Perception versus reality—findings from a phosphor plate quality assurance study

Objective The aim of the study was to evaluate the image quality of a photostimulable phosphor (PSP) plate system to determine if image degradation has occurred after a number of clinical uses. Study Design Twenty DIGORA Optime PSP plates (Soredex Orion Corp., Helsinki, Finland) were imaged throughout clinical use. Image quality was assessed by using spatial and contrast resolution through the use of the dental radiographic phantom designed for the Nationwide Evaluation of X-Ray Trends surveys of 1993 and 1999. Spatial resolution was summarized in line pairs per millimeter. The paired t test was used to analyze the contrast wells. The contrast-to-noise ratio (CNR) was calculated to determine the signal-to-noise ratio as another measure of contrast. Descriptive statistics were used to summarize the CNR ratios. Results Spatial resolution decreased after 48 clinical uses. No significant differences were found for the pairwise comparisons of the contrast wells. No CNR varied by more than two-tenths' value difference. Conclusions Digora Optime PSP plates displayed unaffected image quality up to 48 clinical uses. Additional studies are needed to confirm these results and to establish guidelines for appropriate replacement intervals for PSP plates.