Investigation of Dosimetric Parameters of $^{192}$Ir MicroSelectron v2   HDR Brachytherapy Source Using EGSnrc Monte Carlo Code
  The $^{192}$Ir sources are widely used for high dose rate (HDR) brachytherapy treatments. The aim of this study is to simulate $^{192}$Ir MicroSelectron v2 HDR brachytherapy source and calculate the air kerma strength, dose rate constant, radial dose function and anisotropy function established in the updated AAPM Task Group 43 protocol. The EGSnrc Monte Carlo (MC) code package is used to calculate these dosimetric parameters, including dose contribution from secondary electron source and also contribution of bremsstrahlung photons to air kerma strength. The Air kerma strength, dose rate constant and radial dose function while anisotropy functions for the distance greater than 0.5 cm away from the source center are in good agreement with previous published studies. Obtained value from MC simulation for air kerma strength is $9.762\times 10^{-8} \textrm{UBq}^{-1}$and dose rate constant is $1.108\pm 0.13\%\textrm{cGyh}^{-1} \textrm{U}^{-1}$. 
Hamza Naeem, Chaobin Chen, Huaqing Zheng, Ruifen Cao, Xi Pei, Liqin   Hu, Yican Wu
physics.med-ph