The authors developed a new photodynamic therapy using phoephorbide-A and Nd: YAG Laser (acoustic Q switch). In vitro studies were done using rat T 9 glioma and human glioma cells (T 98 G). The survival rates after PDT at 37.0°C were 68.8% (T 9, 20 min) and 0.4% (T 98 G, 5 min). Histological examination of irradiated rat T 9 tumor showed wide vascular damage just after PDT. This portion eventually became necrotic in one week. Acuostic Q switched Nd: YAG Laser penetrated deeper into the cat brain tissue and showed flat light distribution.
