脉冲Ho:YAG激光诱导水介质空化效应及其对骨硬组织消融的影响

发布时间：2018-07-17 05:19

【摘要】：减少热损伤并提高消融效率是当前激光硬组织消融技术研究的热点、重点和难点。现有研究表明：外部水的介入可以增强激光硬组织消融效果,激光诱导空化效应在液体介导消融中扮演重要角色,然而相关机制并没有得到合理的解释。本文立足于国内外激光消融技术发展现状和临床应用需求,以波长为2.08μm的脉冲Ho:YAG激光为辐射光源,基于高速摄像技术,实验研究了不同水深和不同浓度墨汁溶液对空泡脉动特性及其对牛股骨消融效果的影响。首先,介绍了骨组织的组成结构、基本成分和相关特性,总结了激光直接消融和液体介导消融硬组织的机理,阐述了激光空泡产生、脉动和溃灭,以及空泡脉动特性的影响因素。其次,采用高分辨率高速摄像拍摄了脉冲Ho:YAG激光与水介质相互作用时空泡效应的高速过程。研究得到不同激光能量下,空泡的周期、最大横向宽度、最大纵向长度、空泡的最大体积随光纤入水深度的变化关系。再次,利用高分辨率高速摄像监测了脉Ho:YAG激光与不同浓度墨汁溶液相互作用时空泡的脉动过程。获得空泡的周期、最大横向宽度、最大纵向长度和空泡的最大体积均随脉冲能量的增加而增加；纯水中加入不同墨汁体积,增加纯水的吸收系数,空泡的尺寸反而减小。最后,使用波长2.08μm的脉冲Ho:YAG激光,对空气中、纯水介质不同深度以及不同吸收系数的墨汁溶液中牛股骨进行消融实验,利用高速摄像机进行实时拍摄,OCT扫描系统和体视显微镜系统评价牛股骨组织表面消融形貌的变化。通过对光纤入水深度、液体介质、激光参数的优化选择,可获得无热损伤的消融效果,还可以使消融切口深、边缘光滑干净,形状规则,以及更高的消融速率和效率。
[Abstract]:Reducing thermal injury and improving ablation efficiency are the hot, important and difficult points in laser hard tissue ablation. Current studies have shown that external water intervention can enhance the ablation effect of laser hard tissue, laser induced cavitation effect plays an important role in liquid-mediated ablation, but the relevant mechanism has not been properly explained. Based on the development of laser ablation technology at home and abroad and the requirement of clinical application, this paper takes the pulsed Ho: YAG laser with wavelength of 2.08 渭 m as the radiation source, based on the high speed camera technology. The effect of different water depth and different concentration of ink solution on the pulsation of cavitation and its effect on the ablation of bovine femur was studied. Firstly, the composition, basic components and related characteristics of bone tissue are introduced. The mechanism of direct laser ablation and liquid-mediated ablation of hard tissue is summarized, and the generation, pulsation and collapse of laser cavitation are described. And the influencing factors of cavitation pulsation. Secondly, a high resolution high speed camera is used to photograph the high speed process of the spatiotemporal bubble effect of a pulsed Ho: YAG laser interacting with a water medium. The relationship between the period of cavitation, the maximum transverse width, the maximum longitudinal length and the maximum volume of the cavitation with the depth of the fiber is obtained under different laser energy. Thirdly, the pulsation process of spatiotemporal bubbles of pulse Ho: YAG laser interacting with different concentration of ink solution was monitored by high resolution and high speed camera. The period of cavitation, the maximum transverse width, the maximum longitudinal length and the maximum volume of cavitation increase with the increase of pulse energy, while the absorption coefficient of pure water decreases with the addition of different ink volumes in pure water. Finally, the ablation experiment of bovine femur in different depth of pure water medium and different absorption coefficient of ink solution in air, pure water medium and different absorption coefficient was carried out by using a pulsed Ho: YAG laser at a wavelength of 2.08 渭 m. The changes of surface ablation morphology of bovine femoral bone were evaluated by high speed camera real time Oct scanning system and stereoscopic microscope system. By optimizing the water depth of fiber, liquid medium and laser parameters, the ablation effect without heat damage can be obtained, and the ablation incision depth, smooth edge, regular shape, and higher ablation rate and efficiency can also be obtained.
【学位授予单位】：福建师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：Q682;TN249

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