Personalized medicine is directed to specific molecular targets that are expressed in various diseases. Molecular imaging affords the ability to detect and monitor the expression of these targets to select patients for therapy and to monitor treatment effect. Theranostics is a new field combining diagnostic imaging with therapy. Nanoparticles can serve as diagnostic agents and also carry drugs to selectively treat target tissues and cells. As such, an important aspect of our research involves the development and delivery of theranostic agents, combining imaging with therapeutic agents. Some of our research utilizes target tissue specific ligand-coated nanoparticles that will selectively bind to specific biomarkers upregulated in regions of pathology (e.g., cancer cells). Once delivered to the target region, localized agents can be detected using a variety of imaging techniques methods (e.g., ultrasound, MRI, PET, SPECT, fluorescence, photoacoustics). The imaging agent and delivery system can then be evaluated for its ability to identify regions of pathology. Additionally, these agents can be linked through a delivery system to carry a “payload” of pharmaceutical or biological agents (e.g., a chemotherapeutic agent) to elicit the therapeutic effect. Furthermore, the theranostic can then be used to follow the regression of the disease and evaluate the success of a particular therapy. Finally, we are also exploring targeted contrast agents capable of both molecular imaging and therapy without the use of an active pharmaceutical.
The Drug Development, Delivery, and Evaluation program of the Department of Medical Imaging at the University of Arizona has produced a number of successes in clinical translation. MR-guided Focused Ultrasound was first developed at the University of Arizona. Members of the Department of Medical Imaging have founded several start-up companies and pioneered the development of FDA approved contrast agents, including Definity®, the #1 selling ultrasound contrast agent. Efforts by members of the Department also led to the world’s first multi-center prospective trials of microbubble-enhanced treatment of ischemic stroke. Current efforts have led to clinical trials of a novel nano-emulsion as an oxygen therapeutic to increase tumor pO2 to reverse radiation resistance. The Department is developing novel MR-based imaging methods to validate tumor re-oxygenation. Other current projects include phase-shift nanoparticles for ultrasound imaging/drug delivery, photoacoustic imaging/contrast agents, and nanoparticles to diagnose and treat uveitis and vulnerable plaque.