Quantum Computing Offers Advancements in MRI

Gurudev Dutt, assistant professor in the University of Pittsburgh (Pitt; PA, USA) department of physics and astronomy in the Kenneth P. Dietrich School of Arts and Sciences, and his colleagues reported their study’s findings in an article published online December 18, 2011, in the journal Nature Nanotechnology. The researchers reported on significant advances towards realizing a nanoscale magnetic imager encompassing single electrons encased in a diamond crystal.

“Think of this like a typical medical procedure--a magnetic resonance imaging [MRI]--but on single molecules or groups of molecules inside cells instead of the entire body. Traditional MRI techniques don’t work well with such small volumes, so an instrument must be built to accommodate such high-precision work,” stated Dr. Dutt.

However, a considerable task arose for scientists working on the difficulty of constructing such an instrument: How can a magnetic field effectively be measured using the resonance of the single electrons within the diamond crystal? Resonance is defined as an object’s tendency to oscillate with higher energy at a particular frequency, and occurs naturally everywhere. According to Dr. Dutt, these resonances are especially strong because they allow physicists to make sensitive measurements of quantities such as force, mass, and electric and magnetic fields. “But they also restrict the maximum field that one can measure accurately.”

In magnetic imaging, this means that physicists can only detect a limited range of fields from molecules near the sensor’s resonant frequency, making the imaging process more difficult. “It can be done but it requires very sophisticated image processing and other techniques to understand what one is imaging. Essentially, one must use software to fix the limitations of hardware, and the scans take longer and are harder to interpret,” commented Dr. Dutt.

Dr. Dutt, working with postdoctoral researcher Ummal Momeen and PhD student Naufer Nusran, both in Pitt’s department of physics and astronomy--has employed quantum computing technology to bypass the hardware limitation to view the entire magnetic field. By extending the field, the Pitt researchers have improved the ratio between maximum detectable field strength and field precision by a factor of 10 compared to the conventional method utilized previously. This puts them closer toward developing a future nanoscale MRI instrument that could examine characteristics of molecules, materials, and cells in a noninvasive way, displaying where atoms are located without destroying them; current methods employed for this kind of study inevitably destroy the samples. “This would have an immediate impact on our understanding of these molecules, materials, or living cells and potentially allow us to create better technologies,” said Dr. Dutt.

These are only the early findings, reported Dr. Dutt, and he expects additional enhancements to be made with additional research. “Our work shows that quantum computing methods reach beyond pure electronic technologies and can solve problems that, earlier, seemed to be fundamental roadblocks to making progress with high-precision measurements.”

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