19 March 2014 Photon counting CT at elevated X-ray tube currents: contrast stability, image noise and multi-energy performance
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Abstract
The energy-selectivity of photon counting detectors provides contrast enhancement and enables new material-identification techniques for clinical Computed Tomography (CT). Patient dose considerations and the resulting requirement of efficient X-ray detection suggest the use of CdTe or CdZnTe as detector material. The finite signal pulse duration of several nanoseconds present in those detectors requires strong reduction of the pixel size to achieve feasible count rates in the high-flux regime of modern CT scanners. Residual pulse pile-up effects in scans with high X-ray fluxes still can limit two key properties of the counting detector, namely count-rate linearity and spectral linearity. We have used our research prototype scanner with CdTe-based counting detector and 225μm small pixels to investigate these effects in CT imaging scenarios at elevated X-ray tube currents. We present measurements of CT images and provide a detailed analysis of contrast stability, image noise and multi-energy performance achieved with different phantom sizes at various X-ray tube settings.
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S. Kappler, A. Henning, B. Kreisler, F. Schoeck, K. Stierstorfer, T. Flohr, "Photon counting CT at elevated X-ray tube currents: contrast stability, image noise and multi-energy performance", Proc. SPIE 9033, Medical Imaging 2014: Physics of Medical Imaging, 90331C (19 March 2014); doi: 10.1117/12.2043511; https://doi.org/10.1117/12.2043511
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