生物组织光热传输和热损伤的研究

生物组织的光热作用表现为光凝固、气化、碳化等不同的热效应,激光能量在生物组织中不断累积、扩散,由此引起生物组织产生不同程度的热效应和热损伤.在激光辐照下生物组织的热传输和热平衡机理分析的基础上,深入讨论了被作用靶组织产生的温升、热损伤和激光曝光时间三者之间的相互关系,随着吸收的光能量的增加,热源扩散使得靶组织的温度升高,温升分布将由一个δ函数扩展为一个正态分布,同时,温度升高又伴随着不同程度的热损伤.理论证明,组织温升是激光外科的一个重要因素.临床中由于缺乏被作用组织真实温升的监测措施,为了达到某种治疗效果,要么调高或者调低激光输出功率,要么延长或者缩短曝光时间,这些都可能造成靶组织的过度热损伤或者是照射剂量不足.

Study on Photothermal Transfer and Thermal Damage of Bio-tissues

Thermal interaction of bio-tissues laser heated presents sorts of thermal effects such as coagulation, vaporization, carbonization. Both the thermal effects and thermal damage produce due to the continuously accumulation and diffusion of the laser energy in tissue. Based on the analysis of the mechanism of the thermal propagation and equilibrium, the relationship among temperature rise, thermal damage and exposure duration was deeply discussed. With increasing of the laser energy and thermal source diffuse to the ambient tissue, the distribution of temperature rise changes from a shape δ function to normal function, the higher temperature makes the thermal damage to some extent. It is theoretically proved temperature rise is one of the most important factors in laser surgery. Clinically, with the shortage of the setup to trace the actual temperature of the target tissue, one is only to adjust the laser output or the duration time in order to get better curative effect, which could tend to bring excessive thermal damage or insufficient irradiation.