Altshuler G B, Anderson R R, Manstein D, Zenzie H H, Smirnov M Z
Palomar Medical Technologies, Inc., Burlington, Massachusetts 01803, USA.
Lasers Surg Med. 2001;29(5):416-32. doi: 10.1002/lsm.1136.
We present a new theory of selective thermal damage of non-uniformly pigmented structures in biological tissues. Spatial separation of the heavily pigmented areas and the target requires limitation of the pigment temperature and heat diffusion from the pigmented to the targeted areas.
STUDY DESIGNS/MATERIALS AND METHODS: A concept of selective target damage by heat diffusion is presented for three target geometries: planar, cylindrical, and spherical. An in vitro experiment is described in which the dependence of thermal damage on pulsewidth at constant fluence was evaluated.
The in vitro experiment showed that the size of the damage zone for similar hair follicles was pulsewidth-independent over a very broad range of pulsewidths (30-400 ms). We formulated a new theory (extended theory of photothermolysis) to interpret the experimental results.
Based on this new theory, the treatment pulsewidth for non-uniformly pigmented targets is significantly longer than the target thermal relaxation time (TRT). The theory provides new recommendations for photoepilation and photosclerotherapy parameters.
我们提出了一种关于生物组织中色素分布不均结构的选择性热损伤新理论。色素沉着严重区域与目标区域的空间分离需要限制色素温度以及从色素沉着区域到目标区域的热扩散。
研究设计/材料与方法：针对三种目标几何形状（平面、圆柱和球形）提出了通过热扩散进行选择性目标损伤的概念。描述了一项体外实验，其中评估了在恒定能量密度下热损伤对脉冲宽度的依赖性。
体外实验表明，在非常宽的脉冲宽度范围（30 - 400毫秒）内，类似毛囊的损伤区域大小与脉冲宽度无关。我们制定了一种新理论（光热解扩展理论）来解释实验结果。
基于这一新理论，色素分布不均目标的治疗脉冲宽度明显长于目标热弛豫时间（TRT）。该理论为脱毛和光硬化治疗参数提供了新的建议。
