NOVELTY - The system has a device configured for introduction into an aorta (20) of a heart (10) of a patient and positioning proximate to origins of great vessels i.e. innominate artery (12), left carotid artery (14) and left subclavian artery (16) to head of the patient. A catheter is capable of being curved to follow curvature of the aorta at the origins. Ultrasonic energy emitters (60) carried by the device delivers ultrasonic energy at therapeutic levels sufficient to divert material e.g. fibrin, present in blood that flows through the aorta such that the material moves away from the origins.    USE - System for directing ultrasonic energy through blood flow in an aorta of a patient proximate origins of great vessels i.e. innominate artery, left carotid artery and left subclavian artery, to head of the patient to divert a material such as particulate ,air bubble, embolic material such as blood clot and fragments of clot-like material e.g. platelet emboli, fibrin, atherosclerotic debris, foreign materials introduced into the circulation, gaseous material and infected debris occurring when a heart valve is infected, in the blood flow from the origins of the vessels.    ADVANTAGE - The emitters allow the development of strategies to variably adjust the power to each emitter and the sequence of powering to optimize material deviation or deflection based on the expected size of particles or material in the patient, thus optimizing energy consumption for a given level of brain protection.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a method of directing ultrasonic energy in a region proximate the origins of the great vessels to the head of a patient to divert material in the blood flow away from the origins    (2) an implantable fuel cell for use with an ultrasonic energy emitting device implantable within the cardiovascular system of a patient    (3) a vascular graft for providing protection against embolus traveling to the brain of a patient    (4) an implant for cooling blood in a patient.    DESCRIPTION OF DRAWING(S) - The drawing shows a partially sectioned perspective view of a human heart and blood vessels, and an ultrasonic energy emitting catheter device entering in the left subclavian vein and extending toward the superior vena cava.    Heart (10)    Innominate artery (12)    Left carotid artery (14)    Left subclavian artery (16)    Aorta (20)    Ultrasonic energy emitters (60)    Catheter (62)