Proceedings Article | 6 February 2017
KEYWORDS: Monte Carlo methods, Optical clearing, Computer simulations, Laser therapeutics, Optical simulations, Tissues, Reflectance spectroscopy, Tissue optics, Transmittance, Optical coherence tomography, Scattering, Natural surfaces
Near-IR laser energy in conjunction with applied tissue cooling is being investigated for thermal remodeling of
endopelvic fascia during minimally invasive treatment of female stress urinary incontinence. Previous simulations
of light transport, heat transfer, and tissue thermal damage have shown that a transvaginal approach is more feasible
than a transurethral approach. However, undesirable thermal insult to vaginal wall was predicted. This study
explores whether an optical clearing agent (OCA) can improve optical penetration depth and completely preserve
vaginal wall during subsurface treatment of endopelvic fascia. Several OCA mixtures were tested, and 100%
glycerol was found to be optimal. Optical transmission studies, optical coherence tomography, reflection
spectroscopy, and computer simulations of thermal damage to tissue using glycerol were performed. The OCA
produced a 61% increase in optical transmission through porcine vaginal wall at 37 °C after 30 min. Monte Carlo
(MC) light transport, heat transfer, and Arrhenius integral thermal damage simulations were performed. MC model
showed improved energy deposition in endopelvic fascia using OCA. Without OCA, 62, 37, and 1% of energy was
deposited in vaginal wall, endopelvic fascia, and urethral wall, compared with 50, 49, and 1% with OCA. Use of
OCA also yielded 0.5 mm increase in treatment depth, allowing potential thermal tissue remodeling at 3 mm depth.
