TOKYO, JAPAN, October 29, 1997
Yokogawa Electric Corporation announces the Development of "Magnetoencephalograph (MEG) System"
Development of "Magnetoencephalograph (MEG) System" for Research Yokogawa Electric Corporation (2-9-32 Naka-cho, Musashino-shi, Tokyo, Japan; President: Eiji Mikawa) and Kanazawa Institute of Technology (7-1 Ohgigaoka, Nonoichi-machi, Ishikawa District, Ishikawa Prefecture, Japan; Director General Toshio Izumiya President
:Kenichi Ishikawa) have co-developed a "Magnetoencephalograph (MEG) system" for research purposes.
This system measures activities of brain by employing a non-contact, non-invasive method to detect weak magnetic signals generated in the brain. It has achieved the world's first horizontal whole head construction, using a maximum of 208 channels of magnetic sensors and will be used in highly technical research, such as analysis of brain disturbance and speech function.
What is Magnetoencephalograph (MEG)?
The MEG detects extremely weak magnetic fields (one billionth of a geomagnetic field) generated from the brain by brain activities. These fields are detected without any contact and non-invasive from outside the brain. The system measures both the positions of activities in the brain and the intensity of these activities. Actually, the position and intensity of the current source which emit the magnetic field is localized and is superimposed on a magnetic resonance image (MRI), where MRI gives morphological information while MEG gives functional information. This system has been long waited for and is viewed as a leading mean for brain research into the 21st century.The sensor used for the MEG is a ultimately sensitive magnetic sensor referred to as SQUID, or the "Superconducting Quantum Interference Device". This sensor is being applied to all types of magnetic measurement for living bodies. Presently, investigations to examine the active condition of the spinal cord, the heart, the liver, the gastro-intestine, and fetus are all being implemented using these sensors. Particularly, weak magnetic generation in the brain is useful for the study of the brain function and brain activity measurement. In the past, many have focused on the MEG, as only means of being able to directly measure neuron activities without applying magnetic or radio waves, or X-ray to living bodies externally.
Overview of the MEG system for Research
The MEG system for research, which was co-developed by Yokogawa Electric Corporation and Kanazawa Institute of Technology(KIT) is unique for the following reasons:- It can incorporate up to 208 channels of the gradiometer type SQUID sensor (up to 384 channels can be incorporated on the magnetometer type SQUID sensor). The large MEG, in which more than 150 channels using the gradiometer type sensors can be incorporated, was the first system to be recognized in the world.
- For conventional MEGs, the subject (patient) was requested to take the sitting position and forced to bear under the heavy weight of the system. Now, however, it is possible to take the measurements while the subject lies on his/her back without strain by employing horizontal construction. A new cryogenic vessel has been developed in the cryogenic engineering field, which is considered the most difficult vessel to date. In addition, installation of magnetic sensors using high-performance construction that requires less liquid Helium evaporation despite the large number of channels employed by Blind Bottle Ship Technology (BBST).
- The sensor/Dewer section is housed in a magnetically shielded room to shield it against geomagnetism and magnetic noise in cities or towns, and the shielded room has been made compact to 1/3 or 1/4 in volume of conventional ones. As the magnetically shielded room has a property of increasing performance by being made small, cost reduction and improvement of performance for the system was implemented at the same time. In addition, the developed shielded room has the minimum size in the world, making the magnetically shielded room smaller.
Future Development
The MEG system developed will be further improved for its system completeness. It not only accumulates data and considers the number of channels suitable for various applications, but also includes meeting variations, the measurement accuracy, the measuring object and the measuring form.Collaboration of Yokogawa's SQUID technology with KIT's state of the art technology
Yokogawa Electric Corporation started developing the SQUID technology twenty years ago and developed the highly sensitive flux meter. In 1990, Yokogawa participated in a national project of Superconductive Sensor Laboratory, Ltd. which celebrated the development of the living body's magnetic measurement system and MEG technology. Kanazawa Institute of Technology(KIT) has been positively challenging industry-university cooperative activities for research and development of state of the art technologies pointing to the 21st century and KIT's research and development activities. KIT is now collaborating with Yokogawa to develop this product, and announced their plans to develop the MEG system recently.Further we would like to add that we have obtained cooperation from NKK Plant Construction Co., Ltd in NKK groups (3 Benten-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture, Japan; President: Takeo Katsu) for development of the magnetically shielded room which is a component of this next generation MEG system.
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