基于光子计数探测器的能谱CT的研究

Study of Spectral CT Based on a Photon Counting Detector

摘要: 本文的目的是评估光子计数探测器对CT成像的性能的影响,我们对一款基于碲锌镉(CZT)的光子计数探测器进行了性能测试,并搭建一个成像平台。首先对探测器系统进行能量增益的校正以及坏像素点校正,以减少探测器响应的不均匀性对CT成像的影响。然后对探测器进行能量-阈值标定,以确定探测器的工作能量阈值。最终搭建成像系统,对X光能量分别大于36和45keV的数据,获得了模体的重建结果,并对结果进行了分析。

Abstract: The purpose of this paper is to evaluate the performance of the photon counting detector in CT. We tested the performance of a photon counting detector based on CZT, and built a tabletop X-ray CT scanner. Firstly, in order to reduce non-uniformity of the detectors, calibration of the energy thresholds and dead pixel correction were performed. Then calibration of the energy thresholds was applied to determine the working energy threshold of the detector. In the end we acquired projection data with two energy bins(36 and 45 ke V). The ART-TV algorithm based on the compressed sensing was performed to reconstruct the incomplete projection data.