A cryogenic medical device is provided, including a catheter body defining a proximal portion and a distal portion； a expandable treatment element on the distal portion of the catheter body； a plurality of granules disposed within the expandable treatment element； an encapsulation member surrounding the plurality of granules, the encapsulating member having a plurality of selectable geometric configurations； and an actuator element coupled to the encapsulation member for the selective adjustment thereof. A method for thermally treating a selected region of tissue is also provided.
