The following scientific studies have been published using the Revolution XQ/i:

• Clinical Accuracy
• Image Quality
• Dose
• Physics
• System Design
• Advanced Applications
• Clinical

Comparison of a Flat-Panel Digital System with a Conventional Screen-Film System: Anatomical Visibility and Image Quality in Chest Radiographs of 70 Oncology Patients
In regions for which a difference was measured, the digital chest was judged superior. These regions were the peripheral pulmonary vessels on the PA view and the retrocardiac pulmonary vessels on the lateral view. Overall image quality was judged superior for the digital system. This was true even though the radiation dose was 50% less with the digital system compared to the screen-film system.
C Fink, J Hansmann, PJ Hallscheidt, G Noeldge, A Kampschulte, GW Kauffmann, University of Heidelberg, Germany
Abstract #1424, presented at RSNA 2000.

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A new type of flat panel, X-ray detector system compared to a cassette system direct digitizer in the diagnosis of pneumothorax
Image quality comparison between DR, CR, S-F (anthropomorphic phantom): Even at 50% dose reduction DR was found superior to screen-film and CR. Pneumothorax detection - comparison of DR and CR: On 15 pneumothorax cases, 14 were detected by all radiologists with both DR (1/2 dose) and CR; one case was detected only with DR.
A Kampschulte, C Fink, M Hahmann, U Leutloff, J Hansmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #VO289, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Pneumothorax Detection: Comparison of Flat-Panel Amorphous Silicon and Computed Radiography Detectors
Fifteen pneumothoraces were detected, in 14 cases the pneumothorax was detected by all radiologists with images from both detectors. In the final case, the pneumothorax was detected by 2 of 3 radiologists using the flat-panel detector and was not detected by any of the radiologists using the CR images...[the digital detector was used at] 50% of the dose used for the CR system.
A Kampschulte, J Hansmann, M Hahmann, UC Leutloff, C Fink, GW Kauffmann, University of Heidelberg, Germany
Abstract #106CH, presented at RSNA 2000.

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A new type of flat panel, X-ray detector system in clinical use on the thorax: Evaluation of 70 oncology care patients
GW Kauffmann et al, University of Heidelberg, Germany
presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Study of clinical use in evaluating the image quality of a new digital flat panel, X-ray detector system compared to existing cassette system direct digitizers
These results demonstrate the superior image quality of the digital flat imaging detector workstation with a dose reduction of 50% compared to a CR system.
B Radeleff, A Kampschulte, C Fink, W Hosh, G Kauffmann, J Hansmann, University of Heidelberg, Germany
Abstract #VO288, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Evaluation of Image Presentation Algorithms for Digital Radiography
Digital radiographic PA and Lateral chest images were preferred to popular wide latitude and high contrast film-screen combinations - preferences were statistically significant.
SF Schubert*, KS Kump*, GE Medical Systems, USA
Abstract #959, presented at RSNA 1999.

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Clinical Comparison of a New Digital X-ray Detector with Conventional Screen Film
97% of radiologists say Digital is EQUIVALENT or BETTER than Film. 68% say Digital is BETTER than Film.
S Shi*, K Kump*, GE Medical Systems, USA
Abstract #3659-47, Proceedings of SPIE 1999, Physics of Medical Imaging, vol. 3659, pp. 464-470.

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Image Quality

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Digital chest radiography with a solid-state flat-panel X-ray detector: Contrast-detail evaluation with processed images printed on film hard copy
Using the digital system, radiologists have the option to choose either superior image quality at conventional dose levels or reductions in patient dose while maintaining image quality comparable to that of screen-film radiographs. Test signals with lower inherent subject contrast were detected more readily on digital images than on screen-film images, even when x-ray exposure levels for the digital system were reduced by 20%.
HG Chotas, CE Ravin, Duke, USA
Radiology, March 2001, v. 218, pp. 679-682.

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Processing of X-Ray Images Obtained with an X-Ray Flat Panel Detector
At an equal entrance exposure the digital detector improves object detectability when compared to a standard thoracic screen-film. Approximately 50% dose savings could be obtained for digital while maintaining the same detectability of low-contrast objects.
G Dubroeucq*, P Gobert*, K Kump*, F Pla*, S Schubert*, GE Medical Systems, France
presented at JFR 1999.

