The NIR light source of our device is based on light-emitting diodes (LEDs), which can deliver sufficient light to biological tissues and induce fluorescence emission to meet the needs of the planned clinical studies. It should be noted that the light source is still well under the US FDA recommended limit for NIR exposure and ANSI standard. In addition, the light source is not laser-based, which is significantly safer than other optical imaging systems utilizing laser technologies. The fluorescence signals will be received by the detector portion of our device. Gain-settings could be easily adjusted during operation to optimize the contrast between high fluorescence areas (tumors) and low fluorescence areas (normal tissues). Real-time fluorescence video will be displayed in the goggle eyepiece as well as on a secondary monitor to facilitate viewing by other surgeons in the room.