摘要目的 探讨鼻咽癌三维适形、调强放疗过程中头部和颈部摆位误差是否存在差异.方法 选择中晚期鼻咽癌(T2～4N1～3M0期)患者19例,头颈肩热塑面罩固定,将等中心点置于鼻咽腔附近.由三维激光灯在面罩上定出左、中、右原始十字标志点,并贴上直径约为0.3 mm的铅珠作为显像标记,然后CT扫描.将CT图像通过网络传至Peacock逆向计划系统进行计划设计,然后实施治疗.治疗1～6周每周在CT模拟机进行重复扫描,扫描及固定和摆位方法都与进行计划CT时相同.将每周验证体位重复性CT图像与计划CT图像通过读图软件进行比较,并利用双独立样本t检验头、颈部摆位误差.结果 左右、上下、头脚方向上颈部摆位误差分别为(2.44±2.24)、(2.05±1.42)、(1.83±1.53) mm,头部摆位误差分别为(1.05±0.87)、(1.23±1.05)、(1.17±1.55) mm;颈部和头部的摆位误差差异有统计学意义(t=-6.58、-5.28、-3.42,P=0.000、0.000、0.001).左右、上下、头脚方向上颈部系统误差分别是头部的2.33、1.67、1.56倍,颈部随机误差分别是头部的2.57、1.34、0.99倍.结论 鼻咽癌三维适形、调强放疗过程中采用头颈肩热塑面罩固定情况下,颈部的摆位误差大于头部.

abstractsObjective To investigate the positioning errors of head and neck during intensity-modulated radiation therapy of nasopharyngeal carcinoma.Methods Nineteen patients with middle-advanced nasopharyngeal carcinoma (T2-4N1-3M0), treated by intensity-modulated radiation therapy, underwent repeated CT during their 6-week treatment course.All the patients were immobilized by head-neck-shoulder thermoplastic mask.We evaluated their anatomic landmark coordinated in a total of 66 repeated CT data sets and respective x, y, z shifts relative to their position in the planning CT.ResultsThe positioning error of the neck was 2.44 mm±2.24 mm,2.05 mm±1.42 mm,1.83 mm±1.53 mm in x, y, z respectively.And that of the head was 1.05 mm±0.87 mm,1.23 mm±1.05 mm,1.17 mm±1.55 mm respectively.The positioning error between neck and head have respectively statistical difference (t=-6.58,-5.28,-3.42,P=0.000,0.000,0.001).The system error of the neck was 2.33,1.67 and 1.56 higher than that of the head, respectively in left-right, vertical and head-foot directions;and the random error of neck was 2.57,1.34 and 0.99 higher than that of head respectively.Conclusions In the process of the intensity-modulated radiation therapy of nasopharyngeal carcinoma, with the immobilization by head-neck-shoulder thermoplastic mask, the positioning error of neck is higher than that of head.