Detection of simulated chest lesions with normal and reduced radiation dose: comparison of conventional screen-film radiography and a flat-panel x-ray detector based on amorphous silicon.
OBJECTIVE
The authors compared a solid-state amorphous silicon (a-Si) detector and screen-film radiography (SFR) with regard to the detection of simulated pulmonary lesions. Evaluation of the impact of a dose reduction of 50% with this digital flat-panel detector was of special interest.


METHODS
A self-scanning flat-panel detector, based on a-Si technology with 143 x 143 microm pixel size, 1 k x 1 k matrix and 12-bit digital output was used. An asymmetric state-of-the-art screen-film system was compared with a-Si images taken at the same dose as SFR-images and at a dose reduced by 50%. An anthropomorphic chest phantom was superimposed by templates containing nodules, linear structures, reticular, and micronodular opacities in a random distribution. Receiver operating characteristic analysis was performed for 23,040 observations made by four independent observers. Student's t test (95% confidence-level) was used for statistical analysis.


RESULTS
Receiver operating characteristic analysis showed that a-Si images taken at the same dose as SFR-images were significantly superior to SFR with respect to the detectability of lines (P = 0.01) and micronodular opacities (P < 0.01). For the other objects and the a-Si images taken at a reduced dose, it yielded no statistically significant differences between both imaging modalities.


CONCLUSIONS
The results of this phantom study indicate that a-Si detector technology holds promise in terms of dose reduction in chest radiography without loss of diagnostic accuracy compared with SFR.
Strotzer
M
M
Department of Diagnostic Radiology, University Hospital, Regensburg, Germany.
Gmeinwieser
J K
JK
Völk
M
M
Fründ
R
R
Seitz
J
J
Feuerbach
S
S
D006801:Humans; D019047:Phantoms, Imaging; D012372:ROC Curve; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods*; D013902:Radiography, Thoracic; D012825:Silicon; D013899:Thoracic Neoplasms / Q000000981:diagnostic imaging; D014963:X-Ray Intensifying Screens
D012825:Silicon