EXCITATION WAVELENGTH DEPENDENT RAMAN SPECTROSCOPY OF ARTERY

激发波长相关的动脉拉曼光谱

• 批准号: 6121224
• 负责人: JASON MOTZ
• 金额: $ 1.63万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2000-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6121224
• 关键词: arthritis; bioengineering /biomedical engineering; biomedical resource; human tissue; model design /development; technology /technique

We have formulated the theory of inertially confined mechanism for ablation of biological tissues. The motivation behind this theory is the observation that the energy density (E) absorbed in the tissue subsurface at ablation threshold (for short pulses) is typically ten times smaller than that required for vaporization, and of the order E ~ 200-300 J/cm3. Thus vaporization alone is inadequate to explain pulsed ablation, and other physical mechanisms must be responsible for tissue removal on this short time scale. By studying the steam tables (water is used as a thermodynamic model for soft tissue), one finds that an increase in energy density of 300 J/cm3, under conditions of constant volume, is sufficient to generate a pressure of 900 bars in the tissue. The condition of constant volume is assumed because, for short pulses (less than several hundred nanoseconds), the tissue is inertially confined (it lacks sufficient time to expand). Ablation occurs when the lase r-induced pressure exceeds a threshold value (which is dependent on the structural properties of the tissue) and proceeds through a disassembly of the tissue at the microcracks and subsequent acceleration away from the crater due to the pressure gradient.

我们建立了惯性约束机制理论， 消融生物组织。 这个理论背后的动机是 观察到组织中吸收的能量密度（E） 在烧蚀阈值（对于短脉冲）下的表面下通常是10 比蒸发所需的小1/4，数量级为E ~ 200-300 J/cm 3。 因此，仅仅是蒸发不足以解释 脉冲消融和其他物理机制必须负责 在这么短的时间内切除组织 通过研究蒸汽表 （水被用作软组织的热力学模型），人们发现 在以下条件下，能量密度增加300 J/cm 3， 恒定的体积，足以产生900巴的压力， 组织。 假设体积不变的条件是因为， 短脉冲（小于几百纳秒）， 惯性限制（缺乏足够的时间膨胀）。 消融 当激光R引起的压力超过阈值时 （这取决于组织的结构特性）和 通过在微裂纹处组织的分解进行， 随后由于压力而加速离开陨石坑 梯度离心