Industry Bulletin: Rare Earth Magnets enable advances in MRI Scanners
September 2, 2008
In our ongoing efforts to provide you with broader communications and industry information, we are pleased to issue another Industry Bulletin discussing recent trends in the markets of various rare and strategic metals. This edition looks at the key role that rare earth magnets play in Magnetic Resonance Imaging ("MRI") scanners, a remarkable diagnostic tool that continues to improve in design and efficiency.
It has only been 30 years since the first MRI exam was performed on a human being. It took almost five hours to produce one image. As late as 1982, there were but a handful of MRI scanners in the entire United States. Today there are thousands of these machines in use and images that used to take hours can now be captured in seconds.
There are three basic types of magnets used in MRI systems:
Resistive magnets consist of many windings or coils of wire, wrapped around a cylinder, through which an electric current is passed. This causes a magnetic field to be generated. If the electricity is turned off, the magnetic field dies out. These magnets tend to be relatively inexpensive to construct, but require significant amounts of electricity (up to 50 kilowatts) to operate because of the natural resistance in the wire.
Superconducting magnets are the most commonly used. A superconducting magnet is somewhat similar to a resistive magnet with the important difference that the wire is continually bathed in liquid helium at -452.4 degrees Fahrenheit. This extreme cold causes the resistance in the wire to drop to zero, dramatically reducing the electricity requirement for the system. This makes these systems more economical to operate, but they are still very expensive to build.
Rare earth permanent magnets generate a high strength permanent magnetic field that does not require electricity, so there is no cost to maintain the field and new MRI units constructed with these magnets are coming down in price. The only drawback is their weight with a typical unit containing some 1- 3 tons of Neodymium-Iron-Boron (NdFeB) magnets. However, these MRI units are getting lighter with each new generation, For example, a decade ago such a unit may have weighed 17,000 lbs, while newer ones, being smaller, are weighing in at just under 9,700 lbs with improved portability
In July of this year, a team of researchers from Germany and New Zealand reported that they have developed smaller, portable MRI machines using rare earth permanent magnets in different configurations. They reported that these extra-strong permanent magnets have replaced the large superconducting magnets that required adjunct liquid helium and nitrogen cooling systems. Effectively, these innovations have made it possible for smaller, less expensive, and more portable MRI units, some even powered by batteries, to be more widely available, even mobile. With less bulk, the newer editions of MRI scanners tend to be less expensive and more patient friendly (i.e. less claustrophobic and quieter).
Magnetic Resonance Imaging (MRI) - Body
Currently, there are approximately 25,400 MRI machines operating in the USA, Europe, Japan , China and India alone, of which 11,000 are based in the US. Growth in Europe has been around 50% between 2002 and 2008. Another measure of underlying continuing growth potential in magnetic resonance diagnostics resides in data on the ´Number of MRI systems per one million inhabitants´, where in the USA it is 37 and in Japan 44. In Europe, the statistic is only 11, in China - 3, and only 0.5 in India,
Avalon is well positioned to benefit from this most recent new demand for rare earth magnets, from the medical industry through the development of its large rare metals resources at the Thor Lake deposit in the Northwest Territories, where a major work program is in progress leading to the completion of a pre-feasibility study in early 2009.
If you have any comments or questions, please do not hesitate to post them on Avalon´s official investor relations hub at http://www.agoracom.com/ir/Avalon.
AGORACOM Investor Relations