利用普通放疗定位CT机个体化确定肺部肿瘤内靶区的方法

摘要

目的 探索一种在普通放疗CT机上利用CT自身的坐标系统测量确定内靶区(ITV)的方法.方法 针对20例肺中下部肿瘤体网固定患者,分别采集吸气末、呼气末和自由呼吸3组CT图像,并根据3组CT图像中最大肿瘤层面图像的肿瘤位置信息确定ITV的范围.利用CT层面信息确定Y方向(头足)外放范围;利用CT图像上的坐标系统,分别测量X方向(左右)和Z方向(前后)的外放范围.结果 左右方向X+和X-的距离值分别为:(0.68±0.53)mm和(0.71±0.55)mm (P>0.05);头足方向Y+和Y-的距离值分别为:(4.14±4.11)mm和(4.32±4.53)mm(P>0.05);前后方向Z+和Z-的距离值分别为:(1.14±1.11)mm和(1.32±1.27)mm(P>0.05).Y方向和X、Z方向的距离值数据有统计差异(P<0.05).结论 针对肺中下部肿瘤,该方法借助普通放疗定位CT机,可以作为一种确定ITV的个体化方法.%Objective To explore a method of determining internal target volume (ITV) for middle-inferior lung cancer according to the coordinate system of CT machine. Methods Three groups of CT images including: end of inspiratory, end of expiratory and free breathing were collected from 20 patients fixed with the thermoplastic molds. Then the ITV ranges of X (left-right), Y (head-foot) and Z direction (belly-back) were determined according to the CT images in which the tumor reach the maximum. Results The distance of X+ and X-respectively were (0.68±0.53) mm and (0.71±0.55) mm with P>0.05; the distance of Y+ and Y-respectively were (4.14±4.11) mm and (4.32±4.53) mm with P>0.05; the distance of Z+ and Z-were respectively (1.14±1.11) mm and (1.32±1.27) mm with P>0.05. The data in Y direction were different form that in X and Z direction (P<0.05). Conclusion For radiotherapy of middle-inferior lung tumor, this method might be used as an individual way to determine ITV by using general CT machine.