Engineering Applications of Lasers Department, National Institute of Laser Enhanced Sciences, Cairo University, Giza, Egypt.
Biophysics Department, Faculty of Science, Cairo University, Giza, Egypt.
PLoS One. 2022 Jan 31;17(1):e0263164. doi: 10.1371/journal.pone.0263164. eCollection 2022.
Infrared (IR) lasers are extensively utilized as an effective tool in many medical practices. Nevertheless, light penetration into the inspected tissue, which is highly affected by tissue optical properties, is a crucial factor for successful optical procedures. Although the optical properties are highly wavelength-dependent, they can be affected by the power of the incident laser. The present study demonstrates a considerable change in the scattering and absorption coefficients as a result of varying the incident laser power probing into biological samples at a constant laser wavelength (808 nm). The optical parameters were investigated using an integrating sphere and Kubelka-Munk model. Additionally, fluence distribution at the sample's surface was modeled using COMSOL-multiphysics software. The experimental results were validated using Receiver Operating Characteristic (ROC) curves and Monte-Carlo simulation. The results showed that tissue scattering coefficient decreases as the incident laser power increases while the absorption coefficient experienced a slight change. Moreover, the penetration depth increases with the optical parameters. The reduction in the scattering coefficients leads to wider and more diffusive fluence rate distribution at the tissue surface. The simulation results showed a good agreement with the experimental data and revealed that tissue anisotropy may be responsible for this scattering reduction. The present findings could be considered in order for the specialists to accurately specify the laser optical dose in various biomedical applications.
红外（IR）激光在许多医学实践中被广泛用作有效工具。然而，光穿透被检查组织的深度，这受到组织光学特性的极大影响，是成功进行光学手术的关键因素。尽管光学特性高度依赖于波长，但它们可能会受到入射激光功率的影响。本研究表明，在恒定激光波长（808nm）下，探测生物样本时，入射激光功率的变化会导致散射和吸收系数发生显著变化。使用积分球和 Kubelka-Munk 模型研究了光学参数。此外，使用 COMSOL-multiphysics 软件对样品表面的光密度分布进行了建模。使用接收器操作特性（ROC）曲线和蒙特卡罗模拟对实验结果进行了验证。实验结果表明，随着入射激光功率的增加，组织散射系数降低，而吸收系数略有变化。此外，随着光学参数的增加，穿透深度增加。散射系数的降低导致组织表面的通量率分布更宽且更扩散。模拟结果与实验数据吻合较好，表明组织各向异性可能是散射减少的原因。本研究结果可帮助专家在各种生物医学应用中准确指定激光光学剂量。
