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Proceedings Paper

Low contrast detectability and dose savings with an amorphous silicon detector designed for x-ray radiography
Author(s): Ping Xue; Scott F. Schubert; Richard Aufrichtig
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Paper Abstract

In an observer study we compare low contrast detectability and dose efficiency of an amorphous silicon x-ray detector versus a standard thoracic screen-film (Kodak InSight HC/InSight IT). Twelve images of a CDRAD contrast-detail phantom were acquired with the screen-film system using an entrance exposure corresponding to a conventional chest x-ray. Using the same x- ray system with an interchanged digital detector, we acquired four digital image sets (12 images each) at dose levels corresponding to 27%, 41%, 63% and 100% of the film dose. Prior to laser printing, the digital images were processed to match the film contrast and optical density level. A 4- alternative forced choice (4-AFC) paradigm with seven observers was used to measure the threshold contrasts of disk sizes from 0.5 to 4.0 mm. Further, we estimated the equivalent perceptual dose (EPD), which is the dose level of digital for which the same contrast detectability as film is obtained. Contrast detectability is significantly improved with the digital detector. On average, all disk shaped objects detected from the digital detector have lower threshold contrasts than those from film at the same dose level. The EPD value averaged over disk size is 44%, which corresponds to a 56% dose savings for the digital detector.

Paper Details

Date Published: 14 April 2000
PDF: 7 pages
Proc. SPIE 3981, Medical Imaging 2000: Image Perception and Performance, (14 April 2000); doi: 10.1117/12.383109
Show Author Affiliations
Ping Xue, GE Medical Systems (United States)
Scott F. Schubert, GE Medical Systems (United States)
Richard Aufrichtig, GE Medical Systems (United States)

Published in SPIE Proceedings Vol. 3981:
Medical Imaging 2000: Image Perception and Performance
Elizabeth A. Krupinski, Editor(s)

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