纠正CT引导外定位穿刺点误差的方法  

The correction of puncture point error in CT-guided puncturing biopsy: study of the methods

作　　者：陈兴灿[1] 张永强[1] 刘淼[1] 赵凯宇[1] 何东[1] 

机构地区：[1]解放军第一一七医院医学影像科,杭州310013

出　　处：《介入放射学杂志》2014年第11期972-976,共5页Journal of Interventional Radiology

摘　　要：目的研究一种纠正CT引导外定位穿刺点误差的方法。方法在GE Prospeed F II CT机上行CT引导介入诊疗术201例,为容易理解函数关系的描述,取CT机架角度为0°、5°、10°和20°的4种状态,其中取0°的患者30例;5°的50例;10°的80例;20°的41例。为方便穿刺点皮肤标记,采用外定位线。反复CT扫描法被用于纠正CT引导外定位穿刺点误差,水模实验法测量实际误差值,两者证实公式法纠正CT引导外定位穿刺点误差的正确性。结果当机架角度为0°时,床坐标与图层坐标之间的函数关系为TWM=S190+M,TWM是对应图层移动到外定位点的床坐标值,M为图层坐标值;当机架角度不为0(角度变量为θ)时,用反复CT扫描法成功证实床坐标与图层坐标之间的函数关系为TWM-1=S190/Cosθ+M。机架角度与误差X之间的函数关系为X=|190(1/Cosθ-1)|,公式法计算误差值与反复CT扫描法和水模实验法的误差值完全相同。结论公式法能精确计算出目标图层的床坐标值,快速准确纠正CT引导穿刺点的误差,更重要的是,如果把该公式通过软件制作于CT机内部,让其自身在机架有角度的状态下纠正误差,为医师赢得宝贵的诊治时间,减少患者所受辐射剂量,具有重要的临床意义。Objective To discuss the method of correcting the puncture point error in performing CTguided puncturing biopsy. Methods CT- guided puncture biopsy was performed in 201 cases on a GE Prospeed F II CT scanner. In order to easily understand the function relationship between bed coordinates and scan section coordinates, the gantry slant angles of 0°（n = 30）, 5°（n = 50）, 10°（n = 80） and 20°（n =41） were used separately. Skin- marker was stuck on the skin to indicate the puncture point. CT- guided puncture/biopsy was carried out in all patients. CT scanning was repeated to adjust the puncture point error,and the actual error was estimated by water phantom experiment method. Results A function relationship existed between bed coordinates and scan section coordinates. When the gantry position had no angle, the function formula was： TWM= S190 ＋ M. When the gantry had some angle, the function formula was： TWM=S190/Cosθ ＋ M. The function formula between the error value X and the gantry angle was ： X = ｜190（1/Cosθ-1）｜. The error values obtained from function method were completely in agreement with the values determined by repeated CT scanning. Conclusion Function method can precisely calculate the bed coordinates of target layer and quickly adjust the error of CT- guided puncture point. If these function formulas can be built in the scanner＇s software and worked automatically to adjust the error when the gantry is in angled state, the operation time as well as the radiation dose will be reduced.

关 键 词：放射学 介入性 体层摄影术 X线计算机 研究技术 

分 类 号：R816[医药卫生—放射医学] R446.8[医药卫生—临床医学]