Study of the IsoAid ADVANTAGE (125)I brachytherapy source dosimetric parameters using Monte Carlo simulation.

Monte Carlo calculations have been performed using the MCNP4C code for an iodine seed design. As the ADVANTAGE I-125, Model IAI-125 source is commercially available for interstitial brachytherapy treatment, dosimetric characteristics (dose rate constant, radial dose function and anisotropy function) of this source were theoretically determined following the updated AAPM task group 43 (TG-43U1) recommendations. The dose distribution around the seed was calculated with Monte Carlo simulation in liquid water. The Monte Carlo calculated dose rate constant of this source in water was found to be 0.986cGyh(-1)U(-1), with an approximate uncertainty of 0.4%. The obtained result has been compared with the previous study. Comparison of the calculated dose rate constant with the value presented by Meigooni et al. shows a very good agreement. Also the anisotropy function and the radial dose function for this source are graphically compared.