Radiation Oncology Associates is Proud to Serve New England

Founded in 1971, Radiation Oncology Associates has been serving the needs of cancer patients in New Hampshire, Maine and Massachusetts for over 45 years. One of New England’s oldest and largest practices in radiation oncology, we strive to provide our patients with the freedom to receive the best cancer care close to home. We individualize treatment with compassion and cutting-edge technology to ensure you get the support and medical care that you need.

External Beam Radiation Therapy

External beam radiation therapy, or teletherapy, involves a linear accelerator machine used to generate and direct high-energy X-rays as a treatment. This is the most common category of radiation treatment.

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Brachytherapy

Derived from the Greek words for short distance (brachy) and treatment (therapy), brachytherapy is the use of ionizing radiation much closer to the target tumor, most often placed within the body.

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Systemic Radiation Therapy

This is a type of radiation therapy in which a radioactive substance, such as radioactive iodine, Radium-223, Yttrium-90 or other compound is swallowed or injected into the body.

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About Us

Serving the Needs of Patients in New England for Decades

Radiation Oncology Associates (ROA) is composed of highly trained, board certified Radiation Oncologists with extensive and up-to-date clinical expertise in the compassionate delivery of cancer care. We are fortunate to be have physicians with all levels of experience and clinical interests from those having recently completed training, to our more senior partners with more than 20 years in clinic. The unique size and diversity of our group allows us to deliver exceptional patient care across many sites, translating into better treatment options closer to home for many of our patients.

What to Expect

Learn what to expect from initial consultation through treatment and follow-up visits.

Types of Cancer

Radiation treatment can be new and unfamiliar. Learn about your type of cancer.

Helpful Links

Learn more about radiation treatment through our additional and state-specific resources.

Meet Our Doctors

Jeffrey Brower

Jeffrey Brower

MD, PhD

Jeffrey Brower received his Bachelor of Science degree in Microbiology and Cell Science with a minor in Chemistry from the University of Florida. He then went on to earn his Ph.D. in Molecular Biology, during which time his research led to the discovery of a novel gene responsible for cellular respiration and energy metabolism. During his Ph.D. research, he was awarded the Alumni Fellowship and other research awards to include the Medical Guild award for his work in molecular biology. Following the completion of his Ph.D., Dr. Brower matriculated to medical school at the University of Florida, graduating with research honors in 2012.

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Ping Zhou

Ping Zhou

MD, PhD

Dr. Zhou received her Bachelor of Science degree in Biology from Beijing University and then went to New York, earning a Ph.D. degree in cancer research from Columbia University in 1996. During her Ph.D. research, she studied the molecular mechanisms of cancer and was awarded Fellowships from American Cancer Society and National Foundation for Cancer Research.

Dr. Zhou graduated from Harvard Medical School, cum laude, in 2001. During medical school, she pursued her interest in cancer research at MIT and Dana Farber Cancer Institute, where she won an excellent MD thesis award.

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H. Andy Singh

H. Andy Singh

MD

Andy Singh received his Bachelor of Science degree in genetics from the University of California, Berkeley, in 1991 with honors. In 1995, he received his medical degree from University of Chicago Pritzker School of Medicine.

Dr. Singh completed an internship in internal medicine at Mount Auburn Hospital in Cambridge, MA. He continued his training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where he was named Chief Resident for 1999-2000. During residency, Dr. Singh developed expertise in three dimensional (3D) conformal radiation therapy, intensity modulated radiation therapy (IMRT) and brachytherapy.

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Thomas A. Sheldon

Thomas A. Sheldon

MD

Dr. Sheldon received his Bachelor of Science degree in biochemistry from the University of Wisconsin at Madison in 1976 where he was a member of the Phi Beta Kappa honors society. While in college, he worked with a research team studying interferon. He graduated from Tufts University School of Medicine in 1980. During medical school, he participated in research in radiobiology at the Harvard School of Public Health.

Dr. Sheldon completed an internship in medicine and surgery at Newton-Wellesley Hospital in Massachusetts, where he received the Margaret Derby Scholarship award in 1981.

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Bryan Rowe

Bryan Rowe

MD

Bryan Rowe studied biology at Wesleyan University and received his Bachelor of Arts with honors in 2000. He graduated from the University of Connecticut School of Medicine in 2007 with the Excellence in Medical Studies award.

