Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing, 100084, People's Republic of China.
Lasers Med Sci. 2011 Sep;26(5):633-40. doi: 10.1007/s10103-011-0949-3. Epub 2011 Jul 6.
The theory of selective photothermolysis (SP) is used in many fields of laser surgery and medicine. As several parameters and a number of complicated photothermal interactions are involved in SP, numerical simulations have been providing an important and effective way in SP studies. However, with different photothermal models of SP, simulated results differ considerably. In addition, insufficient attention has been paid to tissue pressure variation during SP in these models, so that vessel rupture and other clinical phenomena cannot be explained. A novel photothermal model of SP was proposed using a Monte Carlo method to simulate the laser transport in the tissue, a heat transfer equation with dynamically changing vaporization temperature to calculate the temperature distribution, and the Arrhenius equation to predict the thermal damage. A factor of trapped vaporized tissue water k was introduced to describe the effects on tissue pressure, temperature, and other related parameters. It was shown that the simulation results are affected significantly by k. Temperature and thermal damage volume are almost identical, respectively, to those obtained with models with vaporization at 100°C and models without vaporization when k = 0 and 1, while thermal damage volume is close to that obtained with models of vaporization at 110°C and 130°C, respectively, when k = 0.022 and k = 0.18. To some extent, the current models without vaporization and models with vaporization at constant temperature can be regarded as special cases at specific situations of this new photothermal model of SP. In addition, more descriptive simulation results, such as temperature, thermal damage, and pressure, are accessible with this model, although the accuracy depends on the value of k, the estimation of which is planned as future work.
选择性光热分解（SP）理论用于激光手术和医学的许多领域。由于 SP 涉及几个参数和许多复杂的光热相互作用，数值模拟一直是 SP 研究的重要有效方法。然而，由于 SP 的光热模型不同，模拟结果差异很大。此外，这些模型中对 SP 期间组织压力变化的关注不够，因此无法解释血管破裂和其他临床现象。本研究提出了一种新的 SP 光热模型，该模型使用蒙特卡罗方法模拟组织中的激光传输，使用具有动态变化的蒸发温度的传热方程来计算温度分布，以及使用阿累尼乌斯方程预测热损伤。引入了一个被捕获的蒸发组织水 k 因子来描述对组织压力、温度和其他相关参数的影响。结果表明，k 对模拟结果有显著影响。当 k = 0 和 1 时，温度和热损伤体积几乎分别与蒸发温度为 100°C 的模型和没有蒸发的模型相同，而当 k = 0.022 和 k = 0.18 时，热损伤体积分别接近蒸发温度为 110°C 和 130°C 的模型。在某种程度上，目前没有蒸发的模型和蒸发温度恒定的模型可以被视为这个新的 SP 光热模型在特定情况下的特殊情况。此外，尽管准确性取决于 k 的值，但可以使用该模型获得更具描述性的模拟结果，如温度、热损伤和压力，尽管 k 的估计是未来的工作。
