Zap-X系统与CyberKnife G4系统射束剂量学比较  

Beam dosimetric comparison between Zap-X and G4 CyberKnife

作　　者：王金媛 鞠忠建 王成成 曲宝林 潘隆盛 戴相昆 Wang Jinyuan;Ju Zhongjian;Wang Chengcheng;Qu Baolin;Pan Longsheng;Dai Xiangkun(Department of Radiation Oncology,First Medical Center of PLA General Hospital,Beijing 100853,China;Department of Neurosurgery,First Medical Center of PLA General Hospital,Beijing 100853,China)

机构地区：[1]中国人民解放军总医院第一医学中心放射治疗科,北京100853 [2]中国人民解放军总医院第一医学中心神经外科,北京100853

出　　处：《中华放射肿瘤学杂志》2023年第11期990-996,共7页Chinese Journal of Radiation Oncology

基　　金：国家重点研发计划(2022YFC2409501)。

摘　　要：目的比较Zap-X系统与CyberKnife G4系统射束的剂量学特性,为Zap-X系统的临床应用提供参考。方法采用PTW三维水箱、半导体电离室分别在水下最大剂量点、50 mm、100 mm、200 mm处测量Zap-X系统与CyberKnife系统的7种不同尺寸准直器(5、7.5、10、12.5、15、20、25 mm)下的两条正交离轴比曲线和等中心处射野大小,应用PTW配套软件MEPHYSTO(version 5.1)分析各参数条件下的射野半影、平坦度、对称性及射野尺寸,采用Origin 2021软件统计数据并作图分析。结果相同的准直器,Zap-X系统的剂量坪区较CyberKnife G4系统的大,且Zap-X系统射野边缘剂量跌落较快。随着准直器的增大,Zap-X系统与CyberKnife系统的半影均呈变大的趋势,平坦度均呈变小的趋势,且Zap-X系统的半影和平坦度均明显小于CyberKnife系统。两个系统都具有较好的对称性(<1%),CyberKnife系统的各项对称性结果(<0.39%)整体优于Zap-X系统(<0.99%)。等中心处Zap-X系统的准直器尺寸精度优于CyberKnife系统。结论与CyberKnife G4系统相比,Zap-X系统具有较小的半影和更好的平坦度,且准直器尺寸精度高,适用于立体定向放射外科治疗。Objective To compare the dosimetric characteristics of beams between Zap-X and G4 CyberKnife and provide reference for clinical application of Zap-X.Methods PTW three-dimensional water tank and dosimetry diode ionization chamber were used to measure the two orthogonal off-axis ratio and field size at isocenter of 7 different collimators(5 mm,7.5 mm,10 mm,12.5 mm,15 mm,20 mm and 25 mm)of Zap-X and CyberKnife at the water depth of maximum dose,50 mm,100 mm,and 200 mm.The penumbra,flatness,symmetry and field size under each parameter condition were analyzed by using PTW supporting software PTW MEPHYSTO(version 5.1).Data analysis and graph were performed using Origin 2021 software.Results With the same collimator,the dose plateau area of Zap-X was wider than that of G4 CyberKnife,and the dose fall-off at the field edge of Zap-X system was faster.With the increase of the collimator,the penumbra of Zap-X and CyberKnife tended to become larger,and the flatness tended to become smaller,the penumbra and flatness of Zap-X were significantly smaller than those of CyberKnife.Both of them had excellent symmetry(<1%),and the symmetry results of CyberKnife(<0.39%)were better than that of Zap-X(0.99%).The accuracy of Zap-X collimator size at isocenter was better than that of CyberKnife.Conclusion Compared with G4 CyberKnife,Zap-X system has smaller penumbra,better flatness and higher accuracy of collimator size,which is suitable for stereotactic radiosurgery.

关 键 词：Zap-X 射波刀 离轴比 半影 平坦度 

分 类 号：R144.1[医药卫生—公共卫生与预防医学]