Radiology is imaging where an X-ray beam passes through the body. On its way through the body, parts of the energy of the X-ray beam are absorbed. This process is described as attenuation of the X-ray beam. On the opposite side of the body, detectors or a film capture the attenuated X-rays, resulting in an image. Conventional radiography produces a 2D image for each exposure.
Fluoroscopy is the use of an x-ray beam during a real-time examination of the patient’s body. Some of the uses include positioning of orthopedic implants during surgery, catheters and pacemakers, viewing the movement of contrast agents, such as barium, through the body and studying the movement of parts of the body.
Contrast agents are used to make organs in the body visible on the images. They can be given by injection into the blood stream or via tubes into internal organs. Barium products can be administered orally or rectally for examining the gastro-intestinal system. Fluoroscopy is often used in procedures to view movement through the gastro-intestinal tract.
The colon is clearly seen on the air-contrast barium enema. The white areas are barium (contrast) and the black regions are air.