Commercial Applications
  1. Properties, History and Challenges
  2. Overview
  3. Electric Power
  4. Transportation
  5. Medical Imaging and Diagnostics
  6. NMR for Medical and Materials Applications
  7. Industrial Processing
  8. High Energy Physics
  9. Wireless Communications
  10. Instrumentation, Sensors, Standards and Radar
  11. Large-Scale Computing
  12. Renewable Energy
  13. Cryogenics: An Enabling Technology

Applications in Medical Imaging and Diagnostics

MRI (Magnetic Resonance Imaging) has become the “gold standard” in diagnostic medical imaging, providing images of soft tissue not available from any other modality. It is not only safe and powerful, but thanks to superconducting magnets and their continued improvements, adds energy efficiency to its long list of benefits. In addition, advanced static and functional imaging techniques, using superconducting sensors, are emerging as complementary methods, enabling additional capabilities at lower cost. These include Ultra-Low-Field MRI, Magnetoencephalography (MEG) and Magnetocardiography (MCG). These advanced systems significantly improve the diagnostic tools available to healthcare providers and hold the promise of reducing lifetime healthcare costs.

Magnetic Resonance Imaging - MRI

Radiation-free Imaging.

Superconducting MRI The introduction of MRI into the healthcare system has resulted in substantial benefits. MRI provides an enormous increase in diagnostic ability, clearly showing soft tissue features not visible using X-ray imaging or ultrasound. At the same time, MRI can often eliminate the need for harmful X-ray examinations. These advantages have greatly reduced the need for exploratory surgery. The availability of very precise diagnostic and location information is contributing to the reduction in the level of intervention that is required, reducing the length of hospital stays and the degree of discomfort suffered by patients.

The basic science of resonance imaging has been understood for many years. The nucleus of most atoms behaves like a small spinning magnet. When subjected to a magnetic field, the nuclear spin tries to align, but the spin means that instead it rotates around the field direction with a characteristic frequency proportional to the field strength. When a pulse of exactly the right radio frequency is applied, some of the energy of the pulse is absorbed by the nucleus, which can be measured as a signal that decays typically within several milliseconds. The timing of this signal decay, or relaxation, was discovered to depend critically on the chemical environment of the atom, and in particular was found to be different between healthy and diseased tissue in the human body. By rapidly switching on and off magnetic field gradients superimposed on the main field, it is possible to determine very accurate position information from these signals. The signals are processed by a computer to produce the now-familiar images from within the human body. Since the first crude MRI images were made in the 1970s, the industry has grown to a turnover of approximately $4B/year in new equipment sales. There are now well over 30,000 MRI systems installed worldwide, and the number is growing by 10% annually.

Advantages of Superconductivity

The heart of the MRI system is a magnet. The typical field values required for the latest generation of MRI cannot be achieved using conventional magnets. Just as importantly, high homogeneity and stability of the magnetic field are essential to achieve the resolution, precision and speed required for economical clinical imaging. The use of superconducting magnets provides a unique solution to these requirements. This trend will continue as field strength continues to progress from the current mainstream 1.5 T (Tesla) and 3 T systems to ever higher strengths in order to improve the clarity of the signal generated and increase the speed of image acquisition.

Expanding Applications of MRI

Functional Magnetic Resonance Imaging (FMRI)Functional Magnetic Resonance Imaging (FMRI), a rapidly growing extension of MRI techniques, uses a sequence of fast images to study dynamic changes, primarily blood flow rates. This has proved to be a powerful tool for imaging the activation of local regions in the brain. It is used to evaluate which areas of the brain are responsible for different functions, such as speaking, comprehension, moving fingers and toes and vision. An even newer technique, MRI guidance imaging, is used to assist physicians during surgery or ion beam therapy to plan the approach and more precisely locate, remove or radiate tumors. Another new technique, Magnetic Resonance Spectroscopy, is used on a limited basis for evaluating brain tumors, neurological diseases and epilepsy. Spectroscopy gives information on the chemical composition and metabolic activity of brain tissue. This information is used to assist in making diagnoses, monitoring changes and evaluating seizure activity. Further advances in the design of MRI systems are also enhancing the ability to utilize smaller, more specialized units dedicated to imaging of the body extremities such as arms and legs. The smaller foot-print of these units makes them more space, energy and resource efficient and allows for the higher throughput at a medical facility when combined with a whole body system for more complicated or extensive scans.

The Future of MRI

The number of MRI installations worldwide continues to grow at a rapid pace, providing ever more access to this powerful tool. MRI systems continue to advance in speed and resolution as the technologies of superconducting materials and superconducting magnets continue to advance. Exciting new methods that build on MRI are enabling new tools for both diagnosis and treatment of disease. It is clear that there are enormous potential benefits of continued support for R&D in superconducting materials and magnets.

Ultra-Low Field Magnetic Resonance Imaging (ULF-MRI)

Conventional Magnetic Resonance Imaging, discussed above, created a revolution in non-invasive imaging procedures, and the technique is used worldwide for many diagnoses. MRI is enabled by the high magnetic fields that only superconducting magnets can produce. Incremental improvements in the performance and cost of this established technology continue, but today researchers are also developing a complementary technique, Ultra-Low-Field MRI. In this new approach, instead of a high magnetic field from a superconducting magnet, a very low field - 10,000 times lower - is used. This low magnetic field is produced by simple, low cost magnets made with room temperature copper wire. To compensate for the loss of the high magnetic field, the extreme sensitivity of a superconducting detector is required. This detector, a “SQUID” (Superconducting Quantum Interference Device), enables the following benefits at low field:

Magnetoencephalography (MEG) and Magnetic Source Imaging (MSI)

MEGThe same extreme sensitivity of SQUIDs that enables ULF-MRI has already enabled the development and use of Magnetoencephalography (MEG), sometimes referred to as magnetic source imaging (MSI). In these systems, which are available commercially, an array of SQUID sensors detects magnetic signals from the brain in a totally non-invasive manner. Major successes include:[1]