Role Of Near-infrared Imaging Technology And Its Effect In Tracing Gastric Cancer

2.1 AIMTo investigate the proper dose of Indocyanine Green (ICG) for the optical imaging of Gastric tumors xenograft in nude mice.Selection of best time for optical imaging in which gastric tumors are visible in Near-infrared light using optical imaging system (SPECTROPEN)To determine the size of the smallest possible tumor visible in NIR light using optical imaging system.2.2 METHODS:MKN-45 human gastric cell line cultured in a medium. Nude mice models were subcutaneously injected with the MKN-45 cells to establish xenograft tumor bearing animal models. Tumor bearing nude mice were injected with different doses of ICG 0.25mg/kg,0.5mg/kg,1 mg/kg, 2mg/kg and 4mg/kg diluted in 5% PBS solution to evaluate the proper dose. Tumor bearing nude mice were imaged using optical imaging system at different time intervals to get the high fluorescence time interval. Cultured MKN-45 cells were injected subcutaneously in nude mice for detection of the smallest possible extent of gastric tumor visible in NIR light of SPECTROPEN optical imaging system.2.3 RESULTS:ICG (indocyanine green) doses of 0.25mg/kg,0.5mg/kg,0.25mg/kg and 1 mg/kg showed very poor fluorescence intensity under Near infrared light as the ICG upload to the tumors with these low doses were not possible at all or with a very low fluorescence intensity under Near infrared light. Dose of 2mg/kg was observed to be the best specific dose in which the tumor showed excellent fluorescence. The smallest possible tumors which we detected using optical imaging system using near infrared light were 3.0mm3 and 5.0mm3 with a high tumor to background ratio.2.4 CONCLUSION:Low doses below 2mg/kg injected into nude mice were not suitable for fluorescence under near-infrared as uptake of ICG into the tumor under these doses were very poor. Time range for the imaging of tumors under NIR optical imaging was 5th to 6th day after intravenous injection of ICG in the tail vein section of the nude mice. The smallest tumor which the optical imaging system detected was 3.0mm3...