Comparing the Measurement Value of Photon Contamination Absorbed Dose in Electron Beam Field for Varian Clinical Accelerator
The IUP Journal of Physics, Vol. IV, No. 3, July 2011, pp. 7-11
Posted: 15 May 2012
Date Written: May 15, 2012
Sometimes in electron radiotherapy, Bremsstrahlung photon is produced in accelerator head. This photon contamination creates various doses in electron beams. In this study, varian accelerator in electron mode has been simulated and the photon contamination depth dose for three energies 6, 9 and 12 MeV in Monte Carlo method was calculated. Also, electron depth dose curves in simulation and measurement were compared. The discrepancies between measurement and simulation of depth dose curves were calculated in high accuracy by a program that was written in FORTRAN language. The error average is less than 1.5% in semilinear region for these three energies. Results show that the simulation has a good accuracy. Also, the graphs demonstrate that the dose of photon contamination is trivial versus electron dose. In phantom surface percentage photon contamination dose for these three energies ranged between 0.284% and 0.340% of maximum dose.
Keywords: clinical dosimetry, Monte Carlo simulation, photon contamination, Bremsstrahlung effect
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