Methods and systems enable thermal treating a portion of a subject using microwave or other electromagnetic radiation without harming other portions of the subject. In an embodiment, a plurality of electromagnetic radiation transmitters are positioned within a thermal treatment system and coupled to a control processor. The electromagnetic radiation may be transmitted as a pseudorandom waveform and maybe microwave radiation. The control processor coordinates the transmitters so that emitted electromagnetic radiation constructively interferes within a treatment volume while radiation passing through the rest of the subject randomly interferes or appears as noise. As a result, in a volume in which the electromagnetic radiation waveforms arrive in phase the power of all the transmitters add constructively resulting in a significant temperature rise, while the rest of the subject is exposed to a much lower average power level and thus a lower temperature rise.
