Computed radiography:
The development of intensifying screen has greatly improved the efficiency of exposure and has reduced the exposure time. The first clinical computed radiography (CR) system was introduced in 1983. CR represents a completely different approach to the problem of producing diagnostic radiographs. Rather than using film to record the X-ray image, a detector system collects the pattern of the X-ray exposure, which is extracted by a reader, and data are converted in a digital signal. The image generated may be displayed on a computer screen or printed in to a film. CR has advantages in comparison to film screen radiography as the displayed image can be manipulated by altering contrast, magnification and degree of edge enhancement. These facilities improve the diagnostic yield of the system.