Patent ID: 8226629

Claim:
A method of treating an occlusion at a treatment site within a patient's vasculature comprising: providing an ultrasonic catheter having a distal region, a proximal region opposite the distal region, a fluid delivery lumen having at least one opening in the distal region, and an ultrasound radiating member positioned within the distal region; positioning the ultrasonic catheter at the treatment site, such that at least a portion of the distal region is within the occlusion; passing a therapeutic compound through the fluid delivery lumen such that the therapeutic compound is delivered to the treatment site; and emitting ultrasonic energy from the ultrasound radiating member operating at a frequency of between 500 kHz and about 20 MHz, wherein the emitted ultrasonic energy has an amplitude that is periodically varied between a low amplitude and a high amplitude, a pulse average power exclusive of the low amplitude periods of between approximately 0.01 watts and approximately 20 watts, a high amplitude pulse duration of between approximately 1 millisecond and approximately 50 milliseconds, a high amplitude pulse repetition rate of between approximately 5 hertz and approximately 150 hertz, and an in situ intensity at an energy radiating surface of between approximately 20 watts in −2 and approximately 90 watts in −2 .