The goal of this reseach was to demonstrate if MRI can be used to determine the Doxorubicin (DOX) concentration delivered in MnSO4 labled liposomes in an invivo tumor model. Using a temperature sensitive liposome formulation, it was found that MnSO4 release significantly increased the MRI signal. The degree of signal enhancment was measured and converted to DOX concentration. This MRI measured concentration was compared to direct histological measurements using fluorescence microscopy of identical regions of interest. There was a linear relationship with a slope and intercept...