Millisieverts (mSv) are a unit of measurement used to quantify radiation exposure. One millisievert is one-thousandth of a sievert (Sv), which is the standard unit for measuring the biological effects of ionizing radiation on human health. This measurement helps assess the potential risk of radiation exposure from various sources, such as medical procedures, environmental factors, and occupational hazards. In everyday life, people are exposed to background radiation from natural sources like cosmic rays and radon gas. For example, a chest X-ray typically delivers a dose of about 0.1 mSv, while a single CT scan can expose a person to around 10 mSv. Understanding millisieverts helps individuals and professionals make informed decisions regarding radiation safety and health risks.