Establishing action levels for EPID‐based QA for IMRT
نویسندگان
چکیده
Although portal dosimetry is used to provide quality assurance (QA) for intensity-modulated radiation therapy (IMRT) treatment plans, trends in agreement between the portal dose prediction (PDP) and the measured dose have not been clarified. In this work, we evaluated three scalar parameters of agreement for 152 treatment plans (1152 treatment fields): maximum gamma (gamma max), average gamma (gamma avg), and percentage of the field area with a gamma value greater than 1.0 (gamma % > 1). These data were then used to set clinical action levels based on the institutional mean and standard deviations. We found that agreement between measured dose and PDP was improved by recalculating the fields at lower dose rates. We conclude that action levels are a useful tool for standardizing the evaluation of EPID-based IMRT QA.
منابع مشابه
Evaluation of a fast method of EPID-based dosimetry for IMRT and Comparison with 3D EPID-based dosimetry system using conventional two- and three-dimensional detectors for VMAT
Introduction: Electronic portal imaging devices (EPIDs) could potentially be useful for intensity-modulated radiation therapy (IMRT) and VMAT QA. The data density, high resolution, large active area, and efficiency of the MV EPID make it an attractive option. However, EPIDs were designed as imaging devices, not dosimeters, and as a result they do not inherently measure dose in ...
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