Varian and the Cincinnati Children's/UC Health Proton Therapy Center announced the completion of enrollment in FAST-01 (FeAsibility Study of FLASH Radiotherapy for the Treatment of Symptomatic Bone Metastases), the first human clinical trial of FLASH therapy. The FAST-01 trial, which is evaluating clinical workflow feasibility of the FLASH therapy and treatment-related side effects, met its enrollment target of 10 participants with bone metastases in the extremities. The clinical trial, informed by years of preclinical work, was designed by experts at Varian and multiple centers in the FlashForwardTM Consortium, including Cincinnati's Children's/UC Health Proton Therapy Center and the New York Proton Center. The FAST-01 trial is being led by John C. Breneman, M.D., principal investigator, and Medical Director of the Cincinnati Children's/UC Health Proton Therapy Center, UC Health radiation oncologist, and professor emeritus at the University of Cincinnati College of Medicine. The trial is supported by Emily Daugherty, M.D., assistant professor of radiation oncology at UC and a UC Health radiation oncologist, and Anthony Mascia, PhD, DABR, adjunct assistant professor of radiation oncology at UC and Director of Medical Physics at the Cincinnati Children's/UC Health Proton Therapy Center.