Sources of Experimental Errors in Specific Absorption Rate Measurement of Magnetic Nanoparticles

Magnetic-nanoparticles cancer hyperthermia, a side effects-free, potential cancer therapy employing magnetic nanoparticle remotely heated by alternating magnetic field (AMF), is receiving considerable attention from researchers and physicians [1–3]. Specific absorption rate (SAR), which is used to quantify nanoparticles’ heat generation under the applied AMF, is defined as the thermal power per unit mass dissipated by the magnetic material [3]. SAR depends on field parameters (magnetic field strength and frequency) and material system (size and magnetic properties of nanoparticles). Accurate measurement of SAR is a critical step in enabling comparison with theoretical predictions for understanding other parameters that may affect the heat generation rate such as nanoparticle functionalization, clustering and immobilization in biological medium [4]. A main drawback is the fact that independent measurements on similar samples often provide significantly different SAR values. For example, the reported SAR of magnetite-based aqueous solution Endorem commercially available from Guerbet greatly differs among Ref. [3], [5] and [6], even when factors such as field intensity, H, and frequency, f, are taken into account.