PD01-03 CHANGES IN STONE CORE TEMPERATURE: FRAGMENTATION VS. DUSTING

Abstract

You have accessJournal of UrologyCME1 Apr 2023PD01-03 CHANGES IN STONE CORE TEMPERATURE: FRAGMENTATION VS. DUSTING Ron Marom, John Robinson, Adam J. Matzger, Adam Maxwell, Khurshid R. Ghani, Timothy L. Hall, and William W. Roberts Ron MaromRon Marom More articles by this author , John RobinsonJohn Robinson More articles by this author , Adam J. MatzgerAdam J. Matzger More articles by this author , Adam MaxwellAdam Maxwell More articles by this author , Khurshid R. GhaniKhurshid R. Ghani More articles by this author , Timothy L. HallTimothy L. Hall More articles by this author , and William W. RobertsWilliam W. Roberts More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003218.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Tailoring and optimizing laser settings to achieve desired ablation effects (dusting vs. fragmenting) is challenging, in part due to an incomplete understanding of the mechanism of laser stone ablation. Recently, the dominance of photothermal over photoacoustic effects has been challenged. Quantification of the photothermal effect by measuring the temperature of the stone with absorption of laser energy could help us better understand the contribution of this mechanism of stone ablation. The objective of this study was to measure stone temperature during laser lithotripsy. METHODS: A cylindrical BegoStone model with a diameter of 8 mm and a height of 10 mm was molded with a thermocouple along its long axis with the tip at its center. A laser fiber was set perpendicular to the long axis and in contact with the stone surface. While the laser was activated for 30 seconds in an air medium, the fiber was moved by a 3D stepper scanning the surface of the stone. Two 10-Watt laser settings were used – 0.2 J × 50 Hz (Dusting) and 1 J × 10 Hz (Fragmentation) for 5 cycles with 30 seconds in between. Additionally, the power outputs of these settings were measured and compared using a power meter. RESULTS: The stone core temperature increased after each cycle of laser activation and did not return to baseline between cycles (Figure 1). Stone temperature of up to 120°C was observed. The 1 J × 10 Hz setting produced greater temperatures, 30°C greater than produced by 0.2 J × 50 Hz after the 5th laser cycle (Figure 2). This significant difference between same power settings can only be partially explained by the inconsistent energy output of the Ho:YAG laser, with up to 15% energy deviation as measured by a power meter. CONCLUSIONS: We have developed a tool to investigate temperature elevation in a stone model and shown that laser lithotripsy can substantially elevate stone temperature. Furthermore, the higher temperature found with higher pulse energy deserves additional exploration as temperature may play a role in determining whether dusting or fragmentation dominates stone comminution. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e63 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ron Marom More articles by this author John Robinson More articles by this author Adam J. Matzger More articles by this author Adam Maxwell More articles by this author Khurshid R. Ghani More articles by this author Timothy L. Hall More articles by this author William W. Roberts More articles by this author Expand All Advertisement PDF downloadLoading ...