Preliminary Results of in vivo Temperature Imaging Based on Harmonic Phase on MPS/MPI Dual-mode System

Magnetic particle imaging (MPI) as a new imaging method which senses magnetic nanoparticles (MNPs) concentration, and the simultaneous temperature mapping is a promising direction. MPI temperature imaging is still in the phantom stage, and a key challenge in achieving in vivo temperature imaging through MPI is how to obtain in vivo calibration parameters for temperature measurement. We used MPS/MPI dual-mode system to obtain the in vitro and in vivo phase difference of MNPs, indirectly obtained the in vivo phase lag parameters of MPI, and calibration of temperature and phase is achieved without heating the animal body. Finally, we achieved simultaneous imaging of in vivo temperature and MNP concentration. For MPI temperature reconstruction, the mean temperature deviation can reach 1.3 ° C in vitro and 2.23 ° C in vivo.Clinical relevance- The accuracy of our results is comparable to the level of temperature measurement with MRI and ultrasound. This demonstrates the potential of MPI multiparameter imaging and opens up new directions for MPI applications, particularly in MPI-guided precision magnetothermal therapy.