Stereotactic Image Guidance in Brain Surgery

Introduction StealthStation
Gamma Knife CyberKnife Links & References


In general, a surgery can be called image-guided if some indirect visualization is used for operation, for example, if fiber optics, endoscopy, ultrasonography or other imaging technique is involved.
A surgery is called stereotactic if a system of three-dimensional (3D)
coordinates is used to locate the operative field, and to navigate surgical instruments around it.
Stereotactic image guidance combines both above-mentioned features by means of real-time registration of the operative field to a preoperative imaging data set, showing the precise location of surgical instruments relative to surrounding anatomical structures.

Stereotactic image guidance is often used in neurosurgery for operating on the brain. In frameless stereotactic system, the skull itself represents a rigid 3D frame of reference, relative to which brain structures of interest are located by registration to computed tomography (CT), magnetic resonance imaging (MRI), and other 3D image data sets.
Stereotactical devices for brain surgery have gone a long way from the first Horseley-Clarke apparatus designed in 1906 for animal experiments, and based on brain atlas, to modern state-of-the-art systems, of which three examples are considered on these web pages.

StealthStation® technology is developed by Medtronic, Inc.   StealthStation is equipped with specialized software that combines pre-operative images from various sources (CT, MRI) into an integrated 3D image set, and has a capability to update those data by intra-operative imaging.  Real-time registration is performed with a 360-degree optical tracking and laser-pointing system.

Gamma Knife® is a stereotactic radiosurgery technology that was originally developed by Swedish neurosurgeon Lars Leksell in 1967, and is currently commercialized by Elekta company. Gamma Knife technology combines images from stereotactic CT, MRI, positron emission tomography (PET), magnetoencephalography (MEG), and/or cerebral angiography, and uses them for target determination and radiation beam focusing.

CyberKnife® stereotactic radiosurgery system was developped at Stanford around 1994, and was approved by FDA in 2001 for radiational treatment of tumors in various parts of the body. The CyberKnife system uses a combination of robotics and image-guidance technologies.