Mouse models of diseases have revolutionized the study of these diseases at their basic genetic and molecular levels. They have been used to identify potential therapeutic targets and study response to therapy in a non-destructive manner that has accelerated the research cycle and aided translation to the clinic. The high field strengths e 4.7T has dominated MR imaging of mice because of their higher signal to noise ratio (SNR). MR Contrast agents, particularly those that shorten T1 have had a significant impact on patient care and with molecular imaging paradigms have the potential to detect cellular targets and enzymes as in vivo biomarkers. The performance of these agents is magnetic field dependent decreasing as field strength exceeds 0.5T. When SNR is considered however, their performance is optimal at 1-1.5T as a balance between loss in relaxivity and gain in SNR. A new variable field 0-3T rodent superconducting magnet has been made available whose operating field can be switched between any two fields within 15 minutes that includes 1.5 and 3T the most popular clinical field strengths. This instrument is an ideal compromise that satisfies the needs of investigators funded to develop MR-based molecular imaging agents as well as those in need of imaging deep seated tumors to time and assess interventions. Of interest to investigators working with iron oxide and those interested in imaging tissues with short T2 such as bone and cartilage is the opportunity to implement the ultrashort TE (UTE) techniques developed by our physics group for clinical imaging at 3T. With the stronger gradients and faster slew rates of the rodent scanner, it is possible that UTE imaging can be improved. We have a self-supporting rodent imaging facility that has been operational since 2004 located at the Moores/UCSD Cancer Center (MCC) adjacent to the vivarium. It serves the MCC and Molecular Imaging and Nanotechnology investigators. The well-developed resource is run by the Dept. of Radiology and is directed by established clinical and basic imaging scientists and is supported by a trained staff. The resource has all rodent imaging systems except MRI mostly because of siting limitations. The proposed instrument is self-shielded, has a small footprint, can be located within our imaging resource, and requires minimal site planning. We have several well-funded investigators whose research would benefit greatly from such a dedicated rodent MR system. They are developing MR molecular imaging agents &/or are interested in imaging rodent models. The scanner will be supported by a well-established MR physics group that has developed advanced imaging techniques on a 3T clinical system such as 2D and 3D UTE and fat/iron quantification that are now used clinically. The addition of such capabilities to the rodet scanner would enable UCSD investigators to expand their research and explore new areas. To promote this capability, the MCC director and the Chair of Radiology have agreed to support installation costs, a technician for 1 year, a postdoc for 2 years and pay for the service contract for one year to speed sequence development and the time to becoming self-supporting.