Gamma Knife
Lars Leksell

The Leksell Gamma Knife was developed by Professor Lars Leksell of the Karolinska Institute in Stockholm, Sweden together with biophysicist Professor Börje Larsson of the Gustaf Werner Institute, University of Uppsala.

In 1949 Professor Leksell created the Leksell Micro-Stereotactic System®, which permitted the mechanical placement of a needle, cannula or electrode at precise locations within the brain without direct visual guidance.

Professor Leksell recognized the need for a tool to allow for treatment of deep-seated intracranial structures, without opening of the skull and the hazards of open surgery. He was convinced that agents other than cannulas or electrodes could be used to eradicate pathologies or to create therapeutic lesions in functional disorders.

In 1951, externally applied X-rays were substituted for the instruments used in the open stereotactic procedures. By coupling a source of radiation with a stereotactic guiding device, the first radiosurgical procedure was thus performed. Leksell found that by administering a single dose of radiation, it was possible to successfully destroy deep brain structures. He called this technique "stereotactic radiosurgery".

During the 1950's and 1960's, intensive research was conducted by Professor Leksell in order to identify the ideal radiation source and equipment for stereotactic radiosurgery. Linear accelerators (photons) and synchrocylotrons (protons) were tried and evaluated. However, none proved to be satisfactory in terms of accuracy, reliability, simplicity, patient safety, expense or maneuverability. A set of criteria for radiosurgical equipment was formulated and the Gamma Knife was developed in response to these needs.

The first stereotactic Gamma Knife using cobalt-60 sources was constructed and installed in Stockholm in 1968. That unit was primarily intended for use in functional brain surgery for the section of deep fiber tracts, as in the treatment of intractable pain and movement disorders.

As sophisticated neuro-imaging (computerized tomography, magnetic resonance imaging and positron emission tomography) evolved, Leksell realized the potential of the Gamma Knife in the treatment of neoplastic and vascular disorders.

In 1974, a second Gamma Knife was installed at the Karolinska Institute in Stockholm, and intense clinical activity commenced. Elekta has subsequently installed Gamma Knife units at leading neurosurgical institutions throughout the world.