title: A two-temperature model for selective photothermolysis laser treatment of port wine stains.
abstract: Selective photothermolysis is the basic principle for laser treatment of vascular malformations such as port wine stain birthmarks (PWS). During cutaneous laser surgery, blood inside blood vessels is heated due to selective absorption of laser energy, while the surrounding normal tissue is spared. As a result, the blood and the surrounding tissue experience a local thermodynamic non-equilibrium condition. Traditionally, the PWS laser treatment process was simulated by a discrete-blood-vessel model that simplifies blood vessels into parallel cylinders buried in a multi-layer skin model. In this paper, PWS skin is treated as a porous medium made of tissue matrix and blood in the dermis. A two-temperature model is constructed following the local thermal non-equilibrium theory of porous media. Both transient and steady heat conduction problems are solved in a unit cell for the interfacial heat transfer between blood vessels and the surrounding tissue to close the present two-temperature model. The present two-temperature model is validated by good agreement with those from the discrete-blood-vessel model. The characteristics of the present two-temperature model are further illustrated through a comparison with the previously-used homogenous model, in which a local thermodynamic equilibrium assumption between the blood and the surrounding tissue is employed.
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
authors.forename: D
authors.initials: D
authors.lastname: Li
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China ; Department of Mechanical Engineering, The University of Akron, Akron, Ohio, 44325-3903, USA.
authors.forename: G X
authors.initials: GX
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
authors.forename: Y L
authors.initials: YL
authors.lastname: He
authors.affiliation: Beckman Laser Institute, University of California, Irvine, California, 92612, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Kelly
authors.affiliation: State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
authors.forename: W J
authors.initials: WJ
authors.lastname: Wu
authors.affiliation: Laser Treatment Center, Department of Dermatology, Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
authors.forename: Y X
authors.initials: YX
authors.lastname: Wang
authors.affiliation: Laser Treatment Center, Department of Dermatology, Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, China.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Ying
keywords: Monte-Carlo method; laser dermatology; local thermal non-equilibrium; porous media; port wine stains; two-temperature model
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