General Radiology The image, or a x-ray film, is produced when a small amount of radiation passes through the body to expose sensitive film on the other side. The ability of x-rays to penetrate tissues and bones depends on the tissue's composition and mass. The difference between these two elements creates the images. The chest x-ray is the most common radiologic examination. Contrast agents, such as barium, can be swallowed to highlight the esophagus, stomach, and intestine and are used to help visualize an organ on film. CT Computed tomography or CT, shows organs of interest at selected levels of the body. They are visual equivalent of bloodless slices of anatomy, with each scan being a single slice. CT examinations produce detailed organ studies by stacking individual image slices. CT can image the internal portion of organs and separate overlapping structures precisely. The scans are produced by having the source of the x-ray beam encircle or rotate around the patient. X-rays passing through the body are detected by an array of sensors. Information from the sensors is computer processed and then displayed as an image on a video screen.