Handheld dual-modality wide-field fluorescent imaging guided dual-axis confocal microscope for fluorescence molecular guidance of precise tumor resection in head and neck surgery (Conference Presentation)

Wide-field fluorescent imaging for fluorescence molecular guidance has become a promising technique for use in imaging guided surgical navigation, but quick and intuitive microscopic inspection of fluorescent hot spots is still needed to confirm local disease states of tissues. To address this unmet need, we have developed a clinically translatable dual-modality handheld surgical microscope that incorporates both, wide-field (mesoscopic) fluorescence imaging and high-resolution (microscopic) horizontal optical-sectioning. This is accomplished by integrating a commercially available wide-field fiberscope, modified for two-color (660nm and 785nm) fluorescent detection, into a compact package (5.5 mm dia.) which also contains a dual-axis confocal (DAC) microscope. DAC microscopy is a high-sensitivity, high-resolution fluorescent imaging technology that benefits from the specificity of molecular probes, and enables interrogation of deeper regions of tissue by performing optical-sectioning of tissue. The DAC microscope has been designed with custom catadioptric micro-lenses to provide broadband multispectral capability for fluorescence imaging of multiple fluorophores over a broad spectral range (VIS to NIR), and also uses a novel MEMS-based scanning system for horizontal sectioning, and thus enables access to deeper regions of tissue at resolutions comparable to histological analysis. Large field-of-view (mm scale) is further provided by image mosaicing. The instrument thus provides simultaneous mesoscopic and microscopic fluorescence imaging over a broad spectral range for intuitively performing fast in-vivo search and microscopic confirmation of optical molecular markers in tissue, which is a capability that will become increasingly important for precise tumor resection in oncology as more optical molecular markers become approved for human use.