A method for delivering ultrasound energy to a patients intracranial space includes the steps of forming a hole in a patients skull, locating an ultrasound transmitter near or into the hole, and transmitting ultrasound from the transmitter into the intracranial space, wherein the Mechanical Index of ultrasound energy traveling through cerebral tissue in the intracranial space is less than 1.0, the power intensity delivered to a target tissue in the intracranial space is greater than 50 mW/cm2 and less than 200 mW/cm2, and the frequency of the transmitted ultrasound is within the range between 500 kHz and 2 MHz. Microbubbles, aspirin, both microbubbles and aspirin, and a mixture of microbubbles and aspirin, can also be delivered into the intracranial space.
