23 February 2012 Experimental evaluation of the pile-up trigger method in a revised quantum-counting CT detector
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Abstract
The application of quantum-counting detectors in clinical Computed Tomography (CT) is challenged by very large Xray photon fluxes present in modern systems. Situations with sub-optimal patient positioning or scanning of small objects can cause unattenuated exposure of parts of the detector. The typical pulse durations in CdTe/CdZnTe sensor range in the order of several nanoseconds, even if the detector design is optimized for high-rate applications by using high sensor depletion voltages and small pixel sizes. This can lead to severe pile-up of the pulses, resulting in count efficiency degradation or even ambiguous detector signals. The recently introduced pile-up trigger method solves this problem by combining the signal of a photon counting channel with a signal indicative of the level of pile-up. Latter is obtained with a photon-counting channel operated at threshold energies beyond the maximum energy of the incident photon spectrum so that its signal arises purely from pulse pile-up. We present an experimental evaluation of the pile-up trigger method in a revised quantum-counting CT detector and compare our results to simulations of the method with idealized detector properties.
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E. Kraft, E. Kraft, F. Glasser, F. Glasser, S. Kappler, S. Kappler, D. Niederloehner, D. Niederloehner, P. Villard, P. Villard, } "Experimental evaluation of the pile-up trigger method in a revised quantum-counting CT detector", Proc. SPIE 8313, Medical Imaging 2012: Physics of Medical Imaging, 83134A (23 February 2012); doi: 10.1117/12.911231; https://doi.org/10.1117/12.911231
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