A medical device, system and method are provided for thermal medical treatment. A medical device for cryogenic treatment may include a tip and a thermal guard or shield. The tip may be at a distal end of a catheter shaft, having a distal surface and lateral surfaces. The thermal guard may be coupled to the catheter proximal of the distal tip, surrounding the longitudinal axis and exposing the distal surface, to resist heat transfer from body fluids to the lateral surfaces of the tip. An efficiency of heat transfer from selected tissue to be treated to the distal surface of the cryogenic tip is thereby increased.