the same year reports of the two first cases, patients with cancer related pain subjected to radiosurgical thalamotomy, were published. Originally, radiosurgery and the gamma unit were developed with the hope that it would offer a bloodless, and less risky, method to be applied principally in functional neurosurgery, for example in thalamotomy for Parkinson's disease. On the other hand, Leksell had always considered his stereotactic instrument a surgical tool that should also be utilized in general neurosurgery in order to enhance precision and minimize hazards. This idea had to some extent been realized by the extensive use of stereotactic technique in puncturing cysts and also in performing biopsies in critical regions. The gamma unit soon proved to be useful in the treatment of some diseases previously requiring neurosurgery, such as pituitary adenomas, acoustic neurinomas and arteriovenous malformations. This use of radiosurgery has revolutionized the management of these conditions but was met with skepticism from the neurosurgical community. Two other examples of Leksell's innovation deserve to be mentioned. He was the first to apply ultrasound in neurosurgical diagnosis by the development of echoencephalography as early as 1955. Moreover, his double action rongeur has become an indispensable tool in the hands of most neurosurgeons. Notes Bibliography Leksell L. - The action potential and excitatory effects of the small ventral root fibres to skeletal muscle (1945), Acta Physiol Scandinavica Leksell L. - The stereotaxic method and radiosurgery of the brain (1951), Acta Chirurgica Scandinavica Leksell L. - A stereotaxic apparatus for intracerebral surgery (1949), Acta Chirurgica Scandinavica Lozano A. et al. - Textbook of Stereotactic, Funct. Neurosurgery (2009), Berlin, pp. 3229 Timothy D. Solberg, Robert L. Siddon, and Brian Kavanagh - Historical Development of Stereotactic Ablative Radiotherapy(2012), Springer, Berlin, pp. 35 Further reading To know more Stephen B. Tatter. "The History of Stereotactical Radiosurgery", Massachusetts General Hospital, Dept. Neurosurgery. Lunsford LD. "Lars Leksell. Notes at the side of a raconteur" Stereotact Funct Neurosurg. 1996–97;67(3–4):153–68. Main writings Leksell L., A Stereotaxic Apparatus For Intracerebral Surgery, Acta Chir Scand, 1949; Leksell L., The stereotaxic method and radiosurgery of the brain, Acta Chir Scand, 1951; Larsson B., Leksell L., Rexed B., et al., The high energy proton beam as a neurosurgical tool, Nature, 1958; Larsson B, Leksell L, B R, Sourander P, Mair W, Andersson B., The High-Energy Proton Beam As A Neurosurgical Tool, Nature 1958; Leksell L., Stereotaxis And Radiosurgery, Acta Neurologica Scandinavica 1970; Meyerson