管电压对PET/CT中CT剂量及图像质量影响的模体研究  

A phantom study on influence of tube voltage on CT dose and CT image quality in PET/CT

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

机构地区：[1]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：《中国医学装备》2015年第4期1-5,共5页China Medical Equipment

基　　金：国际科技合作项目(2009DFA32960)"PET/CT脑分子影像研究与应用平台及针灸中枢机理探索";中国癌症基金会北京希望马拉松专项(LC2013A13)"PET/CT的辐射剂量和图像质量的模型研究"

摘　　要：目的:在保证图像质量的前提下,为降低PET/CT中CT扫描部分的辐射剂量提供数据依据。方法:用GE Discovery ST16型号PET/CT系统,在管电压分别为80 k V、100 k V、120 k V及140 k V条件下,对CT剂量模体和Catphan?500CT性能模体进行扫描。测量在各种管电压下的CT加权剂量指数(CTDIw),计算给定螺距下的CT容积剂量指数(CTDIvol);测量CT图像的相关性能指标;分析CT图像质量与CT剂量的关系。结果:CTDIvol随管电压的增加而线性增加;CT图像高对比度分辨力不受管电压影响;CT图像的低对比度分辨力、CT图像均匀性及噪声性能均随管电压的增加而提高,而性能提高规律并非线性。结论:CT图像性能均随剂量的增加而提高,而性能提高规律并非线性,当剂量达到一定值时,其图像性能随剂量的增加幅度变缓,因此,在保证一定的CT图像质量的条件下,可以通过降低管电压适当降低PET/CT检查中CT部分的辐射剂量。Objective：To examine how to decrease of radiation dose caused by CT in PET/CT while ensuring quality of CT image. Methods：CT dose phantom（DCT 10） and CT performance phantom （Catphan 500） were scanned in the tube voltage 80kV, 100kV, 120kV and 140kV with PET/CT（GE Discovery ST16）. The image quality was evaluated by high contrast resolution, low contrast resolution, uniformity and noise. CTDIw and CTDIvol were calculated. The relationship between CT image quantity and CT dose was analyzed. Results：CT dose increased linearly with the tube voltage. The high contrast resolution of CT image was independent of the tube voltage. The performances of CT image, low contrast resolution, uniformity and noise, improved with increasing tube voltage, and it was nolinear. Conclusion： The performances of CT image improved with increasing CT dose. It improved more slowly when the CT dose reach to a certain value. 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：正电子发射断层摄影术 体层摄影术 X射线计算机 辐射剂量 图像质量 管电压 

分 类 号：R814.42[医药卫生—影像医学与核医学]