Mammography is the process of using low-dose amplitude-X-rays to examine the human breast and is used as a diagnostic as well as a screening tool. The goal of mammography is the early detection of breast cancer, typically through detection of characteristic masses and/or micro calcifications. Mammography is believed to reduce mortality from breast cancer. No other imaging technique has been shown to reduce risk, but breast self-examination and physician examination are considered essential parts of regular breast care. In many countries routine mammography of older women is encouraged as a screening method to diagnose early breast cancer. The United States Preventive Services Task Force recommends screening mammography, with or without clinical breast examination, every 1-2 years for women aged 40 and older.