Combined Fluorescence and Bright Field Imaging via a Single CMOS Detector Without Filters to Improve on Patient Safety during Endoscopic Procedures – An Experimental Study Analysing the Output of both LASER and LED Near Infrared Sources on In Vitro Samples

Many endoscopic systems combine white light and NIR light via LED multiplexing in order to image tissue stained with Near Infrared (NIR) fluorescent markers such as Indocyanine Green (ICG). This can result in unnecessary  in vivo  energy exposure which can cause irreversible damage to tissue. A simple, single detector system is proposed in this work comprising a single excitation channel at a wavelength of 780 nm. We have demonstrated that a single 1.6 Megapixel CMOS camera with quantum efficiency of less than 30% is appropriate to capture both fluorescent and non-fluorescent landmarks at NIR wavelengths. Experimental results indicate that a LASER source generating between up to 10 mW of optical power at 780 nm could be considered as an alternative to LED.