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Improved contrast detail resolution on the thoracic workstation with a solid-state detector compared to screen-film and cassette system direct digitizer
A contrast-detail resolution comparable to screen-film cassette is achieved with approximately 60% dose reduction using a solid state detector. With comparable dose the resolution of contrast of the solid state detector image is superior to the other techniques.
G Erb, K Aretz, J Hansmann, C Fink, M Hahmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #PO15, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Improved Contrast-Detail Detection with Flat-Panel Digital Radiography: Comparison with Computed Radiography and a Conventional Film-Screen System
The contrast-detail detection of a standard conventional film-screen combination can be achieved with flat-panel system with a dose reduction of 60%. Computed radiography showed substantially lower detection than either the flat-panel or film-screen systems. Using the same dose, flat-panel detector images have superior low contrast object detection compared to CR or film-screen systems.
G Erb, K Aretz, M Hahmann, BA Radeleff, J Hansmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #272PH, presented at RSNA 2000.

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Presentation Matching of Digital Radiographic Images to Analog Screen/Film Images
The phantom images showed agreement in optical densities (within 0.2 optical density) over the dynamic range for both simulated screen film types. Clinical images were reviewed by nine radiologists at three institutions to evaluate the image presentation. Overall, the digital images were rated equivalent or better in 85% of all cases.
KS Kump*, SF Schubert*, GE Medical Systems, USA
Abstract #957, presented at RSNA 1999.

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Comparison of a-Si:H/CsI flat-panel digital imaging system with CR and CCD based systems: image quality measurements
For chest imaging, the flat-panel system was shown to have significantly higher DQE (52% at 0 lp/mm) than the CR system (22% at 0 lp/mm). All images were acquired in their commercial packaging and were subject to x-ray attenuation by additional objects in the x-ray path, therefore the DQE numbers are suppressed.
X Liu, CC Shaw, MD Anderson Cancer Center, USA
Abstract #4320-89, Presentation at SPIE 2001 (Poster), Image Processing

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Evaluation of the performance of a new flat panel, X-ray detector system on a thorax phantom with defined pathologies compared to an existing screen-film and cassette system direct digitizer
These results demonstrate the superior detail resolution of the digital flat image detector in comparison to CR and film-screen systems, even with a dose reduction of 50%.
B Radeleff, M Hahmann, A Kampschulte, J Hansmann, G Kauffmann, University of Heidelberg, Germany
Abstract #PO16, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems – a contrast-detail phantom study
The results demonstrated that the flat-panel imaging technique has a low contrast performance far superior to those of screen/film or CR techniques. Compared to screen/film and CR techniques, the flat-panel imaging technique requires only about half of the contrast level to detect and visualize objects of the same size. Alternatively, the x-ray exposure can be reduced substantially to maintain a low contrast performance comparable to those of screen/film and CR techniques.
J Rong, C Shaw, X Liu, M Lemacks, MD Anderson, USA
Presentation #WE-B307-04, presented at the 2000 World Congress on Medical Physics, Chicago, July.

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Two Techniques for Improved Digital Chest Imaging
CC Shaw, X Liu, RF Munden, GJ Whitman, MD Anderson, USA
Space 0102PH, presented at RSNA 1999.

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Low Contrast Detectability and Dose Savings with an Amorphous Silicon Detector Designed for X-ray Radiography
Contrast detectability is significantly improved with the digital detector and 56% dose savings can be achieved using the digital detector.
P Xue*, S Schubert*, R Aufrichtig*, GE Medical Systems, USA
Abstract #3981-28, Proceedings of SPIE 2000, Image Perception and Performance, vol. 3981, pp. 194-200.

