Stanford University, School of Medicine 1 article published in JoVE Medicine Measurement of Tumor T2* Relaxation Times after Iron Oxide Nanoparticle Administration Shakthi Kumaran Ramasamy1, Raheleh Roudi1, Wipawee Morakote1, Lisa C. Adams1, Laura J. Pisani1, Michael Moseley2, Heike E. Daldrup-Link1,3 1Department of Radiology, Molecular Imaging Program at Stanford, Stanford University, School of Medicine, 2Department of Radiology, Radiological Sciences Laboratory (RSL) at Stanford, Stanford University, School of Medicine, 3Department of Pediatrics, Division of Hematology/Oncology, Stanford University, School of Medicine We present a standardized protocol for the quantification of T2* relaxation times of tumors using external software. Multi-echo gradient echo images are acquired and fed into the software to create tumor T2* maps and measure tumor T2* relaxation times.