Ferumoxytol Enhanced MRI for the Detection of Lymph Node Involvement in Prostate Cancer

Background: \- Ferumoxytol is an approved iron replacement therapy agent that has some potential for use as a contrast agent in imaging studies of the lymph system, especially involving lymph nodes that have been affected by cancer. Ferumoxytol is taken up by normal lymph nodes, but excluded from cancerous lymph node tissue. Because Ferumoxytol has not yet been approved for use as an imaging agent, researchers are interested in testing its effectiveness as a contrast agent for studies of normal lymph tissue and cancer tissue in lymph nodes of individuals with prostate cancer. Objectives: \- To evaluate the safety and effectiveness of Ferumoxytol as a contrast agent in individuals who are scheduled to have prostate removal surgery to treat prostate cancer. Eligibility: \- Men at least 18 years of age who have been diagnosed with prostate cancer and are scheduled to have surgery to remove the prostate and surrounding lymph nodes. Design: * Participants will be screened with a full medical history and physical examination, blood and urine tests, and tumor imaging studies. * Participants will have a magnetic resonance imaging (MRI) scan to provide baseline images for the study. * Participants will receive an injection of Ferumoxytol and will return for another MRI scan on the following day (around 24 hours later). * Some participants may have a third MRI scan 48 hours after the initial injection of Ferumoxytol. This third MRI scan is optional and not required by the study. * Although the scanning and followup portion of the study will last only a few days, participants will be considered to be enrolled on the study until after the prostate removal surgery.