摘要
目的比较Rapid Arc容积旋转调强(volumetric modulated arc therapy,VMAT)与动态适形调强(dynamic intensity modulated radiotherapy,d IMRT)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Rapid Arc和固定角度9野d IMRT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Rapid Arc计划相比,d IMRT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Rapid Arc和d IMRT计划剂量相当。结论二弧Rapid Arc计划和9野d IMRT计划的靶区剂量分布均能达到临床要求;d IMRT计划的HI更好,对部分正常器官的保护优于Rapid Arc计划,Rapid Arc计划的机器跳数(MU)较低,约为d IMRT计划的1/3,有利于提高治疗效率。
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.
出处
《中国癌症防治杂志》
CAS
2015年第3期201-205,共5页
CHINESE JOURNAL OF ONCOLOGY PREVENTION AND TREATMENT
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
Nasopharyngeal neoplasm
Nasal Natural killer/T-cell
Lymphoma
Radiotherapy
Dosimetric comparison
RapidArc
Dynamic intensity modulated radiotherapy