X-rays are a type of electromagnetic radiation, just like visible light.
An x-ray machine sends individual x-ray particles through the body. The images are recorded on a computer or film.
- Structures that are dense (such as bone) will block most of the x-ray particles, and will appear white.
- Metal and contrast media (special dye used to highlight areas of the body) will also appear white.
- Structures containing air will be black, and muscle, fat, and fluid will appear as shades of gray.
Mettler FA Jr. Introduction: an approach to image interpretation. In: Mettler FA Jr, ed. Essentials of Radiology. 4th ed. Philadelphia, PA: Elsevier; 2019:chap 1.
Rodney WM, Rodney JRM, Arnold KMR. Principles of x-ray interpretation. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 235.