Kang Hyun Wook
Department of Biomedical Engineering and Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, 45 Yongso-ro, Nam-gu, Busan, 608-737, South Korea,
Lasers Med Sci. 2014 Nov;29(6):1919-25. doi: 10.1007/s10103-014-1604-6. Epub 2014 Jun 10.
Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.
光纤已被用作各种医学领域中的微创工具。然而，由于过多的热量积累，光纤的远端经常遭受严重的熔化或失透，导致在激光治疗期间光纤最终失效。为了使光纤尖端的热损伤最小化，开发了一种光学反馈传感器并在体外进行了测试。使用猪肾组织从信号激活、消融性能和光传输方面评估光学反馈的可行性。测试各种信号阈值表明，3V相对适合触发反馈传感器并防止在肾组织消融期间光纤劣化。基于时间信号特征的发展，全接触模式可能由于热量积累而迅速激活光学反馈传感器。与无反馈情况相比，由光学反馈引起的调制光传输使消融效率降低了30%。然而，长期传输结果证实，借助光学反馈的激光消融能够几乎持续地维持向组织的光传输以及消融效率。因此，光学反馈传感器可以成为一种可行的工具，通过最小化碎片污染和延迟热损伤过程来保护光纤尖端，并确保更高效、更安全的激光诱导组织消融。
