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数值仿真不同治疗参数条件下高强度聚焦超声(high intensity focused ultrasound,HIFU)可治疗区域的变化,对HIFU治疗剂量的确定具有重要的指导意义。本文采用Westervelt方程的近似式,结合Pennes生物热传导方程,以离体猪肝组织为例,在考虑组织声学特性对HIFU焦域温度场影响的条件下,通过时域有限差分法(finite difference time domain,FDTD)对HIFU焦域温度场进行仿真研究。研究结果表明,照射时间越长,组织声学特性的影响就越明显;焦点处的最高温升相同时,可治疗区域的大小差异较小;声强越大,形成可治疗区域所需的时间也越短;当声强一定时,随着照射时间的增加,可治疗区域的长、短轴长度均呈非线性增加;在相同可治疗区域的长轴或短轴长度一定时,输入声强和照射时间呈负相关。
Numerical simulation of different intensity of treatment with high intensity focused ultrasound (HIFU) treatment of regional changes, HIFU treatment dose determination has important guiding significance. In this paper, Westervelt equation approximation, combined with Pennes biological heat conduction equation, to ex vivo porcine liver tissue, taking into account the impact of tissue acoustic properties on the temperature field HIFU focal field conditions, by finite difference time domain method (finite difference time domain , FDTD) to simulate the HIFU focal field temperature field. The results show that the longer the irradiation time, the more obvious the influence of the acoustic characteristics of the tissue; the same when the highest temperature rise at the focal point, the difference of the size of the treatable area is small; the greater the sound intensity, the time required to form the treatable area The shorter the length of the treatable area, the longer the length of the treatable area increases nonlinearly with the increase of irradiation time when the sound intensity is constant. When the length of the long axis or the short axis of the same treatable area is constant, the input sound intensity and Irradiation time was negatively correlated.