激光诱导间质肿瘤热疗中的动态光热作用模型

A Numerical Model of the Dynamic Photo-thermal Interaction Process During Laser-induced Interstitial Thermotherapy

考虑热疗过程中生物组织物性参数的动态变化,建立了描述激光诱导间质肿瘤热疗(LITT)过程中动态光热作用的二维物理数学模型。采用改进的Monte Carlo方法数值模拟了LITT中激光能量在非均质生物组织内的传输过程。基于Pennes生物传热方程和Arrhenius方程数值求解了组织内的温度分布和热损伤体积的变化,分析了光学物性参数、热物性参数及血液灌注率的动态变化对LITT过程的影响。数值模拟结果表明,组织的光学物性参数、热物性参数及血液灌注率的动态变化对于热损伤体积的变化具有重要的影响,应该在光热作用建模中予以考虑。

To describe the complex nonlinear process of laser tissue interactions, a two-dimensional mathematical model considering the dynamic changes in the physical tissue properties was developed here. A modified Monte Carlo method was developed to simulate photon transport in the tissue with a non-uniform optical property field. The finite volume method was used to numerically solve the Pennes bioheat equation to calculate the temperature distribution,and the Arrhenius equation was used to predict the thermal damage extent. The numerical results show that the dynamic changes in the optical properties, thermal properties and blood perfusion rate significantly affect the damage volume accumulation history in tissue and should be included in numerical simulations of the LITT treatment.