Sonodynamic therapy with 5-aminolevulinic acid and focused ultrasound for deep-seated intracranial glioma in rat

Background: 5-Aminolevulinic acid (5-ALA) has already been applied clinically as a photosensitizer. In this study, sonodynamically induced selective antitumour effect of 5-ALA for deep-seated lesions was evaluated. Materials and Methods: First, normal rat brains were sonicated via a transducer placed on the dural surface to confirm safe acoustic conditions for normal rat brains. One week after inoculation of brains with C6 rat glioma cells, brains with/without administration of 5-ALA (100 mg/kg body weight) were sonicated. Results: Sonodynamic therapy (SDT) with 5-ALA and focused ultrasound (10 W/cm², 1.04 MHz, 5 min) achieved selective antitumour effect against deep-seated experimental glioma. Mean tumour sizes in the largest coronal section in sham-operated rats and rats receiving ultrasound with/without 5-ALA were 29.94±10.39, 18.32±5.69 and 30.81±9.65 mm², respectively. Tumour size was significantly smaller in the SDT group than in other groups (p<0.05). Conclusion: This experimental rat model showed that SDT appears to be useful in the treatment of deep-seated malignant glioma.