A patient undergoes treatment in the Proton Center at MedStar Georgetown University Hospital is equipped with state-of-the-art equipment to shrink and eliminate tumors.

Proton Therapy: The Latest Advancement in Cancer Treatment

There’s good news for adults and children with cancer in the nation’s capital and beyond: We're proud to offer proton therapy with HYPERSCAN™ technology at MedStar Georgetown University Hospital.

Proton therapy with HYPERSCAN™

MedStar Georgetown is the first and most experienced facility in the Washington, D.C. area to offer proton therapy with HYPERSCAN™.

Proton therapy can treat tumors, anywhere in the body. It's used to treat a variety of conditions, including:

  • Brain tumors

  • Breast cancer

  • Gastrointestinal cancers

  • Gynecologic cancers

  • Head and neck tumors

  • Lung and chest tumors

  • Lymphomas

  • Pediatric tumors

  • Prostate cancer

  • Recurrent tumors

  • Sarcoma/soft tissue

  • Spinal cord tumors

This highly effective therapy could help get your life back on track, cancer-free. Watch the videos to learn more below.

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Benefits of proton therapy

  • Power to shrink and eliminate cancer and other tumors anywhere in the body
  • Pinpoint accuracy that results in less radiation damage to surrounding healthy tissues
  • Highly customizable treatments tailored to your individual needs
  • Targets and destroys tumors with precise accuracy using pencil beam scanning (PBS)
  • Our HYPERSCAN technology targets the exact location of the tumor, delivering radiation one layer at a time
  • Fewer side effects after treatment, such as nausea and headaches
  • Lower risk of secondary cancer
  • Proton therapy is especially beneficial in certain circumstances
  • Benefits of proton therapy in children

Meet our patients

A woman with a shaved head and wearing a bright blue shirt and floral skirt smiles broadly as she stands on a balcony.
Breast Cancer Patient Chooses Proton Therapy for Precision, Protection

After a routine mammogram detected a lump in her right breast in 2009, Debbie Koss of Rockville, Md., considered herself lucky. The tumor was small and in its very early stages, treatable through a lumpectomy and radiation therapy alone.

Jack Yeatts poses for a photo on the golf course, after undergoing successful proton therapy at MedStar Georgetown University Hospital.
Engineer credits proton therapy with beating stomach cancer.

When Jack Yeatts retired at the age of 67 from his career as a space systems project and electrical engineer, he thought he would spend more time with his family and on the golf course in Stone Ridge, Virginia. However, doctors discovered a tumor in his lower esophagus and referred him to MedStar Georgetown University Hospital for treatment.

Meet the Radiation Medicine team

Our team of physicians at MedStar Georgetown is made up of the D.C. area’s leading experts, who have specialized knowledge in numerous cancer types and are at the forefront of the latest advances in treatment.

We take a compassionate approach to cancer therapy, guided by the principle cura personalis, which means “care for the whole person.”

With multiple advanced cancer treatment options available under one roof, MedStar Georgetown is a leader in Radiation Medicine.

  • Peter Ahn, MD

    Peter Ahn

    Peter H. Ahn, MD, joined the medical staff of MedStar Georgetown Department of Radiation Medicine in 2017, after five years as a radiation oncologist and assistant professor with the University of Pennsylvania Health System. Previously, he was an assistant professor at Thomas Jefferson University and Hospital in Philadelphia.

    Fellowship-trained at MD Anderson Cancer Center and board-certified in Radiation Oncology, Dr. Ahn has extensive experience in treating cancers of the head and neck, skin (including melanoma), skull base, and brain using a variety of therapeutic approaches, including conventional and proton beam radiation therapies. He is nationally recognized by Castle Connolly's annual publication, "America's Top Doctors."

    Dr. Ahn's research has been funded by industry, private and public sources including NIH, and been published in peer-reviewed journals. A frequent guest lecturer and presenter, he is also a reviewer for multiple scientific and medical publications.

    Philosophy of Care:
    "No two cancer patients are exactly alike, so the need and ability to highly customize radiation treatment requires disease-specific training and extensive experience. Minimizing the long-term side-effects of today's advanced treatments is also a major consideration. Dealing with the unique challenges inherent in each patient's social situation, individual goals of care, and tumor characteristics keeps me excited about my work as a member of the dedicated and experienced team of physicians, nurses, technicians and physicists at MedStar Georgetown."

  • Sean P. Collins, MD, PHD


    Radiation Oncologist Sean Collins, MD, PhD, is director of the CyberKnife® Prostate Program at MedStar Georgetown University Hospital and professor of Radiation Medicine at Georgetown University School of Medicine. Dr. Collins joined Georgetown in 2006 after completing his residency in radiation oncology at MedStar Georgetown and the Georgetown Lombardi Comprehensive Cancer Center and, previously, a surgical internship at MedStar Georgetown. In addition to his medical degree, he also holds a doctorate in Biological Chemistry, both from the University of Michigan's Medical Scientist Training Program.

