Jivraj Jamil, Chen Chaoliang, Barrows Dexter, Gu Xijia, Yang Victor X D
Biophotonics and Bioengineering Lab, Department of Electrical and Computer Engineering, Ryerson University, Toronto, Ontario, Canada.
7D Surgical Inc., Toronto, Ontario, Canada.
Biomed Opt Express. 2019 Jun 3;10(7):3114-3123. doi: 10.1364/BOE.10.003114. eCollection 2019 Jul 1.
Laser ablation of bone for the purposes of osteotomy is not as well understood as ablation of homogeneous, non-biological materials such as metals and plastics. Ignition times and etch rate can vary during ablation of cortical bone. In this study, we propose the use of two techniques to optimize bone ablation at 1064nm using a coaxial nitrogen jet as an assist gas and topical application of graphite as a highly absorbing chromophore. We show a two order of magnitude reduction in mean time to ignition and variance by using the graphite topical chromophore. We also show that an increase in volumetric flow rate of the assist gas jet does show an initial increase in etch rate, but increased pressure beyond a certain point shows decreased return. This study also demonstrates a 2 order relationship between exposure time, volumetric flow rate of nitrogen, and etch rate of cortical bone. The results of this study can be used to optimize the performance of laser ablation systems for osteotomy. This is a companion study to an earlier one carried out by Wong et al. [Biomedical Opt. Express6, 1 (2015)].
用于截骨术的骨激光消融，其原理不像金属和塑料等均匀非生物材料的消融那样被人们所熟知。在皮质骨消融过程中，点火时间和蚀刻速率可能会有所不同。在本研究中，我们提出使用两种技术来优化在1064nm波长下的骨消融，即使用同轴氮气射流作为辅助气体，并局部应用石墨作为高吸收发色团。我们发现，通过使用石墨局部发色团，平均点火时间和方差降低了两个数量级。我们还表明，辅助气体射流的体积流量增加确实会使蚀刻速率最初有所增加，但压力超过某一点后，蚀刻速率的增加就会减少。本研究还证明了暴露时间、氮气的体积流量与皮质骨蚀刻速率之间存在二次关系。本研究结果可用于优化用于截骨术的激光消融系统的性能。这是与Wong等人[《生物医学光学快报》6, 1 (2015)]早期进行的一项研究配套的研究。
