PET/CT中CT的剂量与CT图像质量关系的研究  

Study on Relationships Between CT Dose and CT Image Quality in PET/CT

作　　者：张连宇[1,2] 耿建华[1,3] 王弈斌[1] 吴宁[1] 郑容[1] 周纯武[2] 

机构地区：[1]北京协和医学院中国医学科学院肿瘤医院PET-CT中心,北京100021 [2]中国医学科学院肿瘤医院影像诊断科,北京100021 [3]中国医学科学院肿瘤医院核医学科,北京100021

出　　处：《核电子学与探测技术》2012年第3期365-370,共6页Nuclear Electronics & Detection Technology

基　　金：国际科技合作项目(2009DFA32960)

摘　　要：为在保证图像质量的前提下,降低PET/CT中CT扫描部分的辐射剂量提供数据依据。用GEDiscovery ST16型号PET/CT系统,按不同的采集条件扫描CT质量控制模体,测量CT图像的相关性能指标;测量在各种管电流下的加权CT剂量指数,计算不同螺距下的容积CT剂量指数;分析CT图像质量与CT剂量的关系。结果表明:CT图像高对比度分辨力不受CT剂量影响;CT图像的低对比度分辨力随CT剂量增加而提高;CT剂量能影响CT图像的均匀性;CT图像噪声随CT剂量增加而降低,且可用一表达式来表示。得出在保证一定的CT图像质量的条件下,可以适当降低PET/CT检查中CT部分的辐射剂量的结论。Objective： The aim of the study was to examine how to decrease of radiation dose caused by CT in PET/CT while ensuring quality of CT image. Methods ： PET/CT（ GE Discovery ST16 ）, Catphan 500, different scan conditions, total 30 groups. The image quality was evaluated by high resolution,low contrast,uniformity, noise. CTDIw and CTDIvol were calculated. The relationship between CT image quantity and CT dose was ana- lyzed. Results ： CT dose was related to uniformity, but not to high resolution. The low contrast of CT image im- proved with the increasing of CT dose. And the decrease of noise with the increase of CT dose was showed with an expression. Conclusions： The radiation dose by CT in PET/CT could be decreased appropriately under the guarantee of the quality of the CT image.

关 键 词：PET/CT CT 辐射剂量 图像质量 

分 类 号：R814.42[医药卫生—影像医学与核医学] R817.4[医药卫生—放射医学]