The use of beamlets as a dose calculation tool in Intensity Modulated Radiation Therapy (IMRT) treatment planning is widespread and well documented. A beamlet can simply be defined as the contribution of radiation passing through a particular geometrically defined subdivision of a given linear accelerator's emerging radiation field. The most common classes of algorithms used today to calculate the dose distributions deposited by beamlets are the pencil beam convolution and collapsed cone classes of algorithms. Using BEAMnrc, a Monte Carlo (MC) based radiation transport simulation software...