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Walter Heindel - One of the best experts on this subject based on the ideXlab platform.
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experimental evaluation of a portable indirect flat panel detector for the pediatric chest comparison with Storage Phosphor radiography at different exposures by using a chest phantom
Radiology, 2005Co-Authors: Ulrike Rappbernhardt, Thomas M. Bernhardt, H Lenzen, Rainer Esseling, Friedrich W Roehl, Manfred Schiborr, Iris Theobaldhormann, Walter HeindelAbstract:PURPOSE: To compare the exposure dose requirements and performance of a portable indirect flat-panel detector for pediatric use in the depiction of catheters, simulated pulmonary nodules, and simulated interstitial lung disease with those of Storage Phosphor radiography. MATERIALS AND METHODS: Catheters and simulated nodules and subtle interstitial lung disease (miliary, reticular, linear, and ground-glass patterns) were superimposed over an anthropomorphic chest phantom. Images were obtained with different exposures corresponding to simulated speeds of 400 and 800 with a portable flat-panel detector and printed on hard copies. These images were compared with those from Storage Phosphor radiography at a simulated speed of 400, which is typically used in pediatric radiology. Four independent readers recorded 7200 observations per pattern (for a total of 600 statistically independent observations), and these observations were subjected to receiver operating characteristic (ROC) analysis. Differences were co...
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Lumbar spine radiography: digital flat-panel detector versus screen-film and Storage-Phosphor systems in monkeys as a pediatric model.
Radiology, 2003Co-Authors: Karl F. Ludwig, Kathrin Ahlers, Dag Wormanns, Michael Freund, Thomas M. Bernhardt, Stefan Diederich, Walter HeindelAbstract:PURPOSE: To assess image quality and exposure dose requirements of a flat-panel detector system versus screen-film and Storage-Phosphor systems for radiographic depiction of the lumbar spine in Cynomolgus monkeys as a pediatric model. MATERIALS AND METHODS: Twenty Cynomolgus monkeys underwent anteroposterior radiography of the lumbar spine. The size and weight of these monkeys are comparable to those of infants 3–4 months of age. Images were acquired with speed class 400 screen-film, flat-panel, and Storage-Phosphor systems with identical exposure dose. All other conditions were matched exactly. Additional images were acquired with the flat-panel and Storage-Phosphor systems at exposure doses equivalent to speed classes 800 and 1600. All images were obtained at 66 kVp without antiscatter grid. Images were assessed independently by three radiologists for visibility of 60 anatomic structures by using a five-point confidence scale. Scores were calculated for the seven combinations of imaging mode and exposur...
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detection of subtle undisplaced rib fractures in a porcine model radiation dose requirement digital flat panel versus screen film and Storage Phosphor systems
Radiology, 2003Co-Authors: Karl F. Ludwig, Dag Wormanns, Thomas M. Bernhardt, Stefan Diederich, H Lenzen, Christoph Schulke, Paul Brinckmann, Walter HeindelAbstract:PURPOSE: To compare a large-area direct read-out flat-panel detector radiography system with screen-film and Storage-Phosphor systems with regard to detection of subtle undisplaced rib fractures and to assess the diagnostic performance of the flat-panel system with decreasing exposure level. MATERIALS AND METHODS: Subtle fractures were created artificially in 100 of 200 porcine rib specimens. Specimens were enclosed in containers of water to generate absorption and scatter radiation conditions similar to those of a human chest wall. Imaging was performed with flat-panel, screen-film, and Storage-Phosphor systems with conditions that were exactly matched. Different exposure levels equivalent to speed classes (S) of 400, 800, 1,600, and 6,400 were used. All images were independently assessed for the presence of fracture by three radiologists with a five-level confidence scale. Receiver operating characteristic (ROC) analysis was performed for a total of 4,200 observations (600 for each imaging system and ex...
