Thongsima Siremon, Zurakowski David, Manstein Dieter
Wellman Center for Photomedicine, Department of Dermatology, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts, USA.
Lasers Surg Med. 2010 Jan;42(1):32-7. doi: 10.1002/lsm.20882.
There are a wide variety of fractional resurfacing devices that are available and it is important to understand the tissue effect of different devices at different parameters to ensure a well-controlled treatment. Thus, we have chosen to characterize and compare two different fractional laser devices, the Fraxel SR750 and SR1500 (re:store) (Solta Medical, Hayward, CA). While the SR750 has a fixed focus spot diameter, the SR1500 features an internally controlled zoom optic allowing for an adjustable spot size.
Exposures were performed in vitro on human skin samples at 37 degrees C. The exposures were performed for the SR750 at pulse energies between 6 and 40 mJ at 125 MTZ/cm(2) with up to 20 passes, and for the SR1500 between 6 and 100 mJ, at Treatment Level 7 and 8 passes. The skin samples then were processed for serial frozen sectioning, stained with Nitro-Blue-Tetrazolium-Chloride (NBTC) and lesion depth and width was determined.
Mean lesion depth was significantly greater for lesions treated with the SR1500 laser compared to the SR750 at pulse energies of 6, 10, 30, and 40 mJ (P<0.001) with a borderline difference at 20 mJ. Mean lesion width was comparable for energies up to 20 mJ and relatively increased for the SR1500 for higher energies. The depth-to-width ratio (DWR) was in general higher for the SR1500, reaching significance at 6, 10, and 40 mJ.
We have characterized the lesion depth and width for the for two different Fractional Photothermolysis devices (SR750 vs. SR1500). The device with the adjustable spot size (SR1500 or Fraxel re:store) provides generally deeper lesions at the same energy level. It remains to be shown whether increased lesion depth improves efficacy for certain clinical applications.
目前有各种各样的分次激光换肤设备，了解不同设备在不同参数下对组织的影响对于确保治疗的良好控制非常重要。因此，我们选择对两种不同的分次激光设备——飞梭SR750和SR1500（修复版）（索塔医疗公司，加利福尼亚州海沃德市）进行特性分析和比较。SR750的光斑直径固定，而SR1500具有内部控制的变焦光学系统，可实现光斑大小的调节。
在37摄氏度下对人体皮肤样本进行体外照射。对SR750，在125个微热区/平方厘米的条件下，以6至40毫焦的脉冲能量进行照射，最多照射20次；对SR1500，在治疗水平7和8次照射的条件下，以6至100毫焦的能量进行照射。然后对皮肤样本进行连续冷冻切片处理，用氯化硝基四氮唑蓝（NBTC）染色，并测定损伤深度和宽度。
在6、10、30和40毫焦的脉冲能量下，与SR750相比，用SR1500激光治疗的损伤平均深度显著更深（P<0.001），在20毫焦时差异接近临界值。对于高达20毫焦的能量，平均损伤宽度相当，而对于更高的能量，SR1500的损伤宽度相对增加。SR1500的深宽比（DWR）总体上更高，在6、10和40毫焦时达到显著水平。
我们已对两种不同的分次光热解设备（SR750与SR1500）的损伤深度和宽度进行了特性分析。光斑大小可调节的设备（SR1500或飞梭修复版）在相同能量水平下通常能产生更深的损伤。对于某些临床应用，损伤深度增加是否能提高疗效仍有待证实。
