Original scientific paper

Charge-Coupled Device Panoramic Radiography: Area Image Distortion Factors as Selected Image Layer Contours

T. T. Farman ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA
A.G. Farman ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA
M.S. Kelly ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA
F.J. Firriolo ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA
J.M Yanacey ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA
A.V. Stewart ; School of Dentistry The Universitiy of Louisville Louisville, Kentacky, USA

Abstract

Objectives: The aim of this study was to determine the distortion
factor characteristics for selected image layer resolution contours of
the Orthopantomograph OP 100® (Instrumentarium Imaging, Tuusula, Finland), combined with the DigiPan® (Trophy Radiologie, Vincennes, France) charge-coupled device receptor. Material and Methods: Using a resolution grid positioned at intervals along empirically determined beam projection paths, the image layer contours produced with the DigiPan® modification o f the Orthopantomograph OP 100® had previously been determined for resolution limits o f 4.0, 3.0 and 1.5 Ip m m 1. An hexagonal test device was used to determine the magnification factors at the selected resolution limits and horizontal beam angulations using the resident measurement algorithm o f the DigiPan® proprietary software. The horizontal and vertical magnifications were then used to determine the distortion factors at each resolution contour along selected beam angulations. Results: At the image layer resolution contours of 4 Ip m m 1 all area distortion factors approached unity. Furthermore, in the region bounded by these resolution contours the measurement algorithm compensated for the inherent magnification distortion artefact caused by the X-ray beam geometry. At 1.5 Ip m m 1, the area distortion factors ranged from 1.16 to 1.19 facially and 1.14 to 1.22 lingually to image layer contour of maximum resolution. The image layer contour of maximum spatial resolution was positioned lingually to the geometric center o f the focal trough. Conclusion: Using the DigiPan®, and the op 100® the distortion values conform o f those previously found using conventional film/screen receptors. In the region o f maximum resolution, the software measurement algotirhm effectively compensated for beam- projection magnification distortion.

Keywords

digital image processing; distortion factor; measurement algorithm; panoramic radiography

Hrčak ID:

97761

URI

https://hrcak.srce.hr/97761

Publication date:

15.3.1998.

Article data in other languages: croatian

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