Near-Infrared Fluorescence Lymph Node Navigation Using Indocyanine Green for Gastric Cancer Surgery

Abstract

Near-infrared (NIR) fluorescence imaging is a promising method for image-guided surgery, providing robust functional images with relatively good cost-effectiveness. A cyanine vital dye indocyanine green (ICG) is a safe NIR fluorophore emitting 800~840 nm of light and has been used in numerous surgical procedures. The technique has been applied to lymph node navigation of gastric cancer surgery with an expectation of better visualization of lymphatic structures without any risk of radio-hazard compared with a “dual method” using both vital dyes and radioisotopes. Given the characteristics of ICG, such as fast distribution and quenching effect, diluted concentrations, such as 0.05~0.1 mg/ml, are thought to be optimal for sentinel node navigation. Injection into the subserosal layer is feasible; however, endoscopic submucosal injection has advantages of improved accuracy of the injection site and feasibility of injection one day prior to surgery; these advantages are preferred by some investigators due to a smaller number of sentinel nodes compared with injection in the operation theatre. The technology requires evaluation of the sensitivity and specificity, as well as the non-inferiority, compared with the dual method in a large cohort for justification as a safe node navigation method.