This invention is generally in the field of improved methods for the localized delivery of heat and the localised imaging of biological materials. The delivery may be in vitro or in vivo and is useful for the localized treatment of cancer, inflammation or to other disorders involving overproliferation of tissue. The method is also useful for diagnostic imaging. The method involves localized induction of hyperthermia in a cell or tissue by delivering nanoparticles to said cell or tissue and exposing the nanoparticles to an excitation source under conditions wherein they emit heat.
