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Faculty and Staff Overview

Radiation oncology is a team-based specialty requiring complex coordination between faculty and staff members to ensure that the highest quality of care is delivered. The team is led by radiation oncologists, who are physicians that have been specially trained and are experts in the multi-disciplinary treatment of disease. Each of our physicians at UCI Health have specialized areas of expertise and understand how radiation can be integrated in the context of surgery and/or chemotherapy for cancer. All team members have a vital role in ensuring that each patient receives the highest quality treatment plan delivered with a focus on clinical quality, safety and individualized care.

Fighting cancer demands a comprehensive team approach. Our radiation oncology team includes radiation oncologists, radiation therapists, physicists, dosimetrists and oncology-certified nurses. Together we develop a treatment plan tailored to your unique cancer or benign disease. We use the latest radiation therapy technologies and equipment to ensure the best patient experience.  The team members consist of the following:

Radiation Oncologists

Radiation oncologists are the doctors directing your radiation therapy treatments. These physicians work with the other members of the radiation therapy team to develop your treatment plan and make sure that each treatment is given accurately. Your radiation oncologist will also monitor your progress and adjust the treatment as necessary to make sure the radiation is hitting its target while minimizing side effects. Before, during and after your radiation therapy treatments your radiation oncologist will work closely with other cancer doctors, such as medical oncologists and surgeons, to make sure the radiation is most effective.

Radiation oncologists have completed at least four years of college, four years of medical school, one year of general medical training and four years of residency or specialty training in radiation oncology. They have extensive training in cancer medicine and the safe use of radiation to treat disease. After passing a special examination, they are certified by the American Board of Radiology. Meet Our Faculty

Radiation Oncology Residents

Working under the supervision of the radiation oncologists, resident physicians have completed four years of medical school and one year of internship. Your resident physician will meet you, along with your radiation oncologist, on your first visit and during your weekly management visits. Additionally, residents rotate with different attending so you might meet more than one during your treatment course.

Radiation Oncology Nurses

Radiation oncology nurses work together with radiation oncologists and radiation therapists to care for you and your family at the time of consultation, while you are receiving treatment and during your follow-up care. They will explain the possible side affects you may feel and help you manage them. They will assess how you are doing during treatment and can help you cope with the changes you may experience. They can also provide support and counseling to you and your family.

Radiation oncology nurses are licensed registered nurses or licensed practical nurses. Many registered nurses in radiation therapy have additional accreditation in the specialty of oncology nursing. Advanced practice nurses, including clinical nurse specialists and nurse practitioners, have completed master's degree programs.

Radiation Therapists

Radiation therapists work with radiation oncologists to deliver the daily radiation treatments that your doctor has prescribed. They maintain daily records and regularly check the treatment machines to make sure they are working properly. Radiation therapists also closely follow you during treatment to alert your doctor to any problems.

Radiation therapists go through a two to four-year educational program following high school or college. They take a special examination and may be certified by the American Registry of Radiologic Technologists. Many states also require radiation therapists to be licensed.

Medical Physicists

Medical physicists work directly with your radiation oncologist during treatment planning and delivery. They are responsible for developing and directing quality control programs for equipment and procedures. They also make sure the equipment works properly by taking precise measurements of the radiation beam and performing other safety tests regularly. Medical physicists also oversee the work of the dosimetrist and help to ensure that complex treatments are properly tailored for each patient.

Medical physicists have doctorate or master's degrees. They have completed at least four years of college, and then generally two to four years of graduate school. They also typically have one to two years of clinical physics training. Medical physicists are certified by the American Board of Radiology or the American Board of Medical Physics.

Medical Dosimetrists

After you decide on radiation, your doctor works with a dosimetrist to create a treatment plan. They use computers to develop a number of treatment plans to most effectively destroy the cancer while sparing normal tissue. Treatment plans are often very complex so dosimetrists work with the radiation oncologist and medical physicist to create a treatment plan that is right for you and your cancer.

Many dosimetrists start as radiation therapists and then, with intensive training, become dosimetrists. Others are graduates of one-to-two-year dosimetry programs. They are certified by the Medical Dosimetrist Certification Board.

