Regan Thomas D, Uebelhoer Nathan S, Satter Elizabeth, Ross E Victor
Department of Dermatology, San Antonio Military Medical Center, Wilford Hall Medical Center, 2200 Bergquist Dr Ste 1, Lackland AFB, Texas 78236-9908, USA.
Lasers Surg Med. 2010 Jul;42(5):408-11. doi: 10.1002/lsm.20929.
BACKGROUND/OBJECTIVE: The purpose of this study was to assess the effects of fluence, pulse stacking, and multiple passes on the depth of injury caused by a fractionated Er:YAG laser in an in vivo farm pig model. DESIGN/MATERIAL/METHODS: A fractionated 2,940 nm Er:YAG laser (Pixel, Alma Lasers, Caesarea, Israel) was applied to the flank skin of a Yorkshire cross pig. The 11 mmx11 mm handpiece was comprised of either 49 or 81 microbeams (200 microm diameter), depending on the tip configuration. There were six different parameter sets divided according to total energy per pulse (150, 285, and 500 mJ) and tip type (81 or 49 microbeams per 11 mmx11 mm macrospot). Each of these six groups was subdivided according to number of stacked pulses (1, 3, and 6) and number of passes (1, 3, and 6). This resulted in a total of 36 treatment parameters.
With the 49 microbeam configuration, a single pulse resulted in partial epidermal ablation at 150 mJ, complete epidermal ablation at 285 mJ and partial dermal ablation at 500 mJ to a depth of 90 microm. Stacking the pulses resulted in a significant increase in ablation with each fluence with the maximal depth of ablation measured at 140 microm after six stacked pulses at 500 mJ. Increasing the number of passes did not result in a significant increase in ablative depth, but did create a larger surface area of ablation. Residual thermal damage (RTD) was minimal and remained between 10 and 20 microm.
The fractionated Er:YAG laser exhibited some of the same tissue interactions as its fully ablative counterparts. An increase in fluence resulted in an increase in ablative depth with minimal RTD. Additionally, RTD was unaffected by pulse stacking or by additional passes. Differences were that pulse stacking appeared to yield a more rapid decrease in ablation efficiency and additional passes did not seem to increase the depth of ablation.
背景/目的：本研究的目的是在活体农场猪模型中评估能量密度、脉冲叠加和多次照射对分次Er:YAG激光所致损伤深度的影响。设计/材料/方法：使用一台分次2940nm Er:YAG激光（Pixel，Alma Lasers，凯撒利亚，以色列）照射约克夏杂交猪的侧腹皮肤。11mm×11mm的手持件根据尖端配置由49或81个微光束（直径200μm）组成。根据每个脉冲的总能量（150、285和500mJ）和尖端类型（每11mm×11mm大光斑81或49个微光束）分为六个不同的参数组。这六个组中的每一组又根据叠加脉冲数（1、3和6）和照射次数（1、3和6）进一步细分。这总共产生了36个治疗参数。
采用49个微光束配置时，单个脉冲在150mJ时导致部分表皮消融，在285mJ时导致完全表皮消融，在500mJ时导致部分真皮消融，深度达90μm。脉冲叠加导致每次能量密度下的消融显著增加，在500mJ下进行6次叠加脉冲后，测得的最大消融深度为140μm。增加照射次数并未导致消融深度显著增加，但确实产生了更大的消融表面积。残余热损伤（RTD）最小，保持在10至20μm之间。
分次Er:YAG激光表现出与其完全消融同类产品相同的一些组织相互作用。能量密度增加导致消融深度增加，同时RTD最小。此外，RTD不受脉冲叠加或额外照射的影响。不同之处在于，脉冲叠加似乎导致消融效率更快下降，而额外照射似乎并未增加消融深度。
