Enhanced photocoagulation with catheter-based diffusing optical device

Abstract

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 ¼ 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 cm 2 at 1 min irradiation) in tissue in vitro. The prototype device demonstrated the coagulation necrosis of 2.8 AE 1.2 mm (n ¼ 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.

Integration of optical applicator with balloon catheter for photothermal treatment of biliary stricture

“…However, the wall thickness of the balloon is typically less than 100 mm, implying that the thin balloon may still be vulnerable to sudden temperature elevation and higher power irradiation. In fact, previous studies demonstrated that the balloon behaved as a thermal insulating barrier due to different thermal conductivities between PET and air inside the balloon [17,18]. The insulation effect helped rapidly develop the interstitial temperature up to 1008C.…”

Real-time co-registered photoacoustic and ultrasonic imaging for early endometrial cancer detection driven by cylindrical diffuser

“…21 Kang et al proposed a catheter-based CD as a feasible therapeutic tool to photocoagulate endometrial cell layers in an e±cient and safe manner. 22 In previous work by our team, we proposed a PA method for the estimation and reconstruction of 3D light distribution produced by a CD in biological tissue. 23 This paper describes a co-registered PA and US imaging system for EEC detection based on a CD.…”

Computational analysis of endometrial photocoagulation with diffusing optical device

“…In order to accomplish less invasive and more efficient endometrial coagulation, various laser wavelengths including 1064 nm, 1320 nm, and 2.12 μm have also been applied as laser-assisted TBEA treatments [12]. Light absorption by the endometrial tissue typically gives rise to heat, resulting in permanent thermal damage to the endometrium layer once the tissue temperature reaches around 338 K or above [13,14]. However, highly localized tissue coagulation with these wavelengths was quite difficult to predict the degree of thermal damage in uterine tissue and often require high surgical skills for clinicians to achieve the successful removal of the targeted endometrium [12,15].…”

“…In our previous study, a novel balloon-catheter diffusing device was designed and experimentally evaluated in association with visible wavelength 532 nm as a new surgical tool to efficiently and safely treat an endometrial cell layer [13]. Due to high rate of light absorption by the endometrium in uterus, the wavelength showed a capability of rapid tissue coagulation with minimal injury to the peripheral tissue in vitro and in vivo.…”

“…Due to high rate of light absorption by the endometrium in uterus, the wavelength showed a capability of rapid tissue coagulation with minimal injury to the peripheral tissue in vitro and in vivo. The design of light diffusion through the fiber also helped induce the uniform distribution of the laser light, facilitating consistent coagulative necrosis [13]. However, the underlying mechanisms of temperature growth and distribution in tissue during photocoagulation are still poorly understood.…”