The evolution of computers has dramatically affected the quality of human life in the field of medicine. Many developments during the last thirty years of the twentieth century have taken place in the field of diagnostic radiology, which is used to diagnose and sometimes treat illnesses. Among the image analysis tools now available that are derived from advances in computer technology are the ultrasound, computed tomography, nuclear medicine, and magnetic resonance imaging.

Ultrasound

Ultrasound is an example of technology that was first developed to serve military purposes. The principle behind ultrasonography was first used during World War II. Called SONAR, it helped detect the presence of underwater submarines. Ultrasound was not widely used in medicine until the early 1970s. Diagnostic ultrasound uses sound waves that are too high for the human ear to detect (between one million and 20 million cycles per second). These sound...