应用CBCT、EPID研究鼻咽癌2种体位固定方式摆位误差的比较分析

发布时间：2018-07-26 16:04

【摘要】：背景与目的:随着放疗技术和设备的不断发展,鼻咽癌放射治疗已经进入了精确放疗时代,摆位误差成为影响放疗效果的非常重要的因素。本研究在千伏级锥形束CT(cone beam computed tomography,CBCT)与兆伏级电子射野影像系统(electronic portal imaging device,EPID)2种影像模式引导下治疗鼻咽癌,在头枕+头颈肩面膜、真空气垫+头颈肩面膜固定2种方式下的摆位误差分析比较。方法:随机选取40例鼻咽癌患者分成2组(头枕+头颈肩面膜组,真空气垫+头颈肩面膜固定组),每组组内再分成CBCT扫描组和EPID验证组。将CBCT扫描图像与计划CT图像进行自动骨性配准、将EPID拍摄的正侧位片采用突出性骨性标志进行手动配准,分别得出x、y、z共3个线性方向上的摆位误差值,对获得的2组数据进行组内组间两两比较,采用t检验比较数据差异有无统计学意义。结果:头枕+头颈肩面膜组摆位后行CBCT扫描,在x、y、z方向上进行配准所得的平均误差分别为:x方向(0.67±2.01)mm、y方向(0.51±1.71)mm、z方向(0.57±2.04)mm;拍摄EPID验证片配准所得误差均值:x方向(0.69±2.19)mm、y方向(0.54±2.03)mm、z方向(0.61±2.11)mm。真空气垫+头颈肩面膜固定组摆位后行CBCT扫描,在x、y、z方向上进行配准所得的平均误差分别为:x方向(0.42±1.81)mm、y方向(0.33±1.55)mm、z方向(0.50±1.75)mm;拍摄EPID验证片配准误差均值:x方向(0.44±1.87)mm、y方向(0.43±1.70)mm、z方向(0.54±1.77)mm。采用头枕+头颈肩面膜组、真空气垫+头颈肩面膜固定组的误差数据差异均有统计学意义(P0.05)。结论:2种不同的影像模式(CBCT与EPID)进行摆位误差的比对未见明显统计学差异,2种固定方式下头颈部真空气垫+头颈肩面膜固定的患者体位重复性更好。
[Abstract]:Background & objective: with the continuous development of radiotherapy technology and equipment, radiotherapy for nasopharyngeal carcinoma has entered the era of accurate radiotherapy, positioning error has become a very important factor affecting the effect of radiotherapy. The purpose of this study was to treat nasopharyngeal carcinoma (NPC) with two imaging modes: CT (cone beam computed tomographyography (CBCT) and (electronic portal imaging devicedia (EPID), and the head, neck, neck and face of nasopharyngeal carcinoma (NPC) were treated in the head, neck and neck of the head and neck of nasopharyngeal carcinoma. Analysis and comparison of pendulum error under two kinds of fixing methods of head, neck and shoulder mask of vacuum air cushion. Methods: forty patients with nasopharyngeal carcinoma were randomly divided into two groups (head and neck face mask group, vacuum air cushion head and neck facial membrane fixation group). Each group was divided into CBCT scanning group and EPID verification group. The CBCT scan image is automatically registered with the planned CT image, and the positive and lateral images taken by EPID are manually registered with protruding bone markers. The data of the two groups were compared in two groups, and the t test was used to compare the difference between the two groups. Results: CBCT scanning was performed in head, neck, shoulder and face mask group after pendulum. The average error of registration was (0.67 卤2.01) mm / y direction (0.67 卤2.01) mm / y direction (0.51 卤1.71) mm / z direction (0.57 卤2.04) mm / mm respectively, and the mean error of EPID verification film registration was (0.69 卤2.19) mm / y direction (0.54 卤2.03) mm / z direction and (0.61 卤2.11) mm / m ~ (0.61 卤2.11) mm ~ (-1) mm 路m ~ (-1) respectively. CBCT scanning was performed in the vacuum air cushion head, neck and shoulder mask fixation group. The average error of registration was (0.42 卤1.81) mm and (0.33 卤1.55) mm / z and (0.44 卤1.87) mm / z and (0.43 卤1.70) mm / z and (0.54 卤1.77) mm / z respectively in the direction of X ~ + and (0.43 卤1.70) mm / z in the direction of X and (0.43 卤1.70) mm / z, respectively. There were significant differences in the error data between the head and neck facial mask group and the vacuum air cushion head and neck facial membrane fixation group (P0.05). Conclusion there is no statistical difference between the two different imaging models (CBCT and EPID) in comparing the positioning errors. The posture repeatability of the patients with head and neck vacuum air cushion and shoulder mask fixation is better under the two fixation modes.
【作者单位】：复旦大学附属肿瘤医院放射治疗科复旦大学上海医学院肿瘤学系;
【分类号】：R739.63

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