Abstract
Therapeutic ultrasound has mainly been applied for its thermal or mechanical effects. Medical applications of high-energy ultrasound to ablate cancers are now under investigation. 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 a carrier/enhancer of drugs has added a whole new dimension in therapeutic ultrasound. Progress in the past decade from the pharmaceutical side has further added much excitement in applying this technology especially in the field of molecular biology, gene therapy and regenerative medicine. Alternatively from the device side, therapeutic ultrasound catheters and extracorporeal ultrasound probes are under development specifically for this purpose, some already in clinical trials. Non-invasive focused ultrasound in conjunction with anti-cancer drugs may help to reduce tumor size, lessen recurrence as well as reduce 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, advance in molecular imaging has also initiated great expectations in applying ultrasound for both diagnosis and therapy at the same time. Microbubbles or nanobubbles targeted at the molecular level will permit medical doctors to make a final diagnosis of a disease by ultrasound and immediately proceed to therapeutic ultrasound.
