ABSTRACT

IMAGING HAS BECOME AN INTEGRAL PART of medical care. The ability to obtain informationabout the anatomic and physiologic status of the body without the need for direct visualization hasdramatically altered the practice of medicine. X-rays provided the first technical capability to image inside the body. X-rays provide a two-dimensional

image of a three-dimensional space. Their contrast mechanism is primarily dependent upon the absorption of high-energy photons by water and calcium salts within the body. X-rays are therefore very effective at imaging bony structures but less sensitive to soft tissue defects. The use of contrast materials based on x-ray absorbing substances such as barium and iodine allow visualization of the gastrointestinal tract, urinary tract, and cardiovascular system. X-ray techniques initially required a large x-ray generator and a film holder to obtain an image. More recently all-digital systems have been introduced reducing or eliminating the need for film.