High Energy Electron Beams Radiation Therapy : Medical Physics Unit, Clinical Oncology & Nuclear Medicine Dept., Faculty of Medicine, Mansoura University, Egypt

Megavoltage electron beams are an important treatment modality used in modern radiotherapy. They often provide a unique option in treatment of superficial tumors that are less than 5 cm deep. The most clinically useful electron beams have energies ranging from 6 MeV to 15 MeV. The principal applications of electrons are: (a) in the treatment of skin and lip cancers; (b) in chest wall irradiation for breast cancer; (c) in administering boost doses to nodes; and (d) in the treatment of head and neck cancers.This work focuses on the commissioning and QA of two types of treatment planning systems (Precise 3D and Focus 2D Plan) and it is carried out at Clinical Oncology and Nuclear Medicine Department Mansoura University Hospitals. The main aim of the work is the verification and validation process of the commissioning data for the TPS of advanced radiation therapy systems in two and three dimensions (Precise 3D and Focus 2D Plan) that are used to determine the radiotherapy treatment plane. The commissioning data were measured for all energies 6, 8, 10, 12, and 15 MeV linac (Elekta Precise). A comparison between the calculated PDD generated by TPSs and the experimental measureme