Summary: | 碩士 === 國立臺灣大學 === 醫學工程學研究所 === 93 === Because of less invasiveness, focused ultrasound has become apromising tool for localized tumor therapy. Clinical tests of breast tumorablation, however, have shown that the main problems are long treatment time and rib heating. In this study, a target rotating system based on split-focused ultrasound transducer is constructed, and an appropriate heating strategy is designed to cooperate with the system. The transducer is oriented in an angle of 45 degrees to heat the target via temporal switching from separate paths. The aims of the strategy are to increase the therapeutic efficiency and to alleviate rib heating. For targets with a distance more than 2cm from the rib,the results of simulation demonstrated that the strategy could accomplish heating of target with volume 8cm3 without cooling-time interval,and the temperature of the rib was maintain below 50°c during heating process.The distribution of thermal dose tended to be intact and dense after the treatment.Furthermore,the simulation results were also examined by phantom experiments.Both the heating pattern and measured temperature rise of bones matched the simulation results well.
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