Orange County Radiation Oncology
One of The World's Most Comprehensive Radiation Oncology Programs
With a focus on precise imaging, and targeted treatments, our physicians and researchers are industry-leading pioneers killing cancer cells while preserving a patient’s quality of life. Our team is trained in the latest advances in radiation oncology and may use one of the following therapies to treat your cancer:
- Radiation Oncology Research and Trials
- Intensity-Modulated Radiation Therapy (IMRT)
- Stereo Tactic Bady Radiotherapy (SBRT)
- High-Dose Rate Brachytherapy
- Four-Dimensional Computed (4D CT) Scanning
- ETHOS® By Varian
- MRIdian® MR Linac By Viewray
- Trubeam ® By Varian
Our Physicians


For radiation oncologist Percy Lee, M.D., patients’ needs come first. He works closely with experts from other disciplines to offer each person an individually tailored treatment plan based upon both their clinical history and their emotional and social needs. An active listener, he aims to understand what is truly on a patient’s mind.


Radiation oncologist Amanda Schwer, M.D. knew she wanted to be a cancer doctor for as long as she can remember, inspired by the doctors who cured a sibling who faced aggressive disease in early childhood.


Colton Ladbury, M.D., is an assistant professor of radiation oncology at City of Hope® Cancer Center Duarte and the Orange County Lennar Foundation Cancer Center, where he finds nothing more satisfying than offering cancer patients personalized treatments using advanced technology.


As a radiation oncologist, Dr. Julius Weng is dedicated to providing personalized, state-of-the-art treatment tailored to each patient’s physical and emotional needs.