Cell-based therapies in the form of stem cell-based or immune cell-based therapies are becoming important treatment options that are either approved for clinical use or are showing promise in clinical trials. One of the issues regarding cell-based therapies is that, once the cells are injected into a subject, there is no easy way to track where they go, assess whether adequate numbers of cells arrive at the intended therapeutic target and for how long they persist at a given location. To address this issue non-invasive imaging methods have been developed using magnetic resonance imaging (MRI). When used with an appropriate cell labelling contrast agent, Cellular MRI can track cells non-invasively in vivo. Detection of cells is accomplished with an inert imaging agent containing the MRI sensitive fluorine-19 (19F) nuclei. The objective of this study is to demonstrate that 19F-MRI is safe to use in humans so that it can subsequently be used to track cell-based immunotherapies in future clinical trials. The long term goal is to be able to quantify immune cell migration to secondary lymphoid tissues and potentially to tumors and correlate to therapeutic outcomes.