Gamma Knife - History

History

Radiosurgery was first developed at the Karolinska Institute of Stockholm, Sweden in 1949. It was jointly developed by Dr. Lars Leksell, a neurosurgeon and Bjorn Larsson, a radiobiologist from Uppsala University. Leksell initially used protons from a cyclotron to irradiate brain tumor lesions.

In 1968, they developed the Gamma Knife, a new device exclusively for radiosurgery, which consisted of radioactive sources of Cobalt-60 placed in a kind of helmet with central channels for irradiation, using gamma rays. In the latest version of this device, 192 sources of radioactive cobalt direct gamma radiation to the center of a helmet, where the patient's head is inserted. This is called the Leksell Gamma Knife Perfexion. In order to achieve a high degree of precision, the patient's head is placed on a rigid frame of reference called a stereotactic frame that is inserted into a metal helmet.

At some medical centers such as in Boston and in California, particle accelerators built for doing research in high energy physics have been used since the 1960s for the treatment of brain tumors and arteriovenous malformations of the brain in humans.

A linear accelerator (LINAC) may also be used to deliver radiosurgery. LINAC based radiation therapy for cancer therapy began with treatment of the first patient in 1953 in London at Hammersmith Hospital, with an 8 megavolt machine built by Metropolitan Vickers, as the first medical LINAC. However, this machine was not technically a stereotactic radiosurgery machine, as it delivered a wide beam in only one direction and not in three dimensions.

LINAC radiosurgery was pioneered at the University of Florida College of Medicine and introduced by Betti and Colombo in the mid 1980s. Modern LINACs optimized for radiosurgery applications include the Trilogy machine from Varian Medical Systems, and the Novalis Tx radiosurgery platform, produced by Varian and BrainLAB. Both of these are frameless stereotactic systems which sense patient position.

Varian Medical Systems of Palo Alto, California, made its first linear accelerator optimized for stereotactic radiosurgery in 1992, called the Clinac 600SR. The Trilogy is another platform offered by Varian that incorporates tools for delivering highly-accurate image-guided radiotherapy and radiosurgery treatments, including cone-beam (3-D) and kV (2-D) imaging as well as respiratory gating to compensate for tumor motion during treatment. The Trilogy machine can also be outfitted with RapidArc for faster treatment delivery.

In 2007, the Novalis Tx radiosurgery platform was introduced by Varian and BrainLAB. The Novalis Tx radiosurgery platform incorporates sophisticated beam shaping technology, precision targeting computers and robotics that sculpt the treatment beam so that it envelops the tumor while avoiding the surrounding tissues and organs as much as possible. The Novalis Tx radiosurgery platform also offers a broad range of image-guidance tools to further enhance treatment precision. Clinicians are able to generate 3-D scans of the tumor and surrounding tissues prior to every treatment, to ensure that tumors are targeted accurately. The Novalis Shaped Beam Radiosurgery and Novalis Tx radiosurgery platforms are available worldwide, including the US, Europe, Japan, India, Australia, the Asia Pacific region, and the Middle East.

The latest radiosurgery technology available as of 2009 included the CyberKnife and Gamma Knife systems, the Novalis Tx radiosurgery platform, Trilogy linear accelerator, and Tomotherapy.