A Portable Fluorescence Microscopic Imaging System For Cholecystectomy

Currently, cholecystectomy is a standard surgical procedure for the treatment of gallstones and other biliary diseases. However, the procedure may fail to identify biliary structures owing to anatomic anomalies such as short cystic duct or biliary severe adhesion, resulting in accidental injury to the biliary system. In this paper we proposed a portable fluorescence microscopic imaging system for intraoperative display of biliary structure and prevention of iatrogenic injuries during cholecystectomy.The system consisted of a light source module, a CMOS camera, a Raspberry Pi computer and a 5 inch HDMI LCD. Specifically, the light source module was composed of 690 nm and 850 nm LEDs, allowing for the CMOS camera to acquire both fluorescence and background images simultaneously. The system was controlled by the Raspberry Pi using Python programming with an OpenCV library under Linux.Indocyanine green (ICG) was used as a fluorescent contrast agent for experimental validation of the system. Fluorescence intensities of the ICG aqueous solution at different concentration levels were acquired by our fluorescence microscopic imaging system and compared with those of a commercial Xenogen I VIS system. The spatial resolution of the proposed fluorescence microscopic imaging system was characterized by a 1951 USAF resolution target and the dynamic response was evaluated quantitatively with an automatic displacement platform. Finally, we verified the technical feasibility of the proposed system for differentiating between correct and incorrect cholecystectomy procedures using a mouse model in vivo.Our experiments showed that the proposed system facilitated clear visualization of cystic duct, common bile duct and common hepatic duct, for potential applications in image-guided cholecystectomy. The total cost of the proposed portable system is only $300, suitable for deployment in resource-limited settings.