Feasibility Animal Study of Novel ICG Sentinel Node Detection Technique in Head and Neck Region

Objectives:Sentinel node biopsy (SNB) allows head and neck surgeons to avoid unnecessary neck dissection. The popular SNB method using radioisotope (RI) has some drawbacks, such as the strict legal regulations for RI use in Japan. Recently, the SNB technique using real time indocyanine green (ICG) fluorescence image has become prevalent in breast cancer testing. Some reports demonstrated improved detection sensitivity with this method. However, the major problem of ICG method is its quick migration through the lymphatic system, which results in a limited diagnostic time window and detection of downstream subsequent nodes. To overcome this problem, we modified the ICG detection method by making ICG-colloid and demonstrated the feasibility of this technique in a mouse model.Methods:ICG-colloid was formed by mixing ICG and phytate colloids, which are commercially available as a kit for 99mTc-radiocolloid. Twenty microliters of ICG or ICG-colloid was injected into the tongue of a nude mouse, and the fluoresce...