Experimental results of a modified micromachined microelectromechanical systems (MEMS) mirror for substantial enhancement of the transverse laser scanning performance of endoscopic optical coherence tomography (EOCT) are presented. Image distortion due to buckling of MEMS mirror in our previous designs was analyzed and found to be attributed to excessive internal stress of the transverse bimorph meshes. The modified MEMS mirror completely eliminates bimorph stress and the resultant buckling effect, which increases the wobbling-free angular optical actuation to greater than 37°, exceeding the transverse laser scanning requirements for EOCT and confocal endoscopy. The new optical coherence tomography (OCT) endoscope allows for two-dimensional cross-sectional imaging that covers an area of 4.2 mm × 2.8 mm (limited by scope size) and at roughly 5 frames/s instead of the previous area size of 2.9 mm × 2.8 mm and is highly suitable for noninvasive and high-resolution imaging diagnosis of epithelial lesions <i>in vivo</i>. EOCT images of normal rat bladders and rat bladder cancers are compared with the same cross sections acquired with conventional bench-top OCT. The results clearly demonstrate the potential of EOCT for <i>in vivo</i> imaging diagnosis and precise guidance for excisional biopsy of early bladder cancers.
© 2003 Optical Society of America
(170.2150) Medical optics and biotechnology : Endoscopic imaging
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(170.3890) Medical optics and biotechnology : Medical optics instrumentation
(170.4500) Medical optics and biotechnology : Optical coherence tomography
(170.7230) Medical optics and biotechnology : Urology
Tuqiang Xie, Huikai Xie, Gary K. Fedder, and Yingtian Pan, "Endoscopic Optical Coherence Tomography with a Modified Microelectromechanical Systems Mirror for Detection of Bladder Cancers," Appl. Opt. 42, 6422-6426 (2003)