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Proceedings Paper

Laser treatment of female stress urinary incontinence: optical, thermal, and tissue damage simulations
Author(s): Luke A. Hardy; Chun-Hung Chang; Erinn M. Myers; Michael J. Kennelly; Nathaniel M. Fried
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Paper Abstract

Treatment of female stress urinary incontinence (SUI) by laser thermal remodeling of subsurface tissues is studied. Light transport, heat transfer, and thermal damage simulations were performed for transvaginal and transurethral methods. Monte Carlo (MC) provided absorbed photon distributions in tissue layers (vaginal wall, endopelvic fascia, urethral wall). Optical properties (n,μa,μs,g) were assigned to each tissue at λ=1064 nm. A 5-mm-diameter laser beam and power of 5 W for 15 s was used, based on previous experiments. MC output was converted into absorbed energy, serving as input for ANSYS finite element heat transfer simulations of tissue temperatures over time. Convective heat transfer was simulated with contact cooling probe set at 0 °C. Thermal properties (κ,c,ρ) were assigned to each tissue layer. MATLAB code was used for Arrhenius integral thermal damage calculations. A temperature matrix was constructed from ANSYS output, and finite sum was incorporated to approximate Arrhenius integral calculations. Tissue damage properties (Ea,A) were used to compute Arrhenius sums. For the transvaginal approach, 37% of energy was absorbed in endopelvic fascia layer with 0.8% deposited beyond it. Peak temperature was 71°C, treatment zone was 0.8-mm-diameter, and almost all of 2.7-mm-thick vaginal wall was preserved. For transurethral approach, 18% energy was absorbed in endopelvic fascia with 0.3% deposited beyond it. Peak temperature was 80°C, treatment zone was 2.0-mm-diameter, and only 0.6 mm of 2.4-mm-thick urethral wall was preserved. A transvaginal approach is more feasible than transurethral approach for laser treatment of SUI.

Paper Details

Date Published: 29 February 2016
PDF: 6 pages
Proc. SPIE 9689, Photonic Therapeutics and Diagnostics XII, 96891R (29 February 2016); doi: 10.1117/12.2208126
Show Author Affiliations
Luke A. Hardy, The Univ. of North Carolina at Charlotte (United States)
Chun-Hung Chang, The Univ. of North Carolina at Charlotte (United States)
Erinn M. Myers, Carolinas Medical Ctr. (United States)
Michael J. Kennelly, Carolinas Medical Ctr. (United States)
Nathaniel M. Fried, The Univ. of North Carolina at Charlotte (United States)
Carolinas Medical Ctr. (United States)


Published in SPIE Proceedings Vol. 9689:
Photonic Therapeutics and Diagnostics XII
Hyun Wook Kang; Guillermo J. Tearney; Melissa C. Skala; Bernard Choi; Andreas Mandelis; Brian J. F. Wong; Justus F. Ilgner; Nikiforos Kollias; Paul J. Campagnola; Kenton W. Gregory; Laura Marcu; Haishan Zeng, Editor(s)

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