A thermo-pharmacokinetic model of tissue temperature oscillations during localized heating

Abstract

Thermally-induced large blood flow increases and oscillations have been experimentally observed in both muscle and prostate tissues. However, the bio-physical/-chemical mechanisms underlying these phenomena remain undiscovered. To study the basic nature of these coupled thermal-mass transport processes, this study combines a compartmental vasodilator pharmacokinetics model with a bio-heat-transfer temperature model. The resulting simulated temperature responses to different applied power levels closely match both the overall behaviour and the fine structure of the complex temperature responses observed in vivo. This suggests that the coupled thermo-pharmacokinetic model captures the essence of the links between tissue temperature and blood flow oscillations and of the role of the important vaso-active substances. Thus, it appears that such thermo-pharmacokinetic models can provide a basis for helping to understand and quantify the fundamental bio-physical/-chemical processes that couple the transient tissue temperature distributions to blood flow oscillations. Such combined models allow investigators to directly predict tissue blood flow responses to applied power and avoid the need to make ad hoc assumptions regulating the blood flow rates present in heated tissues.