A team from the University of Illinois and Northwestern University has devised a novel nuclear magnetic resonance imaging (MRI) technique that delivers a roughly 10nanometer spatial resolution. This represents a significant advance in MRI sensitivity—modern MRI techniques commonly used in medical imaging yield spatial resolutions on the millimeter length scale, with the highest-resolution experimental instruments giving spatial resolution of a few micrometers.
“This is a very promising experimental result,” said U. of I. physicist Raffi Budakian, who led the research effort. “Our approach brings MRI one step closer in its eventual progress toward atomic-scale imaging.”
Written by Siv Schwink
A team from the University of Illinois and Northwestern University has devised a novel nuclear magnetic resonance imaging (MRI) technique that delivers a roughly 10-nanometer spatial resolution. This represents a significant advance in MRI sensitivity—modern MRI techniques commonly used in medical imaging yield spatial resolutions on the millimeter length scale, with the highest-resolution experimental instruments giving spatial resolution of a few micrometers.
“This is a very promising experimental result,” said U. of I. physicist Raffi Budakian, who led the research effort. “Our approach brings MRI one step closer in its eventual progress toward atomic-scale imaging.”
MRI is used widely in clinical practice to distinguish pathologic tissue from normal tissue. It is noninvasive and harmless to the patient, using strong magnetic fields and non-ionizing electromagnetic fields in the radio frequency range, unlike CT scans and tradiational X-rays, which both use more harmful ionizing radiation.
MRI uses static and time-dependent magnetic fields to detect the collective response of large ensembles of nuclear spins from molecules localized within millimeter-scale volumes in the body. Increasing the detection resolution from the millimeter to nanometer range would be a technological dream come true.
The team’s breakthrough—the new technique introduces two unique components to overcome obstacles to applying classic pulsed magnetic resonance techniques in nanoscale systems. First, a novel protocol for spin manipulation applies periodic radio-frequency magnetic field pulses to encode temporal correlations in the statistical polarization of nuclear spins in the sample. Second, a nanoscale metal constriction focuses current, generating intense magnetic field-pulses.
This illustration of the experimental setup shows the two unique components of the team's novel MRI technique that was successful in producing a 2D MRI image with spatial resolution on the nanoscale. Image courtesy of Raffi BudakianIn their proof-of-principal demonstration, the team used an ultrasensitive magnetic resonance sensor based on a silicon nanowire oscillator to reconstruct a two-dimensional projection image of the proton density in a polystyrene sample at nanoscale spatial resolution.
“We expect this new technique to become a paradigm for nanoscale magnetic-resonance imaging and spectroscopy into the future,” added Budakian. “It is compatible with and can be incorporated into existing conventional MRI technologies.”
This work was supported by the Army Research Office through Grant No. W91 1NF-12-1-0341 and by the Department of Physics and the Frederick Seitz Materials Research Laboratory Central Facilities at the University of Illinois. Work at Northwestern University was supported by the National Science Foundation Grants No. DMI-0507053 and DMR-1006069.
Madeline Stover is a physics doctoral student at the University of Illinois Urbana-Champaign studying atmospheric dynamics applied to forest conservation. She interns as a science writer for Illinois Physics, where she also co-hosts the podcast Emergence along with fellow physics graduate student Mari Cieszynski. When Stover is not doing research or communications, she enjoys hosting her local radio show, singing with her band, and cooking with friends.
Daniel Inafuku graduated from Illinois Physics with a PhD and now works as a science writer. At Illinois, he conducted scientific research in mathematical biology and mathematical physics. In addition to his research interests, Daniel is a science video media creator.
Karmela Padavic-Callaghan, Ph. D. is a science writer and an educator. She teaches college and high school physics and mathematics courses, and her writing has been published in popular science outlets such as WIRED, Scientific American, Physics World, and New Scientist. She earned a Ph. D. in Physics from UIUC in 2019 and currently lives in Brooklyn, NY.
Jamie Hendrickson is a writer and content creator in higher education communications. They earned their M.A. in Russian, East European, and Eurasian Studies from the University of Illinois Urbana-Champaign in 2021. In addition to their communications work, they are a published area studies scholar and Russian-to-English translator.
Garrett R. Williams is an Illinois Physics Ph.D. Candidate and science writer. He has been recognized as the winner of the 2020 APS History of Physics Essay Competition and as a finalist in the 2021 AAAS Science and Human Rights Essay Competition. He was also an invited author in the 2021 #BlackinPhysics Week series published by Physics Today and Physics World.
Karmela Padavic-Callaghan, Ph. D. is a science writer and an educator. She teaches college and high school physics and mathematics courses, and her writing has been published in popular science outlets such as WIRED, Scientific American, Physics World, and New Scientist. She earned a Ph. D. in Physics from UIUC in 2019 and currently lives in Brooklyn, NY.