Jonathan Ashman MD

Jonathan B. Ashman, MD, PhD, is a board-certified radiation oncologist and Professor of Radiation Oncology at Mayo Clinic in Phoenix, Arizona. He specializes in the multidisciplinary treatment of gastrointestinal, sarcoma, central nervous system, and gynecologic malignancies, with expertise in advanced radiation techniques including proton beam therapy, stereotactic radiosurgery, intraoperative electron radiation therapy (IORT), brachytherapy, and total body irradiation.

Dr. Ashman earned both his Doctor of Medicine and Doctor of Philosophy in Immunology from the University of Chicago Pritzker School of Medicine. He completed his residency in Radiation Oncology at Memorial Sloan Kettering Cancer Center, where he served as Chief Resident. His physician-scientist training has provided a strong foundation for integrating translational research with innovative, patient-centered cancer care.

At Mayo Clinic, Dr. Ashman serves as Medical Director of the Mayo Clinic Proton Therapy Program and Co-Leader of the Tri-Site Mayo Clinic Particle Therapy Program. He has also held key educational leadership roles, including Program Director of the Radiation Oncology Residency Program and Vice Chair of Education within the Department of Radiation Oncology. He is widely recognized for his commitment to physician education and mentorship, receiving Mayo Clinic's Program Director of the Year and Educator of the Year honors.

Dr. Ashman's research focuses on improving radiation treatment strategies for gastrointestinal cancers, sarcomas, and central nervous system tumors, with particular emphasis on proton therapy, stereotactic radiation techniques, and multidisciplinary cancer care. He has authored numerous peer-reviewed publications and has contributed to national clinical guidelines and cooperative research initiatives through organizations such as the American Society for Radiation Oncology (ASTRO), the American Society of Clinical Oncology (ASCO), and the Society for Neuro-Oncology.