Dr. Rowe trained in radiation oncology at Yale New Haven Hospital, where he served as chief resident from 2011 to 2012. He gained extensive experience in the most current radiation therapy techniques, including intensity modulated radiotherapy (IMRT), image-guided radiotherapy (IGRT), stereotactic radiotherapy, and brachytherapy.

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Vivek Patel

Vivek Patel

MD, PhD

Vivek Patel received his Bachelor of Science degree from Cornell University in 2006, where he was awarded honors Magna Cum Laude with Distinction in research. He further pursued his interest in biomedical science at the Weill Medical College of Cornell University, where he investigated novel drug therapies for blood disorders. He earned his M.D. and Ph.D. degrees from the Albert Einstein College of Medicine in 2007, where he achieved grant funding from the National Institutes of Health (NIH) and American Medical Association (AMA) for his work on RNA biology. Dr. Patel was elected to the Alpha Omega Alpha honor society upon his graduation from medical school in 2013.

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Etin-Osa Osa

Etin-Osa Osa

MD

Etin-Osa Osa received her Bachelor of Science degree in Biology and Chemistry with highest academic distinction from Howard University in 2005 and earned her medical degree from New York University School of Medicine in 2009.

Dr. Osa went on to complete her internship in General Medicine and residency in Radiation Oncology at New York University (NYU) from 2009 to 2014.

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Klaudia Hunter

Klaudia Hunter

MD

Klaudia Hunter received Bachelor Degrees with Distinction in both philosophy and biology from the University of Illinois at Chicago in 2001. She then graduated with honors from the University of Illinois Medical School in 2006 after completing the James Scholar Program for Independent Study and playing a leadership role in the Alpha Omega Honors Society.

Dr. Hunter completed her surgical internship at the University of California at San Diego in 2007. She continued in the neurosurgical residency training program at the University of California at San Diego until June 2009 when she chose to leave to pursue a career in radiation oncology.

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William O’Meara

William O’Meara

MD

Bill O’Meara received his Bachelor of Arts in English from the University of Notre Dame in 1992 and completed medical training at Tulane University School of Medicine in 1997. While in medical school, he simultaneously obtained a masters degree in public health.

Dr. O’Meara completed an internship in internal medicine in 1998 at the Naval Medical Center in San Diego. From 1998-2002, he served as an active duty Naval medical officer with operational forces.

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Asa J. Nixon

Asa J. Nixon

MD, MPH

Asa Nixon received his Bachelor of Arts degree from Dartmouth College in 1984. In 1988, he graduated with his medical degree from New York University School of Medicine.

Dr. Nixon completed two years of residency in general surgery at New England Deaconess Hospital in Boston, MA. He continued his training in radiation oncology at the Joint Center for Radiation Therapy (JCRT), Harvard Medical School. During residency, Dr. Nixon completed a fellowship in cancer epidemiology from the Harvard School of Public Health, receiving a Masters in Public Health degree.

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Su Metcalfe

Su Metcalfe

MD, MPH

Su Metcalfe received her Bachelor of Arts in Asian Studies from Pomona College in 1996. Following this, she received a Masters of Science in Biology with a focus in Immunology from NYU in 1999 and completed a research fellowship at the National Institutes of Health. She earned a Masters of Public Health degree from Columbia University in 2001. In 2005, she graduated from the University of Vermont College of Medicine.

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Christopher Freese

Christopher Freese

MD

Chris Freese obtained his BBA in Management and Strategic Leadership from Ohio University. After completing his undergraduate studies, he decided to pursue a career in medicine and began working as a research assistant at the Cincinnati Children’s Hospital Medical Center studying the pathogenesis of pulmonary fibrosis. He then matriculated into medical school at the University of Cincinnati College of Medicine where he graduated top of his class and was elected into the Alpha Omega Alpha Honors Society.

Dr. Freese joined Radiation Oncology Associates in 2019 after completing his training. He enjoys developing lasting patient relationships and providing compassionate, effective care to all.

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Andrea B. McKee

Andrea B. McKee

MD

Andrea McKee received her Bachelor of Arts degree in biology in 1992 from the University of Pennsylvania with honors. She graduated from Columbia University College of Physicians and Surgeons in 1996. During college and medical school, she participated in laboratory and clinical research prior to continuing with her clinical training.

