Hola amigos: A VUELO DE UN QUINDE EL BLOG., hemos recibido información de la Fundación Nacional de Ciencias de Los Estados Unidos, indicándonos los beneficios de la utilización de los rayos láser; tanto es así que: Enfoque fotoacústica muestra potencial para expandir el alcance de bioimagen.
NSF, nos dice: " Un cráneo humano, en promedio, es de aproximadamente 0,3 pulgadas de grosor, o aproximadamente la profundidad de la más reciente teléfono inteligente. La piel humana, por otro lado, es de aproximadamente 0,1 pulgadas, o alrededor de tres granos de sal y profundas.
Aunque estas dimensiones son extremadamente delgada, todavía presentan grandes obstáculos para cualquier tipo de imágenes con luz láser.
Aunque estas dimensiones son extremadamente delgada, todavía presentan grandes obstáculos para cualquier tipo de imágenes con luz láser.
Por Qué? La luz del láser contiene fotones, o partículas minúsculas de la luz. Cuando los fotones se encuentran con el tejido biológico, se dispersan. Acorralar las pequeñas balizas para obtener detalles significativos sobre el tejido ha demostrado ser uno de los problemas más desafiantes investigadores láser han enfrentado..............."
More information...........
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=135473&WT.mc_id=USNSF_51&WT.mc_ev=click
 Credit and Larger Version |
June 19, 2015
A human skull, on average, is about 0.3 inches thick, or roughly the depth of the latest smartphone. Human skin, on the other hand, is about 0.1 inches, or about three grains of salt, deep.
While these dimensions are extremely thin, they still present major hurdles for any kind of imaging with laser light.
Why? Laser light contains photons, or miniscule particles of light.
When photons encounter biological tissue, they scatter. Corralling the
tiny beacons to obtain meaningful details about the tissue has proven
one of the most challenging problems laser researchers have faced.
However, one research group at Washington University in St. Louis (WUSTL) decided to eliminate the photon roundup completely and use scattering to their advantage.
The result: An imaging technique that penetrates tissue up to about
2.8 inches. This approach, which combines laser light and ultrasound, is
based on the photoacoustic effect, a concept first discovered by
Alexander Graham Bell in the 1880s.
In his work, Bell found that a focused light beam produces sound when
trained on an object and rapidly interrupted--he used a rotating,
slotted wheel to create a flashing effect with sunlight.
Bell's concept is the foundation for photoacoustics, an area of a growing field known as biophotonics, which joins biology and light-based science
known as phototonics. Biophotonics bridges photonics principles,
engineering and technology that are relevant for critical problems in
medicine, biology and biotechnology.
"We combine some very old physics with a modern imaging concept," says WUSTL researcher Lihong Wang, who pioneered the approach.
Wang and his WUSTL colleagues were the first to describe functional
photoacoustic tomography (PAT) and 3-D photoacoustic microscopy (PAM).
Both techniques follow the same basic principle: When the researchers
shine a pulsed laser beam into biological tissue, it spreads out and
generates a small, but rapid rise in temperature. This increase produces
sound waves that are detected by conventional ultrasound transducers.
Image reconstruction software converts the sound waves into high-resolution images.
Following a tortuous path
Wang first began exploring the combination of sound and light as a post-doctoral researcher.
At the time, he modeled photons as they traveled through biological material. This work led to an NSF CAREER grant to study ultrasound encoding of laser light to "trick" information out of the beam.
"The CAREER
grant boosted my confidence and allowed me to study the fundamentals of
light and sound in biological tissue, which benefited my ensuing career
immensely," he says.
Unlike other optical imaging techniques, photoacoustic imaging
detects ultrasonic waves induced by absorbed photons no matter how many
times the photons have scattered. Multiple external detectors capture
the sound waves regardless of their original locations.
"While the light travels on a highly tortuous path, the ultrasonic wave propagates in a clean and well-defined fashion," Wang says. "We see optical absorption contrast by listening to the object."
The approach does not require injecting imaging agents, so
researchers can study biological material in its natural environment.
Using photoacoustic imaging, researchers can visualize a range of
biological material from cells and their component parts to tissue and
organs. It detects single red blood cells in blood, as well as fat and protein deposits.
While PAT and PAM are primarily used by researchers, Wang and others
are working on multiple clinical applications. In one case, researchers
use PAM to study the trajectory of blood cells as they flow through
vessels in the brain.
"By seeing individual blood cells, researchers can start to identify
what's happening to the cells as they move through the vessels. Watching
how these cells move could act as an early warning system to allow
detection of potential blockage sites," says Richard Conroy, director of the Division of Applied Science and Technology at the National Institute of Biomedical Imaging and Bioengineering.
Minding the gap
Because PAT and PAM images can be correlated with those generated
using other methods such as magnetic resonance imaging or positron
emission tomography, these techniques can complement existing ones.
"One imaging modality can't do everything," says Conroy. "Comparing
results from different modalities provides a more detailed understanding
of what is happening from the cell level to the whole animal."
The approach could help bridge the gap between animal and human research, especially in neuroscience.
"Photoacoustic imaging is helping us understand how the mouse brain
works. We can then apply this information to better understand how the
human brain works," says Wang, who along with his team is applying both
PAT and PAM to study mouse brain function.
Wang notes that one of the challenges currently facing
neuroscientists is the lack of available tools to study brain activity
such as action potentials, which occur when electrical signals travel
along axons, the long fibers that carry signals away from the nerve cell
body.
"The holy grail of brain research is to image action potentials," he says.
With funding from The BRAIN Initiative,
Wang and his group are now developing a PAT system to capture images
every one-thousandth of a second, fast enough to image action potentials
in the brain.
"Photoacoustic imaging fills a gap between light microscopy and
ultrasound," says Conroy. "The game-changing aspect of this [Wang's]
approach is that it has redefined our understanding of how deep we can
see with light-based imaging."
| -- | Susan Reiss, (703) 292-8070 sreiss@associates.nsf.gov |
Investigators
Lihong Wang
Related Institutions/Organizations
Washington University
Related Programs
Biophotonics
Total Grants
$320,736
Related AgenciesNational Institute of Biomedical Imaging and Bioengineering
Related Websites
Brain power: Bright ideas and smart tools for neuroengineering:
Brain power: Bright ideas and smart tools for neuroengineering:
http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=135463
Light technologies and missing professor mystery: A video by the National Science Foundation: https://www.youtube.com/watch?list=PL0ujJTaPsv3ehhaYWjxKE2uCdwikA8ac6&v=D3a2USvTpwQ
Light technologies and missing professor mystery: A video by the National Science Foundation: https://www.youtube.com/watch?list=PL0ujJTaPsv3ehhaYWjxKE2uCdwikA8ac6&v=D3a2USvTpwQ
View VideoPhotoacoustic imaging of single flowing red blood cells.
Credit and Larger Version
The National Science Foundation (NSF)
Guillermo Gonzalo Sánchez Achuteguiayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
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