Ultrasound is a medical exam that uses high-frequency sound waves to create real-time images of your internal organs. The sound waves are emitted from a specialized tool called a transducer that is placed against your skin. As the sound waves bounce off your internal structures, they are recorded by the transducer and transmitted to a computer, where they are compiled into a moving image.

Ultrasounds are commonly used to track the progression of a woman’s pregnancy and check the health and sex of her baby. Most obstetricians perform routine ultrasounds to look for abnormalities in either the fetus or the uterus during early pregnancy. However, ultrasound has many applications beyond that. Diagnostic ultrasound is used to evaluate tumors, assess abdominal organs such as the liver, kidneys, spleen, gallbladder, bile ducts, aorta and pancreas, as well as breasts, thyroid, scrotum, arteries, and other soft tissues throughout the body. Because they allow physicians to monitor organs in real-time, they are often used to guide tumor biopsies as well.