Abstract
Hematoporphyrin derivative photodynamic therapy is evolving as a local treatment for neoplastic disease. Generally argon dye or gold vapor lasers have been used as light sources. We employed an excimer dye laser in anticipation of greater effects. The BALB/C mice receiving i. v. injections of HpD in dose of 5 mg/kg body weight were used in this study. At first, the photodynamic effects of an argon dye laser and excimer dye laser were compared at the same energy in terms of the morphological changes in transplanted tumor of m-KSA cell in the following study. Next, to determine the best conditions for irradiation by the excimer dye laser, tumor-bearing mice were treated with different total doses (10, 30, 50 J/sq cm), dose rates (1, 3, 6 mJ/sq cm), and frequencies (5, 15, 30hz) of light exposure. We obtained necrotic changes in the tumor at depths of up to only 4 mm on average using the argon dye laser (200 mw × 250 sec, 50 J/sq cm). On the contrary, tumoral necrosis at the depth of over 15mm was obtained with the excimer dye laser (6 mJ/puls 5hz 50J/sq cm). Our results showed that the effects of excimer dye laser are related to total power dose and rate dose but not to frequency.
