title: Cross-evaluation of optimal glycerol concentration to enhance optical tissue clearing efficacy.
abstract: OBJECTIVE
  The efficacy of light therapeutic and diagnostic applications can be enhanced by employing optical tissue clearing (OTC) agents to minimize light scattering in tissue. This study aimed to investigate the optimal concentration of glycerol, so that it can be efficiently used as an OTC agent in dermatology.
  
  
  METHODS
  Glycerol was topically applied to avoid the possibility of edema that could be caused by dermal injection. The efficacy of glycerol was quantitatively evaluated for various concentrations using optical coherence tomography (OCT) to evaluate light scattering and ultrasound imaging modality to evaluate collagen dissociation.
  
  
  RESULTS
  The intensity in the OCT images in the deeper regions increased over time after glycerol application owing to enhanced light penetration caused by glycerol permeation into the sample. A comparable decrease over time in the collagen distribution was observed in the ultrasound images after glycerol application.
  
  
  CONCLUSIONS
  The optimal concentration of glycerol to maximize OTC was found to be 70%. The finding of this study may provide a guideline regarding the use of glycerol for efficient light diagnosis and therapy in dermatology.
authors.affiliation: Department of Biomedical Engineering, Yonsei University, Wonju, Korea.
authors.forename: T
authors.initials: T
authors.lastname: Son
authors.affiliation: Department of Biomedical Engineering, Yonsei University, Wonju, Korea.
authors.forename: B
authors.initials: B
authors.lastname: Jung
mesh_terms: D065638:Absorption, Radiation / Q000187:drug effects; D000279:Administration, Cutaneous; D000818:Animals; D003094:Collagen / Q000378:metabolism*; D003287:Contrast Media / Q000008:administration & dosage; D003879:Dermatologic Agents / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005990:Glycerol / Q000008:administration & dosage*; D066298:In Vitro Techniques; D008027:Light; D017319:Photosensitizing Agents / Q000008:administration & dosage*; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012680:Sensitivity and Specificity; D012867:Skin / Q000000981:diagnostic imaging*; D012879:Skin Physiological Phenomena / Q000187:drug effects*; D013552:Swine; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D003879:Dermatologic Agents; D017319:Photosensitizing Agents; D003094:Collagen; D005990:Glycerol
keywords: concentration; glycerol; optical clearing agents; optical tissue clearing