Levin Klausen T, Høgild Keller S, Vinter Olesen O, Aznar M, Andersen F L
Department of Clinical Physiology, Copenhagen University Hospital, Copenhagen, Denmark.
Q J Nucl Med Mol Imaging. 2012 Jun;56(3):268-79.
There has been a longstanding interest in positron emission tomography (PET) in combination with computed tomography (CT). Mostly because of the lack of structural information in PET which makes it difficult to assess the precise location of tissue with metabolic uptake, whereas CT can provide impressive anatomical details. PET/CT designs are facing many challenges such as the conversion of CT numbers to attenuation coefficients, giving rise to artefacts due to the presence of high Zeff material. Patient motion during scans degrades image quality and subsequent analysis, and is a challenge especially as spatial resolution improves. Software based image fusion remains a complex issue outside the brain. State of the art image quality in a modern PET/CT system includes incorporation of point spread function (PSF) and time-of-flight (TOF) information into the reconstruction leading to the high resolution of today's PET/CT systems. This review outlines the background and current knowledge of the PET/CT system design, motion correction and reconstruction approaches.
正电子发射断层扫描（PET）与计算机断层扫描（CT）相结合一直备受关注。主要是因为PET缺乏结构信息，难以评估代谢摄取组织的精确位置，而CT可以提供令人印象深刻的解剖细节。PET/CT设计面临许多挑战，例如将CT数值转换为衰减系数，由于高有效原子序数（Zeff）材料的存在而产生伪影。扫描过程中的患者运动降低了图像质量和后续分析效果，尤其是随着空间分辨率提高，这成为一个挑战。基于软件的图像融合在脑外仍是一个复杂问题。现代PET/CT系统中的先进图像质量包括将点扩散函数（PSF）和飞行时间（TOF）信息纳入重建过程，从而实现了当今PET/CT系统的高分辨率。本综述概述了PET/CT系统设计、运动校正和重建方法的背景及当前知识。
