En-Li Lin1, Hsu-Hsia Peng2, Teng-Yi Huang1, Yu-Shun Wang1, Wen-Shiang Chen3, Wen-Yih Isaac Tseng4
1Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan; 2Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan; 3Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taipei, Taiwan; 4Center for Optoelectronic Biomedicine, Medical College of National Taiwan University, Taipei, Taiwan
High intensity focused ultrasound (HIFU) provided tissue destruction or tumor ablation in a non-invasive way, which was one of the promising thermotherapy treatments. Our group has shown that magnetization-transfer-prepared (MT) gradient-echo sequence is a practical tool to simultaneously monitor the temperature change and MT contrast during HIFU energy transmission. Furthermore, we improved the previous experiment with a movable HIFU transducer mimicking the procedure of the MRIgFUS thermotherapy by multi-spot heating experiment and the efficiency of the MT/temperature measurement mapping was demonstrated in consecutive time. We can notice that the temperature rose after heating and fell gradually after turning off HIFU power, whereas the MT effect retained after heating. However, the MTR mapping was compatible to the widely used PRF-thermometry, which was to detect the tissue damage. In conclusion, this method that can monitor temperature changes as well as the level of MT change opens a potentially useful window to observe the tissue coagulation due to the HIFU power transmission in real-time.