvis/hip - 0.6/mSv.

  • Abdomen - 1/mSv.

  • Chest fluoroscopy - 1/mSv.

  • Cerebral angiography - 2/mSv.

  • Lumbar spine- 2/mSv.

  • Head CT - 2.6/mSv.

  • Urography - 3/mSv.

  • Upper gastrointestinal - 3/mSv.

  • Lower intestinal - 6/mSv.

  • Cardiac angiography - 7/mSv.

  • Body CT - 10.6/mSv.

What Are the Risks Associated With X-Rays?

Radiation Exposure - Ionizing radiation can damage your DNA and cause cancer. The risks of developing deadly cancer in CT scans are about 1 in 2000. The risk may increase with every X-ray exposure in a lifetime. Sensitivity to radiation depends on the age of the patient. Ionizing radiation is more harmful to children as they are growing. You should discuss with your doctor the benefits and potential risks of an x-ray before the scan.

Allergic Reactions to the Contrast Material- Side effects of iodine contrast are:

  • Itching.

  • Headache.

  • Hives (skin rashes).

Some of the severe symptoms of contrast materials are:

  • Breathing difficulties.

  • Hypotension (low blood pressure).

  • Swelling of the body parts.

How to Limit Radiation Exposure During an X-Ray?

Diagnostic X-rays provide necessary information about the disease in patients that helps your health provider to treat the condition appropriately. The rate of getting cancer from radiation exposure is typically less than 0.01 percent. Usage of a lead apron will minimize the radiation exposure to sensitive body parts. Modern X-ray equipment has features that can limit the dose and area irradiated. ALARA (as low as reasonably achievable) is a radioprotection principle which means that, even if it is a small dose, and it has no direct benefit, you should try to avoid it.


An X-ray is a painless, quick test used in medical diagnosis. X-rays are also used as a guiding tool in biopsy and treatment procedures. The radiation exposure from an X-ray is low, and the benefits from these tests are more significant than the risks. X-rays are even used in the screening of cancer which prevents them by treating them earlier.

Frequently Asked Questions


What Are the Significant Harmful Effects of Radiation?

Radiation could damage the DNA present in the cells. Moreover, exposure to extremely high degrees of radiation, like close to an atomic blast, could result in the following effects.

- Acute radiation syndrome or radiation sickness.

- Skin burns.

- Long-term effects like cardiovascular illnesses and cancer.


How Much Radiation Is Considered Harmful?

The individual radiation exposure limit for the radiation workers accounted for over five years is about 100 mSv. The safest radiation exposure limit for people of the general public is 1 mSv per year. According to research and studies, short-term radiation dose between 2 and 10 sieverts is considered harmful as they could cause severe degrees of radiation sickness with raised possibilities of being fatal.


Which Is the Safest Type of Radiation?

The safety and harmful profile of radiation depends on whether the exposure is external or internal. The other significant factors also alter the safety profile of radiation exposure. However, according to radiation therapies, a kind of radiation therapy called proton beam radiation treatment might be safer and serve efficacy similar to traditional radiation therapy.


How to Limit Radiation?

The following ways could help limit radiation exposure.

- Distance limits radiation exposure. The radiation dose reduces markedly as one increases the distance from the source.

- Shielding is a crucial method to limit radiation. Barriers include lead, water, and concrete contribute to effective protection from penetrating gamma rays.


How Does a Radiographer Minimize Radiation Exposure to the Patient?

The radiographer minimizes the radiation exposure to the patient in the following ways:

- Customizing the X-ray scanning according to the size and weight measure of the patient or the part of the body that is about to be scanned.

- Elimination of unnecessary X-ray examinations.

- Investing in the latest software and hardware tools in Computerized Tomography (CT) scans.


How Deep to Evade Radiation?

Deeper places could avoid radiation to a certain extent. An underground shelter covering about one meter or three feet and more of the earth's space contributes to effective protection in case of fallout radiation. Certain unoccupied structures, including caves, tunnels, and stone buildings covered by one meter or more, could be deep to evade radiation.


Which Radiation Is Significantly Damaging?

There are three types of radiation: alpha, beta, and gamma. Of these, gamma rays are considered the most harmful hazard externally. This is because gamma and their associated X-rays could pass through an individual, damaging cells in their access paths. While the beta particle could partially penetrate the skin tissue resulting in beta burns. And alpha particles could not penetrate the intact outer layer of the skin tissue.


Can Mirrors Absorb Radiation?

Mirrors do not absorb radiation but reflect it. According to the definition, mirrors are objects that substantially reflect electromagnetic radiation. Mirrors reflect electromagnetic radiation of distinct wavelengths. Clinical research states that a typical mirror object constitutes a silver layer that reflects a variety of radiation, such as visible light. Nevertheless, unlike X-rays and optical lights, gamma X-rays are neither captured nor reflected by mirrors.


Do X-Rays Pass Through Diamonds?

The penetration of X-day radiation in the diamonds significantly depends upon the properties of diamonds. Diamonds constituting low atomic numbers are specifically transparent to X-rays. Nevertheless, the X-ray penetration and procedures seem workless in the case of the purest of diamonds since stones generally do not radiate X-ray light. The object's density matters when it comes to the penetration of X-rays.


Does Radiation Pass Through Plastic?

The object's density matters when it comes to the penetration of X-rays. No such X-ray technology can detect all forms of plastic. Hence, plastic has no visibility under visible light and X-ray radiation unless there is a significant modification in the plastic form to make it opaque compared to the surrounding objects. This is because the X-day radiation passes through objects of higher density.


Which Is the Strongest to Weakest Radiation?

There are three significant types of X-ray particles: alpha, beta, and gamma. Alpha, beta, and gamma are high-energy particles that generally travel in a straight line. The alpha rays are the weakest, while the gamma rays are the strongest. Intact human skin can inhibit Alpha particles, while the gamma rays require high-density objects like lead to block them.


Is Every Radiation Harmful?

Not every radiation is harmful. It is all about the nature and dosage of radiation. The dosage of the radiation makes it poisonous. Humans receive very low dosages of radiation from the environment daily. Nevertheless, radiation at high degrees could cause potentially threatening complications such as cancer, harming fetuses, and even death.

Dr. Muhammad Shoyab
Dr. Muhammad Shoyab



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