柱模与球模MRI定位伽玛刀治疗精度检测差异探讨  

The Exploration on The Difference Between Spherical and Cylindrical Phantom for Accuracy Detection Under MRI Localization for Gamma Knife Treatment

作　　者：李胜元 李骁杨 高立 郭涛 俞立琛 张鹏飞 

机构地区：[1]解放军第515医院肿瘤科,江苏江阴14400 [2]苏州大学附属第二医院放疗科,江苏苏州215004 [3]西安一体医疗科技有限公司,陕西西安710077

出　　处：《中国医学物理学杂志》2014年第3期4875-4880,共6页Chinese Journal of Medical Physics

摘　　要：目的:探讨周边含水槽柱模与全有机玻球模对MRI定位伽玛刀治疗精度检测结果差异的原因。方法:首先利用柱、球模同步检测证实了两者在MRI定位中Y坐标存在差异,然后用水箱分别采集柱模和更换为双显定位件的球模、以及一组不同直径的简易有机玻璃柱模在有、无硫酸铜溶液背景下的CT和MRI定位图像;最后再用双显定位件的球模与柱模按日常状态对CT和MRI定位治疗精度进行同步检测。结果:柱、球模初次同步检测的CT定位治疗精度相符,但MRI定位在Y轴上较各自CT定位坐标相差-2.0 mm和0.5 mm。两种模具在有无硫酸铜溶液背景下的MRI定位坐标没有变化;不同直径简易柱模在有无硫酸铜溶液背景下的MRI定位坐标也无变化;但各实验模具MRI定位在Y轴上均较CT定位的低了1.7 mm左右。柱模与使用双显定位件球模的再次同步检测,两者MRI定位与CT之间的Y坐标出现了相同的差值,分别为-2.4 mm和-2.3 mm,焦斑检测结果与此相吻合。结论:柱、球模之间MRI定位伽玛刀治疗精度检测差异与模体尺寸及周边有无水槽无关,是伽玛刀调试中球模定位件缺陷造成的系统误差。Objective：To explore the causes of difference between sink-surrounded cylindrical phantom and plexiglass spherical phantom in accuracy detection under MRI localization for gamma knife treatment. Methods：We first implemented synchronous accuracy detection by spherical and cylindrical phantom respectively and then identify the difference on Y-axis between the two types of phantom in accuracy detection under MR/localization. Afterwards the scout images of cylindrical phantom and spheri- cal phantom with locating piece visible in both CT and MR.I are respectively collected by CT and MRI against the context with and without cupric sulfate.Then a set of self-made plexiglass cylindrical phantoms undertook the same procedure. Finally routine accuracy detections are performed synchronously by cylindrical phantom and spherical phantom with locating piece visible in both CT and MRI. Results：The treatment accuracy detected by cylindrical and spherical phantom under CT localization is e- quivalent after first synchronous detection.The coordinates on Y-axis,however,are lower in MRI than CT localization：-2.0 mm for cylindrical phantom and 0.5 mm for spherical one.No matter which phantom we use, there are no obvious changes in coordi- nates between the context with and without cupric sulfate.Yet the coordinates on Y-axis are 1.7 mm lower in MRI than CT local- ization for each phantom.After another round of synchronous accuracy detection,the difference between CT and MR/localiza- tion is -2.4 mm for cylindrical phantom and -2.3 mm for locating piece visible in both CT and MRI,which is of no significant difference.It coincides with the results from focal exposure detection.. Conclusions：The size of phantom and the existence of sounding tank exert no influence on the difference between accuracy detection under MRI localization by cylindrical phantom

关 键 词：MRI定位 伽玛刀治疗精度 球模 柱模 

分 类 号：R815.5[医药卫生—放射医学]