    Dr. Collins uses the very latest radiation oncology techniques and tools including proton therapy, CyberKnife® stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT), intensity-modulated radiation therapy/image guided radiation therapy (IMRT/IGRT/RapidArc®), and brachytherapy.

    The major focus of Dr. Collins' clinical work is the development of prostate cancer treatment protocols using SBRT. Patients receiving conventionally fractionated radiation therapy are treated daily for approximately 8 to 9 weeks. The treatment schedule is based on logistics and life responsibilities, as such prolonged treatment courses may present unnecessary hardship for patients and families.

    To date, Dr. Collins has enrolled more than 500 patients on investigator-initiated, Institutional Review Board (IRB)-approved clinical protocols exploring the role of SBRT in prostate cancer treatment. His work has appeared in the American Journal of Clinical Oncology, Radiotherapy and Oncology, International Journal of Radiation Oncology Biology Physics, Cancer Journal and many other scientific publications. He also serves as a reviewer or editorial board member for numerous other publications, including the New England Journal of Medicine.

    Philosophy of Care:
    We work as a team to make sure that every patient receives the highest quality, most effective treatment available today. That's especially true for prostate cancer patients, where there are so many options. For us, treating prostate cancer is not only about curing the disease, but assuring each patient's long-term quality of life. Toward that end, I establish open communication with my patients, ensuring ease of access and peace of mind from diagnosis through recovery.

  • Andrew Satinsky, MD


    Andrew Satinsky, MD, is an attending radiation oncologist at MedStar Georgetown University Hospital and clinical director of the Radiation Oncology Center at MedStar Southern Maryland Hospital Center.

    A specialist in prostate cancer and lung cancer, Dr. Satinsky uses the very latest radiation oncology techniques and tools including proton therapy, low- and high-dose rate gynecologic brachytherapy, intensity-modulated radiation therapy/image-guided radiation therapy (IMRT/IGRT/RapidArc®), and CyberKnife® stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT).

    Dr. Satinsky has been involved in research on a variety of radiation oncology-related topics. As the chair of the MedStar Georgetown Radiation Oncology Residency Program's Clinical Competency Committee, he helps to train new doctors. Dr. Satinsky also serves as chair of the MedStar Southern Maryland Hospital Cancer Committee and is a member of the education committee.

  • Keith Unger, MD


    Board-certified Radiation Oncologist Keith Unger, MD, is the Clinical Director and Director of the Gastrointestinal Cancer Service Department of Radiation Medicine. Concurrently, he serves as an associate professor of Radiation Medicine at the Georgetown University School of Medicine.

    In addition to general radiation oncology, Dr. Unger specializes in the very latest radiation oncology techniques and tools. These include proton therapy, intensity-modulated radiation therapy (IMRT), CyberKnife® stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS), selective internal radiation therapy (TheraSphere®, SIR-Spheres®), and intraoperative radiation therapy (INTRABEAM®).

    Dr. Unger completed his internship at MedStar Washington Hospital Center and residency at MedStar Georgetown, including a year as chief resident for Radiation Oncology. He received both his undergraduate and medical degree from the University of Virginia, where he was the recipient of numerous academic honors and awards.

    As a researcher and educator, Dr. Unger has been a co-author of multiple text book chapters and publications in peer-reviewed journals, as well as a presenter at major medical meetings. His research focuses on the development of novel radiation therapy techniques and reduction in treatment related side effects.

    Dr. Unger sees patients at both MedStar Georgetown and MedStar Southern Maryland Hospital.

  • Nitika Paudel, MD, PhD


    Nitika Paudel, MD, PhD, has joined MedStar Georgetown Department of Radiation Medicine. She is passionate about improving patient outcomes with collaboration, patient education, and clinical research. Dr. Paudel specializes in:

    • Three-dimensional conformal radiation therapy
    • Intensity and volumetric-modulated radiation therapy
    • Image-guided radiation therapy
    • Stereotactic body radiation therapy
    • Stereotactic radiosurgery
    • Proton therapy
    • High dose rate brachytherapy

    Dr. Paudel is currently an active member of the American Society of Therapeutic Radiology and Oncology, American College of Radiation Oncology, Chicago Radiologic Society, and several other groups. She has been published in several prestigious scientific journals, including Surgical Oncology, Practical Radiation Oncology, International Journal of Radiation Oncology, Biology and Physics, and Journal of Virology.

  • Sonali Rudra, MD


    Sonali Rudra, MD, serves as director of the Breast Cancer Radiation Oncology Program at MedStar Georgetown University Hospital and an assistant professor for the Department of Radiation Medicine at the Georgetown University School of Medicine. She specializes in treating patients with breast cancer, gynecologic malignancies, pediatric malignancies, and central nervous malignancies. She employs a range of technologies, including proton therapy, intensity-modulated radiation therapy/image-guided radiation therapy (IMRT/IGRT/RapidArc®), CyberKnife® stereotactic body radiation therapy (SBRT) stereotactic radiosurgery (SRS), and high-dose rate brachytherapy.

