Association News

Biomedical Optics Express highlights key research.

Press Release Summary:

Dec 21, 2011 - Biomedical Optics Express is OSA's principle outlet for serving the biomedical optics community with rapid, open-access, peer-reviewed papers related to optics, photonics, and imaging in the life sciences. December 2011 issue covers variety of research topics, including New Device for Rapid, Mobile Detection of Brain Injury; Researchers Use Light to Measure Cancer Cells' Response to Treatment; and Nanometer-Scale Growth of Cone Cells Tracked in Living Human Eye.

The Optical Society (OSA) - Washington, DC

Original Press Release

Monthly Tip Sheet: Research Highlights from Biomedical Optics Express - December 2011

Press release date: Dec 20, 2011

WASHINGTON, -The following highlights summarize key research recently published in Biomedical Optics Express, the Optical Society's (OSA) principal outlet for serving the biomedical optics community with rapid, open-access, peer-reviewed papers related to optics, photonics and imaging in the life sciences. The journal scope encompasses theoretical modeling and simulations, technology development, and biomedical studies and clinical applications.

In this issue:
1. New Device for Rapid, Mobile Detection of Brain Injury
2. Researchers Use Light to Measure Cancer Cells' Response to Treatment
3. Nanometer-Scale Growth of Cone Cells Tracked in Living Human Eye

1. New Device for Rapid, Mobile Detection of Brain Injury
Handheld near-infrared imaging device enables quick detection of hematomas in patients with traumatic brain injuries

When accidents that involve traumatic brain injuries occur, a speedy diagnosis followed by the proper treatment can mean the difference between life and death. A research team, led by Jason D. Riley in the Section on Analytical and Functional Biophotonics at the U.S. National Institutes of Health, has created a handheld device capable of quickly detecting brain injuries such as hematomas, which occur when blood vessels become damaged and blood seeps out into surrounding tissues where it can cause significant and dangerous swelling.

A paper describing the team's proof-of-concept prototype for the hematoma detection device appears in the Optical Society's (OSA) open-access journal Biomedical Optics Express. The device is based on the concept of using instrumental motion as a signal in near-infrared imaging, according to the researchers, rather than treating it as noise. It relies on a simplified single-source configuration with a dual separation detector array and uses motion as a signal for detecting changes in blood volume in the tough, outermost membrane enveloping the brain and spinal cord (see video).

One of the primary applications for the finished device will be the rapid screening of traumatic brain injury patients before using more expensive and busy CT and MRI imaging techniques. In cases where CT and MRI imaging facilities aren't available, such as battlefields or on the scene of accidents, the team believes near-infrared imaging will help to determine the urgency of patient transport and treatment, as well as provide a means of monitoring known hematomas at the bedside or outpatient clinic.

Paper: "A hematoma detector - A practical application of instrumental motion as a signal in near infra-red imaging," Biomedical Optics Express, Vol. 3, Issue 1, pp. 192-205 (2012).

2. Researchers Use Light to Measure Cancer Cells' Response to Treatment
Many cancer therapies target specific proteins that proliferate on the outside of some cancer cells, but the therapies are imperfect and the cancer does not always respond. Since it is beneficial for doctors to know as soon as possible how a cancer is affected by treatment, researchers from Vanderbilt University are striving to design tests that assess treatment response rapidly, accurately, and cost-effectively. The team has demonstrated a new way to optically test cultured cancer cells' response to a particular cancer drug. The results appear in the December issue of the Optical Society's (OSA) open-access journal Biomedical Optics Express.

Certain cancer cells display a higher-than-normal number of proteins called human epidermal growth factor receptor 2 (HER2). In healthy cells, HER2 helps mediate cell growth, but overexpression of HER2 can mark one of the most aggressive forms of breast cancer. Drugs that bind to and block growth factor receptors have been shown to prolong life in some cancer patients, but about 30 percent of HER2 overexpressing tumors do not respond to the drug. Tests to identify these non-responding tumors early on would help doctors make important treatment decisions that could improve patient outcomes.

