Using skin heat transfer anisotropy as a diagnostic tool (Measurement of Skin Thermal Properties)

Progress in analytical solutions to bioheat transfer problems is stifled by differences in thermal properties between different people and the variance of these properties based on many variables that are difficult to control or account for. Research was conducted to determine an experiment that could measure thermal properties of skin in vivo, with potential use in calculation of skin burn depth based on skin surface temperature distributions. However, the specific vascular morphology and lack of agreement on one particular model led to the belief that thermal property measurement, which depends on the model to be used, would not be accurate enough for the desired clinical use. Moving beyond strict mathematical models, an experiment was designed that could compare the thermal reaction of skin against itself in order to isolate any anisotropies present due the flow of blood in one or more directions. The expected result is that advected blood, which has a specific direction in the capillary bed, diffuses heat better than conduction through the tissue. This would cause an directional difference on the measured heat rate supplied by an external source on the surface of the skin. The absolute value of this difference should be a function of the amount of bloodflow taking place in the capillaries and arterioles. In burned skin, where there is no bloodflow, this difference will be smaller, depending on the depth of the burn. This allows the directional relevance of heat diffusion to be used as a diagnostic tool for determining the depth of burned skin.