Micromirror-scanned dual-axis confocal microscope utilizing a gradient-index relay lens for image guidance during brain surgery.

A fluorescence confocal microscope incorporating a 1.8-mm-diam gradient-index relay lens is developed for in vivo histological guidance during resection of brain tumors. The microscope utilizes a dual-axis confocal architecture to efficiently reject out-of-focus light for high-contrast optical sectioning. A biaxial microelectromechanical system (MEMS) scanning mirror is actuated at resonance along each axis to achieve a large field of view with low-voltage waveforms. The unstable Lissajous scan, which results from actuating the orthogonal axes of the MEMS mirror at highly disparate resonance frequencies, is optimized to fully sample 500 X 500 pixels at two frames per second. Optically sectioned fluorescence images of brain tissues are obtained in living mice to demonstrate the utility of this microscope for image-guided resections. (C) 2010 society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3386055]