Our Neurosurgeons



Robert E. Breeze, M.D.

Dr. Breeze is the Vice–Chair for the Department of Neurosurgery and the Program Director for CU  Neurosurgery’s Residency Program.  His primary clinical interests are neurovascular surgery and skull-base surgery. He oversees the largest referral center for complex neurovascular surgery in the Rocky Mountain region. Learn more about Dr. Breeze.





J. Adair Prall, M.D.

Dr. Prall is board certified by the American Board of Neurological Surgery. He is experienced in all types of cranial and spinal surgery, and is nationally renowned for his expertise in vascular compression syndromes, including trigeminal neuralgia. Learn more about Dr. Prall.






Stephen Cass, M.D.

Dr. Stephen Cass is Professor in the Department of Otolaryngology at the University of Colorado School of Medicine. Dr. Cass is board certified in Otology and Neurotology, specializing in skull base tumors, hearing loss, and vertigo disorders. Learn more about Dr. Cass.






Stephen D. Johnson, M.D.

Dr. Stephen D. Johnson is a graduate of Dartmouth College and the University of Tennessee College of Medicine. After internship at the University of Tennessee he was a general surgery resident at Virginia Mason Hospital in Seattle, Washington.

Radiation Oncologists

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Brian Kavanagh, M.D.


Dr. Brian Kavanagh graduated summa cum laude with honors in biomedical engineering from the Tulane University School of Engineering and then remained at Tulane to receive his MD and MPH degrees from the School of Medicine and School of Public Health. He completed an internship at the Charity Hospital of Louisiana before entering a radiation oncology residency at Duke University, where he was an American Cancer Society Clinical Oncology Fellow. 





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Arthur K. Liu, M.D., Ph.D.

Associate Professor and Vice-Chair, Department of Radiation Oncology

Dr. Arthur Liu received his B.S. and M.S. in Electrical Engineering and Computer Science and his Ph.D. in Medical Engineering and Medical Physics from the Massachusetts Institute of Technology. Learn more about Dr. Liu.





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Chad G. Rusthoven, M.D.


Dr. Chad Rusthoven is an Assistant Professor of Radiation Oncology at the University Of Colorado School Of Medicine, with a specialization in the treatment of thoracic and central nervous system malignancies. Learn more about Dr. Rusthoven.






Sameer Nath Portrait.jpgSameer (Sam) Nath, M.D.

Dr. Nath received his medical degree from the University of California - San Diego and completed his residency at Yale University School of Medicine. A dedicated clinical researcher, Dr. Nath's interests include treatment techniques for radiotherapy patients. Learn more about Dr. Nath.






 Douglas Tippin, M.D.






Medical Team


Kelly Stuhr, MS, DABR

Ms. Stuhr joined the physics staff at the University of Colorado Department of Radiation Oncology in 1996. Ms. Stuhr is a board certified medical physicist, and is responsible for Gamma Knife Physics services such as treatment planning and quality assurance of the Gamma Knife system.  Ms. Stuhr is also the Senior Medical Physicist in the Department of Radiation Oncology, and assists in the organization and coordination of the dosimetry and physics teams.  Ms. Stuhr’s clinical interests include cranial and extracranial stereotactic radiation therapy, image guided radiation therapy, and high dose-rate brachytherapy. Ms. Stuhr’s primary research interest is investigating various techniques for treatment planning and delivery of stereotactic radiation therapy.





Cem Altunbas, PhD, DABR

Dr. Cem Altunbas is board certified by American Board of Radiology in Therapeutic Medical Physics, and he is responsible for Gamma Knife Physics services, such as treatment planning and quality assurance of the Gamma Knife system. Dr. Altunbas received his Ph.D. in Physics from SUNY Buffalo. Following his Ph.D. work, he completed a postdoctoral fellowship in Imaging Physics at UT MD Anderson Cancer Center and medical physics residency at Virginia Commonwealth University. Dr. Altunbas currently serves as Assistant Professor in the Department of Radiation Oncology, University Of Colorado School of Medicine.


David Thomas, PhD

Dr. Thomas joined the faculty of the Department of Radiation Oncology at the University of Colorado School of Medicine as Assistant Professor in July 2016. He received his PhD from the University of Edinburgh (UK), where his research focused on the physics and acoustics of resonating microbubbles in an ultrasound field, with relevance to contrast enhanced ultrasound imaging of microvasculature perfusion. Following graduation, he began a post-doctoral fellowship at the University of California Los Angeles, where he developed techniques for radiotherapy treatment planning that explicitly consider and compensate for breathing motion. Dr. Thomas is responsible for Gamma Knife Physics services, such as treatment planning and quality assurance of the Gamma Knife system. His current research interests include: Motion management techniques, 4D dose calculations, Functional lung imaging, MRI guided radiotherapy and Adaptive radiotherapy.

 Terri Young

Terri Young, RN

Another 20-year Gamma Knife professional, Terri is the head of the nursing staff at RMGKC. She coordinates all patient treatment from initial scheduling with the physicians’ offices to the University Hospital departments who work with us. Working directly with the insurance companies, Terri obtains pre-authorizations and insures that this important function is fully completed before the treatment date. She spends a great deal of time working with the patient and patient’s family before the treatment, providing valuable education and information designed to ease the patient’s anxiety about this vital procedure. Most importantly, Terri is at the bedside during the treatment day as an advocate for each patient and their family, insuring that they get the same compassion and excellence of care that each of the thousands who have come to the Center before have  received.

For over 30 years, Terri has gathered a wealth of experience as a home health nurse, hospital floor nurse and ICU nurse. Before joining the staff of RMGKC, Terri dedicated more than half of her career as a staff and charge nurse in the Emergency Department.

Linda_Rejvani_RN_3_6.2.16.jpgLinda Rejvani, RN

The newest member of the RMGKC team, Linda comes with over 30 years of nursing experience. Her extensive nursing background includes Neonatal ICU, Pediatric ICU, and over 28 years as a nurse and Team Leader in the Operating Room.

As a Gamma Knife Nurse, Linda works directly with patients, providing education and instructions regarding the Gamma Knife procedure. She coordinates patient treatment and care with physicians’ offices and schedules the patients’ diagnostic tests (such as CT and MRI). Other important aspects of Linda’s work include insurance pre-authorization and data base management, working with the University of Colorado Hospital Electronic Medical Records system.

Linda’s primary focus, and the work she enjoys the most, is patient care and advocacy on the day of the procedure.

Management Team

Rocky-Mountain-Gamma-Knife-WJ-Kochevar.jpgW.J. Kochevar, Executive Manager




Natalie Pratt