Use of square waves incident on magnetic nanoparticles to induce magnetic hyperthermia for therapeutic cancer treatment

Magnetic hyperthermia for treatment of tumors would benefit greatly from increased heating of the magnetic particles relative to the incident electromagnetic wave power. Micromagnetic simulations including thermal fluctuations show that the use of an incident square wave, as opposed to the usual sine wave, increases the normalized heat by at least 50%, with the possibility of much greater improvement for the usual case of particle ensembles that have a distribution of magnetic anisotropies, volumes, and angles to the incident radiation. It is shown that even replacement of the square wave by a limited number of harmonics is highly beneficial. (C) 2010 American Institute of Physics. [doi:10.1063/1.3485292]