An esophageal deflection device includes an elongate outer tube that has a natural curved deflection at a position that corresponds to a targeted esophagus region for deflection. The outer diameter of the outer tube is substantially matched to an inner diameter of the esophagus to closely contact the esophagus wall, or is at least half of the inner diameter, or is smaller and includes suction ports for drawing the esophagus wall inward. An insertion rod or tube includes a portion that is stiffer than the curved deflection, and slides into the elongate outer tube to straighten the tube and can serve to guide the deflection device into an esophagus. Subsequent withdrawal of the insertion tube or rod will allow the curved deflection to return to its natural shape and deflect the targeted region of the esophagus. A three-dimensional array of temperature sensors can be disposed near an outer surface of the elongate outer tube.