According to the Los Alamos National Laboratory (LANL) in New Mexico, its portable MRI has been named one of the Top 10 Breakthroughs of the Year by Physics World, the member magazine of the Institute of Physics. Portable MRI, also called battlefield MRI (bMRI), uses ultra-low-field magnetic resonance imaging to create images of injured soft tissues, such as the brain.
While hospital-based MRI devices are big and expensive, requiring large quantities of liquid nitrogen, helium, and energy, bMRI doesn’t have those same requirements, making it a lighter, less expensive, and low-power alternative that can be deployed to places like the battlefield and remote hospitals around the world.
Currently, soldiers wounded in battle must be flown to a large hospital to undergo an MRI, and most people in emerging nations don’t have access to MRI at all. The LANL reports that doctors who work in the developing world need MRI to help in treating serious diseases in children. Conventional MRI machines use very large magnetic fields that align the protons in water molecules to then create magnetic resonance signals, which are detected by the machine and turned into images. The large magnetic fields create exceptionally detailed images, but they are difficult and expensive to make.
The LANL team wanted to see if images of sufficient quality could be made with ultra-low-magnetic fields, similar in strength to the Earth’s magnetic field. To achieve images at such low fields, they use extremely sensitive detectors called superconducting quantum interference devices (SQUIDs).
SQUIDs are considered to be some of the most sensitive magnetic field detectors available, so interference with the signal is can be a stumbling block. For example, SQUIDs will respond to a truck driving by outside or a radio signal 50 miles away, so the team’s first generation bMRI had to be built in a large metal housing in order to shield it from such interference. Eventually, the LANL team was able to work on the bMRI system without the large metal housing. In future, the field compensation system will also reportedly eradicate invading magnetic field signals.
For more information about the bMRI project and others, visit the Los Alamos National Laboratory website.