title: Simulation of laser-tattoo pigment interaction in a tissue-mimicking phantom using Q-switched and long-pulsed lasers.
abstract: BACKGROUND
  Laser therapy is the treatment of choice in tattoo removal. However, the precise mechanisms of laser-tattoo pigment interactions remain to be evaluated.
  
  
  METHODS
  We evaluated the geometric patterns of laser-tattoo pigment particle interactions using a tattoo pigment-embedded tissue-mimicking (TM) phantom.
  
  
  RESULTS
  A Q-switched (QS) neodymium-doped yttrium aluminum garnet laser was used at settings of 532-, 660-, and 1064-nm wavelengths, single-pulse and quick pulse-to-pulse treatment modes, and spot sizes of 4 and 7 mm. Most of the laser-tattoo interactions in the experimental conditions formed cocoon-shaped or oval photothermal and photoacoustic injury zones, which contained fragmented tattoo particles in various sizes depending on the conditions. In addition, a long-pulsed 755-nm alexandrite laser was used at a spot size of 6 mm and pulse widths of 3, 5, and 10 ms. The finer granular pattern of tattoo destruction was observed in TM phantoms treated with 3- and 5-ms pulse durations compared to those treated with a 10-ms pulse.
  
  
  CONCLUSIONS
  We outlined various patterns of laser-tattoo pigment interactions in a tattoo-embedded TM phantom to predict macroscopic tattoo and surrounding tissue reactions after laser treatment for tattoo removal.
authors.affiliation: Department of Science Education, Jeju National University, Jeju, Korea.
authors.forename: K J
authors.initials: KJ
authors.lastname: Ahn
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.
authors.forename: B J
authors.identifier: http://orcid.org/0000-0003-2320-7621
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Korea.|Kangskin Sillim Dermatology Clinic, Seoul, Korea.
authors.forename: S B
authors.initials: SB
authors.lastname: Cho
mesh_terms: D032701:Biomimetics / Q000379:methods*; D003357:Cosmetic Techniques / Q000009:adverse effects* / Q000295:instrumentation; D062109:Dermatologic Surgical Procedures / Q000379:methods; D006801:Humans; D053685:Laser Therapy / Q000379:methods* / Q000639:trends; D007834:Lasers; D053844:Lasers, Solid-State / Q000627:therapeutic use; D012867:Skin / Q000033:anatomy & histology / Q000528:radiation effects*; D013653:Tattooing
keywords: Q-switched neodymium-doped yttrium aluminum garnet laser; laser; long-pulsed alexandrite laser; tattoo pigment; tissue-mimicking phantom