激光诱导间质热疗中生物组织的温度场研究

激光诱导间质热疗疗效评估的前提是必须获得准确的激光在不同功率、不同照射时间的生物组织温度场分布.利用多物理场直接耦合分析软件COMSOL Multiphysics构建了在组织光学参量不变情况下的三维有限元传热模型.该模型基于Pennes生物传热方程和轴对称高斯形状的激光光束热源方程,参量针对离体猪肝组织,考虑到了生物组织热物性密度、比热和热导率随温度变化的情况.仿真获得激光功率为0.77 W、0.95 W、1.23 W,照射时间为10~90 s,径向距离0~2 mm范围和轴向距离0~4 mm范围的温度场数据集.利用拟合算法,获得了自变量为激光功率、照射时间、径向距离和轴向距离的生物组织温度场分布模型.将功率为0.88 W和1.05 W时的结果与Pennes方程结果相比较,两者误差在5%以内.

Biological Tissue′s Temperature Field During the Laser-Induced Interstitial Thermotherapy

The temperature distribution of the accurate biological tissues in different powers and different irradiation times is the premise of efficacy of laser-induced interstitial thermotherapy assessment.A three- dimensional finite element heat transfer model was constructed by multi-physical field conductive coupling analysis software COMSOL Multiphysics in the invariable tissue optics parameters situation.The model was based on Pennes bio-heat transfer equation and axisymmetric Gaussian shape of the laser beam heat equation.In this model,the parameters were for the liver tissue in vitro,and the thermal properties of biological tissue density,specific heat and thermal conductivity with temperature variations were considered.The temperature field data sets were obtained by simulation under the laser power for 0.77 W,0.95 W,123 W,irradiation time for 10~90 s,radial distance range 0~2 mm and axial distance range 0~4 mm.Fitting algorithm was used to obtain the tissue′s temperature distribution model related to the laser power,irradiation time,radial and axial distance.The results of 0.88 W and 1.05 W were compared with the Pennes equation,and the error between them was within 5%.