基于头颈肩热塑膜固定的鼻咽癌调强放疗分次内误差分析

目的 分析基于头颈肩热甥膜固定的鼻咽癌患者调强放射治疗中分次治疗内的误差.方法 选取50例采用头颈肩热塑膜固定的鼻咽癌调强放射治疗的患者,于摆位后及治疗结束后,采用电子射野影像系统拍摄治疗摆位点的正位(机架角度0°)、侧位(机架角度90°)验证片,通过MOSAIQ系统的匹配功能,将获取的图像进行匹配,获得治疗摆位点在左右(X)、头脚(Y)、前后(Z)3个方向的位移.结果 50例患者的治疗时间为( 16.53±0.52) min；所有患者共进行了300次的摆位点验证匹配,其中X、Y、Z 三维方向分次间治疗摆位点位移分别为(0.45±0.32)mm、( 0.72±0.46 )mm和(0.63±0.45) mm.结论 采用头颈肩热甥膜固定的鼻咽癌患者在调强放射治疗中分次治疗内的治疗摆位误差虽然较小,但在设计时,对PTV的摆位扩边应予以考虑.

Intrafractional setup errors in intensity modulated radiation therapy for nasopharyngeal carcinoma based on head-, neck- and -shoulder thermal model

Objective To analyze the intrafractional set-up errors in intensity modulated radiation therapy （ IMRT ）for nasopharyngeal carcinoma based on head-, neck- and -shoulder thermal model. Methods 50 patients with nasopharyngeal carcinoma received IMRT using head-, neck- and -shoulder thermal model. The films on the position of set-up with the anteroposterior （ gantry angle of 0 degrees ） and lateral （ gantry angle 90 degrees ） position were taken after the patients were positioned and administered treatment. The setup errors on X, Y, and Z axes were analyzed with the MOSAIQ system. Results The average duration of treatment for the 50 patients was （ 16.53 ~ 0.52 ）min. A Lotal of 600 films were taken on 50 patients. The intrafractional setup errors on X, Y and Z axes were （ 0.45 ±0.32 ） mm, （ 0.72 ±0.46 ） mm, and （ 0.63 ± 0.45 ） mm, respectively. Conclusions Ahhough intrafractional setup error i：a IMRT for nasopharyngeal carcinoma based on head-, neck- and -shoulder thermal model is small, it should be taken into account in deciding the clinical margin of PTV.