    Dr. Rudra is widely published in respected clinical journals and serves on an editorial board reviewing clinical articles. She also participates in professional activities, serving as a core member of the team at MedStar Georgetown responsible for accreditation by the National Accreditation Program for Breast Centers (NAPBC) to ensure clinical quality. She is also a member of the Intraoperative Radiation (IORT) Working Group.

    Philosophy of Care:
    I believe in treating my patients as individuals and strive to provide them with the best possible outcomes while minimizing the effect on their lives.

For more information call



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Frequently asked questions

  • What to expect?

    Our team is committed to helping you find out if proton therapy is right for you, answer questions and guide you through the process. Find out what to expect with proton therapy.

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  • What is the difference between proton therapy and conventional radiation?

    Traditional radiation therapy uses photons to treat tumors. Photons radiate not only tumor cells but also everything in their path, including healthy cells and structures around and behind the tumor.

    Proton therapy uses protons to treat tumors. Protons can be controlled better than conventional radiation, making this treatment more precise and accurate. As a result, proton therapy can treat tumors without radiation continuing past the tumor (an “exit dose” of radiation). This protects surrounding tissues from harm.

  • How does proton therapy work?

    Proton therapy uses pencil beam scanning to deliver radiation and match each tumor’s exact shape and size in 3-D. This allows a single layer of a tumor to be treated at a time, in effect painting the tumor with radiation layer-by-layer and slice-by-slice until the entire area has been treated.

  • What are the benefits of proton therapy?

    Proton therapy is more accurate and precise than most other forms of radiation therapy. Because it involves significantly less radiation exposure to normal tissues, proton therapy also lowers the risk of side effects and secondary, radiation-induced cancers. Additionally, proton therapy can treat recurrent cancers and children with cancer.

    This advanced technology:

    • Targets and destroys tumors with pinpoint accuracy
    • Provides better protection to surrounding healthy tissues
    • Requires less radiation
    • Leaves virtually no exit dose; i.e., little to no radiation continues past the tumor
    • Lowers the risk of radiation-induced secondary cancers
    • Results in fewer side effects and better quality of life
    • Is highly customizable, tailored to your needs
  • What types of cancers or tumors can proton therapy treat?

    Proton therapy can treat cancer anywhere in the body, including:

    • Brain tumors
    • Breast cancer
    • Gastrointestinal (GI) cancers
    • Gynecologic cancers
    • Head and neck tumors
    • Lung/chest cancers
    • Lymphomas
    • Pediatric tumors
    • Prostate cancer
    • Recurrent, previously irradiated tumors
    • Sarcoma/soft tissue
    • Spinal cord tumors
  • Who is a candidate for proton therapy?

    An adult or child of any age may be a potential candidate for proton therapy. An evaluation by a radiation oncologist will determine whether proton therapy or another course of treatment is the best option for you.

  • Is proton therapy appropriate for children?

    Yes. Proton therapy is generally accepted as part of the standard of care treatment for many pediatric cancers. It can be particularly beneficial for children because:

    • Children are less likely to develop a secondary cancer later in life when treated with proton therapy as it treats tumors while keeping healthy surrounding cells unharmed.
    • Proton therapy lowers a child’s exposure to radiation, avoiding unnecessary exposure to healthy tissues and resulting in less growth impairment as they develop.
    • Proton therapy causes fewer side effects compared to traditional radiation, allowing children to maintain normal activities during treatment.
  • Does insurance cover proton therapy?

    Medicare is covering proton therapy. Proton therapy is a standard of care for pediatric patients so insurance plans will cover most patients under the age of 21 or 19, depending on the plan. If you are a candidate for the proton therapy, your insurance will be contacted to find out if it is a covered benefit for you. We have hired associates who will help our patients work through and obtain authorization and assist in the appeal process, if necessary.

    We anticipate that insurance plans will cover most patients who need proton therapy, which is just a new way to deliver radiation, a treatment that has been around for decades. We will keep you informed as we pursue the process.

  • How do I know if proton therapy is right for me?

    You will first meet with a radiation oncologist for an evaluation that will include reviewing your medical records, all possible radiation treatments that may be appropriate for your specific health needs, and the risks and benefits of each option. You and your physician will then determine the best plan of care based on a number of factors, including the type of cancer; the tumor’s location, size, and stage; and how well it may respond to different radiation therapies under consideration.

  • What happens next?

    If proton therapy is determined to be your best option, your radiation oncologist and physicist will work together to build a treatment plan. Each plan is carefully configured to meet your needs. If proton therapy is not the best treatment option for you, we offer the full range of radiation therapies available today and can address your needs.

  • How many proton therapy treatments will I need?

    The length of the course of treatment depends on each patient’s specific diagnosis, and is determined by the radiation oncologist. In general, the number of individual treatment sessions ranges from 10 to 40, depending upon the type of tumor. However, every patient is unique, so the actual number of treatment sessions may vary.

  • How do I make an appointment?

    If you would like to make an appointment, please contact Cheryl Savage, administrator, Department of Radiation Medicine: savagech@gunet.georgetown.edu or 202-444-4639