Dr Diaz is an Adjunct Professor of Biology at the Northern Illinois University and Medical Director of the Northern Illinois Institute for Neutron Therapy at Fermi National Accelerator Laboratory. He came from Roswell Park Cancer Institute in Buffalo where he was an attending Physician and Co-Director of the Gamma-Knife Radiosurgery Program. Prior to this he was at the University of Washington Medical Center, Seattle, where he served as Assistant Professor in the Department of Radiation Oncology. Dr. Diaz earned his medical degree from Columbia University College of Physicians and Surgeons, New York in 1988 after having received graduate degrees in Public Health and Nuclear Engineering from those respective schools at Columbia. He completed residency training in Internal Medicine at St. Luke's/Roosevelt Hospital Center, New York, in 1991, and in Radiation Oncology at the University of California at San Francisco, in 1994. Dr. Diaz is board-certified in Radiation Oncology.

After his residencies, Dr. Diaz served as Radiation Ocologist and later Clinical Principal Investigator of the Boron Neutron Capture Therapy clinical trial at Brookhaven National Laboratory in Upton, NY.

Dr. Diaz's research interests include stereotactic radiotherapy including radiosurgery, heavy particle radiotherapy such as fast neutron therapy and boron neutron capture therapy (BNCT), the use of total body irradiation (TBI) in bone marrow transplants (BMT) and the effects of different types of radiation therapies on the central nervous system (CNS).

Dr. Diaz is a member of the American Society for Theraputic Radiology and Oncology, American College of Radiology, Radiation Therapy Oncology Group, New York State Radiological Society, National Comprehensive Cancer Network, Children's Oncology Group and the American Medical Association. He has authored or co-authored more than 30 journal publications, abstracts and book chapters and serves as a reviewer for the International Journal of Radiation Oncology, Biology, Physics.