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

Document Type : Original Article


1 Deprtment of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

2 M.SC. Student in Medical Physics.

3 Assistant Professor of Medical Physics

4 Deprtment of Radiotherapy and Oncology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz,

5 Behbahan Faculty of Medical Sciences, Behbahan, Iran.


Background and Objective: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 Methods: 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.
Results: 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.
Conclusions: 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.


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