One limitation to the efficacy of systemic chemotherapy in the treatment of brain tumors is the blood-brain barrier (BBB). To enhance the delivery of systemically administered chemotherapy agents to brain tumors, an implantable ultrasound device was developed that can be used to temporarily disrupt the BBB. Delivery of pulsed ultrasound, in combination with an ultrasound contrast agent, has been shown to temporarily disrupt the BBB for a duration of more than 6 hours and allow for a significantly increased penetration of systemically administered chemotherapy drugs in pre-clinical studies.