title: Laser interstitial thermotherapy of small breast fibroadenomas: numerical simulations.
abstract: BACKGROUND
  Laser interstitial thermotherapy (LITT) is potentially a novel method to treat small breast fibroadenoma, without the need for surgical removal. Dosimetry planning and conformation of the treated area of tumor remain major issues, especially for a moving organ such as the breast. Pre-treatment simulation planning of this therapy is an effective method to predict the final thermal damage. In this study, a mathematical model is elaborated to simulate the heat distribution and the thermal damage.
  
  
  METHODS
  The mathematical model was based on finite element method (FEM) to solve the light distribution, bioheat, and thermal damage equations. Six simulations were performed with the following powers: 5, 6, 7, 8, 9, and 10 W (λ = 980 nm), and for an irradiation time of 125 seconds, with a 50 °C iso-damage temperature. To validate these simulations, six turkey breast samples were irradiated with parameters used for simulations. Volumes of thermal damage were calculated by using formulas: spherical, Elliptical, and Carlsson volumes and compared to the simulated volumes.
  
  
  RESULTS
  Differences between volumes were from 0.01 to 1 cm3. Interpolations between volumes from ex vivo experiments with corresponding powers were established. The relationship between the volume of the thermal damage and the laser power was described by a polynomial equation (R2  = 0.99). The power estimated by the interpolation to obtain 1 cm3 of thermal damage was 7.4 W (922 J) and the maximum corresponding temperature was 90 °C.
  
  
  CONCLUSIONS
  In this study, a good correlation was established between simulation and ex vivo experiments of LITT for fibroadenoma breast cancer.
authors.affiliation: Inserm, U703, 152 rue du Docteur Yersin, 59120 Loos, France.
authors.forename: Mohamad Feras
authors.initials: MF
authors.lastname: Marqa
authors.forename: Serge
authors.initials: S
authors.lastname: Mordon
authors.forename: Nacim
authors.initials: N
authors.lastname: Betrouni
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000601:surgery*; D003198:Computer Simulation; D005260:Female; D018226:Fibroadenoma / Q000601:surgery*; D020342:Finite Element Analysis; D066298:In Vitro Techniques; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D008954:Models, Biological; D014422:Turkeys