A device for treating esophageal target tissue comprises a catheter, a balloon and a refrigerant delivery device. The catheter has a distal portion and a refrigerant delivery lumen. The balloon is mounted to and the refrigerant delivery device is coupled to the distal portion. The refrigerant delivery device comprises a chamber with the refrigerant delivery lumen opening into the chamber, a refrigerant delivery opening fluidly coupled to the balloon interior, and a distribution passageway fluidly coupling the chamber and the refrigerant delivery opening. A refrigerant is deliverable through the refrigerant delivery lumen, into the chamber, through the distribution passageway, through the refrigerant delivery opening and into the balloon interior so to place the balloon into an expanded, cooled state so that the balloon can press against and cool esophageal target tissue. The medical device may include means for sensing a leak in the balloon.