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performance of a flat panel detector in detecting artificial bone lesions comparison with conventional screen film and Storage Phosphor radiography
Radiology, 2002Co-Authors: Karl F. Ludwig, Dag Wormanns, Stefan Diederich, H Lenzen, Karlfriedrich Kamm, Thomas M Link, Walter HeindelAbstract:PURPOSE: To compare a large-area direct-readout flat-panel detector system with a conventional screen-film system and a Storage-Phosphor system in detecting small artificial osseous lesions simulating osteolytic disease and to assess diagnostic performance with decreasing exposure dose. MATERIALS AND METHODS: Artificial lesions (0.5–3.0 mm) were created in 100 of 200 predefined regions in 20 porcine femoral specimens. Specimens were enclosed in containers filled with water to create absorption and scatter radiation conditions comparable with those in a human extremity. Imaging was performed with a flat-panel detector system, a conventional screen-film system, and a Storage-Phosphor system. Levels of exposure equivalent to speed classes 400, 800, 1600, and 3200 were used. In all images, the presence or absence of a lesion was assessed by three radiologists using a five-point confidence scale. Receiver operating characteristic (ROC) analysis was performed for 4,800 observations (600 for each imaging modalit...
Mathias Prokop - One of the best experts on this subject based on the ideXlab platform.
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Two K versus 4 K Storage Phosphor chest radiography: detection performance and image quality
European radiology, 2007Co-Authors: Claus Koelblinger, Mathias Prokop, Johannes Sailer, Michael Weber, Fabiola Cartes-zumelzu, Cornelia Schaefer-prokopAbstract:The purpose of this study was to evaluate the effect of matrix size (4-K versus 2-K) in digital Storage Phosphor chest radiographs on image quality and on the detection of CT-proven thoracic abnormalities. In 85 patients who underwent a CT of the thorax, we obtained two additional posteroanterior Storage Phosphor chest radiographs, one with a matrix size of 3,520×4,280 (=4-K) and the other with a matrix size of 1,760×2,140 (=2-K). Acquisition, processing and presentation parameters were identical for all radiographs. Two radiologists evaluated the presence of mediastinal, pleural, and pulmonary abnormalities on hard copies of the radiographs, applying ROC analysis. In addition, four radiologists were asked to subjectively rank differences in image quality and to assess the demarcation of anatomic landmarks comparing the images in a blinded side-by-side manner. These data were analyzed using a two-sided binomial test with a significance level of P
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skeletal applications for flat panel versus Storage Phosphor radiography effect of exposure on detection of low contrast details
Radiology, 2004Co-Authors: Martin Uffmann, Ulrich Neitzel, Christian J. Herold, Michael Weber, Cornelia Schaeferprokop, Mathias ProkopAbstract:PURPOSE: To compare exposure requirements for similar detection performance with flat-panel detectors and the most recent generation of Storage-Phosphor plates in the simulated scatter of typical skeletal radiographic examinations. MATERIALS AND METHODS: A contrast-detail test object was covered with varying thicknesses of acrylic to simulate skeletal exposure conditions in the wrist, knee, and pelvis. Three series were obtained with increasing thicknesses of a simulated soft-tissue layer (5, 10, and 20 cm) and increasing tube voltage (50, 70, and 90 kVp). A fourth series was obtained with exposure conditions adapted to the phantom instructions (75 kVp). Images were acquired with a flat-panel detector (cesium iodide scintillator) and Storage-Phosphor plates at five exposure levels (speed class range, 100–1,600). Five readers evaluated 84 images to determine the threshold contrast of 12 lesion diameters (range, 0.25–11.1 mm). Statistical significance of differences between the two digital systems was asses...
