Abstract: A method for controlling a system, comprising repeatedly monitoring a resonant frequency of a system that includes an ultrasonic transducer, wherein the ultrasonic transducer is powered by an ultrasonic generator and is configured to drive a device at a predetermined level of resonant frequency, and wherein the ultrasonic generator includes a controller configured to monitor operational parameters of the system; detecting a change in resonant frequency based on a comparison of the monitored resonant frequency against a predetermined threshold for resonant frequency; inferring a system-use criteria based on the detected change in the resonant frequency; and adapting system control by using the controller to alter the operational parameters of the system based on the inferred use criteria.

Abstract: A medical device, comprising a catheter comprising an end-effector, wherein the end-effector further comprises a proximal portion; and a flexible distal portion, wherein the distal portion further includes a window formed therein; and a flexible ultrasonic waveguide disposed within the end-effector, wherein the waveguide includes an active zone that extends through the window; and a mechanism for bending the waveguide, bending the distal portion, or bending both the waveguide and the distal portion, wherein the mechanism permits desired positioning of the waveguide within a lumen.