Local Hyperthermia with Interstitial Techniques1

The heating of deep visceral tumors with implanted electrodes and with self-regulating ferromagnetic thermoseeds was inves tigated. Clinical trials on six patients heated with implanted electrodes indicate that good local tumor control can be obtained by application of hyperthermia during a normal course of radio therapy. The heating method was found practical, and neither toxicity nor severe patient discomfort was encountered. How ever, temperature inhomogeneity within the tumor volume re mains a problem. Theoretical studies and an animal experiment indicate that temperature homogeneity can be largely improved by heating the tumor with thermoseeds made of an alloy of 70.4% nickel and 29.6% copper. The highly temperature-de pendent rate of heat production in the vicinity of the Curie point, about 50° for this material, provides automatic temperature