Source of Support: None, Conflict of Interest: None
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Electron arc is a special technique very useful in may clinical situations. Detailed measurements and planning were carried out for standardizing electron arc technique at our center. An electron arc cone of appropriate thickness is fabricated to give an area of 5 cm x 35 cm at isocenter. The central axis depth dose data were generated using parallel plate chamber and profiles were generated with cylindrical type chamber at multiple depths using computer controlled water phantom dosimetric system. This data was fed into treatment planning system through a digital interface which avoids manual feeding errors, if digitizer or key board is used. A cylindrical wax phantom was constructed with necessary holes for placement of 0.6 cm3 ion chamber at appropriate depths for energies between 6 MeV and 20 MeV electrons. The monitor units per cGy per degree were determined for various source-to-skin distances. The in vivo measurements were also carried out in phantom and patient and the results were found to match within + 5% of expected value.