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Productivity

Workflow comparison of DR and screen-film dedicated chest systems
In a high volume ambulatory patient care center, a dedicated chest DR can provide improved workflow and technologist productivity over screen-film, and can increase the overall speed-of-service from examination ordering to interpretation available. 10 technologists unanimously preferred DR over the film-based chest unit, rating the DR system as “Much Better” (+2) than film for all areas (including speed, performance, and ease-of-use). The Time to Image Availability for Interpretation was much faster for DR (5.7 ± 2.5 minutes) versus screen-film (29.2 ± 14.3 minutes).
KP Andriole, RG Gould, DM Luth, UCSF, USA
Abstract #4323-33, Presentation at SPIE 2001 (Oral), PACS and Integrated Medical Information Systems

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Dose

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Dose reduction in thoracic imaging: Comparison of absorption in susceptible classes 400 and 640 on a full digital thoracic workstation with a flat panel, X-ray detector
The average surface dose product for the 400 speed settings amounted to 0.951 dGycm2, the 640 speed settings resulted in 0.646 dGycm2. An independent image evaluation resulted in better image scores for 1/3 of all cases; these patients had better scoring in the BWS retrocardiac region, however this difference is not statistically significant different for the two speed settings.
J Hansmann, K Aretz, A Kampschulte, C Fink, M Hahmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #VO283, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Dose Reduction in Clinical Chest Radiography: Comparison of 400 vs 640 Speed Images on a Flat-Panel Chest Radiography Unit
The independent image evaluation resulted in a slightly better depiction of the thoracic vertebral column for the higher dose images [640 versus 400 speed]. Image quality of chest radiographs obtained with a 38% dose reduction are of comparable image quality to those obtained at a 400 speed setting.
J Hansmann, BA Radeleff, A Kampschulte, M Hahmann, K Aretz, GW Kauffmann, University of Heidelberg, Germany
Abstract #1426, presented at RSNA 2000.

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Significant reduction in radiation dose in thoracic diagnosis using a solid-state detector
Using a solid state detector standard image quality with good image sharpness can be achieved using 50-77% dose reduction.
W Hosch, K Aretz, B Radleff, J Hansmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #PO14, presented at the German Radiology Congress 2000, Wiesbaden, abstract in Fortschr Röntgenstr (RöFo), vol. 172, 2000.

Dose Reduction in Chest Radiography: Comparison of a Flat-Panel Amorphous Silicon Detector with a Conventional X-ray Film System
The comparison of chest x-ray images of an anthropomorphic thorax phantom taken with the first generation flat-panel amorphous silicon detector and a conventional x-ray film system demonstrates an improved image quality of this new x-ray-system. The flat-panel amorphous silicon detector offers the possibility for a reduction of the patient's radiation dose of 77% without any loss in image quality.
WP Hosch, K Aretz, G Erb, BA Radeleff, J Hansmann, GW Kauffmann, University of Heidelberg, Germany
Abstract #565PH, presented at RSNA 2000.

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Physics

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Comparison of low contrast detectability between a digital amorphous silicon and a screen-film based imaging system for thoracic radiography
The detector used in this study has a zero frequency DQE in excess of 70%, which is superior to both state-of-the-art screen-film and phosphor plates, for which the DQE(0) only approaches 25%. On average, the disk shaped objects can be detected at 45% less contrast [using the GE a-Si digital detector] than required for screen-film.
R Aufrichtig*, GE Medical Systems, USA
Medical Physics, vol. 26, no. 7, July 1999, pp. 1349-1358.

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Operation of amorphous silicon detectors for chest radiography within system latency requirements
The technique, known as repeated-timing, satisfies several critical system latency requirements and can be used for chest radiography systems which employ automatic exposure control. In addition, repeated timing eliminates large-area artifacts which result from a change in the detector timing.
JM Boudry*, GE Medical Systems, USA
Abstract #3659-33, Proceedings of SPIE 1999, Physics of Medical Imaging, vol. 3659, pp. 336-345.

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Imaging characteristics of an amorphous silicon flat-panel detector for digital chest radiography
Images obtained with the FPD demonstrated excellent uniformity, repeatability, and linearity, as well as MTF and DQE that were superior to those with the storage phosphor CR system. The value of 66% for the DQE at zero frequency at 0.3 mR for the FPD system is substantially higher than the value for the storage phosphor CR system (28%) or screen-film radiography.
CE Floyd Jr, RJ Warp, JT Dobbins III, HG Chotas, AH Baydush, R Vargas-Voracek, CE Ravin, Duke, USA
Radiology, March 2001, v. 218, pp. 683-688.