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Digital thorax radiography: flat-panel detector or Storage Phosphor plates
Der Radiologe, 2003Co-Authors: Cornelia Schaefer-prokop, Martin Uffmann, Johannes Sailer, N Kabalan, Christian J. Herold, Mathias ProkopAbstract:Flat panel detectors are characterized by improved handling and increased dose efficiency. This allows for increasing of work flow efficiency and for reducing the exposure dose by about 50% compared to current systems with a sensitivity of 400. Whether the increased dose efficiency should be used to reduce acquisition dose or to increase image quality in the chest, will be shown by further clinical experience and will be also determined by the subjective preference of the radiologists. The decreased level of image noise opens new perspectives for image processing that way that elaborated multifrequency processing allows for optimizing the display of very small and low contrast structures that was so far limited by overlying image noise. Specialized applications of dual energy subtraction and temporal subtraction will also profit by the new detector technology and will be further driven forward in context with applications such as computed assisted diagnosis even though this is currently not yet broadly applied. Storage Phosphor radiography still represents an important alternative technique based on its larger flexibility with respect to equipment configuration, its broader application options in intensive care and emergency radiology and due to economic reasons. These facts are further underlined by the fact that image quality also in Storage Phosphor radiography could be constantly increased by improving detector technology and image processing and consequently has a high standard.
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Storage Phosphor radiography
European radiology, 1997Co-Authors: Cornelia M. Schaefer-prokop, Mathias ProkopAbstract:Storage Phosphor radiography is a digital technique that uses photo-stimulable Phosphor screens to substitute for conventional screen-film combinations. While the technique is more than 15 years old, it is only recently that technological and economic aspects of these systems have become favourable enough to envisage a more widespread clinical application.
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Detection of simulated chest lesions: comparison of a conventional screen-film combination, an asymmetric screen-film system, and Storage Phosphor radiography.
Radiology, 1995Co-Authors: A. G. A. Leppert, Mathias Prokop, Cornelia Schaefer-prokop, Michael GalanskiAbstract:PURPOSE: To compare a high-contrast asymmetric screen-film system with a conventional screen-film combination and Storage Phosphor radiographs for detection of simulated chest lesions. MATERIALS AND METHODS: To test the diagnostic performance of these three systems, the authors used three types of simulated lesions that were superimposed over the chests of 10 patients and an anthropomorphic phantom. In the patient and phantom study, a total of 1,350 observations by each of the eight radiologists were analyzed by means of receiver operating characteristics. RESULTS: In the patient study, mediastinal nodules were better visualized with high-contrast asymmetric screen-film and Storage Phosphor radiographs compared with the conventional screen-film system. For visualization of pulmonary nodules, the high-contrast asymmetric screen-film system was best. Micronodules were poorly visualized on high-contrast asymmetric screen-film and Storage Phosphor radiographs, but only in the phantom study. CONCLUSION: The hi...
Siegfried Peer - One of the best experts on this subject based on the ideXlab platform.
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Storage Phosphor radiography of wrist fractures: a subjective comparison of image quality at varying exposure levels
European radiology, 2002Co-Authors: R. Peer, S. M. Giacomuzzi, Sigurd Pechlaner, Karl Heinz Künzel, O. Gaber, Werner Jaschke, Anton Lanser, Gerd Bodner, Siegfried PeerAbstract:Image quality of Storage Phosphor radiographs acquired at different exposure levels was compared to define the minimal radiation dose needed to achieve images which allow for reliable detection of wrist fractures. In a study on 33 fractured anatomical wrist specimens image quality of Storage Phosphor radiographs was assessed on a diagnostic PACS workstation by three observers. Images were acquired at exposure levels corresponding to a speed classes 100, 200, 400 and 800. Cortical bone surface, trabecular bone, soft tissues and fracture delineation were judged on a subjective basis. Image quality was rated according to a standard protocol and statistical evaluation was performed based on an analysis of variance (ANOVA). Images at a dose reduction of 37% were rated sufficient quality without loss in diagnostic accuracy. Sufficient trabecular and cortical bone presentation was still achieved at a dose reduction of 62%. The latter images, however, were considered unacceptable for fracture detection. To achieve high-quality Storage Phosphor radiographs, which allow for a reliable evaluation of wrist fractures, a minimum exposure dose equivalent to a speed class of 200 is needed. For general-purpose skeletal radiography, however, a dose reduction of up to 62% can be achieved. A choice of exposure settings according to the clinical situation (ALARA principle) is recommended to achieve possible dose reductions.
