Dosimetric evaluation of intensity modulated proton therapy and photon volumetric modulated arc therapy for bilateral breast cancer
10.3760/cma.j.cn112271-20240716-00262
- VernacularTitle:双侧乳腺癌质子调强与光子容积旋转调强放疗计划的剂量学评价研究
- Author:
Zhongkai JIANG
1
;
Chunfeng FANG
;
Lulu LI
;
Zishen WANG
;
Yumei LI
;
Shouping XU
Author Information
1. 河北一洲肿瘤医院物理技术部，涿州 072750
- Publication Type:Journal Article
- Keywords:
Bilateral breast cancer;
Volumetric modulated arc therapy;
Intensity modulated proton therapy;
Plan quality
- From:
Chinese Journal of Radiological Medicine and Protection
2025;45(7):647-654
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To evaluate the dosimetric characteristics of intensity-modulated proton therapy (IMPT) and photon volumetric modulated arc therapy (VMAT) in radiation therapy planning for patients with bilateral breast cancer after breast-conserving surgery.Methods:On the computed tomography localization images of 18 patients with bilateral breast cancer, target volumes and organs at risk were contoured to develop both IMPT and VMAT plans for each patient. Two IMPT plans were designed based on the clinical target volume (CTV) with robust optimization (RO-IMPT) and the planning target volume (PTV) without RO (NonRO-IMPT), respectively. The RO-IMPT, NonRO-IMPT, and VMAT plans were normalized such that the prescription dose could cover 95% of the target volume. The dosimetric parameters of target volumes and organs at risk were evaluated, and the dosimetric characteristics of the two techniques were compared.Results:In terms of target volumes, the RO-IMPT group showed significantly lower D1%, Dmean, and homogeneity index (HI) and a significantly higher D99% of the CTV than those of the PTV in the VMAT group ( t=-8.96, -8.21, -8.13, 4.96, P<0.05). The NonRO-IMPT group showed significantly lower D1%, Dmean, and HI and a significantly higher conformity index of the PTV than those of the PTV in the VMAT group ( t=-7.75, -6.25, -6.11, 7.53, P<0.05). In terms of organs at risk, the two IMPT groups showed significantly lower values than the VMAT group for the V5- V30 and Dmean of the whole lungs, V5- V40 and Dmean of the heart, D1% and Dmean of the left anterior descending coronary artery, D1% of the spinal cord, Dmean of normal tissues, and Dmean of the skin ( t= -28.47 to -3.25, P<0.05). There was no significant difference in any other evaluation indices ( P>0.05). Conclusions:Both IMPT and VMAT can meet the clinical requirements of radiotherapy plans following breast-conserving surgery for bilateral breast cancer. IMPT has apparent advantages over VMAT in protecting organs at risk.
