A comparison between argon-dye and excimer-dye laser for photodynamic effect in transplanted mouse tumor.
Photodynamic therapy (PDT) utilizing a hematoporphyrin derivative (HpD) as a sensitizer has become a viable option for the local treatment of neoplastic disease. The argon-dye laser system is commonly used as a light source in this treatment modality. The excimer-dye laser, on the other hand, delivers high-energy red light in a pulsatile fashion. In this investigation, we treated BALB/c mice bearing mouse kidney sarcoma cell tumors with PDT using HpD at the dose of 5 mg/kg body weight as a photosensitizer and either a standard argon-dye laser or the pulsatile excimer-dye laser as the light source. At equal light energy doses (50 J/cm2), necrotic changes at depths averaging 4 mm from the tumor surface were obtained with the argon-dye laser (200 mW power output) while tumor necrosis at depths exceeding 15 mm from the tumor surface was obtained using the excimer-dye laser (6 mJ/pulse, 5 Hz). To determine the best conditions for photoirradiation with the excimer-dye laser, tumor-bearing mice were treated with different total light doses (10, 30 and 50 J/cm2), dose rates (1, 3 and 6 mJ/cm2), and frequencies (5, 15 and 50 Hz) of light exposure. Our results indicate that the optimal effects obtained with the excimer-dye laser are related to the total light dose used and the dose rate, but not to the frequency of light exposure.
Okunaka
T
T
Department of Surgery, Tokyo Medical College.
Kato
H
H
Konaka
C
C
Sakai
H
H
Kawabe
H
H
Aizawa
K
K
D000818:Animals; D005260:Female; D006414:Hematoporphyrin Photoradiation / Q000379:methods*; D007680:Kidney Neoplasms / Q000188:drug therapy*; D053685:Laser Therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D012513:Sarcoma, Experimental / Q000188:drug therapy*