Chromophore-enhanced 805 nm laser therapy for gastrointestinal neoplasia

Background: A new technique of 805 nm semiconductor diode laser–tissue interaction potentiation using indocyanine green (ICG) as an exogenous chromophore has been assessed for use in the palliation of advanced gastrointestinal malignancy. Materials and Methods: The tissue effects of ICG potentiated 805 nm laser were assessed bothin-vivo using rat stomach and colon, and in vitro using normal and neoplastic human gastric and colonic mucosa.Results: Intravenous ICG did not potentiate the laser–tissue effects of the 805 nm laser in in-vivo studies. Local techniques of ICG application (submucosal injection±surface painting of 0.1% ICG solution) enhanced the total depth and diameter of laser induced thermal injury in all in-vitro tissues. Without ICG enhancement thermal tissue injury was minimal in normal gastric and colonic mucosa. Conclusion: Local techniques of ICG application enhance laser induced thermal injury in normal and neoplastic gastric and colonic mucosa. This may permit targeting of 805 nm laser–tissue effects with minimal collateral damage during endoscopic laser palliation of advanced gastrointestinal malignancy.