title: Treatment of leg veins with indocyanine green and lasers investigated with mathematical modelling.
abstract: OBJECTIVE
  The treatment of leg veins is routinely performed in clinical practice using near infrared (NIR) lasers. However, due to low absorption of NIR light in blood vessels, the clinical results are still suboptimal. The absorption of the NIR light can be significantly increased with intravenous introduction of an indocyanine green (ICG) dye. In this work a mathematical model was used to delineate clinically valid settings for ICG and NIR lasers for the treatment of leg veins.
  
  
  METHODS
  A finite element commercial package was used to simulate light propagation and absorption and heat generation in a skin-like geometry. The simulations were conducted for 755 nm and 810 nm light wavelengths, which are emitted by alexandrite and diode lasers, respectively. Five different laser settings, six different vessel diameters (0.1-2 mm) and three ICG concentrations (0, 1 or 2 mg/kg body weight (BW)) were used to calculate the temperature field spatial distribution as a function of time.
  
  
  RESULTS
  The diameter of the blood vessels affects the temperature distribution during and following laser irradiation, with and without ICG. Adding 1 or 2 mg/kg bw of ICG will cause significant temperature increase (15-35°C, p ≤ 0.001) in blood vessels with a diameter of 0.1-1 mm and steep temperature gradients in 1.5-2 mm diameter blood vessels.
  
  
  CONCLUSIONS
  Intravenous application of ICG at 1-2 mg/kg may improve coagulation of blood vessels with 0.1-1 mm diameter irradiated with either a diode or alexandrite laser. This should be confirmed with clinical trials in the near future.
authors.affiliation: Department of Otolaryngology, Stephens Spine Center and Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock, USA. shafirsteingal@uams.edu
authors.forename: Gal
authors.initials: G
authors.lastname: Shafirstein
authors.forename: Mauricio
authors.initials: M
authors.lastname: Moreno
authors.forename: Annette
authors.initials: A
authors.lastname: Klein
authors.forename: Eric
authors.initials: E
authors.lastname: Siegel
authors.forename: Philipp
authors.initials: P
authors.lastname: Babilas
authors.forename: Michael
authors.initials: M
authors.lastname: Landthaler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baeumler
mesh_terms: D004396:Coloring Agents / Q000627:therapeutic use*; D006801:Humans; D007208:Indocyanine Green / Q000627:therapeutic use*; D017075:Laser Coagulation; D007834:Lasers; D007866:Leg / Q000098:blood supply; D008954:Models, Biological; D014652:Vascular Diseases / Q000601:surgery*; D014680:Veins / Q000601:surgery*
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green