Radiology

Ultrasound was the first nonradiologic technique used to image the body. Ultrasound in radiology stems from the development of pulse-echo radar during World War II. First used to detect defects in metal structures, ultrasound, or sonography, became a useful diagnostic tool in the late 1950s and early 1970s. As its name suggests, ultrasound uses sound waves rather than electro-magnetic radiation to image structures.

A common use of ultrasound is to provide images of a fetus. A sound transmitter is used to send waves into the body from various angles. As these waves bounce back off the uterus and the fetus, they are recorded both on a television screen and in a photograph. With the more advanced Doppler ultrasound, this technology can be used for everything from imaging atherosclerotic disease (the thickening of arteries) to evaluating the prostate and rectum.