A prototype hybrid intraoperative probe for ovarian cancer detection
ABSTRACT A novel prototype intraoperative system combining positron detection and optical coherence tomography (OCT) imaging has been developed for early ovarian cancer detection. The probe employs eight plastic scintillating fiber tips for preferential detection of local positron activity surrounding a central scanning OCT fiber providing volumetric imaging of tissue structure in regions of high radiotracer uptake. Characterization measurements of positron sensitivity, spatial response, and position mapping are presented for Tl(204)/Cs(137) sources as well as 18F-FDG. In conjunction with co-registered frequency domain OCT measurements the results demonstrate the potential for a miniaturized laparoscopic probe offering simultaneous functional localization and structural imaging for improved early cancer detection.
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ABSTRACT: This study used optical coherence tomography (OCT) compared to scanning electron microscopy (SEM) and optical microscopy (OM) to evaluate qualitatively crack propagation and final fracture in restorative composite materials - Filtek Z250 and Filtek Z350 (3M ESPE) - with fiber reinforcement after cyclic loading. Samples were made using a split mold. Initially, 3-point bending tests were performed to determine the maximum force and tension at the fracture moment using samples without fiber reinforcement. Then, mechanical cycling tests were performed using samples with glass fiber embedded internally. The failures were analyzed using the 3 methods described before. OCT permitted good characterization of internal crack propagation of the dental composites, which, however, could not be visualized by either SEM or OM. OCT was proven to be laboratory research tool that is easy to use, does not require any specific preparation of the samples, and is less expensive than SEM.Brazilian dental journal 01/2010; 21(5):420-7. DOI:10.1590/S0103-64402010000500008
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ABSTRACT: A review is presented on a selection of methods and devices initially developed by the fiber optic, sensing and fiber laser communities which have later found applications in high resolution non-invasive optical imaging. Three avenues have been identified in the modern low coherence interferometry and in the optical coherence tomography technologies which have taken inspiration from fiber optic sensing, fiber optic devices, fiber lasers and fiber optic communications: 1) optical sources; 2) optical configurations; and 3) signal processing. The review will illustrate state of the art examples of concept evolution along these three avenues.Journal of Lightwave Technology 03/2010; DOI:10.1109/JLT.2009.2032787 · 2.86 Impact Factor
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ABSTRACT: Photoacoustic imaging and optical coherence tomography are two emerging imaging modalities which provide complementary optical absorption and scattering contrasts for biological tissues. While photoacoustic imaging provides tissue vasculature information, optical coherence tomography offers micron-scale morphological imaging with penetration depths of 1~3 mms. Pulse-echo ultrasound is readily available from photoacoustic system and it provides tissue structure information at deeper depths with resolutions scalable with the transducer frequency. We present a prototype endoscope that consists of a ball lensed optical coherence tomography probe, a right-angled multimode fiber for delivering the laser beam for photoacoustic imaging, and a high frequency ultrasound transducer of 35 MHz center frequency. The overall diameter is 5mms. Porcine ovaries were imaged ex vivo to demonstrate the capability of this new combined endoscopy. The microvascular and high resolution structural images at subsurface and deeper tissue range demonstrate the synergy of the combined endoscopy over each modality alone.Proceedings of SPIE - The International Society for Optical Engineering 02/2011; DOI:10.1117/12.878862 · 0.20 Impact Factor