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Performance of a 41x41-cm^2 amorphous silicon flat panel x-ray detector for radiographic imaging applications
The measured DQE at an exposure of about 1 mR was 0.66 at zero spatial frequency and fell smoothly with frequency to a value of 0.24 at the Nyquist frequency, 2.5 cycles/mm. For a gain that allows a maximum exposure of 5 mR, the DQE at 0.056 mR was 0.64 at zero frequency and 0.19 at 2.5 cycles/mm. The standard deviation in DQE among measurements on different detectors [15 total] was less than 0.02 at any frequency.
PR Granfors*, R Aufrichtig*, GE Medical Systems, USA
Medical Physics, vol. 27, no. 6, June 2000, pp. 1324-1331.

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DQE(f) of an Amorphous Silicon Flat Panel X-ray Detector: Detector Parameter Influences and Measurement Methodology
DQE degradation can be controlled through careful design in an a-Si flat panel detector with CsI(Tl) scintillator. Thickness of scintillator can be adjusted to optimize performance. Thicker scintillators have greater x-ray absorption, and better low-frequency DQE.
P Granfors*, R Aufrichtig*, GE Medical Systems, USA
Abstract #3977-1, Proceedings of SPIE 2000, Physics of Medical Imaging, vol. 3977, pp. 2-13.

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Performance Characteristics of an Amorphous Silicon Flat Panel X-ray Imaging Detector
Radiography - Detector images equivalent or superior to paired conventional images. Cardiac - Blinded comparison of 19 pairs of cardiac record level sequences found that the flat panel detector scored higher in 40 of 44 categories compared to an image intensifier system. Fluoro - Comparison of 8 pairs of fluoro level sequences found that the flat panel detector scored higher in 36 of 44 categories.
PR Granfors*, GE Medical Systems, USA
Abstract #3659-49, Proceedings of SPIE 1999, Physics of Medical Imaging, vol. 3659, pp. 480-490.

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Performance of an Amorphous Silicon Flat Panel X-Ray Imaging Detector for General Radiography
Detector performance has been verified to be consistent over 15 detectors. Detector response is uniform over the surface of the detector. Detector DQE is superior to selenium flat panel, computed radiography, thoracic film-screen.
PR Granfors*, R Aufrichtig*, GE Medical Systems, USA
Abstract #584, presented at RSNA 1999.

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GE Digital X-Ray Detector Technology
The digital detector] not only has a two to three times greater dynamic range, but a significantly higher DQE than analog film. Preliminary clinical data using 25 paired chest images are presented and analyzed. In 97% of the images, the radiologists considered the digital detector images to be equivalent, better or significantly better than the screen-film images.
K Kump*, P Granfors*, F Pla*, P Gobert*, GE Medical Systems, USA
presented at JFR 1998.

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Comparison of an a-Si:H/CsI:Tl Flat-panel Imager with CR Imaging System
The DQE of DR is significantly higher (by a factor of about 2.5) than those of CR systems. The contrast-detail curves obtained from the phantom images showed that the flat-panel system has a low contrast performance significantly better than those of CR and screen-film systems.
X Liu, CC Shaw, JX Rong, MD Anderson, USA
Abstract #1298, presented at RSNA 2000.

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Evaluation of a CsI:Tl Based a-Si:H Flat-Panel Digital Chest Unit: Correlation of Contrast-Detail Curves with Contrast-to-Noise Ratio Measurements
The results have shown that there is a correlation between low-contrast detectability and the CNR if the noise is averaged over the object area. Various image correction procedures will be necessary to obtain consistent and universal threshold CNRs for detection of low-contrast objects.
JX Rong, CC Shaw, X Liu, MD Anderson, USA
Abstract #1296, presented at RSNA 2000.

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Comparison of a-Si:H/CsI flat-panel digital imaging system with a CCD based system, CR system, and conventional screen-film systems: a contrast-detail phantom study
The results of a contrast-detail phantom study demonstrated that the flat-panel system performed significantly better than the CR and screen/film systems while the latter two systems performed about the same. Alternatively, an exposure reduction by at least 70% is possible if the same performance is maintained.
JX Rong, CC Shaw, X Liu, MR Lemacks, SK Thompson, MD Anderson Cancer Center, USA
Abstract #4320-88, Presentation at SPIE 2001 (Poster), Image Processing

