Medicine & Health
How does an X-ray work?
An X-ray works by sending a beam of high-energy light through your body onto a detector. Dense tissue like bone absorbs more of the beam and shows up bright, while soft tissue lets more through and appears dark — producing a shadow image of what is inside.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how an X-ray works.
Step by step
- 1An X-ray tube accelerates electrons into a metal target, releasing high-energy electromagnetic radiation.
- 2The beam passes through the body; dense material such as bone or metal absorbs more than soft tissue.
- 3A detector behind you records how much radiation made it through at each point.
- 4The result is a shadow image: bone bright, air and soft tissue darker.
Frequently asked questions
- Why do bones show up white?
- Calcium in bone is dense and absorbs more X-rays, so little reaches the detector there — which records as bright on the image.
- Are X-rays safe?
- A single medical X-ray uses a small dose, and the benefit usually outweighs the tiny added risk; technicians still minimize exposure and shield nearby areas.
- How is a CT scan different?
- A CT scan takes many X-ray images from different angles and combines them into detailed 3D cross-sections, rather than one flat shadow.