脑转移瘤三维适形放疗与调强放疗的剂量学比较研究

目的 通过对脑转移瘤三维适形放疗(3D-CRT)和调强放疗(IMRT)计划对比研究,探讨两种放疗方式的剂量学分布特点,为脑转移瘤临床治疗方案制定提供指导.方法对入组10例脑转移瘤患者进行放疗计划剂量学比较.在三维治疗计划系统上对每例患者分别进行3D-CRT及IMRT计划设计,评价靶区覆盖指数(CI)、异质系数(IC)、...

A Comparative Dosimetric Study Between 3D-CRT and IMRT for Brain Metastasis Tumors

Objective To evaluate the characteristics of three-dimensional conformal radiotherapy(3D-CRT) and intensity modulated radiation therapy(IMRT) of brain metastasis tumors,and to provide the guidance for the clinical treatment of the brain metastasis tumor.Methods Ten patients with brain metastasis tumors were enrolled into this study,and they received the radiotherapy.3D-CRT and IMRT plans for each patient were respectively designed,the target isodose distribution and coverage index(CI),inhomogeneity coefficient(IC),Dmean and Dmax of organs at risk were evaluated.Results Between 3D-CRT and IMRT plans,the statistically significant differences were found in CI(t=6.082,P<0.001) and IC(t=6.534,P<0.001) of PTV-G,in CI(t=5.570,P<0.001) and IC(t=4.227,P=0.002) of PTV-C.There were no statistically significant differences in Dmean of the left eyeball(t=0.668,P=0.529) and the right eyeball(t=2.111,P=0.079),and of the left lens(t=0.330,P=0.753)and the right lens(t=2.379,P=0.055).There were also no statistically significant differences in Dmax of the brain stem(t=2.447,P=0.050),the optic chiasm(t=2.409,P=0.053),the left optic nerve(t=1.047,P=0.336) and the right optic nerve(t=1.848,P=0.114).Conclusion The comparison with 3D-CRT,IMRT has a better conformal target,but also a larger target heterogeneity for brain metastasis tumors.The comparison with 3D-CRT,IMRT has no dosimetric advantage for the protection of organs at risk.