Development of a New Laparoscopic Detection System for Gastric Cancer Using Near-Infrared Light-Emitting Clips with Glass Phosphor

Laparoscopic surgery is now a standard treatment for gastric cancer. Currently, the location of the gastric cancer is identified during laparoscopic surgery via the preoperative endoscopic injection of charcoal ink around the primary tumor; however, the wide spread of injected charcoal ink can make it difficult to accurately visualize the specific site of the tumor. To precisely identify the locations of gastric tumors, we developed a fluorescent detection system comprising clips with glass phosphor (Yb3+, Nd3+ doped to Bi2O3-B2O3-based glasses, size: 2 mm × 1 mm × 3 mm) fixed in the stomach and a laparoscopic fluorescent detection system for clip-derived near-infrared (NIR) light (976 nm). We conducted two ex vivo experiments to evaluate the performance of this fluorescent detection system in an extirpated pig stomach and a freshly resected human stomach and were able to successfully detect NIR fluorescence emitted from the clip in the stomach through the stomach wall by the irradiation of excitation light (λ: 808 nm). These results suggest that the proposed combined NIR light-emitting clip and laparoscopic fluorescent detection system could be very useful in clinical practice for accurately identifying the location of a primary gastric tumor during laparoscopic surgery.

Development of New Glass Phosphor for Multimodal Artifact Metrics Applicable for Ceramics

Multi-modal artifact metrics, an anti-counterfeiting technique, was created based on the concept of multi-modal biometrics and can improve the certainty of authenticity and difficulty of counterfeiting as it gives more than one characteristic information to the artifact. In order to give two optical feature information (hue and emission intensity) into the ceramic products, we develop a new type of glass phosphor. This is a novel approach, since up-conversion phosphors with different color hue and emission intensity at each observation point on the material by optical excitation have never been reported. By welding a small amount of phosphor powder onto the surface of the ceramics, the certainty of authenticity and difficulty of counterfeiting would be enhanced than an existing method we proposed. Based on our experiment, we found appropriate blending ratio of two types of rare earth oxides for making glass phosphor with above-mentioned emission characteristics. These characteristics could be seen in other glass phosphor created by different base material glass with same blending ratio.