Dual-modality fluorescence lifetime imaging and polarization sensitive optical coherence tomography system for optical biopsy in brain

Glioblastoma (GBM) is the most aggressive form of malignant brain tumor and current treatment involves maximum surgical resection. However, accurately identifying tumor margins during surgery remains a major challenge. We developed a dual-modality imaging system combining fluorescence lifetime imaging (FLIm) and polarization-sensitive optical coherence tomography (PS-OCT). FLIm provides compositional information based on endogenous fluorophores such as NADH and FAD, while PS-OCT offers structural and depth-resolved imaging with birefringence contrast for white matter and has shown sensitivity to lipid-rich regions, which are an emerging biomarker for GBM. The system is based on a double-cladding fiber coupler and enables robust, co-registered imaging. Initial ex-vivo experiments on goat brain slices demonstrate sufficient signal quality and tissue contrast. This approach has the potential to support real-time, label-free tumor margin detection and improve outcomes in GBM surgery.