CCD camera radiographic systems generate an X-ray image when X-rays interact with a fluorescent (light-producing) screen that
is attached to the underside of the X-ray table. The light produced from this interaction is then focused by a lens and captured
by the CCD chip. In essence, the CCD camera photographs the light produced from X-rays interacting with a screen.
CCD chips are relatively small (2.5 x 2.5 cm to 8 x 8 cm). The large demagnification factor needed to reduce the size of the
patient's image to the size of the CCD may result in loss of information, which has limited the quality of CCD-based images
in the past.2,10 Advances in CCD technology, however, have overcome this limitation, and CCD-based machines are now accepted in human radiographic
applications.12-15 The veterinary experience with CCD cameras is more limited than with CR and flat panel DR detectors. CCD radiography is
used extensively in human and veterinary dental radiography because of the small field of view.
Both CR and DR systems create a set of raw data that will be used to produce a diagnostic radiographic image. Each vendor
has a different method of image processing that may involve several steps that vary in complexity and involve mathematical
manipulations of the raw data. Although there are marked technical differences among various vendors' radiographic systems,
differences in image quality stem mainly from a system's ability to effectively process the image and not necessarily from
the type of equipment used to obtain the image. CR is a relatively inexpensive system of digital radiography that shares a
similar workflow with film-based radiography. DR technologies enable veterinarians to generate radiographic images within
seconds of acquisition.
Sarah M. Puchalski, DVM, DACVR
Department of Surgical and Radiological Sciences
School of Veterinary Medicine
University of California
Davis, CA 95616
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