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DQE measurement results for direct and indirect digital radiography detectors
The purpose of this work was to compare direct and indirect detectors in terms of their modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE). DQE measurements were made on three flat-panel detectors, Philips Digital Diagnost (not reported because of the depressed noise on the axes of the 2D NPS), GE Revolution XQ/i (58% at 0.15 lp/mm), and Hologic Direct-Ray DR1000 (38% at 0.15 lp/mm).
E Samei, MJ Flynn, HG Chotas, JT Dobbins III, Duke, USA
Abstract #4320-90, Presentation at SPIE 2001 (Poster), Image Processing

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System Design

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Assessment of Image Quality among Multiple Output Devices Using Digital X-ray Radiographs
The image presentation is not equal among output devices. However, despite large differences in absolute luminance and image tint, the perception of image contrast (aka grayscale) differences was small.
KS Kump*, J Omernick*, GE Medical Systems, USA
Abstract #832, presented at RSNA 2000.

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Digital X-Ray Detector Technology
The digital detector] not only has a two to three times greater dynamic range, but a significantly higher DQE than analog film. Preliminary clinical data using 25 paired chest images are presented and analyzed. In 97% of the images, the radiologists considered the digital detector images to be equivalent, better or significantly better than the screen-film images.
K Kump*, P Granfors*, F Pla*, P Gobert*, GE Medical Systems, USA
Revue Europeenne de Technologie Biomedicale, vol. 20, no. 9, December 1998.

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Image design criteria for selecting an anti-scatter grid for a digital radiographic x-ray system
In order to minimize the effect of grid line artifacts it is essential to select a line rate at which the spatial sensitivity of the human visual system is decreased. X-ray grids selected for digital imagers must maximize KSNR and minimize image artifacts. A high grid ratio provides better KSNR but requires very accurate alignment.
P Xue*, R Aufrichtig*, GE Medical Systems, USA
Abstract #9, presented at RSNA 1999.

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Advanced Applications

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The development and characterization of a dual-energy subtraction imaging system for chest radiography based on CsI:Tl amorphous silicon flat-panel technology
Given the high detector DQE, and allocation of dose between the two views, we can acquire dual-energy PA and conventional lateral images with total dose equivalent to a conventional two-view chest exam. The quality of the clinical images generated with this prototype exceeds that of CR techniques and demonstrates the potential for improved detection and characterization of lung disease through dual-energy imaging.
JM Sabol*, GB Avinash*, F Nicolas*, B Claus*, J Zhao*, GE Medical Systems, USA
Abstract #4320-34, Presentation at SPIE 2001 (Oral), Physics of Medical Imaging

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Filtered-Backprojection for Improved Blurring in Circular Tomosynthesis
A filtering technique has been developed which alters the impulse response of circular tomosynthesis in order to flexibly control the blurring of off-plane objects. This can be used to generate images [using a flat panel digital detector], using circular motion, which mimic a system with a more complicated geometry (i.e., one that produces a disk-shaped blurring function).
GM Stevens, R Fahrig, NJ Pelc, Stanford, USA
Abstract #468, presented at RSNA 2000.

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Filtered backprojection for modifying the impulse response of circular tomosynthesis
This technique can reconstruct images with a blurring function which is more homogeneous for off-focal plane objects than that from circular tomosynthesis.
GM Stevens, R Fahrig, NJ Pelc, Stanford, USA
Medical Physics, vol. 28, no. 3, March 200,1pp. 295-405.

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Development of a Volumetric Tomosynthesis and Tomography System
An experimental device was developed which allow comparison of radiography, circular tomosynthesis and volumetric CT using a large area digital x-ray detector for a range of potential applications.
GM Stevens, RF Saunders*, NJ Pelc, Stanford, USA
Abstract #604, presented at RSNA 1998.

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System Alignment for a Volumetric Tomography System
Tomosynthesis images generated on the system with the applied geometry correction yield focal lane spatial resolution consistent with the detector pixel size and data interpolation. Resampling and backprojecting radiographs with a spatial resolution of 2.8 lp/mm yields tomosynthesis images with a spatial resolution of 2.2 lp/mm. Geometry misalignment effects can be subtle, with shifts of the optimal reconstruction plane.
GM Stevens, NJ Pelc, Stanford, USA
Abstract #955, presented at RSNA 1999.

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* GE Healthcare