Abstract 4312: Seamless fluorescence guided surgery for pancreatic cancer is facilitated by a hand held electrocautery pencil with excitation light source

Fluorescent labeling of tumors with the goal of fluorescence guided surgical resection (FGS) continues to be perfected and investigated. In addition to a bright fluorophore that specifically and selectively labels tumor tissue, a specific excitation light source that can be turned on as needed by the surgeon without having to take their hands off the dissecting instruments would be the most ideal system. The optimal method for tissue excitation would therefore require the excitation light source to be on the surgeon's dissecting or cutting instrument that could be easily turned on or off as needed and in direct line with the labeled tumor tissue. In designing the excitation light source we decided to use the NIR window (600-1000 nm) due to it's favorable imaging qualities that would allow for fluorophore excitation without the necessity of eliminating white light from the field and with little to no tissue autofluorescence. An electrocautery pencil was fitted with LEDs at the base of the tip with an emitted signal between 633-660nm. The complementary dye selected for labeling was DyLight 650 (Ex: 652 nm, Em: 672 nm). Nude mice were implanted with patient-derived orthotopic xenograft (PDOX) pancreatic tumors and allowed 4 weeks for engraftment. Anti-CA 19-9 antibody was then conjugated to DyLight 650 and injected intravenously 24 hours prior to FGS. After 24 hours the mice underwent surgical exploration for an attempt at FGS with the new device. A Canon EOS 60D camera fitted with a 672 nm emission filter connected to a 19 inch monitor was selected as the fluorescence image-capturing device. The mice were grounded appropriately to a surgical monopolar generator selected to power to the electrocautery pencil. After initial incision and tumor exposure under bright light the tumor was illuminated by the excitation LEDs by simply pushing forward on the cautery activation button on the device. The fluorescently labeled image of the tumor was easily seen and confirmed on the monitor in real-time as the surgery proceeded. The tumor was brightly visible with good background contrast. Using this method had the benefit of allowing tumor resection with electrocautery using both ambient light and the fluorescent image simultaneously to confirm a complete resection. In this respect, critical surrounding structures are visible with the ambient light, helping to avoid inadvertent tissue injury. Coupling an excitation LED light source to an electrocautery pencil allows for