Title: Variability of contrast threshold detail measurements for full field digital mammography systems
Abstract: Image quality evaluation for full field digital mammography detectors, considered an integral part of a quality assurance program in digital mammography, is carried out using the CDMAM test object, a 50mm PMMA breast equivalent phantom with embedded gold discs of varying diameters (0.08 – 2 mm) and thicknesses (0.03 – 1.42 μm). Threshold contrast levels of a system, determined by automated reading software analysis (CDCOM) of CDMAM images, measure the last ‘just visible’ thickness details which can then be compared with acceptable and achievable limits as recommended by the EUREF European guidelines. The test offers a clinically relevant measure of imaging performance, with previous studies having established conversion factors directly relating the threshold contrast levels of a system as determined for human and automated observers. The employment of these conversion factors, which is recommended by the European guidelines, now means the threshold contrast measurements approach the border between acceptable and unacceptable limits, and, thus, it is important that the variability of threshold measurements be established. Furthermore, different sets of ratios have been reported in the literature and consequently the employment of the different ratios may give different contrast thresholds measurements. In this study a number of experiments were carried out on two digital mammography systems to establish the variability of their contrast-detail thresholds with a view to establishing confidence intervals of the CDMAM outputs. This data would offer valuable additional information to the hospital-based medical physicist if met with a borderline case of contrast-detail acceptability.
Publication Year: 2013
Publication Date: 2013-08-17
Language: en
Type: article
Indexed In: ['crossref']
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