仿生物组织模型对高强度聚焦超声焦域影响的研究

Research on the Influence of Tissue Mimicking Phantom on Focal Area of HIFU

运用有限元仿真分析了生物组织声学特性对高强度聚焦超声(HIFU)焦域的影响,为HIFU治疗安全性和可靠性提供理论依据。应用超声传播方程以及频域有限元算法(FEM)仿真HIFU治疗过程中因组织特性和厚度引起的焦域变化,并制作仿生物组织模型,进行实验验证焦域变化,分析讨论组织特性和厚度对聚焦区域、位置的影响。结果表明:随着声速增大,焦域尺寸不变,焦域向换能器一侧靠近;随着厚度增大,焦域尺寸基本不变,如果组织声速大于水的声速,则焦域向换能器一侧靠近;如果组织声速小于水的声速,则焦域向远离换能器一侧移动。

The effect of acoustic characteristics of biological tissue on focal area of HIFU(high intensity focused ultrasound)was analyzed by finite element simulation,which provided theoretical basis for the safety and reliability of HIFU treatment.Ultrasonic propagation equation and frequency-domain finite element method(FEM)were applied to simulate the changes in focal area caused by the characteristics and thickness of tissues during HIFU treatment,and tissue mimicking phantoms were produced to verify the changes in focal area.The influences of characteristics and thickness of tissue on the focus area and location were analyzed and discussed.As a result,with the increase of acoustic velocity,the size of the focal region remained unchanged,and the focal region was closer to the side of the transducer.As the thickness increased,the size of the focal area basically remained unchanged.If acoustic velocity of the tissue was greater than that of the water,the focal area would be closer to the side of the transducer;if acoustic velocity of the tissue was less than that of the water,the focal area would move away from the transducer.