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Novel computed imaging technique
uses blurry images to enhance view
James E. Kloeppel, Physical Sciences Editor
photo to enlarge
courtesy of Beckman Institute
tissue phantom where the scattering points
would represent cells, and images before and after
ISAM are shown.
CHAMPAIGN, Ill. —
Researchers at the University of Illinois at Urbana-Champaign have developed
a novel computational image-forming technique for optical microscopy
that can produce crisp, three-dimensional images from blurry, out-of-focus
Called Interferometric Synthetic Aperture Microscopy, ISAM can do for
optical microscopy what magnetic resonance imaging did for nuclear magnetic
resonance, and what computed tomography did for X-ray imaging, the scientists
“ISAM can perform high-speed, micron-scale, cross-sectional imaging
without the need for time-consuming processing, sectioning and staining
of resected tissue,” said Stephen Boppart, a professor of electrical
and computer engineering, of bioengineering,
and of medicine at the U. of
I., and corresponding author of a paper accepted for publication in
the journal Nature Physics, and posted on its Web site.
Developed by postdoctoral research associate and lead author Tyler Ralston,
research scientist Daniel Marks, electrical and computer engineering
professor P. Scott Carney, and Boppart, the imaging technique utilizes
a broad-spectrum light source and a spectral interferometer to obtain
high-resolution, reconstructed images from the optical signals based
on an understanding of the physics of light-scattering within the sample.
“ISAM has the potential to broadly impact real-time, three-dimensional
microscopy and analysis in the fields of cell and tumor biology, as
well as in clinical diagnosis where imaging is preferable to biopsy,”
said Boppart, who is also a physician and founding director of the Mills
Breast Cancer Institute at Carle Foundation Hospital in Urbana, Ill.
While other methods of three-dimensional optical microscopy require
the instrument’s focal plane to be scanned through the region
of interest, ISAM works by utilizing light from the out-of-focus image
planes, Ralston said. “Although most of the image planes are blurry,
ISAM descrambles the light to produce a fully focused, three-dimensional
ISAM effectively extends the region of the image that is in focus, using
information that was discarded in the past.
“We have demonstrated that the discarded information can be computationally
reconstructed to quickly create the desired image,” Marks said.
“We are now applying the technique to various microscopy methods
used in biological imaging.”
In their paper, the researchers demonstrate the usefulness of computed
image reconstruction on both phantom tissue and on excised human breast-tumor
“ISAM can assist doctors by providing faster diagnostic information,
and by facilitating the further development of image-guided surgery,”
Boppart said. “Using ISAM, it may be possible to perform micron-scale
imaging over large volumes of tissue rather than resecting large volumes
The versatile imaging technique can be applied to existing hardware
with only minor modifications.
In addition to previously mentioned affiliations, Boppart, Carney, Marks
and Ralston hold positions within the department of electrical and computer
engineering and are affiliated with the U. of I.’s Beckman
Institute for Advanced Science and Technology. Boppart also is affiliated
with the university’s Micro
and Nanotechnology Laboratory and the Institute
for Genomic Biology; Carney also is affiliated with the university’s Coordinated Science Laboratory.
The National Institutes of Health, National Science Foundation, and
the Beckman Institute funded the work.
Editor’s note: To reach Stephen Boppart,
call 217-244-7479; e-mail: email@example.com.