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中国癌症防治杂志 ›› 2015, Vol. 7 ›› Issue (3): 201-205.doi: 10.3969/j.issn.1674-5671.2015.03.13

• 临床研究 • 上一篇    下一篇

鼻腔NK/T细胞淋巴瘤RapidArc容积旋转调强与动态适形调强的剂量学比较

  

  1. 广西医科大学第一附属医院放疗科;广西医科大学研究生学院
  • 出版日期:2015-06-25 发布日期:2015-07-13
  • 通讯作者: 王仁生 13807806008@163.com

Dosimetric comparison of volumetric modulated arc therapy (RapidArc)with dynamic intensity-modulated radiotherapy for nasal natural killer/T-cell lymphoma

  • Online:2015-06-25 Published:2015-07-13

摘要:

目的 比较RapidArc容积旋转调强(volumetric modulated arc therapy,VMAT) 与动态适形调强( dynamic intensity modulated radiotherapy,dIMRT) 在鼻腔NK/T细胞淋巴瘤放疗计划中的剂量学差异。方法 用Varian Eclipse 8.6治疗计划系统对10 例鼻腔NK/T细胞淋巴瘤患者分别制订二弧RapidArc和固定角度9野dIMRT放疗计划,靶区照射剂量均为50 Gy/25次,使用剂量体积直方图比较两种计划中靶区、危及器官的剂量学差异。结果 与RapidArc计划相比,dIMRT计划靶区(PTV)的最小剂量(Dmin)增大3.48 Gy(t=-3.810,P=0.004),PTV的最大剂量(Dmax)减小2.12 Gy(t=3.979,P=0.003),PTV的平均剂量(Dmean)减小1.65 Gy(t=4.933,P=0.001),适形指数(CI)无显著差异(t=-1.516,P=0.164),均匀指数(HI)更好(t=5.068,P=0.001);右侧视神经Dmax减小0.75 Gy(t=3.266,P=0.010),右侧眼球Dmean减小2.24 Gy(t=2.351,P=0.043),脊髓Dmax减小1.92 Gy(t=2.828,P=0.020),脊髓Dmean减小0.46 Gy(t=3.497,P=0.007),左侧腮腺Dmean减小1.45 Gy(t=3.483,P=0.007),其余正常组织RapidArc和dIMRT计划剂量相当。 结论 二弧RapidArc计划和9野dIMRT计划的靶区剂量分布均能达到临床要求;dIMRT计划的HI更好,对部分正常器官的保护优于RapidArc计划,RapidArc计划的机器跳数(MU)较低,约为dIMRT计划的1/3,有利于提高治疗效率。

关键词: 鼻咽肿瘤, 鼻腔NK/T细胞, 淋巴瘤, 放射治疗, 剂量学比较, RapidArc, 动态适形调强

Abstract:

Objective To compare dosimetry between volumetric modulated arc therapy (RapidArc) and nine-field fixed-gantry dynamic intensity-modulated radiotherapy(dIMRT) for nasal natural killer/T-cell lymphoma. Methods RapidArc and dIMRT plans were generated for 10 patients with natural killer/T-cell lymphoma based on the Varian Eclipse 8.6 radiation treatment planning system. Planning target volume (PTV) and organs at risk(OAR) were evaluated using dose-volume histograms (DVHs). Results  Compared to RapidArc, the dIMRT approach showed higher Dmin for PTV (3.48 Gy,t=-3.810,P=0.004),lower Dmax for PTV (2.12 Gy,t=3.979,P=0.003),lower Dmean for PTV(1.65 Gy,t=4.933,P=0.001),superior homogeneity index(t=5.068,P=0.001),and similar conformity index. In addition,the dIMRT approach was associated with lower values of Dmax for the right optic nerve(0.75 Gy,t=3.266,P=0.010),Dmean for the right eyeball(2.24 Gy,t=2.351,P=0.043),Dmax for the spinal cord (1.92 Gy,t=2.828,P=0.020),Dmean for spinal cord (0.46 Gy,t=3.497,P=0.007)and Dmean for the left parotid(1.45 Gy,t=3.483,P=0.007). Conclusions Both RapidArc and dIMRT plans satisfied clinical requirements,but dIMRT plans were associated with superior homogeneity index, better protection of some OARs as well as greater monitor unit.

Key words: Nasopharyngeal neoplasm, Nasal Natural killer/T-cell, Lymphoma, Radiotherapy, Dosimetric comparison, RapidArc, Dynamic intensity modulated radiotherapy