关键词: 高强度聚焦超声, 组织变性, 分形截距, 支持向量机

Abstract: A method using Support Vector Machine（SVM） is presented to check biological tissue denaturation based on grey value and fractal intercept feature of mode B ultrasonic image.The digital subtraction is executed for mode B ultrasonic images obtained from fresh vitro pork or porcine liver before and after HIFU radiation，and then its image features are extracted and classified to find the concreting point of biological tissue.Through analyzing the statistical properties and errors of plentiful experimental data，the distinguishing effects of different characteristic parameters are compared.The results show that combining the fractal intercept with the average grey to construct SVM，the denaturation of biological tissue can be monitored better during HIFU therapy.

Key words: High Intensity Focused Ultrasound（HIFU）, tissue denaturation, fractal intercept, Support Vector Machine（SVM）