Showing posts with label device. Show all posts
Showing posts with label device. Show all posts

Wednesday, October 10, 2012

3-D medical scanner: New handheld imaging device to aid doctors on the 'diagnostic front lines'

In the operating room, surgeons can see inside the human body in real time using advanced imaging techniques, but primary care physicians, the people who are on the front lines of diagnosing illnesses, haven't commonly had access to the same technology -- until now. Engineers from the University of Illinois at Urbana-Champaign (UIUC) have created a new imaging tool for primary care physicians: a handheld scanner that would enable them to image all the sites they commonly examine, and more, such as bacterial colonies in the middle ear in 3-D, or monitor the thickness and health of patients' retinas. The device relies on optical coherence tomography (OCT), a visualization technology that is similar to ultrasound imaging, but uses light instead of sound to produce the images.

The team will present their findings at the Optical Society's (OSA) Annual Meeting, Frontiers in Optics (FiO) 2012, taking place Oct. 14 -- 18 in Rochester, N.Y.

To monitor chronic conditions such as ear infections, primary care physicians currently rely on instruments that are essentially magnifying glasses, says UIUC physician and biomedical engineer Stephen Boppart, who will present the team's findings at FiO. The new handheld imaging device would give doctors a way to quantitatively monitor these conditions, and possibly make more efficient and accurate referrals to specialists.

The scanners include three basic components: a near-infrared light source and OCT system, a video camera to relay real-time images of surface features and scan locations, and a microelectromechanical (MEMS)-based scanner to direct the light. Near-infrared wavelengths of light penetrate deeper into human tissues than other wavelengths more readily absorbed by the body. By measuring the time it takes the light to bounce back from tissue microstructure, computer algorithms build a picture of the structure of tissue under examination.

Diabetic patients in particular may benefit from the device. About 40 to 45 percent of diabetics develop leaky blood vessels in their retinas -- a condition called retinopathy, which can lead to thickening of the retina, blurry vision, and eventually blindness. The handheld OCT device would allow doctors to monitor the health of the retina, potentially catching retinopathy in its early stages. In some cases, changes in the eye could help doctors diagnose diabetes, Boppart says.

Boppart and his team are hopeful that falling production costs combined with smaller, more compact designs will enable more physicians to take advantage of the scanners, and become a common point-of-care tool. Eventually, they would like to see the imagers at work in developing countries as well. He and an international team of collaborators recently received a $5 million National Institutes of Health Bioengineering Research Partnership grant to further refine the device.

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Monday, October 8, 2012

Engineers invent new device that could increase Internet download speeds

A team of scientists and engineers at the University of Minnesota has invented a unique microscale optical device that could greatly increase the speed of downloading information online and reduce the cost of Internet transmission.

The device uses the force generated by light to flop a mechanical switch of light on and off at a very high speed. This development could lead to advances in computation and signal processing using light instead of electrical current with higher performance and lower power consumption.

The research results were published October 2 in the online journal Nature Communications.

"This device is similar to electromechanical relays but operates completely with light," said Mo Li, an assistant professor of electrical and computer engineering in the University of Minnesota's College of Science and Engineering.

The new study is based on a previous discovery by Li and collaborators in 2008 where they found that nanoscale light conduits can be used to generate a strong enough optical force with light to mechanically move the optical waveguide (channel of information that carries light). In the new device, the researchers found that this force of light is so strong that the mechanical property of the device can be dominated completely by the optical effect rather than its own mechanical structure. The effect is amplified to control additional colored light signals at a much higher power level.

"This is the first time that this novel optomechanical effect is used to amplify optical signals without converting them into electrical ones," Li said.

Glass optical fibers carry many communication channels using different colors of light assigned to different channels. In optical cables, these different-colored light channels do not interfere with each other. This non-interference characteristic ensures the efficiency of a single optical fiber to transmit more information over very long distances. But this advantage also harbors a disadvantage. When considering computation and signal processing, optical devices could not allow the various channels of information to control each other easily…until now.

The researchers' new device has two optical waveguides, each carrying an optical signal. Placed between the waveguides is an optical resonator in the shape of a microscale donut (like a mini-Hadron collider.) In the optical resonator, light can circulate hundreds of times gaining intensity.

Using this resonance effect, the optical signal in the first waveguide is significantly enhanced in the resonator and generates a very strong optical force on the second waveguide. The second waveguide is released from the supporting material so that it moves in oscillation, like a tuning fork, when the force is applied on it. This mechanical motion of the waveguide alters the transmission of the optical signal. Because the power of the second optical signal can be many times higher than the control signal, the device functions like a mechanical relay to amplify the input signal.

Currently, the new optical relay device operates one million times per second. Researchers expect to improve it to several billion times per second. The mechanical motion of the current device is sufficiently fast to connect radio-frequency devices directly with fiber optics for broadband communication.

Li's team at University of Minnesota includes graduate students Huan Li, Yu Chen and Semere Tadesse and former postdoctoral fellow Jong Noh. Funding support of the project came from the University of Minnesota College of Science and Engineering and the Air Force Office of Scientific Research.

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