Electron beam tomography (EBT) is a scanning method introduced in 1984 that images the heart 10 times faster than helical CT. Over 600 papers have been published on EBT validating its ability to determine and quantify coronary artery calcium. Coronary artery calcification is the hardening of the coronary arteries that has been known for 300 years. Recent research in the past 10 years has found that it is an active process that can occur early in atherosclerotic plaque development and is an intimate part of the fibroproliferative and inflammatory pathophysiology of coronary artery disease. Histological examination shows calcium is present within atherosclerotic plaque.