放疗定位扫描条件对CT值的影响  

Influence of Scanning Conditions on CT Values in Radiotherapy Simulation Positioning

作　　者：张国前[1] 张书旭[1] 余辉[1] 王锐濠[1] 雷怀宇 

机构地区：[1]广州医科大学附属肿瘤医院放疗中心,广东广州510095 [2]广州医科大学研究生学院,广东广州510182

出　　处：《中国医疗设备》2015年第3期13-16,共4页China Medical Devices

基　　金：广州市医药卫生科技项目资助(20131A011165);广州医科大学青年项目资助(2012A16)

摘　　要：目的探讨放疗定位时不同扫描条件对CT值的影响程度。方法对CIRS 062型电子密度体模在不同扫描条件下分别进行CT扫描并测定其CT值,评价和分析管电流、管电压、层厚、螺距、图像重建算法、扫描床面高度、扫描序列的改变对CT值的影响程度。结果管电流、层厚、螺距的改变对CT值的影响基本可以忽略(<1%)。管电压、图像重建算法的改变对高密度组织如密质骨的影响较为显著,对低密度组织的影响则不明显。扫描床面高度及扫描序列的改变对不同密度组织的CT值均有不同程度的影响。结论 CT扫描参数和定位条件的差异可能会使某一组织重建影像的CT值发生改变,值得临床参考。Objective This study was designed to investigate the influence of scanning conditions on CT values in radiotherapy simulation positioning.Methods CT scanning was performed in the electron density phantom（Model：CIRS 062） in different conditions so as to measure relevant CT values.Then,the influence of changes in the tube current and voltage,slice thickness,pitch,image reconstruction algorithm,height of the scanning bed and scanning sequence to the CT values were evaluated and analyzed.Results The tube current,slice thickness,pitch had neglectable influence（〈1%） on CT values.The tube voltage and image reconstruction algorithm showed significant influence on CT values for highdensity phantoms; while no obvious influence was seen on those for low-density phantoms.The height of the scanning bed and scanning sequence had influence on CT values at varying degree for phantoms with various densities.Conclusion CT scanning parameters and positioning conditions can result in changes of CT values for image reconstruction of a certain tissue,which was of great value for clinical references.

关 键 词：肿瘤放疗 CT模拟定位 CT值 管电压 图像重建算法 扫描床面高度 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]