ABSTRACT
This chapter examines the available modalities for their potential for local hyperthermia before discussing the various ways in which ultrasound is used. The principal modalities in clinical use of local hyperthermia are microwave and radiofrequency electromagnetic energy, and ultrasound. Theoretical predictions of their capabilities for controlled, localized heating of deep or superficial tumors have been based on considerations of their propagation characteristics in biological tissues and the heat transfer phenomena, including blood perfusion. The relative amplitude and location of the peaks depends on whether the transducer is driven at or slightly off resonance, on its mounting, but their amplitude can be three times as high as the spatial average intensity. The steady–state temperature distributions obtained in the gluteal muscle mass of dog in vivo from 1.8 MHz ultrasound applied in stationary, planar and scanned, focused modes. The MIT scanned, focused ultrasound system incorporates a confocal diagnostic ultrasound transducer.
