Researchers at Los Alamos National Laboratory are experimenting with MRI just slightly stronger than the earth’s own magnetic field in hopes of developing cheaper, more accurate methods of detecting tumors.
Most MRI machines have a magnetic field of about 1.5 teslas, strong enough to yank metal objects out of the hands of the unwary. Zotev’s machine, however, generates a magnetic field of only 46 microteslas, roughly the same strength as the Earth’s magnetic field.
Researchers at Los Alamos National Laboratory have made what they say are the first images of a human brain using magnetic fields a hundred-thousandth the strength of conventional magnetic resonance imaging (MRI), paving the way for lower cost medical images that might be better at detecting tumors.
Because it needs fewer costly magnets, a weakmagnetic-field MRI machine might cost as little as US $100 000, compared with $1 million or more for a standard MRI system, says Zotev. But perhaps the most exciting thing about low-field imagers is that they can also perform another imaging technique, magnetoencephalography (MEG), which, conveniently, also relies on SQUIDs. MEG measures the magnetic fields produced by brain activity and is used to study seizures. Putting the two imaging modes together could mean matching images of brain activity from MEG with images of brain structure from MRI, and it might make for more precise brain surgery.
Low-field MRI has other advantages, says John Clarke, a physicist at the University of California, Berkeley, who uses a single-SQUID MRI device to image tissue samples. “I’m personally quite excited about the idea of imaging tumors” with low-field MRI, he says. The difference between cancerous and noncancerous tissue is subtle, particularly in breast and prostate tumors, and the high-field strengths used in conventional MRI can drown out the signal. But low-field MRI will be able to detect the differences, Clarke predicts. A low-field MRI might also allow for scans during surgical procedures such as biopsies, because the weaker magnetic field would not heat up or pull at the metal biopsy needle.
Read on at IEEE Spectrum…