Portal imager system now is widely attached as verification system in many models from linear accelerator due to may be used for treatment verification instead of film in as new ear for radiotherapy. The portal imager system has good properties for verification using imaging model and now with better treatment calculation algorithms for use as pretreatment verification for dose evaluation for some new radiotherapy techniques, and modern treatment delivery machines and modes of delivery, to improve possible for using the EPID the conventional Quality Assurance (QA) standards. The current study was done used linear accelerator Varian (model UNIQUEᵀᴹ), which has single photon energy 6 MeV with different dose rate steps start from 100 MU/min. to 600 MU/min equipped by portal imager system aS500, absolute dosimetry system for standard calibration (farmer Ion chamber TM30013, MP3 water phantom and UNIDOS ETM electrometer). The aim of the current study was to quality assurance for the EPID after evaluate the usefulness of EPID method for Quality Assurance and Dosimetry Tool for Medical Linear Accelerator Machine.
In the characteristics study, response of both the detector system, aS500 EPID found to be almost the same and comparable with ion chamber measurements and showed linear relationship with good agreement correlation coefficient of more than 0.974 in compared with absolute dosimetry and quality assurance tool for linear accelerator machine. The EPID system showed good response for different dose rate, different dose and comparable system for many tools using in Quality Assurance protocols for linear accelerator. Our results illustrate the EPID dosimetry can play an important and significant role in the total tests and experimental evaluation for verification procedures that are require for Radiotherapy output. It provides a safety net for easy method to verification advanced treatments, as well as a full account of the dose delivered images from electronic portal imaging device (EPID), which provide a high efficient tool to verify pretreatment verification delivery dose for advance radiation therapy.