The setup errors of thermoplastic head and shoulder molds with or without vacuum pad in HFSRT for brain metastases in the lung cancer
10.3760/cma.j.cn113030-20191102-00450
- VernacularTitle:热塑头肩模与头颈肩真空垫在肺癌脑转移大分割立体定向放疗中固定效果分析
- Author:
An LI
1
;
Jia LIU
;
Jialu LAI
;
Qiang WANG
;
Qingfeng XU
;
Renming ZHONG
;
Yinbo HE
;
Sen BAI
;
Lin ZHOU
Author Information
1. 四川大学华西医院肿瘤中心生物治疗国家重点实验室放疗科，成都 610041
- Keywords:
Thermoplastic head and shoulder molds;
Vacuum pad;
Optical surface monitoring system;
Setup error;
Brain metastasis, lung neoplasm/hypofractionated stereo
- From:
Chinese Journal of Radiation Oncology
2021;30(6):592-597
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To retrospectively analyze the setup errors of thermoplastic head and shoulder molds alone or combined with vacuum pad in hypofractionated stereotactic radiotherapy (HFSRT) for non-small cell lung cancer (NSCLC) with brain metastases.Methods:Fifty-four NSCLC patients with brain metastases who received HFSRT from 2017 to 2019 were enrolled in this study. Twenty-four patients were fixed with thermoplastic head and shoulder molds (group A), and 30 patients were fixed with thermoplastic head and shoulder molds plus vacuum pad (group B). The interfraction and intrafraction setup errors were acquired from cone-beam CT online image registration before and after the HFSRT. Optical surface system was applied in monitoring the intrafraction setup errors. The setup errors in each direction between two groups were analyzed by independent samples t-test. Results:For the interfraction setup errors of the whole group, the proportion of the horizontal setup errors of ≥3mm was 7.0% to 15.4% and 7.0% to 12.6% for the rotation setup errors of ≥2°. In group A, the anteroposterior setup error was (1.035±1.180)mm, significantly less than (1.512±0.955)mm in group B ( P=0.009). In group A, the sagittal rotation setup error was 0.665°±0.582°, significantly less than 0.921°±0.682° in group B ( P=0.021). For the intrafraction setup errors of the whole group, the proportion of horizontal setup errors of ≥1mm was 0% to 0.7%, whereas no rotation setup error of ≥1° were observed. In group B, bilateral, anteroposterior and sagittal rotation setup errors were (0.047±0.212)mm, (0.023±0.152)mm and 0.091°±0.090°, significantly less compared with (0.246±0.474)mm, (0.140±0.350)mm and 0.181°±0.210° in group A ( P=0.004, P=0.020, P=0.001), respectively. Optical surface monitoring data were consistent with the obtained results. Conclusions:Thermoplastic head and shoulder molds (with or without vacuum pad) combined with online image registration and six-dimensional robotic couch correction can be applied in HFSRT for brain metastases from NSCLC. The intrafraction setup errors in group B are smaller than those in group A. Optical surface system has certain value in monitoring the intrafractional movement.
