Heat flow model for laser-irradiated biological tissue

Abstract

Numerical solutions to the basic heat flow equation: K{ ∇2T−1κ∂T∂t }=Q(t)(1) are presented, where Q (t) represents a specified average power density level delivered from a laser source to a target comprised of biological tissue. The model employed assumes such tissue to be homogeneous and characterized by an average thermal diffusivity, κ; an average thermal conductivity, K; and an average density, ρ. We show how computer-generated temperature profiles may be made, and how information extracted from such profiles may be consolidated into plots of surface temperature rise and depth of penetration of a given temperature with respect to exposure time at specified power density levels. Furthermore, we show that computer numerical simulation can predict heat flow characteristics of biological tissue in much the same manner as in previous laser material process modelling, provided limitations and simplifying assumptions of the technique are clearly understood.Numerical solutions to the basic heat flow equation: K{ ∇2T−1κ∂T∂t }=Q(t)(1) are presented, where Q (t) represents a specified average power density level delivered from a laser source to a target comprised of biological tissue. The model employed assumes such tissue to be homogeneous and characterized by an average thermal diffusivity, κ; an average thermal conductivity, K; and an average density, ρ. We show how computer-generated temperature profiles may be made, and how information extracted from such profiles may be consolidated into plots of surface temperature rise and depth of penetration of a given temperature with respect to exposure time at specified power density levels. Furthermore, we show that computer numerical simulation can predict heat flow characteristics of biological tissue in much the same manner as in previous laser material process modelling, provided limitations and simplifying assumptions of the technique are clearly understood.