title: Novel Indocyanine Green-Phytate Colloid Technique for Sentinel Node Detection in Head and Neck: Mouse Study.
abstract: Sentinel node navigation surgery using real-time, near-infrared imaging with indocyanine green is becoming popular by allowing head and neck surgeons to avoid unnecessary neck dissection. The major drawback of this method is its quick migration through the lymphatics, limiting the diagnostic time window and undesirable detection of downstream nodes. We resolved this problem by mixing indocyanine green (ICG) with phytate colloid to retard its migration and demonstrated its feasibility in a nude mouse study.
  
  
  
  Experimental prospective animal study.
  
  
  
  Animal laboratory.
  
  
  
  Indocyanine green at 3 concentrations was tested to determine the optimal concentration for sentinel lymph node detection in a mouse model. Effect of indocyanine green with phytate colloid mixture solutions was also analyzed. Indocyanine green or mixture solution at different mixing ratios were injected into the tongue of nude mice and near-infrared fluorescence images were captured sequentially for up to 48 hours. The brightness of fluorescence in the sentinel lymph node and lymph nodes further downstream were assessed.
  
  
  
  Indocyanine green concentration >50 μg/mL did not improve sentinel lymph node detection. The addition of phytate colloid to indocyanine green extended the period when sentinel lymph node was detectable. Second echelon lymph nodes were not imaged in mice injected with the mixture, while these were visualized in mice injected with indocyanine green alone.
  
  
  
  This novel technique of ICG-phytate colloid mixture allows prolonged diagnostic time window, prevention of downstream subsequent nodes detection, and improved accuracy for the detection of true sentinel lymph nodes.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan kojaraki@ndmc.ac.jp.
authors.forename: Koji
authors.initials: K
authors.lastname: Araki
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Mizokami
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tomifuji
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Ohnuki
authors.affiliation: Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Izumi O
authors.initials: IO
authors.lastname: Umeda
authors.affiliation: Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwa, Chiba, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujii
authors.affiliation: Department of Radiology, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kosuda
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, National Defense Medical College, Tokorozawa, Saitama, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Shiotani
mesh_terms: D000818:Animals; D003102:Colloids; D004195:Disease Models, Animal; D005240:Feasibility Studies; D005453:Fluorescence; D006258:Head and Neck Neoplasms / Q000473:pathology*; D007208:Indocyanine Green / Q000378:metabolism*; D051379:Mice; D010833:Phytic Acid / Q000378:metabolism*; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*
chemical_list: D003102:Colloids; D010833:Phytic Acid; D007208:Indocyanine Green
keywords: head and neck cancer; indocyanine green; phytate colloid; sentinel node navigation surgery