Radiation therapy is used as a treatment for more than half of all cancer patients and can be highly effective at shrinking tumors and killing cancer cells. But radiation treatment can also damage healthy tissue, including tissue in the mouth and gastrointestinal tract. This tissue injury can lead to oral mucositis, esophagitis, and proctitis—painful and sometimes debilitating tissue damage. It’s estimated that these injuries occur in over 200,000 patients in the U.S. each year. In a new paper published in Advanced Science, investigators from Brigham and Women’s Hospital, Dana-Farber Cancer Institute, Massachusetts General Hospital and MIT describe efforts to develop a new personalized, 3D-printed device intended to shield patients who are undergoing radiation therapy and prevent radiation-induced toxicity. The work to date has been conducted in preclinical models and uses simulations to predict effects in humans, laying groundwork for clinical trials for patients.