Monte-Carlo simulations of Al_2O_3 dosimetry in uniform MV photon beams: Influence of field and detector size

摘要

This work was to evaluate the absorbed dose to different sizes Al_2O_3 dosimeter in uniform MV photon beams using Monte Carlo simulation. The absorbed dose ratio factor f md of Al_2O_3 dosimeters was calculated. The incident beams included 4 MV-24 MV X-rays using Mohan's spectra with different field sizes. Results show that the maximum variation of f md due to different dosimeter sizes is 5%. As the field diameter increases from 1 cm to 3 cm, the difference of f md can be up to 8%. The results of this work show that the effect of dosimeter size and the field size can't be neglected when using Al_2O_3 dosimeter.