Multispectral Open-air Intraoperative Fluorescence Imaging

Intraoperative fluorescence imaging informs decisions regarding surgical margins by detecting and localizing signal from fluorescent reporters labeling targets such as malignant tissues. This guidance reduces the likelihood of undetected malignant tissue remaining after resection eliminating the need for additional treatment or surgery. The primary challenges in performing open-air intraoperative fluorescence imaging come from the weak intensity of the fluorescence signal in the presence of strong surgical and ambient illumination, and the auto-fluorescence of non-target components, such as tissue, especially in the visible spectral window (400-650nm). In this work, a multispectral open-air fluorescence imaging system is presented for translational image-guided intraoperative applications which overcomes these challenges. The system is capable of imaging weak fluorescence signal with nanomolar sensitivity in the presence of surgical illumination. This is done using synchronized fluorescence excitation and image acquisition in addition to real-time background subtraction. Additionally, the system uses a liquid crystal tunable filter (LCTF) for acquisition of multispectral images that are used to spectrally unmix target fluorescence from non-target auto-fluorescence. Results are validated by preclinical studies on murine models and translational canine oncology models.