1. A multibaseline method of performing proton resonance frequency (PRF) thermometry, the method comprising the steps of: acquiring a plurality of PRF baseline images of an imaging region, each baseline image corresponding to a PRF phase background during the imaging region's cycle of motion; acquiring a PRF treatment image of the imaging region subsequent to temperature change of a subregion within the imaging region; estimating a phase background of the imaging region by fitting a combination of the PRF baseline images to the treatment image; and estimating a temperature distribution within the subregion based on the treatment image and the estimated phase background.