摘要
目的 建立基于自研模体的磁共振加速器日检质控流程,验证该设备束流精度、MR图像引导精度和临床治疗工作流程,评估其提高日检效率的作用.方法 设计并3D打印与Daily QA-MR探测器矩阵联合使用的自研模体,对其进行CT扫描、计划设计并传输至加速器端进行临床治疗工作流程质控,对图像引导精度及输出量、射线质等束流输出检测项目进行检测.采用配对样本t检验方法比较基于自研模体的日检流程和基于厂家推荐的标准模体日检流程的结果差异.结果 共采集到24组测试结果,标准模体的MR图像引导精度在X、Y、Z方向上偏差分别为(0.1±0.4)、(-0.14±0.16)、(0.07±0.05)mm,自研模体分别为(0±0.02)、(-0.02±0.02)、(0.02±0.01)mm,差异有统计学意义(P＜0.001、=0.001、＜0.001);Daily QA-MR探测器矩阵对输出量、枪靶对称性、射线质变化、Y方向射野大小、Y方向射野中心偏移的检测结果分别为-0.11％±0.20％、-0.10％±0.19％、-0.01％±0.08％、(0.4±0.1)mm、(0.2±0.1)mm;采用新流程较标准流程能节省25％(约9 min)的时间.结论 基于Daily QA-MR探测器矩阵联合自研模体,利用本文提出的方法进行磁共振加速器日检,其准确性和灵敏度满足检测要求并且能够提升日检效率.
Abstract
Objective To establish daily quality assurance workflow based on self-developed phantom to ensure MR-linac performance such as beam accuracy,MR image guidance accuracy,and the clinical treatment workflow to enhance the efficiency of daily quality assurance(QA).Methods The self-developed phantom was made by 3D printer and used in conjunction with Daily QA-MR detector array.After CT-sim scanning,a treatment plan was designed and transmitted to the accelerator,tests were performed such as image guidance accuracy,beam output and beam quality,the differences in daily QA results between the self-developed phantom and standard phantom recommended by the manufacturer were analyzed by using paired t-test.Results A total of 24 sets results were collected,the image guide accuracy in the X,Y and Z directions between standard and self-made phantom were(0.1±0.4),(-0.14±0.16),(0.07±0.05)mm and(0±0.02),(-0.02±0.02),(0.02±0.01)mm,respectively,and the differences were statistically significant(P＜0.001,=0.001 and＜0.001).Daily QA-MR detector array beam measurement results including output,symmetry,beam quality and field size were-0.11％±0.20％,-0.10％±0.19％,-0.01％±0.08％,(0.4±0.1)mm and(0.2±0.1)mm,respectively.The new process saved 25％(approximately 9 min)of the time compared to the standard process.Conclusions The new daily QA process for MR-linac is performed based on self-developed phantom and Daily QA-MR detector array.The accuracy and sensitivity meet the requirements and can improve the QA efficiency.
维普
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