Nanosecond, high-intensity pulsed laser ablation of myocardium tissue at the ultraviolet, visible, and near-infrared wavelengths: In-vitro study
Nanosecond, high-intensity pulsed laser ablation of myocardium tissue at the ultraviolet, visible, and near-infrared wavelengths: In-vitro study
复制标题
DOI：
10.1002/lsm.10002
复制
发表时间：
2001-01-01
影响因子：
2.4
通讯作者：
Ashida, H
中科院分区：
文献类型：
--
作者：
Sato, S;Ogura, M;Ashida, H
背景和目的：激光心肌血运重建术（TMLR）治疗严重缺血性心脏病的临床试验已经进行了大量。各种激光源已被用于或测试用于这种治疗，然而，尚未进行全面的研究来揭示心肌组织消融的机制和最佳激光照射条件。研究设计/材料和方法：采用1064 nm Q开关Nd：YAG激光器及其第二（532 nm）、第三（355 nm）和第四（266 nm）谐波进行消融实验。在每种波长下，25个激光脉冲以近似于2GW/cm（2）的恒定激光强度（峰值激光功率除以激光光斑面积）照射猪心肌组织样品，并测量消融深度。在烧蚀过程中，激光诱导的光和声发射进行了测量，以调查在每个激光波长的烧蚀机制。结果：组织的线性吸收系数与消融效率无直接关系，组织的线性吸收系数在355和1064 nm处最大，在532 nm处最小。在266和1064 nm激光照射下观察到强烈的激光诱导光和声发射。组织学显示，在266、355和532 nm波长下，消融壁附近组织的热变性随着波长的减小而减小，但在1064 nm波长下受到限制。当激光强度接近2GW/cm（2）时，不同波长的激光烧蚀特性发生了显著变化。结果表明，对于266，355和532 nm，组织去除主要通过光热过程实现，但对于266 nm，强激光诱导等离子体形成将导致耦合到组织的激光能量减少。对于1064 nm，光致破裂最有可能作为主要的组织去除过程。由于高消融率和有限的热变性，355-和1064-nm激光可能是TMLR的潜在激光源，尽管需要进一步研究来讨论临床问题。激光外科医学29：464-473，2001年。(C)2001 Wiley-Liss，Inc.
Background and Objective: A large number of clinical trials of transmyocardial laser revascularization (TMLR) have been conducted to treat severe ischemic heart diseases. A variety of laser sources have been used or tested for this treatment, however, no comprehensive study has been performed to reveal the mechanism and the optimum laser irradiation condition for the myocardium tissue ablation. There have been reported limited experimental data of the high-intensity pulsed laser ablation of myocardium tissues.Study Design/Materials and Methods: A 1064-nm Q-switched Nd:YAG laser and its 2nd (532 nm), 3rd (355 nm), and 4th (266 nm) harmonies were used for ablation experiments. At each wavelength, 25 laser pulses irradiated the porcine myocardium tissue samples at a constant laser intensity (peak laser power divided by laser spot area) of similar to2 GW/cm(2) and the ablation depths were measured. During ablation, laser-induced optical and acoustic emissions were measured to investigate the ablation mechanism at each laser wavelength. For the ablated tissues, histological observation was made with a polarization optical microscope.Results: It was shown that the ablation efficiency did not directly depend on the linear absorption coefficient of the tissue; the ablation depth was maximized at 355 and 1064 nm, and minimized at 532 nm. Strong laser-induced optical and acoustic emissions were observed for the 266- and 1064-nm laser irradiations, The histology showed that thermal denaturation of the tissue near the ablation walls decreased with decreasing wavelength for 266, 355, and 532 nm, but it was limited for 1064 nm.Conclusion: At the laser intensity of similar to2 GW/cm(2), ablation characteristics were drastically changed for the different laser wavelengths. The results indicated that for 266, 355, and 532 nm, the tissue removal was achieved mainly through a photothermal process, but for 266 nm the intense laser-induced plasma formation would result in a reduced laser energy coupling to the tissue. For 1064 nm, a photodisruption was most probable as a dominant tissue removal process. Because of the high ablation rate and limited thermal denaturation, the 355- and 1064-nm lasers could be potential laser sources for TMLR, although further investigation is needed to discuss the clinical issues. Lasers Surg. Med. 29:464-473, 2001. (C) 2001 Wiley-Liss, Inc.