Real-time Mapping Of Rat Lymph Nodes Basin By Quantum Dots

Objective:To develop a real-time imaging method for identifying rat lymph nodes basin with quantum dots.Method:15 rats were divided into three groups, and received quantum dots injection at the subserosal layer in the lesser curvature of gastric antrum, the subcutaneous tissue of upper and lower extremities respectively. Afterward, draining lymphatic channels and lymph nodes were visualized with a near-infrared fluorescence imaging system. Dissection was performed under real-time image guidance, and then histological examination was required to confirm the presence of lymph nodes.Twelve rats were divided into two groups, the first group received quantum dots injection while the second received saline injection at the same site. The two groups underwent two weeks'observation to find whether there was any abnormality between them. The distribution of quantum dots was measured by inductively coupled plasma-mass spectrometry.Results:lymph nodes were visualized as soon as 15 minutes in the axillary fossa and groin after quantum dots injection at the subcutaneous of upper and lower extremities. However, the quantum dots did not transferred to the contralateral parts in the whole process. Quantum dots were distributed to the greater curvature of stomach 15minutes and in the back of stomach 30 minutes after the injection at the stomach. The results of Cadmium assay showed that quantum dots mainly accumulated in the livers, spleens and kidneys of the rats. No apparent toxicity was seen during two weeks observation.Conclusion:Near-infrared fluorescence imaging of lymph nodes with quantum dots is a novel and reliable real-time technique to assist identification and resection of lymph nodes.