IEEE Solid-States Circuits Magazine - Spring 2023 - 48

the system to be a highly accurate
indicator of defecation [9], which is
of clinical significance for patients
suffering from fecal incontinence.
Furthermore, we have demonstrated
the iMAG's usage as an in vivo sensor
to detect the location of magnetic
particles and beads [9]. This
approach can be used to label injection
sites, polyps, fistulas, stomas, or
strictures requiring localized therapy,
using anatomic markers such as
magnetic beads or staples. iMAGs can
also delineate complex and curved
trajectories of the retroperitoneally
fixed parts of the GI tract [9], which
are hard to acquire through other imaging
modalities (X-ray/CT).
The real-time and millimeter-scale
localization resolution of iMAGs
holds the potential for significant
clinical benefit. The quantitative assessment
of GI transit time is vital
in the diagnosis and treatment of
pathologies related to delayed or
accelerated motility such as gastroparesis,
Crohn's disease, functional
dyspepsia, regurgitation, constipation,
and incontinence [2]. Additional
capabilities could be added to the
iMAGs, enabling them to measure
and report pH, temperature, and
pressure; deliver drug payloads; and
perform electrical/mechanical stimulation.
The complete iMAG system
can be readily deployed in various
nonclinical settings such as smart
toilets, wearable jackets, or portable
backpacks [Figure 4(a)], thus allowing
real-time GI tract monitoring
without disrupting the daily activities
of the patient. From a consumer
electronics standpoint, the iMAG offers
the potential for the noninvasive
and location-specific measurement
of physiological markers and vital
parameters along the gut, which could
be of interest in the fields of fitness
and smart medicine.
Acknowledgment
This work involved human subjects
or animals in its research. Approval
of all ethical and experimental procedures
and protocols was granted
by the Committee for Animal Care
of the Massachusetts Institute of
Technology for animal experiments.
References
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[2]
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[3] A. M. Franz et al., " Electromagnetic tracking
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[4] D. Vasisht et al., " In-body backscatter
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[6] F. Parent et al., " Intra-arterial image
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[7] S. Sharma et al., " Wireless 3D surgical
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100 μm accuracy using magnetic-field
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[8] S. Sharma et al., " 3D surgical alignment
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[9] S. Sharma et al., " Location-aware ingestible
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s41928-023-00916-0.
About the Authors
Azita Emami (azita@caltech.edu) is
the Andrew and Peggy Cherng Professor
of Electrical Engineering and
Medical Engineering at the California
Institute of Technology (Caltech),
Pasadena, CA 91125 USA. She is also
the director of the Center for Sensing
to Intelligence at Caltech and
currently serves as the executive
officer (department head) for electrical
engineering. She received her
B.S. degree from the Sharif University
of Technology, Tehran, Iran, in
1996 and her M.S. and Ph.D. degrees
in electrical engineering from Stanford
University, Stanford, CA, USA,
in 1999 and 2004, respectively. From
2004 to 2006, she was with the IBM
T. J. Watson Research Center, Yorktown
Heights, NY, USA, before joining
Caltech in 2007. Dr. Emami was
an associate editor of IEEE Journal of
Solid-State Circuits (JSSC) from 2018
to 2022. She was a Distinguished
Lecturer of the IEEE Solid-State Circuits
Society from 2017 to 2018. Her
research interests include integrated
circuits and systems, integrated photonics,
wearable and implantable
devices for neural recording, neural
stimulation, sensing, and drug delivery.
She is a Senior Member of IEEE.
Saransh Sharma (ssharma3@
caltech.edu) received his B.Tech.
degree in electronics and electrical
communication engineering from
the Indian Institute of Technology,
Kharagpur, India, in 2017 and his
M.S. degree in electrical engineering
from Caltech, Pasadena, CA, USA,
in 2018. He is currently pursuing
his Ph.D. degree at the Department
of Electrical Engineering, Caltech,
Pasadena, CA 91125 USA, on analog
and mixed-signal integrated circuits
and system design, with special
emphasis on low-power biomedical
applications. Saransh was with
Medtronic (Mounds View) for the
summer of 2022, working on the
testing and verification of ICs for
cardiac devices. He was a recipient
of the Jakob van Zyl Predoctoral
Research Award at Caltech,
the Charles Lee Powell Fellowship
at Caltech, the 2020 student travel
grant award at ISSCC, the Viterbi
India Scholarship, and the KVPY
Fellowship. He serves as a reviewer
for JSSC, IEEE Transactions on
Medical Imaging, and IEEE Sensors
Journal. He is a Graduate Student
Member of IEEE.
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IEEE SOLID-STATE CIRCUITS MAGAZINE
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