Dosimetric differences between IMRT and VMAT for bilateral breast cancer in postmastectomy radiotherapy(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第4期
- Page:
- 384-388
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric differences between IMRT and VMAT for bilateral breast cancer in postmastectomy radiotherapy
- Author(s):
- SHI Yujing1; JU Mengyang1; HU Xiaowei1; LI Jinkai2; WANG Peipei2; LI Caihong2; CHANG Zhigang2; SUN Xinchen2; LI Shunmei2; ZHENG Hailun2
- 1. Department of Special Medicine, Nanjing Medical University, Nanjing 210009, China; 2. Department of Radiation Oncology, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
- Keywords:
- ; Keywords: bilateral breast cancer; dosimetric difference; volumetric modulated arc therapy; intensity-modulated radiotherapy; conformity index; homogeneity index
- PACS:
- R815.6；R737.9；R312
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.04.003
- Abstract:
- Abstract: Objective To compare the dosimetric differences of target areas and organs-at-risk between volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) plans for bilateral breast cancer in postmastectomy radiotherapy, and discuss the optimal treatment scheme. Methods A total of 8 patients receiving radical or modified radical mastectomy for bilateral primary breast cancer were enrolled in this study. Three-dimensional conformal radiotherapy system was used to design two radiotherapy plans, namely IMRT and VMAT, for each patient. There were 10 fixed fields in IMRT plan. In VMAT plan, the bilateral chest wall was treated with double-arc VMAT. The dosimetric parameters obtained by dose-volume histogram, including the mean dose, V95%, V107%, V110% , conformity index and homogeneity index of planning target volume (PTV), and the dosimetric parameters of normal tissues, such as lungs and heart, were compared between two plans. Results Both the two plans met the prescription requirements. When the target coverage reached 95%, the mean dose of PTV in IMRT plan was better than that in VMAT plan (P=0.04). Compared with those in IMRT plan, the V95% of PTV in VMAT plan was increased by 2.7 cm3 (P=0.02), while the V107% and V110% of PTV were decreased by 2.93 and 0.05 cm3, respectively (P=0.03, 0.03). Moreover, VMAT plan was superior to IMRT plan in the homogeneity index and conformity index (P=0.03, 0.05). The V5 of lungs in VMAT plan was higher than that in IMRT plan, while the other parameters of lungs in VMAT plan were lower than those in IMRT plan. Except the V40 of heart, the dosimetric parameters of heart in VMAT plan were higher than those of IMRT, without statistical differences (P>0.05). Conclusion VMAT plan is superior to IMRT plan in dose distribution and the dosimetric parameters of target areas and lungs. Although the dose of heart in VMAT plan is inferior to that in IMRT plan, the differences are still within acceptable range. Therefore, the patients receiving radical surgery for bilateral breast cancer can benefit more from double-arc VMAT.
Last Update: 2019-04-22