Optimum exposure conditions for computed radiography depending on fixed pattern noise and efficiency of imaging plate-scanner systems

Journal Article · Thu Jun 23 04:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3591892· OSTI ID:21511643

Ewert, U; Heyne, K; Zscherpel, U; Jechow, M ^[1]; Bavendiek, K ^[2]

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1. 1 BAM Federal Institute for Materials Research and Testing, D-12205 Berlin (Germany)
2. YXLON International GmbH, D-22419 Hamburg (Germany)

The presently active standards on Computed Radiography (CR) need a major revision. It was observed by many users that the image quality for class B of EN 14784-2 is not achievable under the same exposure conditions as used for film exposure. A mathematical model was developed and tested, which allows the calculation of the image quality, proven by image quality indicators (IQI), depending on the fixed pattern noise and the efficiency of the used imaging plate (IP) scanner system. All tested IP scanner systems provide a fixed correlation between the measured signal/noise ratio (SNR) and the grey values in the digital images. The maximum achievable SNR{sub max} depends on the fixed pattern noise of the plate (high dose limit). Depending on the exposure dose an optimum visibility of IQIs can be predicted by calculation and measured considering the attenuation coefficient for calculation of the contrast/noise ratio (CNR). The diameter of the just visible wire is proportional to 1/sqrt(CNR). The optimum tube voltage for best visibility of IQIs and maximum CNR depend on the exposure dose. The optimum tube voltage for best visibility is achieved only at exposures with high dose. A dose dependant optimal tube voltage was not observed for film radiography.

• OSTI ID: 21511643
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 1335; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
ATTENUATION
BOSONS
COMPUTERIZED TOMOGRAPHY
CORRELATIONS
DIAGNOSTIC TECHNIQUES
DIMENSIONLESS NUMBERS
EFFICIENCY
ELECTRIC POTENTIAL
ELEMENTARY PARTICLES
FILMS
IMAGE PROCESSING
IMAGES
INDUSTRIAL RADIOGRAPHY
MASSLESS PARTICLES
MATERIALS TESTING
NOISE
NONDESTRUCTIVE TESTING
PHOTONS
PLATES
PROCESSING
SIGNAL-TO-NOISE RATIO
TESTING
TEXTURE
TOMOGRAPHY