title: Evaluation of laser beam profile in soft tissue due to compression, glycerol, and micro-needling.
abstract: OBJECTIVE
  Various methods have been suggested to enhance photon density in biological tissues in an attempt to maximize the efficacy of laser therapy. In this study, the effects of tissue compression, glycerol, and micro-needling methods on the laser beam profile (LBP) were investigated by quantitatively evaluating the spatial distribution of subsurface tissue photon density.
  
  
  METHODS
  The LBP in tissue was obtained by imaging the laser beam transmitted through ex vivo porcine skin samples. The independent and combinational effects of tissue compression, glycerol, and micro-needling methods on the LBP were evaluated by quantitatively analyzing the full width at half-maximum (FWHM), maximum intensity, and total intensity at FWHM.
  
  
  RESULTS
  Experimental results indicate the enhancement of the quality of Gaussian beam profile in ex vivo porcine skin. Glycerol and tissue compression resulted in an increase of maximum and total intensity and a decrease of FWHM. Tissue compression in conjunction with glycerol was determined to be the most effective method for enhancing the LBP. The topical application of glycerol in conjunction with micro-needling reduced the time period to optically clear tissue, which resulted in a further increase of subsurface tissue photon density.
  
  
  CONCLUSIONS
  Tissue compression, glycerol, and micro-needling methods might be used independently or in combination to effectively enhance the photon density delivered to target chromophores in subsurface tissue, thus improving the LBP quality.
authors.affiliation: Department of Biomedical Engineering, Yonsei University, Wonju 220-710, Korea.
authors.forename: Heesung
authors.initials: H
authors.lastname: Kang
authors.forename: Taeyoon
authors.initials: T
authors.lastname: Son
authors.forename: Jinhee
authors.initials: J
authors.lastname: Yoon
authors.forename: Kiwoon
authors.initials: K
authors.lastname: Kwon
authors.forename: J Stuart
authors.initials: JS
authors.lastname: Nelson
authors.forename: Byungjo
authors.initials: B
authors.lastname: Jung
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D005990:Glycerol / Q000494:pharmacology*; D053685:Laser Therapy / Q000379:methods*; D011312:Pressure; D012867:Skin / Q000187:drug effects* / Q000528:radiation effects*; D013552:Swine
chemical_list: D005990:Glycerol
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