A Clinical Trial Evaluating the Effect of Pharmacological Ascorbate on Radiation Therapy for Pancreatic Cancer Patients

This is a randomized phase 2 study is designed to determine initial efficacy and assess adverse events, and quantify pathologic evidence of intestinal radiation injury. The ascorbate is infused before, during, and after the external beam radiation therapy treatment. Each ascorbate infusion is 75 grams (roughly the same amount of vitamin C from 1,000 oranges). For patients eligible for this trial, standard treatment for their cancer includes radiation therapy combined with weekly gemcitabine (a chemotherapy). Participants will: * be randomized (like flipping a coin) to receive the investigational treatment (pharmacological ascorbate plus gemcitabine plus radiation) or standard treatment only (gemcitabine plus radiation) * receive gemcitabine (a chemotherapy) once a week for up to 6 weeks of therapy (all participants) * receive radiation treatments are given once a day, Monday through Friday (all participants). * have routine doctor's visits and be asked about any side effects they are experiencing (all participants). * be interviewed to discuss their side effects, how it impacts their life, and describe their recent activities. * receive pharmacological ascorbate intravenously ascorbate during their daily radiation therapy treatments (if randomized to receive the investigational treatment). Once the patient completes radiation, the ascorbate infusions are also completed. However, the patient will need to return for regular follow-up care at University of Iowa. We are interested in the long-term side effects of radiation - which may not develop for years - so it is important the participant return to radiation oncology for follow-up. We will also conduct interviews at that time to review the side effects and how they impact the participant's quality of life.