Due to the enhanced permeability and retention effect (EPR) or other mechanisms, ICG accumulates largely in the metastases lesions or normal issues to "light up" the targeted tumors or tissues surrounding tumors showing a "signal-to-background" ratio. Relying on this, ICG has been introduced to real-time intraoperatively differentiate tumor lesions or metastases from adjacent tissues in nephrectomy , bullectomy , lung segmentectomy , hepatic resections of liver metastases and hepatocellular carcinoma (HCC) .