Stereotactic radiosurgery: current status and future trends.

The first Gamma Knife was installed in Stockholm in 1968 after nearly two decades of development. Following the opening of the Gamma Knife facility in Pittsburgh in 1987, radiosurgery has seen an explosive expansion. Along with this expansion there has been a development of alternative technologies, of which the most common is the linear accelerator. The past and present status of radiosurgery is reviewed and some possible future trends are outlined in the light of the developments which have already occurred.