Barnes Michael P, Greer Peter B
Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Waratah, NSW, Australia.
School of Medical Radiation Sciences, University of Newcastle, Newcastle, NSW, Australia.
J Appl Clin Med Phys. 2017 May;18(3):56-66. doi: 10.1002/acm2.12072. Epub 2017 Apr 17.
Machine performance check (MPC) is an automated and integrated image-based tool for verification of beam and geometric performance of the TrueBeam linac. The aims of the study were to evaluate the performance of the MPC geometric tests relevant to beam collimation (MLC and jaws) and mechanical systems (gantry and collimator). Evaluation was performed by comparing MPC to QA tests performed routinely in the department over a 4-month period. The MPC MLC tests were compared to an in-house analysis of the Picket Fence test. The jaw positions were compared against an in-house EPID-based method, against the traditional light field and graph paper technique and against the Daily QA3 device. The MPC collimator and gantry were compared against spirit level and the collimator further compared to Picket Fence analysis. In all cases, the results from the routine QA procedure were presented in a form directly comparable to MPC to allow a like-to-like comparison. The sensitivity of MPC was also tested by deliberately miscalibrating the appropriate linac parameter. The MPC MLC was found to agree with Picket Fence to within 0.3 mm and the MPC jaw check agreed with in-house EPID measurements within 0.2 mm. All MPC parameters were found to be accurately sensitive to deliberately introduced calibration errors. For the tests evaluated, MPC appears to be suitable as a daily QA check device.
机器性能检查（MPC）是一种基于图像的自动化集成工具，用于验证TrueBeam直线加速器的射束和几何性能。本研究的目的是评估与射束准直（多叶准直器和光阑）及机械系统（机架和准直器）相关的MPC几何测试的性能。通过将MPC与该科室在4个月期间常规进行的质量保证（QA）测试进行比较来进行评估。将MPC多叶准直器测试与针栅测试的内部分析结果进行比较。将光阑位置与基于内部电子射野影像装置（EPID）的方法、传统的光野和坐标纸技术以及Daily QA3设备进行比较。将MPC准直器和机架与水平仪进行比较，并将准直器进一步与针栅分析进行比较。在所有情况下，常规QA程序的结果都以与MPC直接可比的形式呈现，以便进行同类比较。还通过故意错误校准适当的直线加速器参数来测试MPC的灵敏度。发现MPC多叶准直器与针栅测试的结果在0.3毫米范围内一致，MPC光阑检查与基于内部EPID的测量结果在0.2毫米范围内一致。发现所有MPC参数对故意引入的校准误差都具有准确的敏感性。对于所评估的测试，MPC似乎适合作为日常QA检查设备。
