Katta Nitesh, Sikorski Katherine, Teichman Joel M H, Milner Thomas E
Beckman Laser Institute and Medical Clinic, University of California at Irvine, Irvine, California, USA.
Department of Urologic Sciences, University of British Columbia, Vancouver, Canada.
J Endourol. 2025 Jul;39(7):716-724. doi: 10.1089/end.2024.0733. Epub 2025 May 26.
This study addresses pulse modulation for kidney stone lithotripsy using diode-pumped thulium yttrium aluminum garnet (Tm:YAG, λ = 2.02 µm) and thulium fiber lasers (TFLs, λ = 1.94 µm). Three research questions were investigated: (1) What are the effects of varying pulse duration and energy of the first pulse and varying the interpulse delay in a pulse modulation sequence to increase energy transfer across saline to a stone? (2) Does an optimal pulse modulation profile exist in a single-pulse sequence to provide highest percent radiant energy transfer? (3) Does a higher effective energy transfer to the stone using pulse modulation produce greater stone volumetric removal? We measured radiant energy transmission efficiency (RETE) and ablation volumes in phantom and human stones. RETE was utilized to compare the pulse energy transmission through air and saline media. We recorded fast camera traces and vapor bubble collapse pressures. Craters were created at fiber standoff distances (SDs) of 0.0 mm, 0.5 mm, and 1.0 mm, and volumes were measured using optical coherence tomography. For Tm:YAG laser irradiation, dual-pulse mode significantly increased RETE by as much as 75% at 1 mm SD compared with single-pulse mode. With the Tm:YAG laser, an optimal "dual-pulse" modulation resulted in greater volumetric removal compared with a "single-pulse" across all stone cohorts ( < 0.05) except for calcium oxalate monohydrate stones ( = 0.38) at a 1 mm SD. TFL yielded similar results, but showed heterogeneity across stone compositions. Pulse-modulated diode-pumped Tm:YAG and TFL can deliver higher photon count through a saline layer if the first pulse is optimized. An optimal pulse modulation profile where the second pulse is synchronized with the vapor bubble dynamics of the first pulse results in the highest percent RETE and increased stone volumetric removal.
本研究探讨了使用二极管泵浦掺铥钇铝石榴石（Tm:YAG，λ = 2.02 µm）和掺铥光纤激光器（TFL，λ = 1.94 µm）对肾结石进行碎石术的脉冲调制。研究了三个问题：（1）在脉冲调制序列中改变第一个脉冲的持续时间和能量以及改变脉冲间延迟对增加盐水到结石的能量传递有何影响？（2）在单脉冲序列中是否存在能提供最高辐射能量传递百分比的最佳脉冲调制曲线？（3）使用脉冲调制向结石传递更高的有效能量是否会产生更大的结石体积去除量？我们测量了仿体结石和人体结石中的辐射能量传输效率（RETE）和消融体积。利用RETE比较脉冲能量在空气和盐水介质中的传输情况。我们记录了高速摄像机轨迹和蒸汽泡崩溃压力。在光纤间距（SD）为0.0 mm、0.5 mm和1.0 mm处产生坑洼，并使用光学相干断层扫描测量体积。对于Tm:YAG激光照射，与单脉冲模式相比，双脉冲模式在1 mm SD处使RETE显著提高多达75%。对于Tm:YAG激光，除了在1 mm SD处的一水合草酸钙结石（P = 0.38）外，在所有结石组中，与“单脉冲”相比，最佳“双脉冲”调制导致更大的体积去除量（P < 0.05）。TFL产生了类似的结果，但在不同结石成分中表现出异质性。如果优化第一个脉冲，脉冲调制的二极管泵浦Tm:YAG和TFL可以通过盐水层传递更高的光子数。第二个脉冲与第一个脉冲的蒸汽泡动力学同步的最佳脉冲调制曲线会导致最高的RETE百分比和增加的结石体积去除量。
