Dr. Isabelle Choi is the Clinical Director and Director of Research at the New York Proton Center. Her research focus is in improving outcomes, reducing toxicities, and improving radiotherapy treatment delivery for breast malignancies. She is also an Assistant Member of Radiation Oncology at Memorial Sloan Kettering Cancer Center, where she is a member of the breast service. Before coming to NYPC, Dr. Choi was appointed the Associate Director of Clinical Research and the Chief of the Breast Cancer, Thoracic Oncology, and Gynecologic Services at the California Protons Cancer Therapy Center in San Diego, California. She was then appointed Assistant Professor at the University of Maryland School of Medicine. Among her select national leadership appointments, Dr. Choi is Chair of the Physician Advisory Committee of the National Association for Proton Therapy, Chair of the Proton Collaborative Group (PCG) Breast Committee, and Chair of the American Radium Society Breast Appropriate Use Criteria Committee.