[A new tracer for sentinel node detection in esophageal and lung cancer--fluorescent microspheres]

Tracers commonly used for sentinel node detection are blue dye and radioisotope (RI)-labeled colloids. In esophageal cancer or lung cancer, it is impossible to detect the sentinel node among anthracotic mediastinal nodes with blue dye. RI-labeled colloids must be treated in a special facility under complicated regulations. To overcome these problems, we used fluorescent microspheres as a tracer in animals and detected fluorescence-positive nodes using the ultraviolet light irradiation method. Systemic and local injection of fluorescent microspheres revealed no side effects in rats. Submucosal and subadventitial injection of fluorescent microspheres to the esophagus of pigs stained the lymphatic pathway and sentinel nodes under ultraviolet light irradiation. This sentinel node detection system is considered to be useful for sentinel node detection especially for mediastinal nodes that show anthracotic pigmentation. It should be noted that this non-RI method is acceptable at any general medical facility.