How Does an X-Ray Work?

What do penicillin, Super Glue, and X-rays have in common? Their inventors all stumbled upon them unintentionally!

In 1895, Wilhelm Roentgen, a German physicist, was conducting experiments with electricity in a special tube. His goal was to observe the behavior of electricity in a vacuum. To achieve this, Roentgen removed as much air as possible from the tube, allowing electrons to move at an accelerated pace.

As the electrons moved, they collided with one another and with the glass of the tube, as well as two specific parts of the tube called the cathode and anode. Unbeknownst to Roentgen, when these high-speed electrons collided with the tube’s anode, they emitted a previously unknown type of light. This light is now known as an x-ray.

X-rays are a form of light, similar to the visible light we encounter daily. The distinguishing factor between x-rays and visible light is the wavelength of the rays. Human eyes are incapable of perceiving light with longer wavelengths, such as radio waves, or shorter wavelengths, such as x-rays.

Shortly after, Roentgen noticed that a fluorescent screen in his laboratory began to glow during his experiments. Although he was aware that fluorescent materials typically emit light when exposed to electromagnetic radiation, he was surprised because the tube was surrounded by thick cardboard, which he believed would block the radiation.

Curious, Roentgen conducted further experiments by placing various objects between the tube and the screen. Regardless of what he inserted, the screen continued to emit a glow.

At one point, Roentgen positioned his hand in front of the tube and observed a silhouette of his bones projected onto the screen.

Roentgen not only discovered x-rays but also witnessed firsthand (pun intended!) their immense potential in the field of medicine.

Undoubtedly, the x-ray machine is an invaluable tool for doctors. X-rays have the ability to penetrate nonmetallic objects, including human tissues and organs. An x-ray machine operates like a large camera, enabling doctors to visualize the internal workings of a patient’s body without resorting to surgery.

Developing a safe application for medical use of x-rays required significant time and effort from scientists. Today’s x-ray machines generate a stream of electromagnetic radiation that interacts with an anode in an x-ray tube. The resulting x-rays are then directed towards the specific area of the body under examination. To minimize radiation exposure, x-ray machines focus the x-rays exclusively on the target area.

Upon encountering our body tissues, x-rays produce an image on a metal film. Soft tissues, such as skin and organs, are unable to absorb the high-energy rays, allowing the beam to pass through them. However, denser materials within our bodies, such as bones, effectively absorb the radiation.

Similar to camera film, the x-ray film’s development depends on which areas were exposed to the x-rays. Dark areas on an x-ray indicate regions where the x-rays have passed through soft tissues. Conversely, white areas signify where denser tissues, like bones, have absorbed the x-rays.

Have you ever undergone an x-ray? They are commonly used to detect fractures. Doctors might also request an x-ray to investigate the cause of your discomfort. But don’t worry! X-rays are completely painless. Instead, they assist doctors in finding ways to improve your well-being.

Give it a Try

Find an adult friend or family member to assist you with these activities:

• Have you ever had an x-ray? Read about what the experience is like! Then, write a paragraph for a friend explaining what they should anticipate. Should they feel anxious? What will occur during the procedure?
• Have you ever heard of a superhero with x-ray vision? What unique superpower would you desire? Compose a story in which you become a superhero. What powers do you possess? Do you have a sidekick? How about a villain? Share all the details of your adventures!
• NASA provides even more fascinating information about x-rays. Learn more about these special forms of light. Afterward, discuss what you have learned today with a friend or family member.

Sources of Wonder

• https://www.austincc.edu/rudygarz/xRayMachine/xRayMachine.pdf (accessed 12 June 2019)
• https://science.nasa.gov/ems/11_xrays (accessed 12 June 2019)
• https://www.nde-ed.org/EducationResources/CommunityCollege/Radiography/Introduction/history.htm (accessed 12 June 2019)

FAQ

1. What is an X-ray and how does it work?

An X-ray is a type of electromagnetic radiation that can pass through solid objects. It is used in medical imaging to create images of the inside of the body. X-rays work by emitting a beam of high-energy photons that can penetrate the body. When the X-ray beam passes through the body, it is absorbed by different tissues to varying degrees. Dense tissues, such as bones, absorb more X-rays and appear white on the X-ray image. Less dense tissues, such as muscles and organs, absorb fewer X-rays and appear darker. This allows doctors to see the internal structures of the body.

2. Are X-rays safe?

X-rays are generally considered safe when used in moderation and with proper shielding. However, excessive exposure to X-rays can be harmful and increase the risk of developing cancer. The level of radiation exposure during an X-ray procedure is typically low, but it is important to minimize unnecessary exposure. Pregnant women should avoid X-rays if possible, as the radiation can potentially harm the developing fetus. The use of lead aprons and other protective measures can further reduce the risk of radiation exposure during X-ray procedures.

3. What are some common uses of X-rays?

X-rays are commonly used in medical imaging to diagnose and monitor various conditions. They are particularly useful for examining bones and detecting fractures, dislocations, and other abnormalities. X-rays can also be used to visualize the lungs and diagnose respiratory conditions, such as pneumonia and lung cancer. In dentistry, X-rays are used to detect cavities and assess the health of the teeth and jawbone. Additionally, X-rays are used in security screening at airports to detect concealed objects.

4. How long does an X-ray procedure take?

The duration of an X-ray procedure depends on the specific area of the body being examined. In general, X-ray procedures are relatively quick and can be completed within a matter of minutes. The patient will be positioned accordingly, and the X-ray technician will take a series of images from different angles. The process of capturing the X-ray images is usually painless and non-invasive. However, some discomfort may be experienced if the patient needs to hold a particular position or if an injured area is being examined.

5. Are there any risks or side effects associated with X-rays?

The risks and side effects associated with X-rays are generally minimal. However, some individuals may experience a mild allergic reaction to the contrast dye used in certain types of X-ray procedures. In rare cases, exposure to high levels of radiation during X-ray procedures can cause skin burns or radiation sickness. It is important to inform the healthcare provider about any allergies or previous reactions to contrast dye or radiation. Pregnant women and young children are more sensitive to radiation and may be at a higher risk of adverse effects.

6. Can X-rays be used to diagnose all medical conditions?

X-rays are a valuable diagnostic tool, but they are not suitable for diagnosing all medical conditions. Some conditions, such as soft tissue injuries and certain cancers, may not be visible on X-ray images. In such cases, other imaging techniques, such as ultrasound, MRI, or CT scans, may be more appropriate. X-rays are best suited for visualizing bones and detecting abnormalities in the skeletal system. The healthcare provider will determine the most suitable imaging method based on the specific symptoms and suspected condition.