Background: Malignancies affecting the central nervous system are intractable to conventional therapies thereby requiring an alternative strategy, such as ultrasound irradiation.
Materials and methods: We originally designed a transducer for intracranial insonation and investigated the effect of 210.4 kHz ultrasound on malignant glioma cells.
Results: The insonation of 2.61 W/cm2 effectively disrupted the malignant cells. This effect was reinforced by the echo-contrast agent, Levovist. The condition was applied to tumor-bearing animals and external insonation inhibited subcutaneous tumor growth. It also repressed the growth of intracranially implanted tumors and prolonged survival of the animals. When Levovist was stereotactically injected into the tumors, the effect of insonation was significantly enhanced.
Conclusion: A neuronavigation system or stereotactic device has been used commonly for patients with brain tumor. Administration of combination therapy consisting of insonation and a local echo-contrast agent will have a role in improving the treatment for malignant gliomas.