Optimization of Percentage Depth Dose by Combination of Electron Beams with Different Energies and Different Contribution

Recently, electron beams are widely used for superficial and skin lesions treatment. Since the accelerator devices, create electron beams with finite energies, the treatment area is limited to a specified depth. The objective of this study was to assess the effect of combination of electron beams with different energies and different contribution in order to produce PDD curve with a more uniform central dose distribution for the shallow superficial lesions treatment (up to cm 3). The results were compared with using a single electron beam energy. Subjects and at First, percentage depth dose (PDD) was measured by using a Varian accelerator devices for energies 4, 6, 9, 12 Mev of electron beams and field size 20 × 20 cm2. Then, PDD curve was converted to dose curve. 4 Gaussian function was fit to dose curve using MATLAB software and the best combination was selected by combining different proportions of each of this functions. percentage of the build up dose increased to about %90-%95 maximum dose and also percentage of the surface dose increases to about %90 maximum dose by combination of electron beams with different energies and different contribution. low energy electron beams Combination cause optimization of the dose distribution PDD curve. Furthermore, we can produce electron beam with arbitrary energy by this method.