Margin expansion for treatment field of volumetric modulated arc therapy for breast cancer
10.3760/cma.j.issn.1004-4221.2018.09.012
- VernacularTitle:乳腺癌容积调强弧形治疗的射野边界外放方法
- Author:
Chenlei GUO
1
;
Yingjie XU
;
Jianrong DAI
Author Information
1. 国家癌症中心/ 国家肿瘤临床医学研究中心/ 中国医学科学院北京协和医学院肿瘤医院放疗科
- Keywords:
Breast neoplasms/ volumetric modulated arc therapy;
Beam aperture
- From:
Chinese Journal of Radiation Oncology
2018;27(9):845-849
- CountryChina
- Language:Chinese
-
Abstract:
Objective We developed a method to expand margin of beam aperture for VMAT treatment planning of breast cancer and evaluated its effectiveness in clinic. Methods An expanded VMAT (E-VMAT) plan for breast cancer using Pinnacle39. 10 planning system was made. A small tissue-equivalent bolus was added at the middle of the breast surface as part of the target and the VMAT plan was generated with beam aperture automatically expanded. Then the tissue-equivalent bolus was removed and the final dose distribution was calculated. Ten patients with breast cancer undergoing breast conserving surgery were tested. The dosimetrical metrics and delivery efficiency were compared between the E-VMAT plans and the routine VMAT plans. Results On the BEV view, it was observed that in E-VMAT plans the collimator and MLC leaf positions was extended outside the skin along the anterior-posterior direction of the thorax. There were no significant differences in conformity index and homogeneity index of target volume between the two types of plans and the planned delivery efficiency was consistent (P>0. 05). Conclusions The method established in this study can automatically generate expansion of VMAT beam apertures and prevent missing of target volume due to respiratory motion and/ or setup error of the patient. The method does not require programming skill and available for different treatment planning systems.
