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DOI

10.1016/j.jds.2011.10.002

First Page

43

Last Page

47

Abstract

Abstract Background/purpose The aim of this study was to compare the physical and psychophysical characteristics of a new generation of the Digora storage phosphor plate (SPP) system [Digora Optime (Soredex, Helsinki, Finland)] with its previous version [Digora fmx (Soredex, Helsinki, Finland)]. Materials and methods Radiographs of an aluminum test object with a pattern of holes that varied in depth and diameter were exposed to 65 kVp and 10 mA for nine different time settings ranging from a minimum (0.05 seconds) to a maximum (3.2 seconds) using the Digora Optime and Digora fmx SPP systems. For each system, pixel-intensity (the mean gray value) measurements, contrast resolution, and exposure range were determined and compared. In addition, a perceptibility curve test was used to compare the psychophysical properties of the two SPP systems. Repeated-measures of analysis of variance and paired t tests were used to compare the mean gray values and perceptible number of details at each exposure level (P = 0.05). The average measured intraclass correlation coefficient (AMICC) was used to compare inter-rater agreement for the number of perceived details. Results The mean gray level output of fmx images was higher, whereas the contrast was lower than Optime images at all exposure levels (P < 0.05). Images obtained with the Optime system achieved the best contrast at a lower exposure than that of the fmx images. Digora Optime operated over a wide range of exposures; however, the fmx showed a narrower dynamic range. The number of details perceived on Optime images was significantly higher than that obtained on the fmx images at all exposure levels (P < 0.05). Agreement among observers in terms of the number of perceived details was excellent, with the AMICC ranging from 0.845–0.889. Conclusion Digora Optime achieved the best contrast at a lower exposure and demonstrated a better dose response. In addition, the perceptibility of low-contrast details was significantly higher for Digora Optime at a wide range of exposures.

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