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Flat-Panel X-ray Detector Based on Amorphous Silicon versus Asymmetric Screen-Film System: Phantom Study of Dose Reduction and Depiction of Simulated Findings¹

¹ From the Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Strasse 33, 48129 Muenster, Germany (U.R.B., T.M.B.); Department of Biometrics and Medical Informatics, Otto-von-Guericke University, Magdeburg, Germany (F.W.R.); Department of Radiology, Wesley Medical Center, Wichita, Kan (R.C.G.); ECO, Barleben, Germany (H.S.); and Institute for Diagnostic and Interventional Radiology, University of Essen, Germany (U.W.K.). From the 2000 RSNA scientific assembly. Received April 20, 2001; revision requested June 8; final revision received October 28, 2002; accepted November 22. Address correspondence to U.R.B. (e-mail: bernhart@uni-muenster.de).

View larger version (21K): [in a new window]   Figure 1a. Graph shows Az values with SDs obtained with both systems at different speeds (a) for ground-glass, miliary, linear, and reticular patterns over lucent lung, as well as for catheters over obscured chest regions, and (b) for nodules (<10 mm and 10 mm) over obscured chest regions and lucent lung.

View larger version (22K): [in a new window]   Figure 1b. Graph shows Az values with SDs obtained with both systems at different speeds (a) for ground-glass, miliary, linear, and reticular patterns over lucent lung, as well as for catheters over obscured chest regions, and (b) for nodules (<10 mm and 10 mm) over obscured chest regions and lucent lung.

View larger version (142K): [in a new window]   Figure 2a. Hard-copy film images of the whole chest of the phantom obtained with (a) the asymmetric screen-film system and with (b) the 400-speed flat-panel detector.

View larger version (151K): [in a new window]   Figure 2b. Hard-copy film images of the whole chest of the phantom obtained with (a) the asymmetric screen-film system and with (b) the 400-speed flat-panel detector.

View larger version (148K): [in a new window]   Figure 3a. Hard-copy film images obtained with (a) flat-panel detector at speed of 1,600 (digital images) and (b) asymmetric screen-film system depict ground-glass pattern (arrows). The difference was not statistically significant (P = .09).

View larger version (152K): [in a new window]   Figure 3b. Hard-copy film images obtained with (a) flat-panel detector at speed of 1,600 (digital images) and (b) asymmetric screen-film system depict ground-glass pattern (arrows). The difference was not statistically significant (P = .09).

View larger version (132K): [in a new window]   Figure 4a. Hard-copy film images show better visibility of the linear pattern (arrows) with flat-panel detector at (a) speed of 400 than at (b) speed of 1,600. The difference was statistically significant (P = .002).

View larger version (140K): [in a new window]   Figure 4b. Hard-copy film images show better visibility of the linear pattern (arrows) with flat-panel detector at (a) speed of 400 than at (b) speed of 1,600. The difference was statistically significant (P = .002).

View larger version (151K): [in a new window]   Figure 5a. Digital images acquired at speeds of (a) 1,600 and (b) 400 depict miliary patterns (arrows). A statistically significant decreased result was achieved at the speed of 1,600 (P < .001).

View larger version (157K): [in a new window]   Figure 5b. Digital images acquired at speeds of (a) 1,600 and (b) 400 depict miliary patterns (arrows). A statistically significant decreased result was achieved at the speed of 1,600 (P < .001).

View larger version (142K): [in a new window]   Figure 6a. Hard-copy film images acquired with flat-panel detector at digital speeds of (a) 400 and (b) 1,600 depict simulated reticular pattern (arrows) . Visibility of this pattern was poorer on the image acquired at a speed of 1,600. The difference was statistically significant (P < .001).

View larger version (153K): [in a new window]   Figure 6b. Hard-copy film images acquired with flat-panel detector at digital speeds of (a) 400 and (b) 1,600 depict simulated reticular pattern (arrows) . Visibility of this pattern was poorer on the image acquired at a speed of 1,600. The difference was statistically significant (P < .001).

View larger version (132K): [in a new window]   Figure 7a. (a) Hard-copy film image obtained with asymmetric screen-film system at a speed of 400 showed a nodule (arrow) smaller than 10 mm in the region of the mediastinum. (b) Hard-copy film image obtained with flat-panel detector at speed of 1,600 demonstrated that this nodule (arrow) was not as visible as it was with the asymmetric screen-film system at a speed of 400. This result was statistically significant (P < .005).

View larger version (137K): [in a new window]   Figure 7b. (a) Hard-copy film image obtained with asymmetric screen-film system at a speed of 400 showed a nodule (arrow) smaller than 10 mm in the region of the mediastinum. (b) Hard-copy film image obtained with flat-panel detector at speed of 1,600 demonstrated that this nodule (arrow) was not as visible as it was with the asymmetric screen-film system at a speed of 400. This result was statistically significant (P < .005).

View larger version (164K): [in a new window]   Figure 8a. Hard-copy film images generated with the flat-panel detector at speeds of (a) 400 and (b) 1,600 depict catheters (arrows) over obscured chest regions (mediastinum). Radiologists’ ability to detect catheters was better at the speed of 400 than it was at a speed of 1,600, and this difference was statistically significant (P < .001).

View larger version (162K): [in a new window]   Figure 8b. Hard-copy film images generated with the flat-panel detector at speeds of (a) 400 and (b) 1,600 depict catheters (arrows) over obscured chest regions (mediastinum). Radiologists’ ability to detect catheters was better at the speed of 400 than it was at a speed of 1,600, and this difference was statistically significant (P < .001).