THE INFLUENCE OF SODIUM PENTOBARBITAL ANESTHESIA ON in vivo PHOTODYNAMIC THERAPY

The use of sodium pentobarbital anesthesia 50 jig gm −1 during localized photodynamic therapy (PDT) was examined in C57BL/6 mice transplanted with the pigmented B‐16 melanoma. A 10 mg kg −1 i.p. injection of Photofrin II was administered 24 h prior to light exposure (630 nm, 150 mW, cm −2 , 300‐500 J cm −2 ). Separate groups of mice were utilized to monitor tumour temperature and PDT tumor response. Core tumor temperatures decreased by approx. 10 o C following sodium pentobarbital administration. Tumor responses were determined by documenting the percentage of treated animals without tumor recurrences for a period of 50 days following PDT. Superior PDT induced tumor responses were obtained in control (non‐anesthetized) mice following light doses of 400 and 500 J cm −2 . The results of this study indicate that sodium pentobarbital can induce a protective effect on B‐16 melanomas treated with PDT.