Ultrasound is a procedure that uses high-frequency sound waves to view internal organs and produce images of the human body. The human ear cannot hear the sound waves used in an ultrasound. Ultrasound is: Noninvasive, which means it does not penetrate the skin or body openings, and Diagnostic, which means it is used to determine what disease or condition is present The technical term for ultrasound imaging is sonography. Ultrasound technology was originally developed as sonar to track submarines during World War I. It was first used medically in the 1950s and is considered very safe. The original ultrasound scanners produced still images, but modern scanners produce moving pictures, which are easier to interpret.