激光辐照生物细胞时热累积的研究

Research of Heat Accumulation of Laser Irradiated Biological Cells

光热效应是激光与生物组织相互作用时发生的重要效应之一，但其产生、传输和作用机理尚不十分清晰。激光辐照生物细胞时，温度是衡量其作用效果的重要参数，生物细胞中温度的变化间接反映了细胞的多种物理特性，在l临床应用中有重要作用。建立了激光辐照生物细胞时的数值模拟模型，通过热传输方程，运用有限元软件模拟并分析了激光辐照生物细胞时的热累积现象。拟合并分析了不同斩波周期下生物细胞的温度变化过程，并拟合出斩波周期为0．1s、辐照时间为0．2s时出现的两次温升、两次温降方程。实验结果表明只有当斩波频率达到一定值时才会出现热累积现象；同一激光辐照细胞热模型到达的最高温度与激光的斩波频率有关，激光斩波频率越高，所产生的光热效应越低。

Photo-thermal effect is one of the most important effects in the interactions between laser and biological tissue cells, however, its generation, transmission and action mechanisms are not yet clear. When laser irradiates biological cells, temperature is the decisive parameter in that temperature change in biological cells reflects a variety of physical properties of cells, which plays an important role in clinical applications. A numerical simulation model is built, and the heat accumulation process is simulated and analyzed using finite element software according to the heat transfer equations when laser irradiates biological cells. The temperature variation process of biological cells under different chopping cycles is analyzed, and equations of two temperature rise processes and two temperature drop processes are fitted when the chopper period is 0.1 s and the irradiation time is 0.2 s. It is concluded that the phenomenon of heat accumulation will appear only when the chopping frequency reaches a certain value; the highest temperature of thermal model which is irradiated by laser is related to the chopping frequency, and the higher the chopping frequency is, the lower the biological cell＇s thermal effect is.