5 June 2003 Use of MTF calculation in global and local resolution assessment in digital mammography
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Abstract
The purpose of this study is to propose a test procedure for global and local resolution assessment in digital mammography to detect sharpness problems. The MTF calculation was based on the presampled edge method. In a first phase, we compared the effect of geometry and exposure conditions on the MTF. Results were: (1) the MTF was reproducible; (2) MTF data can be corrected for edge angle; (3) scatter conditions have significant influence; (4) edge position in the detector plane has negligible influence; (5) the required edge length for our algorithm is longer than the critical length to get rid of noise effects; (6) exposure conditions have no major influence except at very low dose levels. We propose to approximate clinical working conditions for the global MTF-check, with an edge-object embedded in 45mm PMMA and clinical exposures. Localized MTF calculations with this phantom and software can be automated for QA by the medical physicist. For sharpness analysis all over the detector, we designed a test-object with oblique, parallel bars and automatic software tools are being developed. By means of software simulations, local variations in the sharpness could be detected. Validation in practice and further automation of the software tools is ongoing.
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Frank Rogge, Hilde Bosmans, Peter Willems, Guy Marchal, "Use of MTF calculation in global and local resolution assessment in digital mammography", Proc. SPIE 5030, Medical Imaging 2003: Physics of Medical Imaging, (5 June 2003); doi: 10.1117/12.480008; https://doi.org/10.1117/12.480008
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