Noninvasive Thermometry in High-Intensity Focused Ultrasound Ablation.

High-intensity focused ultrasound (HIFU) is emerging as an effective and promising treatment modality for the formation of coagulative necrosis inside the cancer/tumor noninvasively. To guarantee the efficacy and efficiency of HIFU ablation, the temperature field and consequent thermal dose should be monitored accurately in a high temporal and spatial resolution in real time. However, because of the significant variations of the tissue properties and deep penetration of HIFU beam, especially in the abdominal application, noninvasive thermometry is a very challenging topic, which may hamper the wide acceptance of HIFU by physicians worldwide. In this article, currently available thermometry techniques are reviewed, and their translation from hyperthermia range to the higher temperature for irreversible lesion production is discussed. With the technology improvement and/or development of new approaches, the performance of noninvasive thermometry may meet the clinical requirements.