Comparison of positioning accuracy between personalized polyurethane foam with wing boards and negative pressure vacuum bag in radiotherapy for lung cancer
10.3760/cma.j.issn.1004-4221.2018.03.014
- VernacularTitle:聚氨酯发泡胶结合翼板个体化塑形与负压真空袋固定肺癌放疗摆位精度比较
- Author:
Yingting ZHANG
1
;
Bingzhong LIU
;
Wenfen CHEN
;
Hong HUANG
;
Chengguang LIN
Author Information
1. 华南肿瘤学重点实验室 中山大学肿瘤防治中心放疗科
- Keywords:
Lung neoplasms／radiotherapy;
Polyurethane foam;
Vacuum bag;
Setup errors;
Margin
- From:
Chinese Journal of Radiation Oncology
2018;27(3):299-302
- CountryChina
- Language:Chinese
-
Abstract:
Objective To compare the positioning accuracy between personalized polyurethane foam with wing boards and negative pressure vacuum bag in radiotherapy for lung cancer using kilovoltage cone beam computed tomography(CBCT). Methods Thirty-nine patients with lung cancer who received chest radiotherapy in our hospital from 2015 to 2016 were enrolled as subjects. In those patients, 20 were immobilized by negative pressure vacuum bags(VB group)and the others by personalized polyurethane foam with wing boards(PF group).CBCT images were acquired weekly and registered with planning CT images. Setup errors in the left-right, superior-inferior, and anterior-posterior directions, three-dimensional(3D) displacement vector,and setup time were recorded. The margin of the planning target volume(PTV)was calculated using the Van Herk formula(2.5∑+0.7σ). Between-group comparison was made by paired t test. Results The PF group had a significant smaller setup error in the y-direction than the VB group (2.54±1.79 vs.3.19±2.14 mm,P=0.03),while there were no significant differences in setup errors in the x-or z-direction between the two groups(1.80± 1.48 vs. 1.90± 1.41 mm, P=0.46;2.14± 1.75 vs. 2.25± 1.75 mm,P=0.35). There were no significant differences in rotational setup errors in the Rx-,Ry-,or Rz-direction between the two groups(1.15°±0.76°vs. 1.15°±0.85°, P=0.50;0.71°±0.60°vs. 0.72°±0.43°, P=0.45;0.62°±0.54° vs. 0.46°±0.30°,P=0.06). The PTV margins in the x?,y?,and z?directions were expanded by 5.56, 8.57, and 7.02 mm, respectively, in the PF group, and by 5.62, 9.27, and 7.23 mm,respectively,in the VB group. The proportion of patients with 3D displacement vectors larger than 5 mm was 40% in the PF group and 45% in the VB group.Conclusions For patients undergoing radiotherapy for lung cancer,personalized polyurethane foam with wing boards can,to a certain extent,reduce the setup error in the superior-inferior direction and PTV margin expansion.[Key words] Lung neoplasms/radiotherapy; Polyurethane foam; Vacuum bag; Setup errors;Margin
