CHROMOPHORE-ENHANCED IN-VIVO TUMOR-CELL DESTRUCTION USING AN 808-NM DIODE-LASER

Rat mammary tumors were treated using an 808-nm diode laser in a power range of 3-15 W. Photothermolysis was selectively enhanced by the chr omophore indocyanine green (ICG), which has an absorption peak corresp onding to the laser wavelength. ICG, injected into neoplastic tissues 24 h before laser exposure, was retained in sufficient quantity to pro duce a strong photothermal reaction. With appropriate laser power and adequate irradiation duration, laser energy could inflict severe photo thermal damage to the entire targeted tumor tissue while leaving the s kin and other interdicted tissue undamaged. Higher laser powers (10-15 W) produced more surface damage that limited light transmission and a s a result gave rise to reduced regions of thermal destruction. Post-t reatment observation revealed the survival of numerous tumor cells. Th is finding questions the long term efficacy of the photothermal effect of a single treatment using the combination of the ICG and the diode laser, particularly in the absence of other modalities.