Abstract
Successful use of kinetic models of thermal damage processes depends critically upon the identification of a quantitative measure of thermal damage. Most clinically relevant processes are qualitative in nature and are not easily studied by the standard Arrhenius formulation. Quantitative markers of thermal damage include: 1) loss of birefringence properties in muscle and collagen, 2) loss of hemoglobin from red blood cells, 3) uptake of enzymatically active dyes and 4) diffusion of dyes across vessel walls. When a quantitative marker is used the kinetic coefficients estimated from experiments over different time scales are significantly different. Application of coefficients determined in long term studies (exposure times on the order of hours) to short term exposures (electrosurgical coagulation or short laser pulses) is questionable and often leads to counter-intuitive predictions of damage boundaries. Short term exposures, on the other hand, are by definition not of constant temperature and often defy estimation of the coefficients from the transient history. We present and compare several sets of estimated thermal damage coefficients for similar and differing processes and a preliminary method for extracting estimates from transient histories.
