A central venous catheter comprises an ultrasound assembly. In one arrangement, the radiating member is used to remove a blockage from the central venous catheter. In another arrangement, inserting an ultrasound assembly into a central venous catheter. The ultrasound assembly comprises an ultrasound radiating member mounted on an elongate support structure. The method further comprises positioning the ultrasound assembly within the central venous catheter such that the ultrasound radiating member is adjacent to a deposited material formed on a portion of the central venous catheter. The method further comprises supplying an electrical current to the ultrasound radiating member to expose the deposited material to ultrasonic energy. The method further comprises passing a therapeutic compound through the central venous catheter to expose the deposited material to the therapeutic compound simultaneously with ultrasonic energy.