Description (provided by application): The broad, long-term objective of the proposed research is to develop a noninvasive system for optical biopsy using microelectromechanical system (MEMS) technology. We propose to combine the advances in biomedical imaging and MEMS technology to develop a high speed, endoscopic functional OCT with a miniaturized probe for early diagnosis of lesions and tumors in gastrointestinal (GI), respiratory, and urogenital tracts. This is a collaborative project involving scientists, engineers, and clinicians at UCI Beckman Laser Institute and Medical Clinic (Zhongping Chen), UCI Department of Medicine and Endoscopic Ultrasound Center (Kenneth Chang), UCI Department of Electrical and Computer Engineering and Center for BioMEMS (Mark Bachman and Guann-pyng Li), and UC Davis Department of Electrical Engineering and Computer Engineering (Norman Tien). This bioengineering research partnership will be led by Zhongping Chen of UCI. The specific aims of this work are to: 1) design and develop a high speed, fiber optic based high resolution functional OCT system for endoscopic imaging of in vivo structure and blood flow dynamics in GI tracts, and investigate and develop hardware systems and imaging processing algorithms for speckle noise minimization and imaging enhancement (Chen); 2) design and develop scanning probes with silicon MEMS technology (Tien); 3) design and develop scanning probes with polymer MEMS technology (Li & Bachman); 4) integrate MEMS probe with OCT system and perform in vitro and in vivo testing (Chen, Tien, Li, Bachman, Chang); 5)investigate the applications of MEMS based endoscopic OCT for early diagnosis of lesions and tumors in GI tracts (Chang & Chen). This is a collaborative project that involves PI and Co-PIs with expertise in biomedical optics, silicon and polymer MEMS technology, and endoscopic imaging. The scanning probes developed using MEMS technology have the advantage that they are compact, robust, low cost, low power requirement, and high speed. In addition, lateral resolution of the current endoscopic OCT that uses axial scanning followed by lateral scanning is limited by the focal depth of the probe beam. The high scanning rate the probe made with MEMS technology offers the potential to increase lateral resolution by performing lateral scanning first in order to maintain the beam waist at the zero optical path length. Furthermore, a scanning probe fabricated with MEMS technology has the potential to provide three-dimensional imaging of tissue structure and physiology with high imaging speed. Finally, the scanning probe technology developed in this proposal can also be used for endoscopic confocal and two-photon imaging.