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Lori M. Murphy, Steven Chalfin; Modeling Detection and Characterization of Intraocular Foreign Bodies Using Ultrawideband Radar. Invest. Ophthalmol. Vis. Sci. 2011;52(14):4089.
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Several technologies are presently used in clinical practice for intraocular foreign body (IOFB) detection, including X-ray, CT, MRI, and ultrasonography, but each has significant limitations, particularly in the combat casualty care setting. The potential advantage of Ultrawideband (UWB) detection technology is that it offers greater sensitivity compared to existing detection methods, and may be accomplished using a small, portable device. Our study uses a novel UWB detection system for the ophthalmic application, to model interactions between UWB energy and various metallic and nonmetallic foreign bodies.
An R2a nanoscale impulse radar (Novelda, Oslo, NO), coupled to Vivaldi 004 directional antennas (Imego, Gothenberg, SE), was used to acquire radar signatures. This system has a center frequency of 3.4 GHz and a bandwidth of 1 to 5.8 GHz. An explanted porcine eye was placed 44 cm. from the radar antennas. Metallic (hypodermic needle) and nonmetallic (wood) foreign bodies were placed at two different testing positions on the eye (cornea and posterior sclera) to detect changes in the reflected UWB energy compared with the eye alone. The radar used strobed sampling to capture data from 250 pulses over a 2 second interval.
Radar signatures of the explanted eye were complex, but reproducible. Placement of metallic and non-metallic foreign bodies resulted in characteristic alterations in both the position and amplitude of reflected radar energy peaks of the radar signature (Figure).
UWB radar technology is able to detect both metallic and nonmetallic IOFBs at varying positions but will require further refinement of radar parameters to more accurately detect, localize, and characterize foreign bodies.
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