欧阳斌+丘敏敏+钟嘉健

    [摘要] 目的 探讨CT模拟定位扫描协议中各项参数对CT图像质量的影响，为确定精确放疗定位图像的扫描协议参数提供依据。 方法 采用Philips16排大孔径螺旋CT模拟定位机扫描Catphan600模体和Philips图像校准模体，改变扫描及重建参数获取不同的图像序列，分析其对图像噪声、均匀度、不同物质的CT值、高对比度分辨力及低对比度分辨力等的影响。 结果 管电压、扫描部位及滤过器影响物质的CT值；管电压、管电流、重建层厚、滤过器及滤过器增强则影响图像的噪声；扫描部位影响图像的均匀度。图像高对比度分辨力与滤过器、滤过器增强相关，而低对比度分辨力则与噪声相关。 结论 通过全面系统的模体测试可充分了解CT扫描协议中各项参数对图像质量的影响，有利于确定精确放疗CT模拟定位扫描协议参数和设定CT值-电子密度曲线以确保精准放射治疗的实施。

    [关键词] CT扫描协议；图像质量；参数；放射治疗

    [中图分类号] R445.3 [文献标识码] A [文章编号] 1673-7210(2017)01(a)-0004-04

    [Abstract] Objective To investigate the impact of CT scanning and reconstructed parameters on the quality of CT image， in order to provide basis for establishing the standard of high quality image for precision radiation therapy. Methods Catphan600 phantom and Philips image calibration phantom were scanned by Philips Big-Bore Brilliance CT. Images were acquired at different protocols varying scan and reconstruction parameters. The impact of scanning and reconstruction parameters on image noise ......