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Proceedings Paper

Practical method for detected quantum efficiency (DQE) assessment of digital mammography systems in the radiological environment
Author(s): Frank Rogge; Dirk A. Vandenbroucke; Luc Struye; Hilde Bosmans; Peter Willems; Guy Marchal
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Paper Abstract

X-ray detector systems can be characterized by their measured or estimated detective quantum efficiency (DQE). Assessment of DQE includes a measurement of the modulation transfer function (MTF) and the normalized noise power spectrum (NNPS). The incoming X-ray quantum flux has to be estimated. In this paper, the influence of the different possibilities regarding the measurement methods and phantoms, the X-ray quantum flux estimation models and the exposure geometry on the DQE of a full field digital mammography detector is assessed. Physical models were used to fit MTF measurements from bar-pattern and edge phantoms. The NNPS was calculated by 2D-FFT on a large number of flat-field subimages. The flux was calculated using anode spectra models (Boone, 1997) and attenuation data (NIST). We compared the influence of scattered radiation MTF calculations of both phantoms were similar. The edge method is preferred for practical reasons. NNPS data were similar to 1D synthetic-slit measurements. DQE data compared well with literature. Different exposure geometry conditions (with scattered radiation) showed similar results but a siginificantly lower DQE than in absence of scattered radiation. DQE assessment is feasible using normal exposure conditions, an edge phantom and calculated estimations of the flux.

Paper Details

Date Published: 3 May 2002
PDF: 11 pages
Proc. SPIE 4682, Medical Imaging 2002: Physics of Medical Imaging, (3 May 2002); doi: 10.1117/12.465609
Show Author Affiliations
Frank Rogge, Univ. Hospital Gasthuisberg (Belgium)
Dirk A. Vandenbroucke, Agfa-Gevaert NV (Belgium)
Luc Struye, Agfa-Gevaert NV (Belgium)
Hilde Bosmans, Univ. Hospital Gasthuisberg (Belgium)
Peter Willems, Agfa-Gevaert NV (Belgium)
Guy Marchal, Univ. Hospital Gasthuisberg (Belgium)

Published in SPIE Proceedings Vol. 4682:
Medical Imaging 2002: Physics of Medical Imaging
Larry E. Antonuk; Martin Joel Yaffe, Editor(s)

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