Choi B, Barton J K, Chan E K, Welch A J
The University of Texas at Austin Biomedical Engineering Laser Laboratory, 78712, USA.
Lasers Surg Med. 1998;23(4):185-93. doi: 10.1002/(sici)1096-9101(1998)23:4<185::aid-lsm1>3.0.co;2-7.
Several published reports describe the benefits of using the carbon dioxide laser for cutaneous resurfacing. The mechanisms on which skin resurfacing work are still not completely understood. This study was performed to obtain quantitative and qualitative information describing the thermal response of skin during high-energy, short-pulsed CO2 laser irradiation.
STUDY DESIGN/MATERIALS AND METHODS: A Tissue Technologies TruPulse CO2 laser was used to irradiate an in vivo rat model. The laser parameters that were used were a 100-micros pulse width, a 1-Hz repetition rate, a 3 mm x 3 mm square spot size, and 2.4 J/cm2 and 3.9 J/cm2 radiant exposures. A 3-5 microm thermal camera was used to obtain temperature information during irradiation. Single spots were irradiated with one pulse, and the temperature-time history was obtained. In a different experiment, 15 pulses were applied to single spots, and both thermal and video images were obtained.
Irradiation with one pulse at 2.4 J/cm2 and 3.9 J/cm2 led to peak temperatures >100 degrees C. The temperature relaxation time was approximately 25-150 ms. Multiple-pulse irradiation at 2.4 J/cm2 led to a slight rise in the peak temperature with each pulse. At 3.9 J/cm2, the peak temperature increased with successive pulses until pulse 10, after which the peak temperature oscillated between 300 and 400 degrees C. Video images showed concurrent burning events that occurred during pulses 10-15.
Temperatures >100 degrees C were measured during CO2 laser irradiation of skin. Pulse stacking can lead to peak temperatures approaching 400 degrees C and to tissue charring with as few as three stacked pulses. It is crucial for the physician to manipulate the laser handpiece at parameters with which he or she can avoid pulse overlap.
多篇已发表的报告描述了使用二氧化碳激光进行皮肤磨削术的益处。皮肤磨削术的作用机制仍未完全明确。本研究旨在获取关于高能短脉冲二氧化碳激光照射皮肤时热反应的定量和定性信息。
研究设计/材料与方法：使用组织技术公司的TruPulse二氧化碳激光照射活体大鼠模型。所用激光参数为100微秒脉冲宽度、1赫兹重复频率、3毫米×3毫米方形光斑尺寸以及2.4焦每平方厘米和3.9焦每平方厘米的辐射暴露量。使用一台3 - 5微米的热成像仪在照射过程中获取温度信息。对单个光斑照射一个脉冲，获取温度 - 时间历程。在另一个实验中，对单个光斑施加15个脉冲，同时获取热图像和视频图像。
以2.4焦每平方厘米和3.9焦每平方厘米的能量照射一个脉冲会导致峰值温度超过100摄氏度。温度弛豫时间约为25 - 150毫秒。以2.4焦每平方厘米的能量进行多脉冲照射时，每个脉冲会使峰值温度略有上升。在3.9焦每平方厘米的能量下，峰值温度随着连续脉冲增加，直到第10个脉冲，之后峰值温度在300到400摄氏度之间振荡。视频图像显示在第10 - 15个脉冲期间发生了同时性的烧灼事件。
在二氧化碳激光照射皮肤过程中测得温度超过100摄氏度。脉冲叠加可导致峰值温度接近400摄氏度，并且仅三个叠加脉冲就会导致组织炭化。对于医生而言，至关重要的是在操作激光手柄时选择能够避免脉冲重叠的参数。
