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近年来,基于光子计数探测器成像的能谱CT(Computed Tomography)是辐射成像领域内的一个研究热点。通过设置不同的能量阈值,光子计数探测器可将不同能量的入射光子分能窗计数,使采集信号携带了能量信息。通过对多个能窗的CT数据进行解析,能谱CT不仅可以进行物质识别,还可以具有高信噪比、高分辨率等特点,并降低被测物体所受辐射剂量。本文从光子计数探测器、能谱CT重建算法和能谱CT系统三个方面对能谱CT的关键技术和研究现状进行阐述:1光子计数探测器的工作原理及标定方法,并讨论影响标定的因素;2能谱CT的多能分解方法和重建算法;3能谱CT系统平台及应用;最后总结了各个方向的研究内容及热点。
In recent years, Computed Tomography (CT) based on photon counting detector imaging is a hot topic in the field of radiation imaging. By setting different energy thresholds, the photon counting detector can count the incident photons of different energies into the energy window so that the collected signals carry the energy information. By analyzing CT data of multiple energy windows, spectrum CT can not only identify substances, but also have high signal-to-noise ratio, high resolution, and reduce the radiation dose of the measured object. In this paper, the key technologies and research status of energy spectrum CT are described from three aspects of photon counting detector, energy spectrum CT reconstruction algorithm and energy spectrum CT system: 1 photon counting detector working principle and calibration method, and discuss the impact of calibration Factors; 2 energy spectrum CT multi-energy decomposition method and reconstruction algorithm; 3 energy spectrum CT system platform and application; finally summarizes the research content and hot spots in all directions.