Clinical Application of Portal Dosimetry for Pre-treatment Dosimetric Verification Across Various Diagnoses Using Electronic Portal Imaging Integrated with Epibeam

<i>Introduction and Objective: </i>Unlike other LA users, most Elekta users use a 2D Array or other external devices for Patient specific QA purpose. In India, we experimented with a third-party portal dosimetry system called EPI Beam from DosiSoft, France, for PSQA. EPI (Electronic Portal Imaging) Beam Portal Dosimetry is a method used to verify the dose delivery in radiation therapy. It utilizes the Elekta iViewGT EPID to measure the radiation dose distribution delivered to the patient. The acquired portal images are then compared with the predicted dose distribution from the treatment planning system (TPS). The objective of this study is to analyze the gamma pass rate with this technology in various sites and treatment techniques in 100 patients. <i>Material and methods: </i>Pre-treatment verification using Portal Dosimetry was performed on 100 patients utilizing an Elekta iViewGT™ EPID and EPI Beam software on an Elekta Harmony Pro linear accelerator having 6 MV, 15 MV, and 6FFF photon energies. Elekta’s portal dosimetry system eliminates the need for a separate QA plan or a phantom, as the patient's treatment plan is directly delivered to the Electronic Portal Imaging Device (EPID) panel. The delivered dose is then calculated and compared to the planned dose, ensuring accurate dose delivery and proper linear accelerator functioning before the patient’s first treatment fraction. <i>Results: </i>In all plans that were done by Volumetric Modulated Arc Therapy (VMAT) for various diagnoses were analyzed and the average gamma pass rate for Head and Neck, Thoracic, Pelvis, Breast, are 99.34%, 98.97%, 98.78% and 99.35% respectively. <i>Conclusions: </i>The gamma evaluation indicates a good correlation between predicted and acquired EPID image doses. The EPID-based pre-treatment verification using EPI Beam from DosiSoft is a time-saving and comfortable tool for performing pre-treatment verification. This method enhances the precision and safety of cancer treatments.