International Journal on Magnetic Particle Imaging IJMPI
Vol. 12 No. 1 Suppl 1 (2026): Int J Mag Part Imag
https://doi.org/10.18416/IJMPI.2026.2603031

Proceedings Articles, ID 942

Magnetic particle imaging of tumor retention and leakage of magnetic nanoparticles reveals high inter-subject variability

Main Article Content

Ali Shakeri-Zadeh (Johns Hopkins University), Asif Itoo (1The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA 2Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA), Janani Gurumurthy (1The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA 2Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA), Preethi Korangath (3Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA), Robert Ivkov (3Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA), Jeff Bulte (1The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA 2Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA)

Copyright (c) 2026 Ali Shakeri-Zadeh, Asif Itoo, Janani Gurumurthy, Preethi Korangath, Robert Ivkov, Jeff Bulte

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Intratumoral (i.t.) injection of magnetic nanoparticles (MNPs) is a clinically relevant strategy for localized therapy, including magnetic fluid hyperthermia (MFH). However, the fate of i.t.-injected MNPs remains poorly characterized. Here, we employed magnetic particle imaging (MPI) to quantitatively and longitudinally monitor MNP retention and leakage of i.t.-Synomag®-D70 in a mouse subcutaneous 4T1 breast tumor model. Mice (n=4) were scanned serially (15 min to 8 day) using 2D MPI with fiducial calibration. At day 8, 3D MPI and CT co-registration were performed, followed by ex vivo imaging. A strong linear calibration (R²=0.967) between MNP concentration and MPI signal enabled accurate iron quantification. All tumors showed strong initial MPI signal with an 1.8 to 3.0-fold signal reduction by day 8, indicating gradual tumor clearance. Liver and spleen uptake could only be observed in 2 out of 4 mice, while none of the other major organs showed uptake. The high inter-subject variability in MNP tumor retention calls for integrating MPI quantification for developing individualized MFH treatment plans.

Article Details

References

1. Maier-Hauff K, Ulrich F, Nestler D, Niehoff H, Wust P, Thiesen B, et al. Efficacy and safety of intratumoral thermotherapy using magnetic iron-oxide nanoparticles combined with external beam radiotherapy on patients with recurrent glioblastoma multiforme. Journal of neuro-oncology. 2011;103(2):317-24.
2. Carlton H, Salimi M, Arepally N, Bentolila G, Sharma A, Bibic A, et al. Ranking Magnetic Colloid Performance for Magnetic Particle Imaging and Magnetic Particle Hyperthermia. Adv Funct Mater. 2025;35(2):2412321.
3. Salimi M, Kuddannaya S, Bulte JWM. Pharmacokinetic Profiling of Unlabeled Magnetic Nanoparticles Using Magnetic Particle Imaging as a Novel Cold Tracer Assay. Nano Lett. 2024;24(49):15557-64.
4. Healy S, Bakuzis AF, Goodwill PW, Attaluri A, Bulte JW, Ivkov R. Clinical magnetic hyperthermia requires integrated magnetic particle imaging. Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology. 2022;14(3):e1779.
5. Shakeri-Zadeh A, Bulte JW. Imaging-guided precision hyperthermia with magnetic nanoparticles. Nature reviews bioengineering. 2025;3(3):245-60.
6. Tay ZW, Chandrasekharan P, Chiu-Lam A, Hensley DW, Dhavalikar R, Zhou XY, et al. Magnetic Particle Imaging-Guided Heating in Vivo Using Gradient Fields for Arbitrary Localization of Magnetic Hyperthermia Therapy. ACS Nano. 2018;12(4):3699-713.

Most read articles by the same author(s)