Sonodynamic cancer therapy: a non-invasive and repeatable approach using low-intensity ultrasound with a sonosensitizer.

The low-intensity ultrasound that is used in clinical diagnoses, such as abdomen echo inspection, is a non-invasive treatment, and penetrates deeper into the body than light. Recently, sonodynamic therapy (SDT), which uses low-intensity ultrasound together with a sonosensitizer, has been developed for cancer therapy in applying such properties of ultrasound. So far, most sonosensitizers that have been developed are sensitive to light as well as ultrasound, implying that the shortcomings of photosensitizers used during photodynamic therapy, such as skin sensitivity, still need to be overcome in SDT. Some exceptions were, however, reported in recent studies in which sensitizers were activated mainly by ultrasound but not by light. Furthermore, recent in vivo studies have demonstrated that SDT with a sonosensitizer has a great potential as a non-invasive and repeatable treatment for cancer therapy.