Medical Design Briefs - December 2021 - 94

GlobAl
INNOVATIONS
New Sensor Enables Precise, Sensitive Brain Imaging Tool
Skolkovo Institute of Science and Technology, Moskva, Russia
joint team from the Russian
Quantum Center, Skoltech, and
the Higher School of Economics
has presented a novel supersensitive
solid-state magnetometer operating at
room temperature. The researchers for
the first time used it to detect and record
brain electrical activity with a technique
called magnetoencephalography (MEG),
which could become dozens of times
cheaper with the new device. The paper
was published in Human Brain Mapping.1
High accuracy is a key advantage of
magnetoencephalography over other
similar techniques used for studying the
electrical activity of the brain. Biological
tissues are transparent for magnetic
fields. However, only a very limited number
of laboratories have MEG equipment,
which uses either extremely cold
liquid helium or high-temperature gas
and is very expensive and difficult to
manufacture.
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The team has developed a new sensor
using yttrium-iron garnet films. It is based
on a quantum sensor and is capable of
registering very weak or deep electrical
sources in the brain. Because of its wide
dynamic range, the device requires less
magnetic shielding, which means a lower
cost of both the hardware and the entire
research infrastructure (see Figures 1-3).
To test the new sensor in action, the
researchers performed an experimental
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Fig. 2 - The OP-MEG system used to find locations
with high magnitude of alpha waves (a) and
(b); the scheme of OPM locations on the scalp
(c). (Credit: Human Brain Mapping)
study, measuring a simple brain-induced
field - the alpha rhythm - which constitutes
sinusoidal electric currents in
the back of the brain. The new sensor
successfully detected the onset of alpha
rhythm, and the result was validated by
other methods.
In the future, the team plans to study
various sensor configurations, including
a flexible band-type device placed
around a patient's head to ensure the
utmost efficiency and accuracy in detecting
the exact location of electrical activity
in the cerebral cortex. The current
findings call for further exploration of
the technology and a step-by-step development
of an MEG device based on
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Fig. 1 - Sensor linear sizes and sensitive axes;
Tangential and normal field component: YIGM
sensitive element in winding (a) ; sensor head of
OPM QZFM Gen 1.0 (top) and 2.0 (bottom)
magnetometers (b). YIGM, yttrium-iron garnet
films. (Credit: Quspin.com/Human Brain
Mapping)
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Fig. 3 - The experimental setup for alpharhythm
registration using the YIGM: the sensor
(a), subject position for alpha-rhythm registration
(b); YIGM sensitive axes with respect to
mutual head-sensor location: tangential displacement
(c); normal displacement (d). YIGM,
Yttrium-iron garnet magnetometer. (Credit:
Human Brain Mapping)
www.medicaldesignbriefs.com
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(d)
Reference
1. Koshev, N., Butorina, et al. (2021).
Evolution of MEG: A first MEG-feasible
fluxgate magnetometer. Human Brain
Mapping, 42 (15), 4844-4856. https://
doi.org/10.1002/hbm.25582.
For more information, visit www.skoltech.
ru/en.
Medical Design Briefs, December 2021
CENTER OF CELL
solid-state sensors, which will mark an
important step forward in noninvasive
neuroimaging and neurointerfaces.
" The initial concept of this sensor was
proposed by the project engineering
lead, Pyotr Vetoshko, back in the mid1990s.
The MEG market is expected to
reach $1.3 billion by 2025, " says Maxim
Ostras, the head of the project at RQC.
" Although our quantum device and the
classical flux-gate sensor have similar
operating principles, in our case, the
quantum exchange interaction helped
detect a magnetic field with a magnitude
1,000 times lower compared to conventional
solutions. Moreover, its high sensitivity
coupled with all the advantages of
classical flux-gate sensors makes our
device a truly universal magnetometer
ideally suited for brain research. "
" Even the first prototype of the sensor
in some cases showed higher sensitivity
in MEG as compared to existing systems,
which, combined with its simplicity and
solid-state nature, suggests that systems
based on this technology have a bright
future ahead of them, " says Nikolay
Koshev, an assistant professor at Skol -
tech. " Of course, there is still a lot of
work to be done, including further
research into the physical properties of
the sensor and the development of a new
mathematical apparatus that will ensure
high-efficiency signal processing for this
new specific type of magnetometer. "
" Given the potentially low cost and
high reliability of the new sensors, we
hope that MEG will become available
and affordable for broader user audiences, "
notes Prof. Alexei Ossadtchi, the
director of the Center for Bioelectric
Interfaces
Economics.
at the Higher School of
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https://www.doi.org/10.1002/hbm.25582 http://www.skoltech.ru/en http://www.Quspin.com/Human http://www.medicaldesignbriefs.com
Medical Design Briefs - December 2021

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