How do X-Rays work?

The X-Ray, first discovered in 1895, by Professor Wilhelm Conrad Roentgen is a branch of Electromagnetic Radiation. Due to its high energy, it is able to penetrate through many different objects, as well as the human body. But why does it have such high energy that allows it to do that? The cause of its high energy stems from the fact that X-Rays have extremely short wavelengths and high frequencies. In physics, energy rises as frequency increases. X-rays typically have wavelengths between 0.01 to 10 nanometres, which is much shorter than visible light. Hence the reason why visible light can’t penetrate materials the way X-rays do. Due to the wavelength and frequency, it is given powerful energy that ranges from 1 to over 100 kiloelectronvolts (keV), which makes it strong enough to pass through soft tissue but get absorbed by denser materials like bone. So how does the X-ray actually work? In order to capture a radiograph, the patient is positioned so that the area of interest lies between the X-ray source and the detector. Once the machine is on, X-rays pass through the body, but not all tissues absorb them equally. This variation depends on radiological density, which is influenced by both the material’s physical density and its atomic number (the number of protons in its atoms). For example, since bones are rich in calcium, (an element with a high atomic number,) bones appear bright white on the final image. While softer tissues such as fat, muscle, or the lungs absorb far fewer X-rays, allowing more radiation to reach the detector. These areas show up in varying shades of gray, creating the contrast that makes radiographs so useful in medical diagnosis. Sooo…. Does this come with any risks? Yes actually, while the X-Ray is a useful invention, it does have its drawbacks, one of them being the fact that x-rays produce ionization radiation, a harmful type of radiation that could possibly damage a tissue, or cause cancer. Children are generally more prone to cancer from radiation more than adults since they’re described as more sensitive to ionizing radiation. Although radiation can increase cancer risk, the chances from routine medical exposure are typically quite low. In short, the X-ray is a powerful diagnostic tool that uses high-energy electromagnetic waves to reveal the hidden structures inside the human body, without a single incision made. This invention has revolutionized modern medicine by helping doctors see broken bones, detect infections, and diagnose many conditions with clarity and speed.

References: 

National Institute of Biomedical Imaging and Bioengineering (NIBIB). (n.d.). X-rays. U.S. Department of Health and Human Services. Available at: https://www.nibib.nih.gov/science-education/science-topics/x-rays#pid-1116 (Accessed: 14 May 2025).

Nondestructive Testing Resource Center. (n.d.). History of Radiography. Available at: https://www.nde-ed.org/NDETechniques/Radiography/Introduction/history.xhtml (Accessed: 14 May 2025).

Brian Nett, How Radiology Works. (n.d.). Basic X-ray Properties. Available at: https://howradiologyworks.com/basic-x-ray-properties/ (Accessed: 14 May 2025).