Do you know how many times we hear a colleague say, “What this patient really needs is an MRI…” only to gaze wistfully off in the general direction of the neurology department…The unspoken reality is that MRIs take forever to schedule, they require lots of approval and they’re expensive as hell.
That may change! According to New Scientist, handheld MRIs may become reality, if these developers are right:
Dmitri Budker, and colleagues in the physics department at the University of California, provided part of an alternative solution by developing a radically different detector. It uses polarised laser light to align rubidium atoms in a vapour.
The atomic alignment changes in response to faint magnetic signals and the same laser can measure these slight changes. This means much less powerful magnets can be used to align atomic nuclei for imaging. “It’s a particularly simple technique,” Budker says. “All we deal with are laser beams, which are easy to manipulate and detect.”
The team’s so-called “magneto-optical detector” is nearly as sensitive as a superconducting quantum interference device (SQUID), which uses quantum-tunnelling effects to detect magnetic fields. But SQUIDs, like conventional MRI scanners, require ultra-low temperatures. “Our detector is basically a room-temperature technology,” Budker says.
A team led by Berkeley chemist Alexander Pines produced a second key innovation, by developing a means of encoding and detecting the magnetic signal in separate locations. In an experimental set-up, water flowing through a tube was exposed to a magnetic field at one point. The magnetic signals from atomic nuclei in the water were then measured approximately a second later using the laser detector at another point. Separating these processes makes it possible to improve the sensitivity of the detector further. “That has orders-of-magnitude advantages,” Pines adds.
Our crack physician fact-checkers at Medgadget.com confirmed that 1) Rubidium is, in fact, an element and 2) physicists talk about SQUIDs in real scientific journals. Beyond that, we’ll have to hope the rest of this works out and someday soon our hospitals will have handheld laser-MRIs just lying around, waiting to analyze that old sports injury or mental status change.
More from the Proceedings of the National Academy of Sciences…