Tuesday, February 12, 2008
Elekta Neuromag has recently attracted the order of their latest magnetoencephalography (MEG) instrument by the Nebraska Medical Center in Omaha.
This should come as welcome news to the hospital’s patients, many of whom could benefit from the enhanced treatment for epilepsy that will come from the installation of Elekta’s device. Scheduled to arrive this spring or summer, the MEG device will help neurosurgeons, neurologists and those in related fields will be able to non-invasively record human brain activity in real time, better and more accurately than ever before.
MEG technology is regarded as an efficient method for tracking brain activity at millisecond resolution, and is emerging as a competitor to more prevalent methods such as electroencephalography.
Compared to EEG technology, MEG has uniquely accurate localization capabilities. Other technologies, for example computed tomography (CT) and magnetic resonance imaging (MRI), provide only anatomical or metabolic information; whereas MEG is a direct measure of neuronal electric activity. When complemented with MRI, MEG increases the ability to understand brain activity and to improve treatment of functional disorders and, in particularly, epilepsy.
A brain signal is comparatively weak, measured in femto-Tesla range. Electrical activity in neurons produces magnetic fields that can be recorded outside the skull and used to identify the locations of the activity within the brain. The magnetic signals pass unaffected through brain tissue and the skull, so it can be recorded outside the head.
To record the signals a superconducting quantum device (Super Quantum Interference Device, or SQUID) immersed in liquid helium is used. This eliminates the impedance and allows for high sensitivity. To successfully obtain clinical MEG a magnetic shielded room is needed to eliminate magnetic noise generated in the environment.
The data is transferred to the Elekta’s own Neuromag software, which is set up for data acquisition and processing, source modeling and anatomic visualization as well as DICOM 3.0-based image transfer system.
The detector array comprises triple-sensor elements that are evenly distributed over the entire head. The size and extend of the detector array ensure that activities from even the most peripheral areas, such as frontal and temporal lobes and the cerebellum can be acquired with high precision.
The sensor elements consist of two orthogonal planar gradiometers and one magnetometer coupled to a multi-SQUID. The patient helmet array provides field distribution sampling 510 distinct positions, with sensors configured a total of 306 independent channels.
According to Elekta Neuromag, the 306-channel MEG sensor array has a higher density of detectors than any other system on the market, leading to a more accurate representation of brain activity. The system also has the highest-available immunity to magnetic interference, either patient-related or external.
“We are extremely excited about our upcoming Magnetoencephalography system installation,” says Sanjay Singh, director of The Nebraska Epilepsy Center at The Nebraska Medical Center and Associate Professor in the Department of Neurological Sciences at the Univ. of Nebraska Medical Center.
“We plan to use the MEG extensively as a vital part of our pre-surgical epilepsy evaluation. The highly accurate localization capability is exactly what is needed when dealing with complex intractable epilepsy cases.” Singh continues. “Adding MEG technology will enable our doctors to more accurately pinpoint the site of a seizure and determine the type of epilepsy.”
He believes the system will be especially useful with patients who are unresponsive to medications. It will also help measure patients who have an implanted vagal nerve stimulator.
http://www.elekta.com/healthcare_us_press_release_20070179.php SOURCE: Elekta Neuromag