Sonodynamic therapy

Recently, there have been numerous reports on the application of non-thermal ultrasound energy for treating various diseases in combination with drugs. Furthermore, the introduction of microbubbles and nanobubbles as carriers/enhancers of drugs has added a whole new dimension to therapeutic ultrasound. Non-thermal mechanisms for effects seen include various forms of energy due to cavitation, acoustic streaming, micro jets and radiation force which increases possibilities for targeting tissue with drugs, enhancing drug effectiveness or even chemically activating certain materials. Examples such as enhancement of thrombolytic agents by ultrasound have proven to be beneficial for acute stroke patients and peripheral arterial occlusions. Non-invasive low intensity focused ultrasound in conjunction with anti-cancer drugs may help to reduce tumor size and lessen recurrence while reducing severe drug side effects. Chemical activation of drugs by ultrasound energy for treatment of atherosclerosis and tumors is another new field recently termed as "Sonodynamic therapy". Lastly, advances in molecular imaging have aroused great expectations in applying ultrasound for both diagnosis and therapy simultaneously. Microbubbles or nanobubbles targeted at the molecular level will allow medical doctors to make a final diagnosis of a disease using ultrasound imaging and then immediately proceed to a therapeutic ultrasound treatment. (C) 2008 Elsevier B.V. All rights reserved.