自动和逆向3DCRT与逆向IMRT计划剂量学比较

目的 比较自动3DCRT、逆向3DCRT、逆向IMRT计划的剂量学差异。方法 选取2014—2015年间单一靶区肺癌10例和颅内肿瘤10例,经网络传输至RayStation4.5TPS。采用自动3DCRT、逆向3DCRT和逆向IMRT方法分别对20例病例进行治疗计划设计,3种PTV和OAR剂量体积限制条件一致、射野数相同,比较3种计划的等剂量分布、靶区和OAR剂量参数。采用多相关变量和双相关变量分布分析。结果 肺癌病例中IMRT计划D_98%、D_50%、D_2%、CI和HI均优于逆向3DCRT和自动3DCRT计划(P=0.007、0.001、0.002、0.000、0.000);自动3DCRT计划的CI优于逆向3DCRT计划(P=0.000),3种计划中心脏D₃₃、脊髓D_max和D_{1 cm³}、双肺的各参数受量均相近(P=0.702、0.237、0.163、0.739、0.908、0.832、0.886、0.722、0.429、0.840、0.702);颅内肿瘤病例中逆向IMRT和自动3DCRT计划的CI优于逆向3DCRT计划(P=0.002、0.034),其他靶区参数相近(P=0.648、0.783、0.256、0.931),3种计划全脑受量各参数相近(P=0.446、0.755、0.772、0.0266、0.440、0.290、0.939)。结论 单一靶区肺癌和颅内肿瘤病例中,与逆向3DCRT技术相比,自动3DCRT技术可提高靶区CI;与逆向IMRT技术相比,对OAR保护相近,考虑到3DCRT的简便性和低成本,自动3DCRT技术可以作为一种新放疗技术进行推广。

Dosimetric comparison between automatic three-dimensional conformal radiotherapy,inverse three-dimensional conformal radiotherapy,and inverse intensity-modulated radiotherapy

Objective To compare dosimetric parameters between automatic three-dimensional conformal radiotherapy (a3DCRT),inverse three-dimensional conformal radiotherapy (i3DRT),inverse intensity-modulated radiotherapy (iIMRT).Methods Ten lung cancer patients with a single target and 10 intracranial tumor patients also with a single target,who were treated in our radiotherapy center from 2014 to 2015,were included in the study.Their image data were transferred to RayStation 4.5 via network,and then the treatment plans for a3DCRT,i3DCRT,and iIMRT were designed for the 20 patients.The dosimetric parameters for planning target volume (PTV) and organs at risk (OAR) were compared between the three plans using multiple dependent variables and two dependent variables.Results For lung cancer patients,iIMRT achieved better results in D98％,D50％,D2％,conformity index (CI),and homogeneity index (HI) than i3DCRT and a3DCRT (P=O.007,0.001,0.002,0.000,and 0.000),and the CI of a3DCRT was superior to that of i3DCRT (P=O.000);there were no significant differences in heart D33,spinal cord Dmax and D1 cm3,and both lungs between the three plans (P=O.702,0.237,0.163,0.739,0.908,0.832,0.886,0.722,0.429,0.840,and 0.702).For intracranial tumor patients,there were no significant differences in dosimetric parameters between the three plans,except that the CI of iIMRT and a3DCRT was superior to that of i3DCRT (P=O.648,0.783,0.256,0.931,0.002,and 0.034);there were no significant differences in whole brain irradiation dose between the three plans (P=0.446,0.755,0.772,0.0266,0.440,0.290,and 0.939).Conclusions For the single target in patients with lung cancer and intracranial tumors,a3DCRT can improve the CI of PTV compared with i3DCRT,and shows no significant dosimetric disadvantage for OARs compared with iIMRT.Considering the simplicity and low cost of 3DCRT,a3DCRT holds promise as a novel radiotherapy technique.