To design such a test, the Vanderbilt team took advantage of the fact that some cancer cells preferentially use a different metabolic pathway when compared to normal cells. The researchers visualized the relative use of the different pathways by shining the cells with frequencies of light that caused two different metabolic molecules to naturally fluoresce. They then calculated a ratio between the two levels of fluorescence, called an optical redox ratio. The team found that, of the different cell lines they tested, HER2 overexpressing cells had the highest optical redox ratio. They also found that when HER2 cancer cells were treated with an HER2-blocking drug, the ratio decreased. This decrease, however, was not observed in cancer cells that were resistant to the drug. The findings lay the groundwork for future in vivo studies and hold the promise that real-time tumor response to treatment might be measured optically.

Paper: "Optical imaging of metabolism in HER2 overexpressing breast cancer cells," Biomedical Optics Express, Vol. 3, Issue 1, pp. 75-85 (2012).

3. Nanometer-Scale Growth of Cone Cells Tracked in Living Human Eye
Humans see color thanks to cone cells, specialized light-sensing neurons located in the retina along the inner surface of the eyeball. The actual light-sensing section of these cells is called the outer segment, which is made up of a series of stacked discs, each about 30 nanometers (billionths of a meter) thick. This appendage goes through daily changes in length. Scientists believe that a better understanding of how and why the outer segment grows and shrinks will help medical researchers identify potential retinal problems. But the methods usually used to image the living human eye are not sensitive enough to measure these miniscule changes. Now, vision scientists at Indiana University in Bloomington have come up with a novel way to make the measurements in a living human retina by using information hidden within a commonly used technique called optical coherence tomography (OCT). They discuss their results in the Optical Society's (OSA) open-access journal Biomedical Optics Express.

To make an OCT scan of the retina, a beam of light is split into two. One beam scatters off the retina while the other is preserved as a reference. The light waves begin in synch, or in phase, with each other; when the beams are reunited, they are out of phase, due to the scattering beam's interactions with retinal cells. Scientists can use this phase information to procure a precise measurement of a sample's position. But since in this case their samples were attached to live subjects, the researchers had to adapt these typical phase techniques to counteract any movements that the subjects' eyes might insert into the data.

Instead of measuring the phase of a single interference pattern, the researchers measured phase differences between patterns originating from two reference points within the retinal cells: the top and bottom of the outer segment. The team used this hidden phase information to measure microscopic changes in hundreds of cones, over a matter of hours, in two test subjects with normal vision. Researchers found they could resolve the changes in length down to about 45 nanometers, which is just slightly longer than the thickness of a single one of the stacked discs that make up the outer segment. The work shows that the outer segments of the cone cells grow at a rate of about 150 nanometers per hour, which is about 30 times faster than the growth rate of a human hair.

Paper: "Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics," Biomedical Optics Review, Vol. 3, Issue 1, pp. 104-124 (2012).

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About Biomedical Optics Express
Biomedical Optics Express is OSA's principal outlet for serving the biomedical optics community with rapid, open-access, peer-reviewed papers related to optics, photonics and imaging in the life sciences. The journal scope encompasses theoretical modeling and simulations, technology development, and biomedical studies and clinical applications. It is published by the Optical Society and edited by Joseph A. Izatt of Duke University. Biomedical Optics Express is an open-access journal and is available at no cost to readers online at http://www.OpticsInfoBase.org/BOE.

About OSA
Uniting more than 130,000 professionals from 175 countries, the Optical Society (OSA) brings together the global optics community through its programs and initiatives. Since 1916 OSA has worked to advance the common interests of the field, providing educational resources to the scientists, engineers and business leaders who work in the field by promoting the science of light and the advanced technologies made possible by optics and photonics. OSA publications, events, technical groups and programs foster optics knowledge and scientific collaboration among all those with an interest in optics and photonics. For more information, visit www.osa.org.