Closed-loop feedback control of phased-array microwave heating using thermal measurements from magnetic resonance imaging

Microwave heating is a promising technique for hyperthermia treatment of tumors, but is not yet a standard clinical method. Problems include the inability to control automatically and noninvasively the temporal and spatial temperature behavior. Magnetic resonance imaging (MRI) can be used to map thermal changes via phase shifts in gradient-echo images and has recently been incorporated into simple feedback systems for ultrasound heating. In this paper, we show the first demonstration of closed-loop feedback control of microwave heating using MRI-derived maps of both temperature and specific absorption rate as the inputs to a feedback algorithm. (C) 2002 Wiley Periodicals, Inc.