ABSTRACT
Before the invention and application of simple X-ray shadow imaging in the early 20th century, the only noninvasive means of diagnosing diseases affecting internal organs was by palpation and visual observation of outward symptoms involving the skin, gums, eyes, tongue, teeth, breathing, urine, stool, etc. In the past 30 years, medical imaging systems have gained tremendous sophistication and effectiveness, largely due to the evolution of 2-and 3-D digital signal processing algorithms implemented on modern computers.
