Our staff physicians are all faculty at Harvard Medical School and include some of the world's most knowledgeable and skilled radiation oncologists.


Anthony Zietman

Anthony Zietman, MD, FASTRO
Interim Chief, Radiation Oncology
Jenot and William Shipley Professor of Radiation Oncology, Harvard Medical School

MD, London University; Residency, Mass General Hospital, Harvard Medical School, and Middlesex Hospital Medical School, London.


Kevin Oh

Kevin Oh, MD
Clinical Director, Radiation Oncology

MD, University of Michigan Medical School; Residency, University of Michigan Medical Center


Helen Shih

Helen Alice Shih, MD
Medical Director, MGH Proton Therapy Centers
Director, CNS Service
MGH Associate Program Director - Harvard Radiation Oncology Residency Program

MD, University of Pennsylvania School of Medicine; Residency, Mass General Hospital.


Thomas Bortfel

Thomas Bortfeld, PhD
Chief of Physics, Radiation Oncology; Professor, Harvard Medical School

MS (Diploma): University of Heidelberg, Germany, 1988, Physics; PhD: University of Heidelberg, Germany, 1990, Applied Physics; Habilitation: University of Heidelberg, Germany, 1995, Physics; Fellow, The Institute of Physics, 2004; Fellow, American Association of Physicists in Medicine, 2009.


Tiffany Koolakian

Tiffany Zewe, MBA
Senior Administrative Director, Radiation Oncology

BS, University of Vermont; MBA, Simmons College.


Brian Napolitano

Brian Napolitano, MHL, CMD
Director of Medical Dosimetry, Radiation Oncology

BS, Biological Sciences, State University of New York at Binghamton; MHL, Healthcare Leadership, Brown University.


Kelly Seybolt

Kelly Seybolt, MS, RTT
Senior Director of Radiation Therapy, Radiation Oncology

BS, Radiation Biology, Suffolk University; MS, Radiologic Science - Management Track, Thomas Jefferson University.