Scientists at Johns Hopkins Medicine have demonstrated the use of magnetic particle imaging (MPI) to track cell therapy injections in mice, a technique that could significantly enhance the personalization of treatments for autoimmune diseases and cancers. The study, published on May 6, 2026, in *Science Advances*, reveals that MPI allows researchers to visualize therapeutic cells during injection, addressing limitations of existing imaging technologies like MRI and CT scans. Led by Jeff Bulte, M.S., Ph.D., the team used mesenchymal stem cells and neural precursor cells, both tagged with ultra-tiny superparamagnetic iron oxide nanoparticles, to investigate their delivery and accumulation in various organs. Results showed that injecting cells into the artery led to effective targeting of key organs, including the brain and spleen, which is crucial for conditions like multiple sclerosis. The researchers emphasize that while MPI shows promise, the optimal delivery method may vary among individuals, and further studies will explore its application in personalizing treatments for both cancer and neurological disorders.