鼻咽癌调强放疗中的摆位误差分析及其与患者体重指数的关系

Analysis of setup errors and its relationship with body mass index(BMI) in patients treated with intensity-modulated radiation therapy for Nasopharyngeal Carcinoma

目的:鼻咽癌调强放疗计划会在肿瘤靶区周围产生剂量的梯度陡降,因此对患者的精确摆位是至关重要的。本文为量化放疗摆位方法的科学性,并且讨论体重指数对摆位误差的影响因素。方法:对2014年1月至6月收治通过调强放疗治疗的20名鼻咽癌肿瘤患者分别进行多组CT图像的采集,获得患者在RL(左右),SI(头脚)和AP(腹背)三个方向的偏移数据,从而计算出的摆位误差,验证摆位方法。结果:系统误差在RL、SI和AP方向分别为2.1 mm、2.4 mm和3.0 mm,随机误差在RL、SI和AP方向分别为2.8 mm、2.6 mm和3.5 mm。结论:肯定了摆位方法的科学合理,确定了CTV到PTV的外扩边界大小。患者摆位误差与体重指数并无相关性。

Objective： To quantify the accuracy of patient positioning in intensity-modulated radiation therapy （IMRT） for nasopharyngeal carcinoma for formulating appropriate expansion from clinical target volume （CTV） to planning target volume（PTV）, and assess the correlation between body mass index（BMI） and setup error. Methods： CT images of 20 patients treated with IMRT at our institution were examined,date in three directions （Right-Left, superior-Inferior, and Anterior-Posterior） were obtained and the setup error in patients treated with IMRT was calculated to venfy patient positioning Average of BMI was calculated and correlation between the setup error and BMI was analyzed. Results： The systematic error in the three directions was 2.1 mm, 2.4 mm and 3.0 mm, and the random error was 2.8 mm, 2.6 mm and 3.5 mm respectively. Condusion： The appropriate range of expansion from CTV to PTV is determined to make the IM-WPRT plan more scientific and rational. There was no correlation between the setup error and BMI.