Radiation therapy requires a combination of disparate and fast-evolving technologies. We have drafted and prosecuted many patent applications relating to linear accelerators, electron guns, collimators and other beam blocking/filtering devices, contrast agents, focused kilovoltage therapy; therapeutic protocols, image-or dose-guided therapy, signal-, image- and/or time-gated therapy, scintillators, flat panel imaging devices, combined imaging and therapy systems, and patient positioning technologies.