During an ablation procedure, such as ablation of the left ventricle of the heart, thermal damage to adjacent structures is avoided by this method. An ultrasound probe is placed within the esophagus near the left atrium, or placed at other locations sufficiently close to the ablation site to image tissues to be protected from excessively high (or low) thermal energy during ablation. The ultrasound probe reflected signal gathered by a sensor thereof is analyzed. Using one or more algorithms, this signal analysis identifies changes in speed of sound of transmitted and received sound waves and correlates the speed of sound changes to changes in temperature of the associated tissues and the result is displayed. Such ultrasound thermometry is used to monitor temperature of tissues surrounding the ablation site to minimize potential for thermal damage thereto. The method also evaluates motion occurring near the ablation site, correcting for such motion.