- 學位論文
模擬超音波燒灼肝腫瘤過程
Numerical investigation of liver tumor ablation by high-intensity ultrasound
並列摘要
This study is aimed to predict the temperature near a liver tumor using the proposed acoustics-thermal-fluid coupling model. For capable of modeling heat absorption by tissues, the nonlinear acoustic model for simulating the high-intensity ultrasound is chosen so that wave distortion due to finite-amplitude propagation can be taken into account. The nonlinear hemodynamic model is also incorporated into the prediction of thermal dose in the physical domain, which has been split into the tissue domain, where homogenization dominates in perfusion domain and advection heat transfer is essential in the blood domain. Acoustic streaming, which may not be a negligible force in the determination of blood flow acceleration, will be also included in the present therapeutic system. In HIFU (High Intensity Focused Ultrasound), ultrasound is normally associated with the high frequency sound, which makes the calculation of acoustic pressure from the employed nonlinear Westervelt equation very expensive. This motivated us to develop a computationally very efficient alternating direction implicit scheme to solve the three dimensional wave equation by the proposed sixth-order accurate compact scheme for solving the inhomogeneous Helmholtz equation.