Simulated bone erosions in a hand phantom: Detection with conventional screen-film technology versus cesium iodide-amorphous silicon flat-panel detector

PURPOSE: To assess the diagnostic performance of an active-matrix flat-pane l x-ray detector for reduced-dose imaging of simulated arthritic lesions. MATERIALS AND METHODS: A digital x-ray detector based on cesium iodide and amorphous silicon technology with a panel size of 43 x 43 cm, matrix of 3,0 00 x 3,000 pixels, pixel size of 143 mu m, and digital output of 14 bits wa s used. State-of-the-art screen-film radiographs were compared with digital images obtained at doses equivalent to those obtained with system speeds o f 400, 560, and 800. The phantom was composed of a human hand skeleton on a n acrylic plate with drilled holes simulating bone erosions of different di ameters and depths. Results of four independent observers were evaluated wi th receiver operating characteristic curve analysis. RESULTS: The cesium iodide and amorphous silicon detector resulted in bette r diagnostic performance than did the screen-film combination, with the dos e being the same for both modalities (P < .05). For digital images obtained at reduced doses, no significant differences were found. CONCLUSION: The improved diagnostic performance with digital radiographs ob tained with the cesium iodide and amorphous silicon detector suggests that this detector technology holds promise in terms of dose reduction for speci fic diagnostic tasks, without loss of diagnostic accuracy.