Radiosurgery Technique

Radiosurgery is a concept originally devised by Lars Leksell. This concept involves the destruction of intracranial targets and induction of desired biologic effects in target tissue with the use of a single high dose of focused ionizing beams through the intact skull. Over time, the concept was expanded to include delivery of ionizing radiation in one to five sessions, or fractions. Currently, the majority of radiosurgical experience has been with photon-based sources such as the Gamma Knife and linear accelerators (LINACs). A few centers use charged particles such as protons for radiosurgery. In some ways the principles of radiation delivery are similar for conventional fractionated radiation and single-session radiosurgery. However, in other ways radiosurgery is distinctly different from fractionated radiation therapy. This chapter focuses on the techniques of radiosurgery in terms of the unique fundamentals of radiobiology and medical physics.