VALIDATION OF A NEW VIRTUAL WEDGE MODEL

Results of a validation study of a commercial virtual wedge device rec ently 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 exponent ial 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. Me asured and calculated central axis wedged/open field ratios as a funct ion of depth are also compared. (C) 1998 American Association of Physi cists in Medicine.