1Department of Physiology, Fukuoka University School of Medicine, 2Department of Anatomy, Fukuoka University School of Medicine, 3First Department of Internal Medicine, Fukuoka University School of Medicine
Purpose. To determine if low-intensity ultrasound (US) in combination with porfimer sodium (Pf) can kill leukemic tumor cells in vivo. Materials and Methods. Porfimer sodium (100 μg) was administered peritoneally to mice (BDF 1) in which L-1210 leukemia cells had been implanted. The mice were then irradiated with ultrasound (47 kHz, 5×104 Pa) for 5 minutes. Control mice were separated into a porfimer sodium administration alone group, an ultrasound irradiation alone group, and a neither porfimer sodium administration nor ultrasound irradiation group, and the survival times of the groups were compared. Results and Discussion. Average survival time was 15.7±1.8 (mean±SD) days in the group treated with neither porfimer sodium administration nor ultrasound irradiation, 14.3±1.6 days in the porfimer sodium administration alone group, and 15.2±2.5 days in the ultrasound alone group. The group treated with both porfimer sodium administration and ultrasound irradiation (22.2±8.8 days) survived significantly longer than those in the control groups. This result suggests that the longer survival resulted from the greater tumor-cell killing effect of the combination of ultrasound and porfimer sodium than of porfimer sodium or ultrasound alone. Conclusion. Administration of porfimer sodium and ultrasound irradiation to tumor implanted mice significantly extended survival time.