Mixing electrons with intensity modulated photon beams to reduce integral dose

A single, well-chosen electron beam, suitably modulated by additional photon beams, can deliver a homogeneous dose to the target while reducing the integral dose to normal tissue. This work compares plans using 21 MeV electrons mixed with modulated photons, with 6 MV intensity modulated photons alone in several configurations. The mixed beam plan achieved a 2-fold reduction in integral dose with little compromise in target homogeneity.