CT剂量指数估算方法研究  

An approach to estimate the characterizations of mmulti-detector CT

作　　者：庄静文[1] 郑钧正[1] 白玫[1] 

机构地区：[1]首都医科大学宣武医院医学工程处,北京100053

出　　处：《中国医学装备》2016年第7期1-4,共4页China Medical Equipment

基　　金：国家自然科学基金(81372923)"宽探测器螺旋CT所致辐射剂量评价方法研究";国家科技支撑计划(2011BAI02B02)"医用光学与放射影像设备计量标准及溯源体系研究"

摘　　要：目的：研究多排螺旋CT辐射剂量表征量的校正系数。方法：使用CT-SD 16长杆电离室测量西门子SOMATOM Definition Flash CT不同直径模体中不同准值宽度、螺距以及管电压下剂量分布曲线,计算加权剂量指数无穷（CTDI_∞）与加权CTDI_（100）的比值,并以对结果有影响的扫描条件为依据对此比值分类取平均值。结果：使用头部模体进行测量时加权CTDI_∞与加权CTDI_（100）的比值为1.123~1.162,使用体部模体进行测量时加权CTDI_∞与加权CTDI_（100）的比值在1.118~1.173之间,并随着准直宽度的增加此比值增大。结论：检测结果表明,CTDI_（100）低估了多排螺旋CT辐射剂量水平,因此应对CTDI_（100）进行校正。Objective： The purpose of the current study was to investigate the correction coefficient of the characterizations of multi-detector CT （MDCT）. Methods： The dose profile of Siemens SOMATOM Definition Flash CT scanner was measured with CT-SD 16 detector under the conditions of different collimations, pitches and tube voltages in phantoms of different diameters, and the ratio between weighted CTDI∞and weighted CTDI100 was calculated. Results：The ratio between weighted CTDI∞and weighted CTDI100, which is growing for increasing beam collimation, was found to range from 1.123 to 1.162 in head phantom and range from 1.118 to 1.173 in body phantom. Conclusion： For MDCT, the use of CTDI100, which is one of the most commonly used characterizations of CT, has always underestimated the levels of radiation dose. Therefore, CTDI100 should be corrected.

关 键 词：多排螺旋CT CT剂量指数 校正系数 

分 类 号：R814.42[医药卫生—影像医学与核医学]