This work forms the clinical foundation of our prostate imaging research program. The accurate characterization of prostate cancer is a major problem in the management of individual prostate cancer patients and in monitoring therapy. To address this pressing need, we have developed over the past 25 years a large research program to develop new anatomic and metabolic (MR spectroscopic imaging, MRSI) methods to provide an improved assessment of prostate cancer in individual patients. This has been a truly translational, multidisciplinary research project that has ranged from basic MR development to now routine clinical usage of these magnetic resonance imaging tools in the clinic. In conjunction with GE Healthcare we developed a commercial MRI/MRSI staging exam ("PROSE") for prostate cancer patients, and provided the leadership and training for an NIH funded multi-center trial of this commercial exam (ACRIN 3359). Additionally we have been investigating other imaging methods that can provide additional functional information within the same MR staging exam. Specifically, we have developed a multiparametric MR prostate cancer imaging exam, that includes T2- weighted MR, proton MR spectroscopic imaging, diffusion weighted imaging, dynamic contrast enhanced MR, and quantitative T2 weighted imaging. In collaboration with GE Healthcare and funded by the NIH we are optimizing and clinically validating this multiparametric prostate MR exam. I have directed the UCSF prostate imaging program, now called the Prostate Imaging Research Interest Group, in the Department of Radiology and Biomedical Imaging for the last 18 years and have applied these advanced imaging techniques in over 6,000 patients. In a number of ongoing grants, we are investigating the ability of multiparametric imaging to detect and characterize the extent and aggressiveness of prostate cancer for improved therapeutic selection, treatment planning, and therapeutic follow-up. We are also applying multiparametric imaging for direct MR guided biopsy and therapy. We currently have a FDA approved device for direct MR guided prostate biopsies, and are in the process of starting a MR Guided high intensity focused ultrasound prostate cancer treatment program.