Neurologists have built an ultrasound device which uses focused sound waves to destroy stroke-causing blood clots in brains. The procedure is non-invasive - requiring no drugs or surgery - and is already being tested on patients.
The machine and procedure allows doctors to "surround the head with an array of transducers that can focus ultrasound beams on a single spot in the brain without damaging the skull." This means that diseased tissue could be destroyed without any collateral damage or risky surgery. [Technology Review via Pop Sci]