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Proceedings Paper

Exploration of exposure conditions with a novel wireless detector for bedside digital radiography
Author(s): Hilde Bosmans; Joris Nens; Louis Delzenne; Nicholas Marshall; Herman Pauwels; Walter De Wever; Raymond Oyen
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Paper Abstract

We propose, apply and validate an optimization scheme for a new wireless CsI based DR detector in combination with a regular mobile X-ray system for bedside imaging applications. Three different grids were tested in this combination. Signal-difference-to-noise was investigated in two ways, using a 1mm Cu piece in combination with different thicknesses of PMMA and by means of the CDRAD phantom using 10 images per condition and an automated evaluation method. A Figure of Merit (FOM), namely SDNR2/Imparted Energy, was calculated for a large range of exposure conditions, without and with grid in place. Misalignment of the grids was evaluated via the same FOMs. This optimization study was validated with comparative X-ray acquisitions performed on dead bodies. An experienced radiologist scored the quality of several specific aspects for all these exposures. Signal difference to noise ratios measured with the Cu method correlated well with the threshold contrasts from the CDRAD analysis (R2 > 0.9). The analysis showed optimal FOM with detector air kerma rates as typically used in clinical practice. Lower tube voltages provide higher FOM than the higher values but their practical use depends on the limitations of X-ray tubes, linked to patient motion artefacts. The use of high resolution grids should be encouraged, as the FOM increases with 47% at 75kV. These scores from the Visual grading study confirmed the results obtained with the FOM. The switch to (wireless) DR technology for bedside imaging could benefit from devices to improve grid positioning or any scatter reduction technique.

Paper Details

Date Published: 9 March 2012
PDF: 9 pages
Proc. SPIE 8313, Medical Imaging 2012: Physics of Medical Imaging, 83135K (9 March 2012); doi: 10.1117/12.911588
Show Author Affiliations
Hilde Bosmans, Univ. Hospitals Leuven (Belgium)
Joris Nens, Univ. Hospitals Leuven (Belgium)
Louis Delzenne, Univ. de Liège (Belgium)
Nicholas Marshall, Univ. Hospitals Leuven (Belgium)
Herman Pauwels, Univ. Hospitals Leuven (Belgium)
Walter De Wever, Univ. Hospitals Leuven (Belgium)
Raymond Oyen, Univ. Hospitals Leuven (Belgium)

Published in SPIE Proceedings Vol. 8313:
Medical Imaging 2012: Physics of Medical Imaging
Norbert J. Pelc; Robert M. Nishikawa; Bruce R. Whiting, Editor(s)

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