UCLA Campus    |   UCLA Health    |   School of Medicine Translate:
UCLA Health It Begins With U

Radiation Oncology UCLA


Stereotactic Radiosurgery (SRS)

The UCLA Radiosurgery Program, One of The Most Advanced Facilities in the World

The UCLA Department of Radiation Oncology, in conjunction with the Department of Neurosurgery, has been engaged in stereotactic irradiation for nearly 20 years. Radiosurgery began at UCLA, and in the United States, with the installation of the first Gamma Knife in 1981. In 1990, the Gamma Knife was discarded in favor of a modern linear accelerator. With the installations of the world's first Novalis system for shaped beam surgery in 1997, UCLA continues in its pioneering efforts to provide the highest levels of patient care. 

Stereotactic irradiation involves the delivery of a dose of X-ray treatment precisely focused on a target within the brain. The use of stereotactic methods allows delivery of a high target dose with significantly lower dose to brain tissue in the immediately surrounding the region. The result is an enhanced ability to control intracranial disease coupled with a reduction in the risk of side effects from radiation therapy. At UCLA, this unique form of radiotherapy can be delivered in a single session, termed stereotactic radiosurgery (SRS), or as a series of daily treatments , termed stereotactic radiotherapy (SRT). SRS and SRT are used for a variety of brain tumors. These tumors can be malignant (gliomas, metastases) or benign (acoustic neurinomas, pituitary adenomas, meningiomas). SRS is also used for certain non-tumor conditions such as vascular malformations and trigeminal neuralgia (View list of other clinical indications). At UCLA, the use of a special beam shaping device permits efficient stereotactic irradiation of irregularly shaped targets.

Our Experts

Radiation Oncologists
Phillip Beron MDPhillip J. Beron, MD
Dr. Beron is a board-certified radiation oncologist and Assistant Professor in the Department of Radiation Oncology at the David Geffen School of Medicine at UCLA. His professional career spans private and academic practice. Dr. Beron specializes in treatment of all cancer types with emphasis in the treatment of breast cancer. He is an experienced brachytherapist (implant physician) and performs prostate, GYN, and breast implants.  He is trained in partial breast radiation techniques such as Mammosite.
Dr. Tania Kaprealian - UCLA Radiation OncologyTania Kaprealian, MD
Dr. Tania Kaprealian is an Assistant Professor in the Department of Radiation Oncology at the David Geffen School of Medicine at UCLA.  She completed her medical degree and residency training in Radiation Oncology at the University of California in San Francisco.  Subsequently she practiced at the American University of Beirut Medical Center where she was an Assistant Professor and Program Director in their Department of Radiation Oncology before joining the UCLA Radiation Oncology Department.
Percy LeePercy Lee, MD
Percy Lee, M.D. earned his medical degree from Harvard Medical School, where he graduated magna cum laude. At Harvard, he was also a Howard Hughes Medical Institute Research fellow. He interned at Massachusetts General Hospital and received specialty training in Radiation Oncology from Stanford University. Dr. Lee is an Assistant Professor in Radiation Oncology and Clinical Director of the Stereotactic Body Radiation Therapy (SBRT) program.
Medical Physicists
Nzhde Agazaryan, Ph.D., DABRNzhde Agazaryan, PhD, DABR
Professor of Radiation Oncology and Chief of Clinical Medical Physics. Dr. Agazaryan is a Professor of Radiation Oncology and the Chief of Clinical Medical Physics at the UCLA Radiation Oncology. He is also a Professor of Biomedical Physics Graduate Program. His appointment in the Department of Radiation Oncology involves research, teaching and clinical practice. His research and clinical interests include stereotactic radiosurgery (SRS/SRT), stereotactic body radiotherapy (SBRT), small field dosimetry, image-guided radiotherapy (IGRT), functional image-guided radiotherapy, gated radiotherapy, eye plaque brachytherapy.
Minsong CaoMinsong Cao, PhD DABR
Dr. Cao received his Ph.D. in Medical Physics from Purdue University in 2007. Prior to joining UCLA, he was appointed as an Assistant Professor in the Department of Radiation Oncology at the Indiana University. He is certified by the American Board of Radiology in radiation therapy physics. His research interests include image guidance in radiation oncology, functional and physiological imaging and stereotactic body radiation therapy.
Phillip ChowPhillip Chow, MS DABR
Phillip Chow graduated from UCLA with a Bachelor of Science degree in Physics in 1990. While attending graduate school in Astrophysics, he began working as a Medical Dosimetrist in 1992. He received his certification from the Medical Dosimetrist Certification Board (MDCB) in 1995. He then moved to Bangor, Maine in 1996 where he worked for two years as a Certified Medical Dosimetrist before being offered a position at Kaiser Permanente in Southern California.
Chul LeeChul Lee, MS, DABR
Chul Lee has been working as a medical physicist at UCLA Radiation Oncology since January 2006. He obtained Master's degree in Medical Physics from Medical College of Ohio in December 2005. Prior to coming to UCLA, he worked as a researcher in radiochemistry laboratory for ten years at University of Michigan - Ann Arbor.
Steve TennSteve Tenn, PhD DABR
Stephen Tenn joined the UCLA Department of Radiation Oncology in November of 2008. He received his PhD from the UCLA Biomedical Physics Graduate Program in 2007. His dissertation project focused on the accuracy of image guidance and gated radiotherapy using the Novalis Radiosurgery system. After completing his PhD Dr. Tenn left UCLA for a one year post doctoral fellowship at the Stanford University Department of Radiation Oncology.
UCLA Rated One of the Top Hospitals in the Nation