Validation of a new virtual wedge model.

Results of a validation study of a commercial virtual wedge device recently installed at our institution are presented. The wedge simulation produces an energy fluence from the treatment head that is equivalent to the primary energy fluence attenuated through a wedge-shaped slab of water with the central axis fluence set to unity. A simple exponential formula used to compute off-axis wedge factors is compared to beam profiles measured in a water phantom. A fast Fourier transform (FFT) convolution dose calculation is compared to measured dose profiles. Measured and calculated central axis wedged/open field ratios as a function of depth are also compared.