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Direct Digital Radiography Versus Storage Phosphor Radiography in the Detection of Wrist Fractures
Clinical radiology, 2002Co-Authors: Siegfried Peer, Ulrich Neitzel, S. M. Giacomuzzi, Sigurd Pechlaner, Karl Heinz Künzel, R. Peer, Eva Gassner, Iris Steingruber, O. Gaber, Werner JaschkeAbstract:Abstract AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art Storage Phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art Storage Phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while Storage Phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art Storage Phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures . Peer, S. et al . (2002). Clinical Radiology 57 , 258–262.
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Comparison of low-contrast detail perception on Storage Phosphor radiographs and digital flat panel detector images
IEEE transactions on medical imaging, 2001Co-Authors: Siegfried Peer, Ulrich Neitzel, S. M. Giacomuzzi, R. Peer, Eva Gassner, Iris Steingruber, Werner JaschkeAbstract:A contrast detail analysis was performed to compare perception of low-contrast details on X-ray images derived from digital Storage Phosphor radiography and from a flat panel detector system based on a cesium iodide/amorphous silicon matrix. The CDRAD 2.0 phantom was used to perform a comparative contrast detail analysis of a clinical Storage Phosphor radiography system and an indirect type digital flat panel detector unit. Images were acquired at exposure levels comparable to film speeds of 50/100/200/400 and 800. Four observers evaluated a total of 50 films with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. The overall results show that low-contrast detail perception with digital flat panel detector images is better than with state of the art Storage Phosphor screens. This is especially true for the low-exposure setting, where a nearly 10% higher correct observation ratio is reached. Given its high detective quantum efficiency the digital flat panel technology based on the cesium iodide scintillator/amorphous silicon matrix is best suited for detection of low-contrast detail structures, which shows its high potential for clinical imaging.
Thomas M. Bernhardt - One of the best experts on this subject based on the ideXlab platform.
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experimental evaluation of a portable indirect flat panel detector for the pediatric chest comparison with Storage Phosphor radiography at different exposures by using a chest phantom
Radiology, 2005Co-Authors: Ulrike Rappbernhardt, Thomas M. Bernhardt, H Lenzen, Rainer Esseling, Friedrich W Roehl, Manfred Schiborr, Iris Theobaldhormann, Walter HeindelAbstract:PURPOSE: To compare the exposure dose requirements and performance of a portable indirect flat-panel detector for pediatric use in the depiction of catheters, simulated pulmonary nodules, and simulated interstitial lung disease with those of Storage Phosphor radiography. MATERIALS AND METHODS: Catheters and simulated nodules and subtle interstitial lung disease (miliary, reticular, linear, and ground-glass patterns) were superimposed over an anthropomorphic chest phantom. Images were obtained with different exposures corresponding to simulated speeds of 400 and 800 with a portable flat-panel detector and printed on hard copies. These images were compared with those from Storage Phosphor radiography at a simulated speed of 400, which is typically used in pediatric radiology. Four independent readers recorded 7200 observations per pattern (for a total of 600 statistically independent observations), and these observations were subjected to receiver operating characteristic (ROC) analysis. Differences were co...
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Lumbar spine radiography: digital flat-panel detector versus screen-film and Storage-Phosphor systems in monkeys as a pediatric model.
