A method to maintain a constant magnification factor throughout the exposure of rotational panoramic radiographs.
The magnification factor can be held constant throughout the exposure of a panoramic radiograph by maintaining the physical centre of rotation equidistant from the central plane of the image layer. This may be accomplished with computer-controlled movement patterns while the effective centre of rotation follows a path selected to provide an optimal projection of the jaws. Theoretical considerations for creation of a constant magnification factor are presented and the practical implementation of the technique in a commercially available device (OrthOralix SD, Philips, Monza, Italy) is described. This technique minimizes distortion in panoramic radiographs and makes horizontal measurements possible in certain selected cases.
McDavid
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Tronje
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Welander
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D003201:Computers; D006801:Humans; D011862:Radiography, Panoramic / Q000295:instrumentation / Q000379:methods*