An ultrasound scan, also referred to as a sonogram, diagnostic sonography, and ultrasonography, is a device that uses high frequency sound waves to create an image of some part of the inside of the body, such as the stomach, liver, heart, tendons, muscles, joints and blood vessels. Experts say that as sound waves, rather than radiation are used, ultrasound scans are safe. Obstetric sonography is frequently used to check the baby in the womb.