title: Enhanced photocoagulation with catheter-based diffusing optical device.
abstract: A novel balloon catheter-based diffusing optical device was designed and evaluated to assist in treating excessive menstrual bleeding. A synthetic fused-silica fiber was micro-machined precisely to create scattering segments on a 25 mm long fiber tip for uniform light distribution. A visible wavelength (λ=532  nm) was used to specifically target the endometrium due to the high vascularity of the uterine wall. Optical simulation presented 30% wider distribution of photons along with approximately 40% higher irradiance induced by addition of a glass cap to the diffuser tip. Incorporation of the optical diffuser with a polyurethane balloon catheter considerably enhanced coagulation depth and area (i.e., 3.5 mm and 18.9  cm2 at 1 min irradiation) in tissue in vitro. The prototype device demonstrated the coagulation necrosis of 2.8±1.2  mm (n=18) and no thermal damage to myometrium in in vivo caprine models. A prototype 5 cm long balloon catheter-assisted optical diffuser was also evaluated with a cadaveric human uterus to confirm the coagulative response of the uterine tissue as well as to identify the further design improvement and clinical applicability. The proposed catheter-based diffusing optical device can be a feasible therapeutic tool to photocoagulate endometrial cell layers in an efficient and safe manner.
authors.affiliation: Pukyong National University, Department of Biomedical Engineering, 45 Yongso-ro Nam-gu, Busan, 608-737, Republic of Korea.
authors.forename: Hyun Wook
authors.initials: HW
authors.lastname: Kang
authors.forename: Jeehyun
authors.initials: J
authors.lastname: Kim
authors.forename: Jungwhan
authors.initials: J
authors.lastname: Oh
mesh_terms: D000818:Animals; D057785:Catheters; D002417:Cattle; D004058:Diffusion; D004717:Endometrium / Q000098:blood supply; D004867:Equipment Design; D005260:Female; D006041:Goats; D006801:Humans; D008028:Light Coagulation / Q000295:instrumentation*; D008595:Menorrhagia / Q000628:therapy*; D023421:Models, Animal; D055096:Optical Devices; D055100:Optical Fibers; D055620:Optical Phenomena; D012822:Silicon Dioxide
chemical_list: D012822:Silicon Dioxide