计算网格大小对脑转移瘤计划剂量计算精度的影响  

Effect of computational grid size on the validation rate of brain metastases

作　　者：孙斌 钟思瑶 南贤秀 徐程 高玉艳 SUN Bin;ZHONG Siyao;NAN Xianxiu;XU Cheng;GAO Yuyan(Department of Radiotherapy,Beijing Luhe Hosiptal Affiliated to Capital Medical University,Beijing 101100,China.)

机构地区：[1]首都医科大学附属北京潞河医院放疗科,北京101100

出　　处：《现代肿瘤医学》2024年第15期2845-2851,共7页Journal of Modern Oncology

基　　金：首都医科大学附属北京潞河医院青年科研孵育专项(编号:LHYY2020-LC07)。

摘　　要：目的:研究Eclipse计划系统Acuros XB算法不同计算网格大小对脑转移瘤计划验证通过率的影响。方法:选取17例脑转移瘤患者进行全脑及转移灶推量的放疗方式,使用Eclipse 15.5计划系统对所选病例进行3个全弧计划设计,采用Acuros XB算法,对每例患者分别使用0.25 cm、0.20 cm、0.15 cm、0.10 cm计算网格大小进行计划剂量计算,同时记录不同网格计划计算时间。利用电子射野影像装置(electronic portal imaging device, EPID)进行数据采集,用Portal Dosimetry分析得到3%/3 mm、3%/2 mm、3%/1 mm、2%/3 mm、1%/3 mm不同评判标准的Gamma通过率,并对不同网格大小的Gamma通过率进行比对分析。结果:随着剂量计算网格的减小,计划计算时间数倍增长差异具有统计学意义(P<0.05),当网格大小从0.15 cm降到0.10 cm时,计算时间平均增加18分钟。对于计划通过率,除0.10 cm与0.15 cm的3%/1 mm Gamma通过率无差异(P=0.356)外,计算网格大小为0.10 cm的Gamma通过率优于0.25 cm、0.20 cm和0.15 cm(P<0.05),同时随着计算网格的减小,通过率增加幅度逐渐变缓,0.10 cm与0.15 cm的通过率差异极小。结论:对于全脑及转移灶推量的计划,使用0.15 cm网格在不显著增加计算时间的同时,可以增加计划的通过率。Objective:To investigate the effect of different computational grid sizes of Acuros XB algorithm in Eclipse planning system on the pass rate of brain metastases planning.Methods:17 patients with brain metastases were selected for whole brain and metastatic focus radiotherapy.Eclipse 15.5 planning system was used to design three full arc plans for the selected patients.Acuros XB algorithm was used to calculate the planned dose for each patient using 0.25 cm,0.20 cm,0.15 cm and 0.10 cm calculation grids,and record the calculation time of different grid plans.Electronic portal imaging device(EPID)was used for data acquisition,and the Gamma pass rates of 3%/3 mm,3%/2 mm,3%/1 mm,2%/3 mm,and 1%/3 mm were obtained by Portal Dosimetry analysis,the Gamma passing rates of different grids were compared analyzed.Results:With the decrease of computational grid sizes,the planned calculation time increased several times,and the difference was statistically significant(P<0.05).When the grid size was reduced from 0.15 cm to 0.10 cm,the calulation time increased by an average of 18 minutes.For the planned pass rate,except fo the 3%/1 mm Gamma pass rate of 0.10 cm and 0.15 cm,which had no difference(P=0.356),Gamma passing rate of 0.10 cm grid size was better than 0.25 cm,0.20 cm and 0.15 cm(P<0.05).At the same time,with the decrease of the grid,the increase of the pass rate gradually slowed down,and the difference between the pass rate of 0.10 cm and 0.15 cm was very small.Conclusion:For whole brain and metastatic push plans,using 0.15 cm grid can increase the plan pass rate without significantly increasing the calculation time.

关 键 词：计算网格 计算时间 脑转移 Gamma通过率 

分 类 号：R739.41[医药卫生—肿瘤]