Near-infrared (NIR) fluorescence-based imaging has the potential to detect tumors with high sensitivity and high specificity in real time. Current approaches employ fluorescent dyes and operate mostly in the first NIR window (NIR-I, 700 - 900 nm) for image-guided use. To image tissue, visible light and fluorescence images are either taken with the same detector or with multiple cameras in different spectral ranges simultaneously or sequentially. Systems that can detect both visible and fluorescent imaging simultaneously use silicon-based detectors that are sensitive to visible and NIR-I spectral bands. However, to properly separate these narrowly-spaced passbands, expensive spectral filters with narrow fields-of-view are required. Other systems which instead use multiple cameras to detect visible light, NIR-I, and/or the second NIR window (NIR-II, 1000 - 1700 nm), must fuse the images from all these detectors to create the combined image via post processing. This image fusion requires precise optical alignment and positioning, which ultimately increases the size, weight, and cost of the imaging system. This fluorescence-based imaging technology overcomes the limitations of these two approaches. Moreover, NIR-II imaging technology can offer better tissue penetration, reduced light scattering, and lower tissue autofluorescence.
The present invention is an improved method for image acquisition in both the NIR-I and NIR-II spectral windows using a single image detection system. It is also compatible with nearly all LED surgical illuminators.