A novel endoscopic fluorescent clip for the localization of gastrointestinal tumors.

Accurate tumor localization is essential for gastrointestinal surgery, especially in cases of early cancer. This study was designed to develop a novel fluorescent clip for rapid and exact visualization of tumor sites. A transparent polymer matrix containing highly bright fluorochromes was coated on the front end of endoscopic clips. The fluorescent clips were placed on the mucosal surface of a porcine colon and stomach, and the operator then attempted to identify the fluorescent clips from the outer serosal side of the colon and stomach. A 532-nm diode laser and filter glass were used for visualizing the fluorescence signals through the colonic tissue. A 650-nm diode laser and a digital charge-coupled device (CCD) camera equipped with a bandpass emission filter were used for the imaging of the fluorescent clips through the thick stomach tissue. When a green light from a 532-nm diode laser (power density=0.35 mW/cm2) was applied on the serosal surface of the porcine colon, we could identify all clips that had been placed endoscopically on the mucosal surface of the inner colonic wall. By using the light from a 650-nm diode laser (power density=0.7 mW/cm2), we identified all fluorescent clips through the stomach wall in real time. Similar results were also obtained with the filtered xenon lamp. An endoscopic fluorescent clip can be useful for the rapid and exact localization of tumors, and this technique can also be useful during laparoscopic surgery.