Mp43-12 Effect of Pulse Modulation on Stone Ablation Using a Diode-Pumped Tm:yag Laser

You have accessJournal of UrologySurgical Technology & Simulation: Instrumentation & Technology II (MP43)1 May 2024MP43-12 EFFECT OF PULSE MODULATION ON STONE ABLATION USING A DIODE-PUMPED TM:YAG LASER Nitesh Katta, Katherine Lydia Sikorski, Joel Teichman, and Thomas E. Milner Nitesh KattaNitesh Katta , Katherine Lydia SikorskiKatherine Lydia Sikorski , Joel TeichmanJoel Teichman , and Thomas E. MilnerThomas E. Milner View All Author Informationhttps://doi.org/10.1097/01.JU.0001008720.96896.83.12AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: We studied how pulse characteristics affect stone ablation, seeking to find the optimal pulse modulation with a diode-pumped thulium yttrium aluminum garnet (Tm:YAG) laser. We also examined the impact of effective energy transmission (EET) from the fiber tip to the stone through optimal pulse modulation at various stand-off distances (SD). METHODS: We used a diode-pumped Tm:YAG laser (2060 nm, 1500 W) with adjustable pulse parameters, in single- and dual-pulse modes to assess EET from the fiber tip to stone target through water at varying stand-off distances (SD). EET was calculated for each experiment using EET=100*(REwater/REair) %, where REsaline is the measured pulse radiant energy through water versus REair is the measured pulse radiant energy in air. We tested single and dual-pulse ablation with gypsum stones and natural human kidney stones including calcium oxalate monohydrate (COM), uric acid (UA), calcium oxalate dihydrate (COD), calcium phosphate (CaPO4). Post-ablation, optical coherence tomography was used to image craters and calculate ablation volume. Student's t-test was used for statistical analysis. RESULTS: Dual-pulse modulation using diode-pumped Tm:YAG provided higher EET compared to single pulses at SD>0.5 mm, corresponding to more photons reaching the stone (Figure 1A). Dual-pulse mode consistently showed greater gypsum phantom stone crater ablation volume at SD=0.5 mm (p<0.001) and and SD=1 mm (p<0.001), and for hardened gypsum (p<0.004) and for Ultracal30 (p<0.003). For native stones, dual-pulse outperformed single pulse mode in crater volume across most cohorts. In COM, the difference in crater volume was not statistically significant (p=0.4), but was significant for UA (p=0.02), CaPO4 (p=0.04), and COD (p=0.03) at SD=1 mm (Figure 1B), and COM (p<0.01), UA (p<0.05), CaPO4 (p<0.008), and COD (p<0.004) at SD=0.5 mm. CONCLUSIONS: Effective energy transmission is essential for photothermal stone removal. Experimental results support that photothermal effects dominate stone removal mechanism of action across all compositions and conditions with diode-pumped lasers. Pulse pause duration affects fragmentation. Pulse modulation can enhance ablation volumes per unit radiant energy in phantom stones but can vary with stone composition. Download PPT Source of Funding: University of California at Irvine (UCI) school of medicine start-up funds to Thomas E. Milner © 2024 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 211Issue 5SMay 2024Page: e698 Advertisement Copyright & Permissions© 2024 by American Urological Association Education and Research, Inc.Metrics Author Information Nitesh Katta More articles by this author Katherine Lydia Sikorski More articles by this author Joel Teichman More articles by this author Thomas E. Milner More articles by this author Expand All Advertisement PDF downloadLoading ...