摘要
目的测试MapCHECK2二维半导体矩阵探测器性能,验证在临床各部位肿瘤调强放射治疗(Intensity Modulated Radiation Therapy,IMRT)尤其是多靶点放疗计划剂量验证中的效果。方法使用Precise型加速器的6 MV均整光子束,在特定照射条件下,取矩阵中心区域5 mm范围内的5个探测器的测量平均值作为点剂量值,分析剂量重复性、剂量线性和剂量率响应。采用γ分析方法对比矩阵测量与计划系统计算的面剂量分布,研究对称性和角度响应。选择不同部位肿瘤的40例IMRT计划,制定基于矩阵的QA计划并执行剂量验证。结果矩阵重复性最大偏差不超过0.18%,剂量线性确定系数R^(2)=1,剂量率偏差不超过1.6%。0°和180°对称性对比γ通过率最大差异为0.21%。在与垂直入射偏转80°范围内(机架角0°~80°和280°~0°),γ(3%/2 mm)通过率大于96.4%。在与垂直入射偏转60°范围内(机架角0°~60°和300°~0°),γ(2%/2 mm)通过率大于92.4%。40例临床IMRT计划平均γ(3%/2 mm)、γ(2%/2 mm)通过率分别为98.3%±0.3%/98.5%±0.4%和96.5%±0.6%/96.7%±0.8%。结论MapCHECK2半导体矩阵探测器性能满足基于6 MV均整光子束的各部位肿瘤临床IMRT计划在垂直单射束依次照射方法下的剂量验证工作要求,真实复合方法下的剂量验证工作需要配置专门设计的模体。
Objective To test the performance of MapCHECK2(two-dimensional semiconductor matrix detector)and verify its effect on intensity modulated radiation therapy(IMRT),especially the dose verification of multi-target radiotherapy plans.Methods Used the 6 MV photon beam of Precise accelerator under specific irradiation conditions,took the measured average value of five detectors within 5 mm of the central axes of matrix as the point dose value,and analyzed the dose repeatability,dose linearity and dose rate response.The symmetry and angular response were studied by gamma indices analysis comparing the dose distributions calculated by matrix measurement and the planning system.Forty cases of IMRT plans for tumors in different parts were selected,and a matrix-based QA angle plan was developed and dose validation was performed.Results The maximum deviation of matrix repeatability was not exceed 0.18%,the dose linear determination coefficient R^(2)=1,and the dose-rate deviation was not greater than 1.6%.The deviation of gamma passing rate was not more than 0.21%for the symmetry of 0°and 180°.Theγ(3%/2 mm)passing rate was greater than 96.4%in the range of 80°deflection with vertical incidence(gantry 0°~80°and 280°~0°),theγ(2%/2 mm)passing rate was greater than 92.4%in the range of 60°deflection with vertical incidence(gantry 0°~60°and 300°~0°).The averageγ(3%/2 mm)andγ(2%/2 mm)passing rate of 40 IMRT plans were 98.3%±0.3%/98.5%±0.4%and 96.5%±0.6%/96.7%±0.8%respectively.Conclusion The performance of the MapCHECK2 semiconductor matrix detector meets the dose verification work under the vertical single beam sequential irradiation method in the clinical IMRT plans of tumors at various parts based on 6 MV uniform photon beam.The dose verification under the real composite method requires the equipment to be equipped with specially designed phantom.
作者
李小红
梅杰
龙浩
杨晶
LI Xiaohong;MEI Jie;LONG Hao;YANG Jing(Department of Oncology,Liyuan Hospital,Tongji Medical College,Huazhong University of Science and Technology,Wuhan Hubei 430077,China;Cancer Center,Union Hospital,Tongji Medical College,Huazhong University of Science and Technology,Wuhan Hubei 430022,China;College of Electronic and Information Engineering,South-Central Minzu University,Wuhan Hubei 430074,China)
出处
《中国医疗设备》
2022年第4期23-26,34,共5页
China Medical Devices
基金
国家自然科学基金面上项目(12075322)
中央高校基本科研业务费专项基金资助项目(2018KFYYXJJ115)。
关键词
调强放射治疗
二维半导体矩阵探测器
性能测试
多靶点放疗计划
剂量验证
intensity modulated radiation therapy
two-dimensional semiconductor matrix detector
performance test
multi-target radiotherapy plan
dose verification
