Research on the fsPB of Arbitrary Collimator Rotational Angle by Coordinate Transformation

Based on the dose distribution results under the condition of vertical incident beam by finite-size Pencil Beam (fsPB) matrix model using Monte Carlo simulation, this paper introduces the means of coordinate transformation, which can transform the dose distribution from the condition of vertical incident to the arbitrary collimator rotational angel. The dose distribution results of test examples are compared with the simulation results of Electron-Gamma Shower (EGS), the effective and accuracy of the algorithm are proved.