Accurate and Real-Time Temperature Monitoring during MR Imaging Guided PTT

Photothermal therapy (PTT) is an efficient approach for cancer treatment. However, accurately monitoring the spatial distribution of photothermal transducing agents (PTAs) and mapping the real-time temperature change in tumor and peritumoral normal tissue remain a huge challenge. Here, we propose an innovative strategy to integrate T₁-MRI for precisely tracking PTAs with magnetic resonance temperature imaging (MRTI) for real-time monitoring temperature change in vivo during PTT. NaBiF₄: Gd@PDA@PEG nanomaterials were synthesized with favorable T₁-weighted performance to target tumor and localize PTAs. The extremely weak susceptibility (1.04 × 10^-6 emu g^-1 Oe^1-) of NaBiF₄: Gd@PDA@PEG interferes with the local phase marginally, which maintains the capability of MRTI to dynamically record real-time temperature change in tumor and peritumoral normal tissue. The time resolution is 19 s per frame, and the detection precision of temperature change is approximately 0.1 K. The approach achieving PTT guided by multimode MRI holds significant potential for the clinical application.