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Samuel Day, MD, PhD

Radiation Oncologist

Accepting New Patients!


Dr. Day graduated with Honors from the University of Arizona, where he also received the Outstanding Senior Award in the College of Science. He was selected for the prestigious Graduate Partnerships Program at the National Institutes of Health and obtained his PhD in Biochemistry from Cambridge University in the United Kingdom. During his time at Cambridge, MRI imaging tools that he invented were successfully translated from preclinical models into human patients. After medical school at the University of Colorado, he returned home to Tucson for his internship at the University of Arizona, before completing subspecialty training in radiation oncology at the University of Washington and Seattle Cancer Care Alliance. During his studies in Seattle, he received awards for patient care and resident education.

Dr. Day is experienced in treating all types of cancer using a variety of different radiation treatment modalities. He has special expertise using HDR brachytherapy to treat prostate, breast and gynecological cancers, and is highly experienced with high-dose radiosurgical techniques including stereotactic spine radiosurgery (SBRT). He is also certified to administer SpaceOAR® hydrogel spacer to minimize the potential toxicities of radiation therapy in men with prostate cancer. Dr. Day has authored over 20 peer-reviewed scientific papers and textbook chapters and has presented his research at both national and international scientific meetings. He is also a strong patient advocate with an interest in wholistic care, rehabilitation and survivorship.

He is is certified by the American Board of Radiology-Radiation Oncology and the National Board of Medical Examiners.


University of Arizona

Graduate School:

Cambridge University
Cambridge, England

National Institutes of Health
Bethesda, Maryland

Medical School:

University of Colorado


University of Arizona

Board Certification:

Radiation Oncology