Nicholas C Giglio1, Thomas C Hutchens1, Austin A South2, Nathaniel M Fried1. 1. University of North Carolina at Charlotte, Department of Physics and Optical Science, Charlotte, Nor, United States. 2. University of North Carolina at Charlotte, Department of Mechanical Engineering, Charlotte, North Ca, United States.
Abstract
SIGNIFICANCE: Water is a primary absorber of infrared (IR) laser energy, and urinary stones are immersed in fluid in the urinary tract and irrigated with saline during IR laser lithotripsy. Laser-induced vapor bubbles, formed during lithotripsy, contribute to the stone ablation mechanism and stone retropulsion effects. AIM: Introduction of a surfactant may enable manipulation of vapor bubble dimensions and duration, potentially for more efficient laser lithotripsy. APPROACH: A surfactant with concentrations of 0%, 5%, and 10% was tested. A single pulse from a thulium fiber laser with wavelength of 1940 nm was delivered to the surfactant through a 200-μm-core optical fiber, using a wide range of laser parameters, including energies of 0.05 to 0.5 J and pulse durations of 250 to 2500 μs. RESULTS: Bubble length, width, and duration with surfactant increased on average by 29%, 17%, and 120%, compared with water only. CONCLUSIONS: Our study demonstrated successful manipulation of laser-induced vapor bubble dimensions and duration using a biocompatible and commercially available surfactant. With further study, use of a surfactant may potentially improve the "popcorn" technique of laser lithotripsy within the confined space of the kidney, enable non-contact laser lithotripsy at longer working distances, and provide more efficient laser lithotripsy.
SIGNIFICANCE: Water is a primary absorber of infrared (IR) laser energy, and urinary stones are immersed in fluid in the urinary tract and irrigated with saline during IR laser lithotripsy. Laser-induced vapor bubbles, formed during lithotripsy, contribute to the stone ablation mechanism and stone retropulsion effects. AIM: Introduction of a surfactant may enable manipulation of vapor bubble dimensions and duration, potentially for more efficient laser lithotripsy. APPROACH: A surfactant with concentrations of 0%, 5%, and 10% was tested. A single pulse from a thulium fiber laser with wavelength of 1940 nm was delivered to the surfactant through a 200-μm-core optical fiber, using a wide range of laser parameters, including energies of 0.05 to 0.5 J and pulse durations of 250 to 2500 μs. RESULTS: Bubble length, width, and duration with surfactant increased on average by 29%, 17%, and 120%, compared with water only. CONCLUSIONS: Our study demonstrated successful manipulation of laser-induced vapor bubble dimensions and duration using a biocompatible and commercially available surfactant. With further study, use of a surfactant may potentially improve the "popcorn" technique of laser lithotripsy within the confined space of the kidney, enable non-contact laser lithotripsy at longer working distances, and provide more efficient laser lithotripsy.
Authors: Yuri A Pishchalnikov; William Behnke-Parks; Kazuki Maeda; Tim Colonius; Matthew Mellema; Matthew Hopcroft; Alice Luong; Scott Wiener; Marshall L Stoller; Thomas Kenny; Daniel J Laser Journal: Proc Meet Acoust Date: 2019-01-17