title: A method to maintain a constant magnification factor throughout the exposure of rotational panoramic radiographs.
abstract: 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.
authors.forename: W D
authors.initials: WD
authors.lastname: McDavid
authors.forename: G
authors.initials: G
authors.lastname: Tronje
authors.forename: U
authors.initials: U
authors.lastname: Welander
mesh_terms: D003201:Computers; D006801:Humans; D011862:Radiography, Panoramic / Q000295:instrumentation / Q000379:methods*