基于仿真头颈模体研究处方等剂量线对射波刀计划质量的影响  

Effect of prescription isodose line on the quality of CyberKnife plan designed on anthropomorphic head and neck phantom

作　　者：杨晶[1] 柳刚 聂鑫 刘洪源 梁志文 韩军 李勤[1] YANG Jing;LIU Gang;NIE Xin;LIU Hongyuan;LIANG Zhiwen;HAN Jun;LI Qin(Cancer Center,Union Hospital,Tongji Medical College,Huazhong University of Science and Technology,Wuhan 430022,China)

机构地区：[1]华中科技大学同济医学院附属协和医院肿瘤中心,湖北武汉430022

出　　处：《中国医学物理学杂志》2018年第12期1371-1374,共4页Chinese Journal of Medical Physics

基　　金：国家重点研发计划(2016YFC0106701)

摘　　要：目的:基于仿真头颈模体研究不同处方等剂量线的选取对射波刀计划质量的影响。方法:以仿真头颈模体中球方中心球体作为靶区,体积为16.9 cc,设置4个剂量限值壳层分别距离靶区表面2、20、40、60 mm,其中最内层的剂量限值为主要优化参数,通过改变其限值参数,在靶区处方覆盖率接近100%的情况下获得不同处方等剂量线计划。结果:分别获得39%、44%、49%、57%、61%和65%处方等剂量线计划,其中49%处方等剂量线计划的剂量梯度指数、适形度指数、V_5、V_9、V_(12)参数相对于其它计划各参数的最大值分别降低了17.5%、9.8%、12.9%、16.1%、21.3%,但49%处方等剂量线计划具有最多的射束数和最长的计划时间。结论:基于仿真头颈模体的射波刀计划研究表明,颅内肿瘤计划的处方等剂量线选择须综合考虑多种因素。提高肿瘤照射剂量并减小正常脑组织照射体积有利于提高肿瘤控制率并降低放射性损伤,但与此同时增加的治疗时间要求患者具有更强的耐受性。Objective To study the effects of different prescription isodose lines(PIDL)on the quality of CyberKnife plans designed on anthropomorphic head and neck phantom.Methods The spherical center sphere in anthropomorphic head and neck phantom was selected as the target area.The volume of the target area was 16.9 cc.Four dose-limit shells were set to be 2,20,40,and 60 mm from the target surface,respectively.The dose limit of the innermost shell was the main optimization parameter.By changing the limit parameters,the plans of different PIDL were obtained under the condition that the prescription coverage of target area approached 100%.Results Plans of 39%,44%,49%,57%,61%and 65%PIDL were obtained.The dose gradient index,conformity index,V5,V9,and V12 of plan of 49%PIDL were reduced by 17.5%,9.8%,12.9%,16.1%,and 21.3%compared with the maximum values of the other plans.However,the plan of 49%PIDL had the largest number of beams and the longest planning time.Conclusion The research of CyberKnife plan designed on anthropomorphic head and neck phantom shows that multiple factors should be considered in the selection of PIDL for intracranial tumor plan.Increasing the radiation dose to the tumor and reducing the irradiation volume of normal brain tissues can improve the tumor control probability and reduce radiation damage,but meanwhile increase treatment time which requires better tolerance in patients.

关 键 词：颅内肿瘤 仿真头颈模体 射波刀 处方等剂量线 计划质量 

分 类 号：R312[医药卫生—基础医学] R815