A pulmonary treatment catheter and handle system including a catheter assembly with insertion tube coupled to a handle assembly. The system is further removably coupleable to a delivery device, such as a flexible bronchoscope or endoscope, having a port for coupling the handle assembly thereto, and a working channel in communication with the port for delivering the catheter assembly through the delivery device and into a body lumen. Optionally, a port channel of the port can be collinear with the working channel of the delivery device. The catheter assembly, handle assembly, and delivery device cooperate together to facilitate delivery and positioning of a catheter electrode in a treatment site, such as an airway, conduit, or vessel for treatment of the tissue, while minimizing damage to portions of the catheter assembly, the delivery device, or both.