Radiology, 2003Co-Authors: Karl F. Ludwig, Kathrin Ahlers, Dag Wormanns, Michael Freund, Thomas M. Bernhardt, Stefan Diederich, Walter HeindelAbstract:PURPOSE: To assess image quality and exposure dose requirements of a flat-panel detector system versus screen-film and Storage-Phosphor systems for radiographic depiction of the lumbar spine in Cynomolgus monkeys as a pediatric model. MATERIALS AND METHODS: Twenty Cynomolgus monkeys underwent anteroposterior radiography of the lumbar spine. The size and weight of these monkeys are comparable to those of infants 3–4 months of age. Images were acquired with speed class 400 screen-film, flat-panel, and Storage-Phosphor systems with identical exposure dose. All other conditions were matched exactly. Additional images were acquired with the flat-panel and Storage-Phosphor systems at exposure doses equivalent to speed classes 800 and 1600. All images were obtained at 66 kVp without antiscatter grid. Images were assessed independently by three radiologists for visibility of 60 anatomic structures by using a five-point confidence scale. Scores were calculated for the seven combinations of imaging mode and exposur...
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detection of subtle undisplaced rib fractures in a porcine model radiation dose requirement digital flat panel versus screen film and Storage Phosphor systems
Radiology, 2003Co-Authors: Karl F. Ludwig, Dag Wormanns, Thomas M. Bernhardt, Stefan Diederich, H Lenzen, Christoph Schulke, Paul Brinckmann, Walter HeindelAbstract:PURPOSE: To compare a large-area direct read-out flat-panel detector radiography system with screen-film and Storage-Phosphor systems with regard to detection of subtle undisplaced rib fractures and to assess the diagnostic performance of the flat-panel system with decreasing exposure level. MATERIALS AND METHODS: Subtle fractures were created artificially in 100 of 200 porcine rib specimens. Specimens were enclosed in containers of water to generate absorption and scatter radiation conditions similar to those of a human chest wall. Imaging was performed with flat-panel, screen-film, and Storage-Phosphor systems with conditions that were exactly matched. Different exposure levels equivalent to speed classes (S) of 400, 800, 1,600, and 6,400 were used. All images were independently assessed for the presence of fracture by three radiologists with a five-level confidence scale. Receiver operating characteristic (ROC) analysis was performed for a total of 4,200 observations (600 for each imaging system and ex...
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Detection of simulated interstitial lung disease and catheters with selenium, Storage Phosphor, and film-based radiography.
Radiology, 1999Co-Authors: Thomas M. Bernhardt, Dirk Otto, Gerhard Reichel, Kathrin Ludwig, Sylke Seifert, Siegfried Kropf, Ulrike Rapp-bernhardtAbstract:PURPOSE: To evaluate the diagnostic performance of Storage Phosphor and digital selenium radiography (DSR) with asymmetric and symmetric screen-film systems at different speeds in the detection of simulated interstitial lung disease and catheters. MATERIALS AND METHODS: Patterns of simulated interstitial lung disease and catheters were superimposed over an anthropomorphic chest phantom. Hard-copy images were generated at DSR (200-, 400-, and 600-speed), Storage Phosphor radiography (200- and 400-speed), and asymmetric (400-speed) and symmetric (200- and 400-speed) screen-film imaging. Surface doses were measured, and receiver operating characteristic analyses were performed. RESULTS: No statistically significant differences were found between the detector systems with the same speeds for each interstitial pattern. Significantly poorer results were found at 600-speed DSR than at 200-speed DSR. Detection of catheters and nodules over high-attenuation areas was significantly worse with the symmetric screen-f...
Werner Jaschke - One of the best experts on this subject based on the ideXlab platform.
