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Proceedings Paper

Validation of software for QC assessment of MTF and NPS
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Paper Abstract

Modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) are widely accepted measures of digital radiographic system performance. However the implementation of these measurement methodologies has been limited to a handful of researchers using an assortment of techniques. A prototype edge tool and easy-to-use software program, which can generate MTF, NPS, and DQE results quickly and easily in the field, have been developed. The edge tool consists of 1mm or 250 μ thick tungsten with two polished edges. Edge and NPS data were obtained and analyzed by 3 investigators using three analysis methods: Method A, the software under development for this report; Method B, code available on the web site of one of the investigators [Saunders and Samei, Med. Phys. 33, 308-319 (2006)]; and Method C, code developed by two other of the investigators [Samei and Flynn, Med Phy. 30, 608-622, (2003)]. In all cases the differences between the results using Method B and Method A were less than 1%. The differences between Method A and Method C were larger, up to 5.26%. NPS were calculated using Method A and B. The results were very close, with average errors less than 2.5% for exposures of 27.3, 9.3, and 2.7 μGy. Analysis of data for a 10 cm misalignment shows no significant error for either the 250 μ or 1mm edge. The method developed gives results that correlate closely with results obtained from established methods. The software is easy-to-use and flexible in its application. The Edge Tool developed has the necessary precision to accurately determine the MTF values of the system. Further validation of NPS and DQE is ongoing.

Paper Details

Date Published: 22 March 2007
PDF: 7 pages
Proc. SPIE 6510, Medical Imaging 2007: Physics of Medical Imaging, 65104F (22 March 2007); doi: 10.1117/12.713434
Show Author Affiliations
Walter Peppler, Univ. of Wisconsin-Madison (United States)
Wei Hong, Gammex, Inc. (United States)
Robert Steinhauser, Gammex, Inc. (United States)
Bruce Whiting, Mallinckrodt Institute of Radiology (United States)
Ehsan Samei, Duke Advanced Imaging Lab. (United States)
Michael Flynn, Henry Ford Health System (United States)
Steven Don, Mallinckrodt Institute of Radiology (United States)
Nathan Corradini, Univ. of Wisconsin-Madison (United States)


Published in SPIE Proceedings Vol. 6510:
Medical Imaging 2007: Physics of Medical Imaging
Jiang Hsieh; Michael J. Flynn, Editor(s)

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