Figure 1

Transport lattice method – Geometry with transport, source and storage models. The one-dimensional model of human skin (top) is represented by a lattice of conduction models (M _c ) and source, storage and sink models (M _s ). The subscripts denote the different layers of the model, namely, a: air, e: epidermis, d: dermis and s: subcutaneous tissue. The equivalent circuit models are shown for each layer: R _c represents heat conduction, R _p represents heat removal by perfusion (not present in epidermis) and C represents heat storage. The conduction model, M _c , is represented by R _c while the storage, perfusion and power input model, M _s , is represented by the combination of R _p , C and I (Table 2). (a) Surface Contact Heating: The surface temperature T _s is elevated from 33°C to 45°C at t = 0. (b) Spatially Distributed Heating: A layer of air contacting the skin is added to the model with the air temperature (T _air ) held at 25°C. The local microwave power dissipation is represented by the current source (I) at each node. The arterial reference temperature T _a is represented by a common node. A ladder-like network of variable resistors, R _p , represents the temperature dependent perfusion in dermis and subcutaneous tissue.