A catheter assembly for locating an object of interest (e.g., an anatomical region such as a muscle, nerve bundle, etc.) is provided. The catheter assembly includes a catheter having a catheter body defining a proximal end and a distal end； a transducer located at the distal end of the catheter； one or more transducer wires extending from a proximal end of the transducer towards the proximal end of the catheter； and a length of tubing surrounding the catheter, the transducer, and the one or more transducer wires, wherein the length of tubing has a proximal portion and a distal portion, wherein the proximal portion surrounds the one or more transducer wires and the distal portion surrounds the transducer, wherein the proximal portion includes a conductive filler.
