A geometrically based method for automated radiosurgery planning

Purpose: A geometrically based method of multiple isocenter linear accelera tor radiosurgery treatment planning optimization,vas developed, based on a target's solid shape. Methods and Materials: Our method uses an edge detection process to determi ne the optimal sphere packing arrangement with which to cover the planning target. The sphere packing arrangement is converted into a radiosurgery tre atment plan by substituting the isocenter locations and collimator sizes fo r the spheres. Results: This method is demonstrated on a set of 5 irregularly shaped phant om targets, as well as a set of 10 clinical example cases ranging from simp le to very complex in planning difficulty. Using a prototype implementation of the method and standard dosimetric radiosurgery treatment planning tool s, feasible treatment plans were developed for each target. The treatment p lans generated for the phantom targets showed excellent dose conformity and acceptable dose homogeneity within the target volume. The algorithm was ab le to generate a radiosurgery plan conforming to the Radiation Therapy Onco logy Group (RTOG) guidelines on radiosurgery for every clinical and phantom target examined. Conclusions: This automated planning method can serve as a valuable tool to assist treatment planners in rapidly and consistently designing conformal multiple isocenter radiosurgery treatment plans. (C) 2000 Elsevier Science Inc.