Intensity-modulated radiotherapy (IMRT) technique is the most common radiotherapy technique used to treat cancer, the IMRT and rapid arc give uniform desired dose distribution to the target volume with adequate sparing of the nearby critical structures. In this work, twenty cases of dynamic IMRT plans were selected for the patient-specific QA study using portal dosimetry and a 2-D array system. Pl. Material and Methods in the current study Varian 6MVlinear accelerators unique model at el Hussein hospital the aSi500 electronic portal imaging device (EPID) is a flat panel X-ray imager. The 2-D array system consists of 1020 parallel plate ion chambers. Results and Discussions, We intend to use it for IMRT in pre-treatments to help select Pγ%< 1 point and relevant transition criteria to assess the reproducibility of treatment fractions. Compared to a 2D Array system., although the 2D array, that observation of approximately 1,000 points (200 per beam) is sufficient for a detailed evaluation of portal dose reproducibility across multiple treatment fractions. This type of verification can be performed during treatment by inserting the 2D crosshair into a special device that can track the rotation of the portal view.
Conclusion in comparison the portal dosimetry soft for portal imager device (EPID) has a good result for breast cancer plan evaluation versus 2D array results and agreement with international publish data, in addition, reduces the time for calibration due to there is no need for extended cable for measurement is compared with a 2D array