Dr. Eugene S. Ahn

Eugene S. Ahn

Eugene S. Ahn
Eugene S.
Radiation Oncologist

Languages spoken


Expert in

Radiation Oncology



Simi Valley (Radiation oncology)
Simi Valley (Radiation oncology)

2985 North Sycamore Dr.
Simi Valley, California 93065

34.28977079289876, -118.74543447116463
Thousand Oaks (Radiation oncology)
Thousand Oaks (Radiation oncology)

2230 Lynn Rd, Suite 103
Thousand Oaks, California 91360

34.2089303, -118.8845857


Dr. Ahn is board certified in therapeutic radiology with a particular interest in stereotactic radiosurgery for brain tumors and head and neck cancers. He has significant experience in MammoSite brachytherapy for early stage breast cancer, and he initiated the first MammoSite treatment in Ventura County in 2004. The breast brachytherapy program in Thousand Oaks is now the largest in Ventura, Santa Barbara, and San Luis Obispo counties. Dr. Ahn has published on stereotactic radiosurgery and was the recipient of the Young Oncologist Research Award 2003 from the American Radium Society. He is Vice President of Coastal Radiation Oncology Medical Group, the medical director of Coastal’s Simi Valley Radiation Oncology Center, in collaboration with GenesisCare, and is co-medical director of the Los Robles Gamma Knife Center in Thousand Oaks. Dr. Ahn practices at Coastal Radiation Oncology, in collaboration with GenesisCare; Thousand Oaks, Westlake Village and Simi Valley locations.

Career positions

Current position(s)

  • Coastal Radiation Oncology - Radiation Oncologist, Ventura, California



  • University of Washington, Bachelor of Arts, Political Science, Seattle
  • New York University Graduate School of Arts and Sciences, Master of Arts, Philosophy with concentration in Medical Ethics and Health Policy, New York
  • New York University School of Medicine, Doctor of Medicine, New York


  • New York University Downtown Hospital, PGY-1 in Internal Medicine, New York


  • UCLA Medical Center, Radiation Oncology, Los Angeles

Professional associations


Awards and honors

  • Cum Laude Graduate, Phi Beta Kappa, Elie Wiesel Award for best essay in Ethics