Experimental study of optimal energy weighting in energy-resolved CT using a CZT detector

Franco Rupcich; Taly Gilat-Schmidt

doi:10.1117/12.2008439

6 March 2013 Experimental study of optimal energy weighting in energy-resolved CT using a CZT detector

Franco Rupcich, Taly Gilat-Schmidt

Proceedings Volume 8668, Medical Imaging 2013: Physics of Medical Imaging; 86681X (2013) https://doi.org/10.1117/12.2008439
Event: SPIE Medical Imaging, 2013, Lake Buena Vista (Orlando Area), Florida, United States

Abstract

Recent advances in energy-resolved CT can potentially improve contrast-to-noise ratio (CNR), which could subsequently reduce dose in conventional and dedicated breast CT. Two methods have been proposed for optimal energy weighting: weighting the energy- bin data prior to log normalization (projection- based weighting) and weighting the energy-bin data after log normalization (image-based weighting). Previous studies suggested that optimal projection-based and image-based energy weighting provide similar CNR improvements for energy resolved CT compared to photon-counting or conventional energy-integrating CT. This study experimentally investigated the improvement in CNR of projection-based and image-based weighted images relative to photon counting for six different energy-bin combinations using a bench top system with a CZT detector. The results showed CNR values ranged between 0.85 and 1.01 for the projection- based weighted images and between 0.91 and 1.43 for the image- based weighted images, relative to the CNR for the photon-counting image. The range of CNR values demonstrates the effects of energy-bin selection on CNR for a particular energy weighting scheme. The non-ideal spectral response of the CZT detector caused spectral tailing, which appears to generally reduce the CNR for the projection-based weighted images. Image-based weighting increased CNR in five of the six bin combinations despite the non-ideal spectral effects.

Citation Download Citation

Franco Rupcich and Taly Gilat-Schmidt "Experimental study of optimal energy weighting in energy-resolved CT using a CZT detector", Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 86681X (6 March 2013); https://doi.org/10.1117/12.2008439

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