Sonodynamic therapy consisting of focused ultrasound and a photosensitizer causes a selective antitumor effect in a rat intracranial glioma model.

Unlabelled: In this study we sought to determine the optimal focused ultrasound acoustic conditions with photosensitizers for the ablation of experimental intracranial glioma in rats.

Materials And Methods: Normal rat brains were sonicated via a transducer placed on the dural surface with or without a prior intravenous injection of the photosensitizer Rose Bengal (50 mg/kg of body weight). The ultrasound intensity was varied to 25, 110 or 150 W/cm(2), and the duration of irradiation was 10 s, or 1, 3, or 5 min. In experimental intracranial gliomas, one week after inoculation of C6 rat glioma cells in the rat brain, the rat brain was sonicated through a 10 mm-diameter craniotomy.

Results: A selective antitumor effect against cerebral glioma while sparing normal brain tissues was achieved by sonodynamic focused therapy consisting of focused ultrasound at 25 W/cm(2) at 1 MHz for 5 min and Rose Bengal (50 mg/kg of body weight). The areas of tumors in sham-operated rats and in rats that received sonodynamic therapy without and with Rose Bengal at an intensity of 25 W/cm(2) for 5 min were 19.53+/-3.89, 10.64+/-2.21 and 3.01+/-1.74 mm(2), respectively. The tumor area was significantly smaller in the ultrasound therapy groups than in control non-treated animals (p=0.002). There was no significant temperature change in tumor tissues during sonication with 25 W/cm(2) at 1 MHz.

Conclusion: This is the first report to demonstrate the usefulness of sonodynamic therapy consisting of focused ultrasound and photosensitizer for the treatment of experimental malignant glioma.