This invention concerns magnetic nanoparticles for use in a magnetic hyperthermia therapeutic treatment, prophylactic treatment or diagnosis method, wherein the magnetic nanoparticles are administered to a body part of an individual and the body part is exposed to a magnetic field oscillating at a high frequency and at a medium and/or low frequency, wherein the high frequency is 1 MHz at the most, the medium frequency is lower than the high frequency, and the low frequency is lower than the high frequency and lower than the medium frequency when it is present.
