EXCIMER LASER PHOTO ABLATION OF ATHEROSCLEROTIC PLAQUE

拟议的研究集中在准分子激光的细节 在流体介质存在下与冠状动脉组织的相互作用。 这项研究的目的是了解光消融是如何 在患病的动脉中通过脉冲准分子辐射通过 被流体场包围的光纤。 这些信息至关重要 用于优化和控制经皮激光器中的激光能量 激光血管成形术 准分子激光的作用机制将由全方位的 冠状动脉节段的生物物理学和光化学测量。 测量将用受激准分子波长进行， 我们以前的工作表明，有效地通过光学传输 纤维（351 nm），并能够在组织中实现光消融 存在生理盐水、Fluosol和血液。 这些测量将包括： 1.冠状动脉段光消融阈值的测定 流体 2.排放的颗粒物形成程度的测定 流体介质 3.气相和液相释放的光产物分析 4.伴随光烧蚀的光电子分析 5.光烧蚀自由基形成程度的测定 自旋捕捉 6.用光声光谱法测定激光能量的扩散 拟议的研究计划将带来光谱的全部力量， 和现代分析测量来确定详细的 冠状动脉内准分子激光消融过程的认识 动脉粥样硬化病变 不像以前的几个准分子研究 与心血管组织的相互作用，包括我们自己的组织， 实验室，确定积极的生物物理机制将是 在存在三个重要流体场的情况下完成-血液， 生理盐水和血液替代品氟素 这些实验预计将 对于确定最佳激光器至关重要 受激准分子激光能量的受控使用所需的参数， 经皮激光血管成形术

The proposed research is focused on the details of excimer laser light interaction with coronary artery tissue in the presence of a fluid medium. The purpose of the research is to understand how photoablation is accomplished in a diseased artery by pulsed excimer radiation through an optical fiber surrounded by a fluid field. Such information is essential for the optimization and control of laser light energy in a percutaneous laser angoiplasty procedure. The mechanism of excimer laser action will be determined by a full range of photophysical and photochemical measurements on coronary artery segments. The measurements will be made with excimer wavelengths which have been shown by our previous work to be efficiently transmitted through optical fibers (351 nm) and capable of effecting tissue photoablation in the presence of saline, Fluosol and blood. These measurements will include: 1. determination of the photoablation threshold for coronary segments under fluid 2. determination of extent of formation of particulate matter released in fluid media 3. analysis of photoproducts released in both gas and liquid phase 4. analysis of photoemission accompanying photoablation 5. determination of extent of free radical formation on photoablation by spin trapping 6. determination of spread of laser energy by photoacoustic spectroscopy The proposed research program will bring the full power of spectroscopic and modern analytical measurements to the determination of the detailed understanding of the excimer photoablation process in coronary atherosclerotic lesions. Unlike several previous studies of excimer interactions with cardiovascular tissue, including those from our own laboratory, the determination of photophysical mechanisms active will be accomplished in the presence of three important fluid fields - blood, saline and the blood-substitute, Fluosol. Such experiments are expected to be of central importance to the determination of the optimum laser parameters required for the controlled use of excimer laser light energy in percutaneous laser angioplasty.