Radiosurgery: identification of efficient treatment beams guided by autostereoscopic visualization

In robotic radiosurgery, an arrangement of cylindrical beams forms a high dose area conformal to the target region. Beams start at various positions around the patient, and are oriented towards arbitrary points in the target. Due to the large number of potential beams, only a small subset of beams can be considered during treatment planning. An efficient heuristics to select promising candidate beams can substantially shorten and improve treatment planning. We have developed a tool to visualize the 3D dose distribution and the beams. Using a hypsometric color scheme, the visualization toolkit (VTK), and an autostereoscopic display, we established the spatial extent of cold and hot spots and the effect of beams. With this new visualization tool we assessed the dose distribution and the beam arrangement of two treatment plans for intra-cranial tumors. Based on the visual analysis of the dose distribution and the effect of the beams, we derived a heuristics to place beams. Treatment plans computed for the heuristically placed beams were compared to the original plans. The results suggest that a heuristic pre-selection of potential treatment beams is possible. The visualization proved useful for 3D analysis of treatment plans and as a tool for rapid development of beam placement heuristics.