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Storage Phosphor radiography of wrist fractures: a subjective comparison of image quality at varying exposure levels
European radiology, 2002Co-Authors: R. Peer, S. M. Giacomuzzi, Sigurd Pechlaner, Karl Heinz Künzel, O. Gaber, Werner Jaschke, Anton Lanser, Gerd Bodner, Siegfried PeerAbstract:Image quality of Storage Phosphor radiographs acquired at different exposure levels was compared to define the minimal radiation dose needed to achieve images which allow for reliable detection of wrist fractures. In a study on 33 fractured anatomical wrist specimens image quality of Storage Phosphor radiographs was assessed on a diagnostic PACS workstation by three observers. Images were acquired at exposure levels corresponding to a speed classes 100, 200, 400 and 800. Cortical bone surface, trabecular bone, soft tissues and fracture delineation were judged on a subjective basis. Image quality was rated according to a standard protocol and statistical evaluation was performed based on an analysis of variance (ANOVA). Images at a dose reduction of 37% were rated sufficient quality without loss in diagnostic accuracy. Sufficient trabecular and cortical bone presentation was still achieved at a dose reduction of 62%. The latter images, however, were considered unacceptable for fracture detection. To achieve high-quality Storage Phosphor radiographs, which allow for a reliable evaluation of wrist fractures, a minimum exposure dose equivalent to a speed class of 200 is needed. For general-purpose skeletal radiography, however, a dose reduction of up to 62% can be achieved. A choice of exposure settings according to the clinical situation (ALARA principle) is recommended to achieve possible dose reductions.
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Direct Digital Radiography Versus Storage Phosphor Radiography in the Detection of Wrist Fractures
Clinical radiology, 2002Co-Authors: Siegfried Peer, Ulrich Neitzel, S. M. Giacomuzzi, Sigurd Pechlaner, Karl Heinz Künzel, R. Peer, Eva Gassner, Iris Steingruber, O. Gaber, Werner JaschkeAbstract:Abstract AIM: To define the value of digital radiography with a clinical flat panel detector system for evaluation of wrist fractures in comparison with state of the art Storage Phosphor radiography. MATERIAL AND METHODS: Hard copy images of 26 fractured wrist specimens were acquired with the same exposure dose on a state of the art Storage Phosphor radiography system and a clinical flat panel detector. Image features like cortical bone surface, trabecular bone, soft tissues and fracture delineation were independently analysed by 4 observers using a standardised protocol. Image quality ratings were evaluated with an analysis of variance (ANOVA). RESULTS: Flat panel detector radiographs were rated superior with respect to cortical and trabecular bone representation as well as fracture evaluation, while Storage Phosphor radiographs produced better soft tissue detail. CONCLUSION: In some of the observed image quality aspects, the performance of caesium iodide/amorphous silicon flat panel detector exceeds state of the art Storage Phosphor radiography. This makes it well suited for skeletal imaging particularly in trauma as seen in the detection of wrist fractures . Peer, S. et al . (2002). Clinical Radiology 57 , 258–262.
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Comparison of low-contrast detail perception on Storage Phosphor radiographs and digital flat panel detector images
IEEE transactions on medical imaging, 2001Co-Authors: Siegfried Peer, Ulrich Neitzel, S. M. Giacomuzzi, R. Peer, Eva Gassner, Iris Steingruber, Werner JaschkeAbstract:A contrast detail analysis was performed to compare perception of low-contrast details on X-ray images derived from digital Storage Phosphor radiography and from a flat panel detector system based on a cesium iodide/amorphous silicon matrix. The CDRAD 2.0 phantom was used to perform a comparative contrast detail analysis of a clinical Storage Phosphor radiography system and an indirect type digital flat panel detector unit. Images were acquired at exposure levels comparable to film speeds of 50/100/200/400 and 800. Four observers evaluated a total of 50 films with respect to the threshold contrast for each detail size. The numbers of correctly identified objects were determined for all image subsets. The overall results show that low-contrast detail perception with digital flat panel detector images is better than with state of the art Storage Phosphor screens. This is especially true for the low-exposure setting, where a nearly 10% higher correct observation ratio is reached. Given its high detective quantum efficiency the digital flat panel technology based on the cesium iodide scintillator/amorphous silicon matrix is best suited for detection of low-contrast detail structures, which shows its high potential for clinical imaging.
