Advanced Physics for Brachytherapy 2018

Type B uncertainty … scoring ➢ CPE can be assumed and only photons need be simulated

Photon-only simulation introduces errors >2% @ distances at or below 1.6, 3, and 7mm for Ir-192, Cs-137, and Co-60 sources, respectively (Perez-Calatayud et al. 2012) but this is source specific and clinically irrelevant in most cases.

➢ Scoring cell dimensions are important! See Taylor et al. (2007) for details and Rivard et al. (2004) and Perez-Calatayud et al. (2012) for recommendations

➢ For analogue MC increasing voxel size will reduce type A but increase volume averaging

➢ For track length estimators reducing voxel thickness while preserving surface will reduce volume averaging without affecting type A