A study of the positioning errors of head and neck in the process of intensity modulation radiated therapy of nasopharyngeal carcinoma
10.3760/cma.j.issn.1004-4221.2011.04.018
- VernacularTitle:鼻咽癌三维适形和调强放疗过程中头部与颈部摆位误差比较研究
- Author:
Chengguang LIN
;
Liuwen LIN
;
Bingti LIU
;
Xiaomao LIU
;
Guowen LI
- Publication Type:Journal Article
- Keywords:
Nasopharyngeal neoplasms/radiotherapy;
Radiotherapy,three-dimensional conformal;
Radiotherapy,intensity modulation;
Set-up error
- From:
Chinese Journal of Radiation Oncology
2011;20(4):322-325
- CountryChina
- Language:Chinese
-
Abstract:
Objective 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.