She continued her training in radiation oncology at Memorial Sloan-Kettering Cancer Center, where she was named Chief Resident for 2000-2001.

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Arul Mahadevan

Arul Mahadevan

MD

Arul Mahadevan received his Bachelor of Medicine and Surgery from the University of Madras (Chennai) in 1987 and his Master of Surgery in Orthopedics from the University of Bombay in 1991.

Since joining Radiation Oncology Associates in 2008, Dr. Mahadevan has helped us make new radiation technologies available. He remain active in clinical trials with RTOG and serves on the Government Relations Committee and Education Committee for the American Society of Radiation Oncology. He is also the Medical Director of the Radiation Therapy Training Program of the New Hampshire Technical Institute.

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Jeffrey Lemons

Jeffrey Lemons

MD, MS

Jeff Lemons earned his Bachelor of Science degree from the University of Michigan in Ann Arbor, MI with a major in Cellular, Molecular, and Developmental Biology and a minor in Spanish. After finishing at Michigan, he matriculated into medical school at Temple University School of Medicine in Philadelphia, PA and graduated in 2013 as a member of the Alpha Omega Alpha Honor Society.

After medical school, Dr. Lemons completed internship at Crozer Chester Medical Center in Upland, PA followed by radiation oncology residency at the University of Chicago where he served as Chief Resident in his final year.

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Brian R. Knab

Brian R. Knab

MD

Brian Knab received a Bachelor of Arts degree in interdisciplinary studies at the University of Virginia in 1997. He graduated from Duke University Medical School in 2002 as a member of the Alpha Omega Alpha medical honor society. While in medical school, he participated in a year-long laboratory research program at the University of California at San Francisco investigating new cancer treatments.

Following medical school, Dr. Knab returned to the University of Virginia to complete an internship in internal medicine.

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Matthew S. Katz

Matthew S. Katz

MD

Matt Katz received his Bachelor of Arts degree in history from Northwestern University in 1992 and graduated from the University of Massachusetts Medical School in 1998. During medical school, he also completed a fellowship in pathology.

Dr. Katz completed his radiation oncology residency at Memorial Sloan-Kettering Cancer Center in 2003. He developed expertise in the use of newer technologies such as intensity modulated radiation therapy (IMRT) to improve the accuracy and safety of radiation therapy. From 2003-2004, Dr. Katz was on staff at the Massachusetts General Hospital in the Department of Radiation Oncology.

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Howard Hsu

Howard Hsu

MD

Howard Hsu received his Bachelor of Science degree in Bioengineering from the University of California Berkeley in 1998. He served as a Peace Corps Volunteer in a rural village of South Africa from 1999-2001, working on education and community health projects. He earned his medical degree from Cornell University Medical College in 2005.

Dr. Hsu served for three years as an intern and resident in General Surgery at Washington University / Barnes-Jewish Hospital from 2005-2008. He subsequently pursued research training in radiation biology at the University of California San Francisco / Lawrence Berkeley National Laboratory.

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Stephen Harris

Stephen Harris

MD

Stephen Harris graduated with distinction with a degree in biomedical engineering from Purdue University in 2001. He went on to Indiana University School of Medicine in 2005 where he was a member of the Alpha Omega Alpha medical honor society. Dr. Harris stayed in Indianapolis to complete his internship at Indiana University before moving to the University of North Carolina to complete his residency in radiation oncology. While at UNC, Dr. Harris served as chief resident from 2008-2010.

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Jeffrey Brower

MD, PhD

Ping Zhou

MD, PhD

H. Andy Singh

MD

Thomas A. Sheldon

MD

Bryan Rowe

MD

Vivek Patel

MD, PhD

Etin-Osa Osa

MD

Klaudia Hunter

MD

William O’Meara

MD

Asa J. Nixon

MD, MPH

Su Metcalfe

MD, MPH

Christopher Freese

MD

Andrea B. McKee

MD

Arul Mahadevan

MD

Jeffrey Lemons

MD, MS

Brian R. Knab

MD

Matthew S. Katz

MD

Howard Hsu

MD

Stephen Harris

MD

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