Imaging-guided precision hyperthermia with magnetic nanoparticles

Magnetic nanoparticles, including those formed of superparamagnetic iron oxides (SPIOs), are employed in various magnetic imaging and therapeutic techniques. In vivo imaging techniques based on the detection of magnetic nanoparticles inside the body include magnetic resonance imaging (MRI), magnetic particle imaging (MPI), magneto-motive ultrasonography (MMUS) and magneto-photoacoustic imaging (MPAI). Preclinical data indicate that the conditions required to heat up magnetic nanoparticles, including energy considerations, particle modifications, localization and exposure time, can be dynamically modulated during a single treatment procedure by monitoring imaging data acquired from the same magnetic nanoparticles. This Review explores the potential use of magnetic-nanoparticle-mediated imaging techniques combined with magnetic fluid hyperthermia (MFH) to selectively and precisely heat tumour locations while avoiding damage to surrounding healthy tissue. Imaging-guided MFH could provide individualized treatment plans based on information about the biodistribution of magnetic nanoparticles within the tumour and adjacent organs, as well as the volumetric distribution of the thermal dose. Requirements for the clinical translation of MFH-enabled magnetic imaging techniques are also discussed — the development of magnetic nanoparticle formulations with a favourable biosafety profile, optimal magnetic heating properties and maximal magnetic imaging signals; and the integration of magnetic imaging and heating hardware into a single platform. This Review details the use of multifunctional magnetic nanoparticles in advanced magnetic imaging modalities and therapeutic hyperthermia. The potential of magnetic nanoparticles for imaging-guided precision heating of tumours and the need for integrated magnetic imaging and heating platforms are highlighted.