Clinical and in vitro film quality comparison of manual and automatic exposure control in panoramic radiography

Objective. Automatic exposure control has been used successfully in medicin e to improve image quality and reduce the number of retakes necessitated by inadequate operator selection of exposure factors. The purpose of this stu dy was to assess the influence of automatic exposure control on panoramic i mage quality. Study design. A total of 352 patients were imaged with either the OP 100 or the Orthophos plus panoramic machine. An expert consensus panel judged fil m quality using a 5-point scare. Differences in quality that would have res ulted from the use of operator-determined exposures were calculated through use of an algorithm validated with test images of a human phantom. Results. McNemar's test demonstrated significant improvements in quality wi th automatic exposure control (P = .001) in comparison with manual exposure control. No quality difference was found between the 2 machines (P = .9661 ). Manual exposure selection by oral and maxillofacial radiology residents was better than selection by technologists and assistants (P = .006). Conclusions. This study confirms the utility of automatic exposure control for panoramic radiography.