Dosimetric study of 5 fixed-jaw techniques in volumetric modulated arc therapy for nasopharyngeal carcinoma(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第2期
- Page:
- 133-137
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Dosimetric study of 5 fixed-jaw techniques in volumetric modulated arc therapy for nasopharyngeal carcinoma
- Author(s):
- WU Fan1; LANG Jinyi1; XU Jinghui1; YUAN Jiawei2; KANG Shengwei1; CHEN Yazheng1; WU Junxiang1
- 1. Sichuan Key Laboratory of Radiation Oncology/Radiation Oncology Center, Sichuan Cancer Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu 610041, China; 2. Department of Oncology, Sichuan Science City Hospital, Mianyang 621900, China
- Keywords:
- Keywords: nasopharyngeal carcinoma; fixed-jaw technique; volumetric modulated arc therapy; dosimetry
- PACS:
- R815；R312
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.02.001
- Abstract:
- Abstract: Objective To compare dosimetric differences of X-axis directional fixed-jaw techniques in volumetric modulated arc therapy (VMAT) for nasopharyngeal carcinoma (NPC) for investigating the optimal fixed-jaw scheme. Methods In Eclipse 11.0 treatment planning system, 5 fixed-jaw techniques were used to design radiotherapy plans for 10 NPC patients. The differences in dosimetric parameters of target areas and organs-at-risk as well as monitor units were compared among 5 plans, and SPSS 23.0 software was used to perform paired sample t-test on the obtained data. Results There was no significant difference among 5 plans in the Dmean, D95 and homogeneity index of target areas (P>0.05), but the conformity index in FJ1 plan in which the jaw was fully closed in X2 direction was better than that in other fixed-jaw techniques (t=-2.97--1.06, P<0.05). The Dmax of spinal cord, the V30 and Dmean of parotid glands, larynx and oral cavity in FJ1 plan were lower than those in the others, with statistical significances (t=-5.83-1.14, P<0.05). No statistical significance was found in brainstem, cochlea and temporal lobes (t=-0.99-2.99, P>0.05). Moreover, FJ1 plan had the highest monitor units (t=8.15-8.86, P<0.05). Conclusion All the 5 fixed-jaw techniques can meet the clinical requirements, while FJ1 techniques can reduce organs-at-risk doses, but increase monitor units and delivery time. Compared with FJ1 techniques, FJ2 technique in which the jaw is changed from half-open to fully-closed in X2 direction has inferior organs-at-risk sparing, but improves treatment efficiency.
Last Update: 2020-03-03