射波刀治疗脑动静脉畸形的剂量学分析  

Dosimetric analysis of CyberKnife in treatment of cerebral arteriovenous malformations

作　　者：景生华 李益坤 李静 邱祥南 张琰 丁巍 孙向东 JING Sheng-hua;LI Yi-kun;LI Jing;QIU Xiang-nan;ZHANG Yan;DING Wei;SUN Xiang-dong(Department of Radiation Oncology,General Hospital of Eastern Theater Command,Nanjing 210002,China)

机构地区：[1]东部战区总医院放疗科,南京210002

出　　处：《医疗卫生装备》2023年第11期56-60,共5页Chinese Medical Equipment Journal

摘　　要：目的:探究影响射波刀治疗脑动静脉畸形(arteriovenous malformation,AVM)的肿瘤靶区(gross tumor volume,GTV)和正常组织剂量分布的因素,分析不同直径的准直器对脑AVM剂量分布的影响,为脑AVM射波刀治疗计划的设计提供参考。方法:选取2015—2020年在某院经脑AVM栓塞术后接受射波刀治疗的12例脑AVM患者,根据GTV横断面长径的30%、40%、50%、30%+40%+50%选取不同尺寸的准直器,为每位患者制订4个不同的治疗计划,分别作为A组、B组、C组、D组。分析GTV形状和体积、准直器的大小对靶区剂量分布的影响,并对靶区外的剂量跌落情况进行分析。采用SPSS 20.0软件进行统计学分析。结果:GTV宽度、高度、体积和规则度对适形性指数、新适形性指数、几何适形性指数和治疗射野数的影响均有统计学意义(P<0.05)。C组与A组、B组和D组相比,GTV的最小剂量、中位吸收剂量、靶区覆盖率、靶区梯度指数和处方剂量线提高,GTV的适形性指数、新适形性指数、几何适形性指数及射波刀治疗计划的治疗机器跳数、治疗节点数和治疗射野数降低,且差异有统计学意义(P<0.05)。C组虽然靶区外20 mm以外正常组织的中位吸收剂量降低,但靶区外15 mm范围内正常组织的中位吸收剂量增大。结论:在射波刀治疗脑AVM时,根据GTV横断面长径的50%选取准直器可以实现更理想的剂量分布,同时提高射波刀治疗计划的执行效率。Objective To investigate the factors affecting the dose distribution to the tumor target volume(GTV)and normal tissues in cerebral arteriovenous malformation(AVM)treated with CyberKnife,and to analyze the effect of collimators of different diameters on the dose distribution of cerebral AVM,so as to provide references for cerebral AVM CyberKnife treatment plans.Methods Totally 12 cerebral AVM patients receiving CyberKnife treatment after embolization in some hospital between 2015 and 2020 were selected.Collimators were determined according to 30%,40%,50%,30%+40%+50%of the GTV cross-sectional long diameters,and four different treatment plans were developed for each patient and then enrolled into Group A,Group B,Group C,and Group D,respectively.The effects of the shape and volume of GTV and the size of collimator on the dose distribution in the target area were analyzed,and the dose fall-off outside the target area was investigated.SPSS 20.0 software was used for statistical analysis.Results The effects of width,height,volume and regularity of GTV on the conformity index(CI),new conformity index(nCI),geometric conformity index(gCI)and number of beams were statistically significant(P<0.05).When compared with group A,B and D,group C had the minimum dose,median absorbed dose,target area coverage,target gradient index and prescription dose line of GTV increased while the CI,nCI,gCI of GTV and the number of monitor units,treatment nodes and beams decreased significantly(P<0.05).In group C median absorbed dose of normal tissue more than 20 mm apart from the target area decreased,while median absorbed dose of normal tissue not longer than 15 mm apart from the target area increased.Conclusion During CyberKnife treatment of cerebral AVMs,collimator selection based on 50%of the GTV cross-sectional long diameter can achieve an optimal dose distribution while improving the efficiency of the execution of the CyberKnife treatment plan.

关 键 词：射波刀治疗 脑动静脉畸形 准直器 剂量分布 

分 类 号：R743[医药卫生—神经病学与精神病学] R815[医药卫生—临床医学]