Abstract
Endoscopic diode laser ablation using indocyanine green (ICG) as a photosensitizer was studied to develop the treatment for early gastric cancer. The ICG solution with Img/ml concentration was administrated to the submucosal layer. When 25W diode laser emitted with 0.2seconds repeated irradiation with 0.2seconds interval, the submucosa was not ablated because of mucosal carbonization. Histology of the specimen in this case revealed total submucosal coagulation without any proper muscle damage. When the irradiation condition was 1 seconds irradiation repeated with foot switch control with an output of 25W, the mucosa was removed and submucosa was ablated progressively. The proper muscle was intact from thermal and direct laser injury as far as the ICG containing submucosal tissue remained. We could control the ablated depth by the endoscopic observation of the ablated surface. We think our therapy might be useful for the early gastric cancer with/without the submucosal invasion, in particular inoperable case.
