title: Temperature-monitored optical treatment for radial tissue expansion.
abstract: Esophageal stricture occurs in 7-23% of patients with gastroesophageal reflux disease. However, the current treatments including stent therapy, balloon dilation, and bougienage involve limitations such as stent migration, formation of the new strictures, and snowplow effect. The purpose of the current study was to investigate the feasibility of structural expansion in tubular tissue ex vivo during temperature-monitored photothermal treatment with a diffusing applicator for esophageal stricture. Porcine liver was used as an ex vivo tissue sample for the current study. A glass tube was used to maintain a constant distance between the diffuser and tissue surface and to evaluate any variations in the luminal area after 10-W 1470-nm laser irradiation for potential stricture treatment. The 3D goniometer measurements confirmed roughly isotropic distribution with less than 10% deviation from the average angular intensity over 2π (i.e., 0.86 ± 0.09 in arbitrary unit) from the diffusing applicator. The 30-s irradiation increased the tissue temperature up to 72.5 °C, but due to temperature feedback, the interstitial tissue temperature became saturated at 70 °C (i.e., steady-state error = ±0.4 °C). The irradiation times longer than 5 s presented area expansion index of 1.00 ± 0.04, signifying that irreversible tissue denaturation permanently deformed the lumen in a circular shape and secured the equivalent luminal area to that of the glass tube. Application of a temperature feedback controller for photothermal treatment with the diffusing applicator can regulate the degree of thermal denaturation to feasibly treat esophageal stricture in a tubular tissue.
authors.affiliation: Department of Biomedical Engineering, Pukyong National University, 45 Yongso-ro Nam-gu, Busan, 48513, Republic of Korea.
authors.forename: Jinoh
authors.initials: J
authors.lastname: Bak
authors.affiliation: Department of Biomedical Engineering, Pukyong National University, 45 Yongso-ro Nam-gu, Busan, 48513, Republic of Korea. wkang@pukyong.ac.kr.|Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, South Korea. wkang@pukyong.ac.kr.
authors.forename: Hyun Wook
authors.initials: HW
authors.lastname: Kang
mesh_terms: D000818:Animals; D004947:Esophagus / Q000528:radiation effects*; D006801:Humans; D007834:Lasers; D008028:Light Coagulation; D008297:Male; D055620:Optical Phenomena; D034421:Sus scrofa; D013696:Temperature; D013997:Time Factors; D015626:Tissue Expansion
keywords: Esophageal stricture; Optical diffuser; Photocoagulation; Temperature monitoring