不同源图像距离对容积旋转调强放射治疗剂量验证的影响研究  

Research on the influence of the different source image distances on the VMAT dose verification

作　　者：孙小喆 盛康 王昊 梁克明 任贵兵 Sun Xiaozhe;Sheng Kang;Wang Hao;Liang Keming;Ren Guibing(Department of Oncology,Specialized Medical Center of the Chinese People's Armed Police Force,Tianjin 300162,China)

机构地区：[1]中国人民武装警察部队特色医学中心肿瘤科,天津300162

出　　处：《中国医学装备》2025年第3期17-21,共5页China Medical Equipment

摘　　要：目的:研究射野剂量测定中射野剂量学(PD)验证系统射束中心轴上不同源图像距离(SID)影像面板对容积旋转调强放射治疗(VMAT)计划验证的影响,为剂量验证选择合适SID位置及评价标准提供参考。方法:选取2022年7月至2024年5月武警特色医学中心收治的10例不同部位肿瘤放射治疗患者,所有患者均进行VMAT,根据患者资料创建10个模拟剂量验证计划,共10个弧段,非晶硅影像面板在射束中心轴上分别距离等中心为0、-30、-40、-50和-60cm处校准并建立PD系统的验证计划,利用加速器机载非晶硅影像面板电子射野影像装置(a-Si EPID)进行剂量验证,分别对3%/3mm和3%/2mm标准下γ通过率进行对比分析。结果:在3%/3mm评价标准下,SID分别为100、130、140、150和160cm时则采集的剂量γ通过率分别为(98.93±0.81)%、(94.77±9.00)%、(92.18±11.34)%、(89.72±12.54)%和(87.05±13.06)%,均高于3%/2mm评价标准下的γ通过率,差异有统计学意义(t=2.75、3.44、3.59、4.16、6.47,P<0.05)。SID 100cm时采集剂量的平均γ通过率在3%/3mm和3%/2mm评价标准下,与γ通过率为100%比较,差异均有统计学意义(t=-3.21、-3.62,P<0.05),而SID在其他位置得到的γ通过率差异均无显著统计学意义(P>0.05)。结论:在3%/3mm和3%/2mm评价标准下,SID 100cm时采集的剂量γ通过率最高,130cm时采集的剂量γ通过率可满足临床验证基本要求,EPID剂量验证中优选在SID为100cm进行剂量采集,且剂量验证γ通过率更高,干扰影响小,验证结果可信度高。Objective:To study the influence of image panel of different source image distances(SID)of beam central axis of Portal Dosimetry(PD)dose verification system on the verification of volumetric modulated arc therapy(VMAT)plan,so as to provide reference for dose verification in selecting the appropriate SID position and evaluation criteria.Methods:From July 2022 to May 2024,10 patients,who received radiotherapy on tumor at different-site in Specialized Medical Center of the Chinese People's Armed Police Force,were selected.All patients underwent VMAT.Ten simulated dose verification plans were established according to the data of patients,with a total of 10 arcs.The non-crystalline silicon image panel was calibrated at 0,-30,-40,-50 and-60 cm from the isocenter on the beam central axis,and the verification plans of PD system were established.Dose verification was carried out using electronic portal imaging device(EPID)(a-Si EPID)of non-crystalline silicon image panel that was onboard by accelerator.Theγpass rates under the standards of 3%/3 mm and 3%/2 mm were compared and analyzed.Results:Under the evaluation standard of 3%/3 mm,theγpass rates of the collected doses were(98.93±0.81)%,(94.77±9.00)%,(92.18±11.34)%,(89.72±12.54)%and(87.05±13.06)%when the SID values were respectively 100,130,140,150 and 160 cm,which were all higher than these under the evaluation standard of 3%/2 mm,and the differences were statistically significant(t=2.75,3.44,3.59,4.16,6.47,P<0.05).There were significant differences between the averageγpass rate of the collected dose under evaluation standards of 3%/3 mm and 3%/2 mm when SID was 100cm,and the 100%ofγpass rate(t=-3.21,-3.62,P<0.05),while the differences of the obtainedγpass rates among other SID positions were not statistically significant(P>0.05).Conclusion:Under the evaluation standards of 3%/3 mm and 3%/2 mm,theγpass rate of the collected dose at SID 100 cm is the highest.Theγpass rate of the collected dose at SID 130 cm can meet the basically clinical requirements.In EPI

关 键 词：不同源图像距离 剂量验证 非晶硅影像面板 γ通过率 容积旋转调强放射治疗(VMAT) 

分 类 号：R144.1[医药卫生—公共卫生与预防医学]