In one embodiment of the present invention, an ultrasound catheter system comprising a catheter having at least one ultrasonic element； and a control system configured to generate power parameters to drive the ultrasonic element to generate ultrasonic energy is provided. The control system is configured to provide an ultrasonic pulse with a high pressure gradient with respect to time and/or distance. In another embodiment, a method of enhancing delivery of a therapeutic compound comprising delivering the therapeutic compound to a treatment site in a patient； and exposing the treatment site to an ultrasonic energy generated by an oscillating electrical signal pattern having a rise or fall rate greater than an sinusoidal pattern for the same amplitude and frequency is provided.
