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Image-receptor performance: a comparison of Trophy RVG UI sensor and Kodak Ektaspeed Plus film
1Department of Diagnostic Sciences and General Dentistry, University of North Carolina at Chapel Hill, USA. jbl@email.unc.edu
Unlabelled:
Objective. This study compares the physical characteristics of the RVG UI sensor (RVG) with Ektaspeed Plus film.
Study Design:
Dose-response curves were generated for film and for each of 6 available RVG modes. An aluminum step-wedge was used to evaluate exposure latitude. Spatial resolution was assessed by using a line-pair test tool. Latitude and resolution were assessed by observers for both modalities. The RVG was further characterized by its modulation transfer function.
Results:
Exposure latitude was equal for film and RVG in the periodontal mode. Other gray scale modes demonstrated much lower latitude. The average maximum resolution was 15.3 line-pairs per millimeter (lp/mm) for RVG in high-resolution mode, 10.5 lp/mm for RVG in low-resolution mode, and 20 lp/mm for film (P <.0001). Modulation transfer function measurements supported the subjective assessments.
Conclusions:
In periodontal mode, the RVG UI sensor demonstrates exposure latitude similar to that of Ektaspeed Plus film. Film images exhibit significantly higher spatial resolution than the RVG images acquired in high-resolution mode.