van Gemert M J, Welch A J, Pickering J W, Tan O T, Gijsbers G H
Laser Centre, Academic Medical Center, Amsterdam, The Netherlands.
Lasers Surg Med. 1995;16(2):147-55. doi: 10.1002/lsm.1900160204.
This report presents analytical modelling of the influence of wavelength on the amount of volumetric rate of heat produced in dermal blood vessels by millisecond laser radiation.
STUDY DESIGN/MATERIALS AND METHODS: A new anatomical model is proposed that represents port wine stains as well as telangiectatic lesions. It consists of a target blood vessel, representing the deepest dermal blood vessel that requires irreversible injury, and a layer of whole blood, representing all other dermal blood vessels above the target vessel. The laser light that interacts with the blood vessels is assumed to be diffuse. Selective photothermolysis is the basis for the analysis. We consider wavelengths between 577 nm and 600 nm, the argon laser wavelengths at 488/515 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm.
The rate of volumetric heat production of absorbed laser light in the target blood vessel is expressed analytically as a function of blood absorption, the concentration of additional dermal blood, and the depth of the target vessel.
The model explains why 585 nm is a good compromise for treating port wine stains that vary widely in number of dermal blood vessels. It predicts that wavelengths between 577 nm and 582 nm are excellent for the treatment of port wine stains in young children, and it suggests a possible explanation as to why the argon laser is sometimes said to be capable of treating dark mature port wine stains. The copper vapour laser wavelength at 578 nm, and the frequency doubled Nd:YAG laser wavelength at 532 nm, are predicted to be suitable for the treatment of port wine stains that contain, respectively, a small to moderate and a moderate number of dermal blood vessels. When laser beam spotsize becomes smaller, the best wavelength for producing maximal rate of heat in the target vessel is predicted to shift to 577 nm.
本报告介绍了毫秒激光辐射波长对真皮血管内热产生体积速率影响的分析模型。
研究设计/材料与方法：提出了一种新的解剖模型，该模型可呈现葡萄酒色斑以及毛细血管扩张性病变。它由一条目标血管和一层全血组成，目标血管代表需要不可逆损伤的最深层真皮血管，全血层代表目标血管上方的所有其他真皮血管。假设与血管相互作用的激光为漫射光。选择性光热解是分析的基础。我们考虑了577纳米至600纳米之间的波长、488/515纳米的氩激光波长以及532纳米的倍频Nd:YAG激光波长。
目标血管中吸收激光的体积热产生速率被解析表示为血液吸收、额外真皮血液浓度和目标血管深度的函数。
该模型解释了为何585纳米是治疗真皮血管数量差异很大的葡萄酒色斑的良好折衷波长。它预测577纳米至582纳米之间的波长对于幼儿葡萄酒色斑的治疗非常理想，并且对为何有时称氩激光能够治疗深色成熟葡萄酒色斑给出了一种可能的解释。预计578纳米的铜蒸气激光波长和532纳米的倍频Nd:YAG激光波长分别适用于治疗真皮血管数量少至中等和中等数量的葡萄酒色斑。当激光束光斑尺寸变小时，预计在目标血管中产生最大热速率的最佳波长将移至577纳米。
