الفهرس 
Title pageOnly 14 pages are availabe for public view
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Abstract
The goal of radiation therapy is to administer a therapeutic dose of radiation to a target while limiting the side effects caused by delivering the dose to surrounding tissues and vital organs. The ongoing pursuit to achieve an optimal dose distribution has prompted the radiation therapy profession to develop new techniques that incorporate advances in technology. In radiation therapy today, modern techniques that include three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) are routinely used in the treatment of cancers.
In Radiotherapy treatment process using many of multiple photon energy. The suitable photon energy is determined according to the sit and separation of tumor and founding it by site organ at risk. In the process of radiation therapy there are many different energies that are used in the treatment of different tumors, whether photon energy or electron energy. The energy used is determined by the location, size, and extent of the tumor and its proximity to healthy organs.
The aim of this study was dosimetric evaluation studies for advantages of using 6 MV in comparison to 10MV and 15 MV photons Three-dimensional conformal radiation therapy (3D-CRT), Intensity-modulated radiation therapy (IMRT) and Volumetric-Modulated Arc Therapy (VMAT).
Techniques for brain cancer patients.
This study included 15 cancer patients with brain carcinoma, 135 treatment plans were performed using different photon energies 6MV, 10MV and 15MV and using different techniques (3D-CRT), (IMRT) and (VMAT).
Summary
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Our results showed that:
In 3D-CRT plan the mean dose received by PTV D2%, D5%, D50%, D95% and D95% were insignificantly different between different photon energies. Regarding organ at risk, dose comparison for different photon energies showed insignificant difference.
In IMRT plan the mean dose received by PTV D2%, D5%, D50%, D95% and D95% were insignificantly different between different photon energies. Moreover, dose comparison for different photon energies for organ at risk showed insignificant difference.
In VMAT plan the mean dose received by PTV D2%, D5%, D50%, D95% and D95% were insignificantly different between different photon energies. In addition, dose comparison for different photon energies showed for organ at risk insignificant difference.
The plan quality and treatment efficiency parameters comparison showed: no statistical significant differences in the 6, 10, and 15 MV plans in terms of PTV coverage and OARs in different planning techniques.