Advanced Physics for Brachytherapy 2018

2D Anisotropy Function

• F ( r , θ ) is always unity for a perfect point source

• F ( r , θ ) = 1 at θ 0

• F ( r , θ ) accounts for dose-rate variation over angles due to differing attenuation by source capsule, internal components, …

• Must know source orientation use 2D formalism – otherwise, use the 1D formalism

slide courtesy of Luc Beaulieu