Modeling off-axis beam-softening to improve 3D dose-calculation accuracy for wedged photon beams

We have shown that, by explicitly including the off-axis beam softening effect into the dose calculation algorithm, one can completely resolve the dose over-estimation problem along the non-wedged direction for a wedged beam, without degrading the calculation accuracy along the wedged direction. This results in considerable improvement for calculations of 3D dose-distributions when a wedge is involved.