Animal Experiments with Interstitial Water Hyperthermia

Abstract

Invasive hyperthermia methods have been developed as an alternative when noninvasive systems are inefficient or not adapted for producing therapeutic temperatures throughout the entire tumor volume, without overheating normal tissues. Another major interest is the synergistic effect of interstitial hyperthermia combined with irradiation (Emani et al, 1984; Cosset et al, 1985a). When interstitial irradiation is combined with external irradiation or is employed alone, the heating can be added using previously implanted catheters. Thus, the heating could be better localized and controlled than in noninvasive methods. This is particularly true for deep-seated tumors where hyperthermic levels cannot be always obtained by noninvasive methods (Dutreix et al, 1982). The methods for interstitial hyperthermia mostly used at present are implantable microwave antennas, localized current fields, and ferromagnetic seeds (e.g. Strohbehn and Mechling, 1986; Stauffer et al, 1989). The ferromagnetic seed technique differs from the other two in that the heating of tissue is completely dependent upon its thermal conduction and blood flow cooling. Thermal seeds are in this case “hot sources”. Another hot source can be hot water circulating through an array of implanted tubes (Handl-Zeller et al, 1986) which are subsequently loaded with Ir-192 wires.