University of California, Riverside, Department of Bioengineering, Riverside, California, United States.
University of California, Irvine, Beckman Laser Institute and Medical Clinic, Irvine, California, United States.
J Biomed Opt. 2018 Nov;23(12):1-10. doi: 10.1117/1.JBO.23.12.121616.
Pulsed dye laser irradiation in the wavelength range of 585 to 600 nm is currently the gold standard for treatment of port-wine stains (PWSs). However, this treatment method is often ineffective for deeply seated blood vessels and in individuals with moderate to heavy pigmentation. Use of optical particles doped with the FDA-approved near-infrared (NIR) absorber, indocyanine green (ICG), can potentially provide an effective method to overcome these limitations. Herein, we theoretically investigate the effectiveness of particles derived from erythrocytes, which contain ICG, in mediating photothermal destruction of PWS blood vessels. We refer to these particles as NIR erythrocyte-derived transducers (NETs). Our theoretical model consists of a Monte Carlo algorithm to estimate the volumetric energy deposition, a finite elements approach to solve the heat diffusion equation, and a damage integral based on an Arrhenius relationship to quantify tissue damage. The model geometries include simulated PWS blood vessels as well as actual human PWS blood vessels plexus obtained by the optical coherence tomography. Our simulation results indicate that blood vessels containing micron- or nano-sized NETs and irradiated at 755 nm have higher levels of photothermal damage as compared to blood vessels without NETs irradiated at 585 nm. Blood vessels containing micron-sized NETs also showed higher photothermal damage than blood vessels containing nano-sized NETs. The theoretical model presented can be used in guiding the fabrication of NETs with patient-specific optical properties to allow for personalized treatment based on the depth and size of blood vessels as well as the pigmentation of the individual's skin.
脉冲染料激光在 585nm 到 600nm 的波长范围内的辐照是目前治疗葡萄酒色斑（PWS）的金标准。然而，这种治疗方法对于深层血管和中度到重度色素沉着的患者往往效果不佳。使用经美国食品和药物管理局批准的近红外（NIR）吸收剂吲哚菁绿（ICG）掺杂的光学颗粒，可能提供一种有效的方法来克服这些限制。在此，我们从理论上研究了含有 ICG 的红细胞衍生颗粒在介导 PWS 血管光热破坏方面的有效性。我们将这些颗粒称为近红外红细胞衍生换能器（NETs）。我们的理论模型包括一个蒙特卡罗算法来估计体积能量沉积，一个有限元方法来求解热扩散方程，以及一个基于阿伦尼乌斯关系的损伤积分来量化组织损伤。模型几何形状包括模拟的 PWS 血管以及通过光学相干断层扫描获得的实际人类 PWS 血管丛。我们的模拟结果表明，与在 585nm 下未辐照含有微米或纳米尺寸 NETs 的血管相比，含有微米或纳米尺寸 NETs 且在 755nm 下辐照的血管具有更高水平的光热损伤。含有微米尺寸 NETs 的血管也比含有纳米尺寸 NETs 的血管显示出更高的光热损伤。所提出的理论模型可用于指导具有特定于患者的光学特性的 NETs 的制造，以便根据血管的深度和大小以及个体皮肤的色素沉着进行个性化治疗。
