Radiosurgery is a medical procedure that allows non-invasive treatment of benign and malignant tumors and other brain pathologies, such as trigeminal neuralgia and some cases of epilepsy. The initial application of radiosurgery was in treatment of lesions in the brain, a technique also known as stereotactic radiosurgery (SRS). The compound word stereotactic is made up from Greek words: στερεος, which means solid, and τακτική (hinted τηχνη) which means "ability in disposition," meaning "tactic" as used in military language. In fact radiosurgery is stereotactic only if the distribution of radiation beams is in three dimensions and not in two as in traditional radiotherapy. In addition to cancer, it has also been shown to be beneficial for the treatment of some non-cancerous conditions, including functional disorders such as arteriovenous malformations (AVMs) and trigeminal neuralgia.
There are many neurological disorders for which conventional surgical treatment is difficult or inadvisable due to the required displacement or cutting of surrounding tissue, which can damage nearby arteries, nerves, and other vital structures.
Radiosurgery operates by directing tightly focused beams of ionizing radiation with high precision from multiple directions at intracranial and extracranial tumors and other lesions. The beam paths converge in the target volume, delivering a lethal cumulative dose of radiation, while exposing adjacent healthy tissue to a much smaller level of radiation.
It is a relatively recent technique, first developed in 1951 by Swedish physician Lars Leksell. His radiosurgery device (the "Gammaknife") used a helmet, in which the patient's head was locked in place, and could only treat cranial disorders.
In 1982, the technique was augmented with the use of a high precision linear accelerator as radiation source, and the patient was attached to a couch that could rotate on multiple axes, for three-dimensional treatments similar to those obtained with Gammaknife.
Recent innovations in radiosurgery (Cyberknife 1994) include platforms that sense the position of the patient and adjust the radiation to patient position, to avoid the effects of patient movement and breathing. This maintains the necessary precision for irradiating a very small target. It also allows radiosurgery of extracranial lesions, enormously extending treatment possibilities.
The latest radiosurgery technology available as of 2009 included the CyberKnife and Gamma Knife Perfexion systems, the Novalis Tx radiosurgery platform, and the Trilogy linear accelerator by Varian.
Other articles related to "gamma knife, gamma":
... stereotactic radiosurgery systems is the Gamma Knife ... The Gamma Knife was originally developed by Lars Leksell, remains the gold standard method for delivery of stereotactic radiosurgery to the brain, and is manufactured by Elekta ... The Gamma Knife system is equipped with a series of 4 collimators of 4mm, 8mm, 12mm and 16mm diameter, and is capable of submillimeter accuracies ...
... These systems differ from the Gamma Knife in a variety of ways ... The Gamma Knife produces gamma rays from the decay of Co-60 of an average energy of 1.25 MeV ... The Gamma Knife has over ~200 sources arrayed in the helmet to deliver a variety of treatment angles ...
... 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 ... 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 ...
Famous quotes containing the word knife:
“They warsled up, they warsled down,
Till Sir John fell to the ground,
And there was a knife in Sir Willies pouch,
Gied him a deadlie wound.”
—Unknown. The Twa Brothers (l. 58)