목적: Lymph node metastasis (LNM) is a most significant prognostic factor in a variety of cancer, including head and neck cancer. Small nests of cancer cells in sentinel lymph nodes often cannot be detected even in molecular imaging due to technical problems. To enhance the diagnosis of small LNM and to detect the pre- metastatic micro-environmental changes in the lymph node, we tried the multi-target (tumor and micro-environment) in-vivo imaging of LNM. 방법:We designed proteinase activity specific nano-probes to target tumor micro-environmental imaging. The specificity of novel nano- probes was tested in-vitro and in-vivo. Using these nano-probes we tried molecular imaging in an in-vivo model of LNM, and the signal intensity of targets was analyzed. In addition, conventional histology sections evaluated the diagnostic accuracy of in-vivo imaging. 결과:First, we demonstrated that MMP-9 (-2) was over-expressed in the sentinel lymph nodes and the level increased as LNM progressed. Using GFP tagged cancer cells and the injection of proteinase activity specific nano-probes we could detect the pre-metastatic and metastatic lymph nodes via in-vivo imaging. The diagnostic specificity was proved to be optimal by measuring the signal intensity, and the findings were validated by histology evaluation. 결론:In-vivo imaging using proteinase activity can detect the pre- metastatic and micro-metastatic lymph nodes consistently, which could be useful to target the metastasis-prone sites and to reduce recurrence.