[Calculation of the dynamic heating process in multilayer model tissues during local hyperthermy using the CMT...

The hyperthermic dose necessary for triggering the mechanism of irreversible occlusion of vessels in cancer tissues was assessed to be in the order of 42 degrees C--30 min. (Compare: using hyperthermy without adjuvant measures, the temperature dose needed is at least 42.5 degrees C--140 min) In order to avoid any impairment of skintight tissue and to apply the temperature dose 42 degrees C--30 min also to deep-seated tumors which might be surrounded by normal tissue well supplied with blood, we developed a two-stage local hyperthermy technique with homogenized energy supply to different body sections according to the CMT Selectotherm scanning principle. The method and the results of heat-theoretical calculations made for understanding the dynamic heating process in multilayer tissue models are reported. Employing an electronic computer we succeeded in calculating convenient parameters for an improved applicator system of our CMT Selectotherm device as well as in determining the time course of the spatial temperature topography in three--or fourlayered model tissues under different conditions. It follows from the calculated data that the therapeutic applicability of his new local hyperthermic method can be decisively improved by intensive skin cooling and by short-term manipulation of blood-flow parameters (e.g., by unbloody localized blood pressure reduction). Finally, it is emphasized that the empirical use of hyperthermy in cancer treatment, as it has been employed by other clinical research groups up to now, seems to be no longer responsible. Due to the complicated interrelationships of therapeutically relevant factors, only a solid theoretical standpoint based on and controlled by many thousands of experiments (measurements) provides both an useful procedure adapted to every individual case and the maximum prospects of success.