This hyperthermia project is to determine whether localized hyperthermia alone or in conjunction with ionizing radiation and/or chemotherapy, can improve the outcome in the treatment of cancer over that which can be achieved by irradiation alone. In order to accomplish this objective: a) methods of heating superficial and deep tumors must be improved; b) the optimum frequency, duration, and temperature of the heating must be resolved; and c) the interaction of certain chemical modifiers of both heat and irradiation must be tested. Applicators for heating superficial neoplasms include several ultrasonic devices ranging from 2 cm. to 6 cm. in diameter, which were designed and fabricated in our own laboratories, and commercial microwave units designed by BSD and Varian Associates. Applicators for localized heating of deep seated neoplasms include an isospherical ultrasound unit with six pre-focused piezo-electric crystals, and the BSD-2000 annular phased array, which will be used for regional heating. In addition, two interstitial units are to be developed, one an RF unit to be fabricated in our own laboratories, and the other a microwave unit to be fabricated by Varian Associates. The latter two will be fabricated under the auspices of complementary programs but tested in this project. The latter two will be fabricated under the auspices of complementary programs but tested in this project. Once the technology of heating local neoplasms has been more thoroughly understood, experiments will be conducted on the most appropriate scheduling of heat and radiation, and on the interaction of radiation sensitizers of the misonidazole variety, with various combinations of heat and radiation. In conjunction with the above studies, a variety of temperature-measuring devices will be tested. These include Baily thermocouple sensors for ultrasound heating and Bowman thermistor probes for microwave heating. We will also study linear arrays of miniature silicon sensors fabricated in the Stanford Electrical Engineering laboratories, and non-metallic optical probes which use GaAs crystals which reflect light in a manner depending on crystal temperature (Christensen probes).
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