The present disclosure is directed to a method for treating tissue in a passageway within a body. The method may include positioning a medical device adjacent a treatment site in the passageway. The medical device may include an elongate member having a proximal end and a distal end, and an energy emitting portion positioned adjacent the distal end. The method may further include supplying an amount of energy from an energy source to the energy emitting portion. A first portion of the amount of the energy may be transmitted through the energy emitting portion to the tissue and a second portion of the amount of energy may be reflected from the energy emitting portion. The method may further include monitoring a signal corresponding to one of the first portion of the amount of energy and the second portion of the amount of energy.
