High-intensity ultrasound is being used to destroy tumors rather deep in the brain. How is this possible without damaging the tissue above?

Does this mean that it is possible to create something like an interference pattern of sound waves that “focuses” the energy at a specific point, distant (on the level of centimeters in the above case) from the device that generates them?How does this work? via /r/askscience https://ift.tt/2FY3CB5