Robotic Radiosurgery with Beams of Adaptable Shapes

Abstract: In radiosurgery, a moving beam of radiation acts as an ablative surgical instrument. Conventional systems for radiosurgery use a cylindrical radiation beam of xed cross-section. The radiation source can only be moved along simple standardized paths. A new radiosurgical system based on a six degree-of-freedom robotic arm has been developed to overcome limitations of conventional systems. We address the following question: Can dose distributions generated byrobotic radiosurgery be improved by us-ing non-cylindrical radiation beams of adaptable cross-section? Geometric methods for planning the shape of the beam in addition to planning beam motion are developed. De-sign criteria considered in this context are: treatment time, radiation penumbra as well as transparency of interactive treatment planning. An experimental evaluation com-pares distributions generated with our new radiosurgical system using cylindrical beams to distributions generated with beams of adaptable shapes.