Flat-panel x-ray detector based on amorphous silicon versus asymmetric screen-film system: phantom study of dose reduction and depiction of simulated findings.
OBJECTIVE
To compare a large-area amorphous silicon flat-panel detector with an asymmetric screen-film system for the depiction of simulated patterns of interstitial lung disease, nodules, and catheters, as well as for evaluation of dose reduction.


METHODS
Ground-glass, linear, miliary, and reticular patterns; nodules; and catheters were superimposed over an anthropomorphic chest phantom. Hard copies were generated at different dose levels (speeds: 400, 800, and 1,600) with a flat-panel detector and were compared with copies generated with an asymmetric screen-film system (speed, 400). Detection performance of eight radiologists was compared with a receiver operating characteristic analysis of 19,200 observations per pattern. A difference was significant with a P value of.05.


RESULTS
There was no statistically significant difference between the flat-panel detector and the asymmetric screen-film system at the same speed (P >.05) and between the flat-panel detector at a speed of 800 and the asymmetric screen-film system at a speed of 400 (P >.05). The visibility of linear, miliary, and reticular patterns over lucent lung and of nodules smaller than 10 mm and catheters over obscured chest regions on copies generated at a speed of 1,600 with the flat-panel detector decreased, compared with the visibility of these features on copies generated with the asymmetric screen-film system (P <.05).


CONCLUSIONS
The diagnostic performance of the flat-panel detector is comparable to that of the asymmetric screen-film system for depiction of all simulated patterns of interstitial lung diseases, nodules, and catheters at the same speed and offers the potential of dose reduction to a speed of 800.
Rapp-Bernhardt
Ulrike
U
Department of Clinical Radiology, University of Muenster, Albert-Schweitzer-Strasse 33, Germany. bernhart@uni-muenster.de
Roehl
Friedrich W
FW
Gibbs
Robert C
RC
Schmidl
Hagen
H
Krause
Ulrich W
UW
Bernhardt
Thomas M
TM
D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011859:Radiography; D012825:Silicon; D014963:X-Ray Intensifying Screens
D012825:Silicon