Clinical Trials Coordinator

The clinical trials coordinator works behind the scenes to ensure that you have access to the most current drugs, therapies and diagnostic tools through clinical trials. If you meet the criteria for a trial, you can decide if you would like to participate. By doing so you have the potential to help yourself and others.

Cancer Biologists

Cancer and radiation biologists analyze the interaction between radiation and body systems through conducting advanced research. Their goal is to better understand how to employ radiation to fight cancer and other benign diseases.

Patient Care Representative

When you come to the Department of Radiation Oncology, you will be warmly greeted by a patient care representative. This person will check you in and make sure you are comfortable as you wait for your appointment. Should you have any initial questions or concerns, this person can assist you.

Financial Counselor

A financial counselor is available to help you understand the financial considerations of radiation treatment. To meet with the financial counselor, please ask when calling our facility.


A UCI dietician is available to meet with you to provide general nutrition counseling and suggestions for coping with side effects of cancer treatments. This individual specializes in nutritional therapy for patients diagnosed with cancer. To meet with the dietician, please ask when calling our facility.

Social Worker

A social worker is available to you during your treatment to help you solve practical problems or find the resources you need. Examples of assistance the social worker can provide include: lodging, financial concerns, transportation, support groups, coping techniques and more. To meet with the social worker, please contact the UCI facility.

Physical Therapist

Physical therapists use exercises to help your body function properly while you are undergoing treatment. These exercises can help manage side effects, alleviate pain and keep you healthy.

Administrators & Support Staff

Out of public sight, administrators and support staff such as information technology specialists, administrative assistants, and medical records technicians guarantee that all members of your team are able to provide you the utmost care.


At the UC Irvine facility, dedicated patient care schedulers manage the clinic calendars and will assist you in setting up your appointments.

Other Doctors

Treating cancer requires a team effort that often includes doctors other than your radiation oncologist. Other doctors you may also see include surgeons, medical oncologists, radiologists, dentists and your own family doctor. You may need to see other specialists depending on your type of cancer. Ask your radiation oncologist about the role these healthcare providers may play in your treatment.

Meet OurFaculty

    • Allen M. Chen, MD, MBA Home

      Allen M. Chen, MD, MBA

      Professor and Chair
    • Peter Maxim, PhD

      Peter Maxim, PhD

      Professor and Vice Chair
    • Charles Limoli, PhD

      Charles Limoli, PhD

      Professor and Vice Chair
    • Jeffrey V. Kuo, MD

      Jeffrey V. Kuo, MD

    • Varun Sehgal

      Varun Sehgal, PhD

    • Aaron B. Simon, MD, PhD

      Aaron B. Simon, MD, PhD

      Assistant Professor
    • Jeremy P. Harris, MD

      Jeremy P. Harris, MD

      Assistant Professor
    • Steven N. Seyedin, MD

      Steven N. Seyedin, MD

      Assistant Professor
    • Erin Healy, MD

      Erin Healy, MD

      Assistant Professor
    • Robert Hesselgesser, MD

      Robert Hesselgesser, MD

      Assistant Professor
    • Steven Davis, MD

      Steven Davis, MD

      Assistant Professor
    • Michael Reilly, PhD

      Michael Reilly, PhD

      Assistant Professor
    • Mengying Shi, PhD

      Mengying Shi, PhD

      Assistant Professor
    • Munjal Acharya, PhD

      Munjal Acharya, PhD

      Associate Professor
    • Shuaib Juma, MS

      Shuaib Juma, MS

      Staff Physicist
    • Janet Baulch, PhD

      Janet Baulch, PhD

      Project Scientist
    • Warren Inouye, MD

      Warren Inouye, MD

      Assistant Professor
    • Robert Kwan, MD

      Robert Kwan, MD

      Assistant Professor
    • Annie Truong, APRN

      Annie Truong, APRN

      Nurse Practitioner

Office LocationContact Us

Department of Radiation Oncology

UCI Medical Center

  • UCI Chao Family Comprehensive Cancer Center

    101 The City Drive, Bldg. 23, Orange
    CA 92868-3298
    Fax: (714) 456-7170
  • UCI Health
  • UC Irvine Health School of Medicine
  • University of California Irvine