Noninvasive Multimodality Imaging of the Tumor Microenvironment: Registered Dynamic 1H MRI and 18F PET Studies of a Preclinical Model of Tumor Hypoxia.

HyungJoon Cho¹, Ellen Ackerstaff¹, Sean Carlin¹, Mihaela Lupu¹, Ya Wang¹, Asif Rizwan¹, Joseph O'Donoghue¹, Clifton Ling¹, John Humm¹, Pat Zanzonico¹, Jason Koutcher¹

In vivo knowledge of the spatial distribution of viable, necrotic and hypoxic areas can provide prognostic information about the risk of developing metastases, the distribution of radiation sensitivity, and may possibly be used for localized dose escalation in radiation treatment. In this study, multimodality in vivo Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) imaging using stereotactic fiduciary markers in the Dunning R3327-AT prostate tumor was performed, focusing on the relationship between Dynamic Contrast-Enhanced (DCE)-MRI using Magnevist (Gd-DTPA), and dynamic 18F-fluoromisonidazole (18F-Fmiso) PET. The non-invasive measurements were verified using tumor tissue sections stained for haematoxylin/eosin (H&E) and pimonidazole.