Find A Doctor

Our Proton Therapy Physician Team

Indiana University Health Proton Therapy Center radiation oncologists are among the finest in the nation. Our physicians are affiliated with the Indiana University School of Medicine and have decades of experience in radiation oncology. This ensures they are aware of the latest developments in prostate cancer treatment and technology and are actively involved in research. Our patients benefit from our physicians’ involvement in teaching the next generation of physicians and researchers and exploring developments in the field. Our physicians have access to some of the most innovative treatment technology in the world. They collaborate to use this technology to benefit each patient and to pioneer discoveries in cancer treatment.

Our medical team is committed to providing you with the highest standards of patient care and expertise in proton therapy. We will provide you with the highest quality of care and will consistently align our priorities with the needs of our patients and their caregivers.

Peter Johnstone, MDMedical Director

Medical Director, IU Health Proton Therapy Center; and Professor of Radiation Oncology, IU School of Medicine

On staff since December 2007.

Specialities: Prostate and breast cancer



As the country grapples with healthcare reform, Dr. Peter Johnstone, IU Health Proton Therapy Center medical director, remains optimistic about the future of proton therapy in Bloomington, Ind.

“Proton therapy is a unique opportunity for Indiana, and it is not available at many other places in the country,” says Dr. Johnstone. “We have a stable, solid workforce; experienced physicists and staff operating our proton beam; the support of a great national institution in the Indiana University School of Medicine; and a powerhouse of a regional health network in Indiana University Health. That is a lot of potential to tap into.”

“We are in a very advantageous position,” he explains. “What we have to do is get the word out to the patients who can benefit from this unique treatment. Proton therapy is a marvelous opportunity for pediatric patients and for patients with head and neck and brain cancer.” In addition to treating these patients, the IU Health Proton Therapy Center also sees prostate cancer patients and patients with recurrant cancers. 

Just as many consumers have the misperception that proton therapy is a “new” or “experimental” therapy, many doctors are unaware of the advantages proton therapy can offer cancer patients. Unfortunately, some referring physicians are not yet suggesting proton therapy – which may involve moving away from home to Bloomington for a period of weeks – as a treatment option for patients. “If a patient leaves their hometown for proton therapy, that community loses the healthcare dollars that would have been spent locally on cancer treatment,” explains Dr. Johnstone. “But…there are cadres of patients for whom proton therapy makes perfect sense.”

To help educate members of the medical community, Johnstone is increasing the IU Health Proton Therapy Center’s emphasis on research, both through publications and presentations at national and international medical meetings. Dr. Johnstone has degrees in both communications and medicine, has spent the last 25 years working as an administrator, grant-funded researcher and professor/practitioner of radiation oncology.

During more than a quarter of a century of service in the U.S. Navy, Dr. Johnstone served as both director of clinical support services and as chief of radiation oncology at San Diego’s Naval Medical Center. In between, he managed multi-million dollar projects and facilities including the Navy Medical Center San Diego Breast Health Center – which won the 1999 Wyeth-Ayerst Gold HERA Award for excellence in women's health care – and eventually became an advisor on radiation oncology to the Navy’s Surgeon General.

Internationally known as an expert in prostate cancer, he has authored hundreds of peer-reviewed articles, abstracts and scientific posters in addition to serving for nearly a decade as editor-in-chief of the journal Current Problems in Cancer.


  • BS, chemistry, United States Naval Academy, Annapolis, Md.
  • MA, communication, University of Oklahoma – Norman
  • MD, Uniformed Services University of the Health Sciences, Bethesda, Md.
  • President, American Radium Society (2011)
  • President, Society for Integrative Oncology (2007)
  • Fellow of the American College of Radiology (ACR) and currently on the ACR Board of Chancellors
  • Board certified in radiation oncology
  • Author of six book chapters, more than 200 peer-reviewed papers, and more than 100 scientific posters, with national and international lecture presentations on radiation oncology and proton therapy
  • Previous appointments at Emory University School of Medicine and Emory Winship Cancer Center, Atlanta, Ga.; Grady Memorial Hospital; Uniformed Services University of the Health Sciences, Bethesda, Md.; and University of California – San Diego
  • Named as Top Doctor by Castle Connolly and HealthTap (formerly Avvo)

Jeffrey Buchsbaum, MD, PhD, AMRadiation Oncologist

Radiation Oncologist, IU Health Proton Therapy Center; and Associate Professor of Radiation Oncology, Pediatrics, and Neurological Surgery, IU School of Medicine

On staff since July 2010.

Specialties: Pediatric cancers; tumors of the head, neck and brain; prostate cancer



Once he decided to join the staff of the IU Health Proton Therapy Center in 2010, Dr. Jeffrey Buchsbaum had a lot to be excited about.

A radiation oncologist specializing in the treatment of children, Dr. Buchsbaum – who has both a master’s degree in physics and a doctorate in molecular biophysics and biophysical chemistry in addition to his medical degree – knew he wanted access to proton therapy.

“I am absolutely convinced that using protons to treat children and certain tumors in adults is superior to photons (which are used in traditional X-ray radiation therapy),” he says. “Children truly benefit from proton therapy through fewer growth and memory problems and secondary cancers.”

The precision-targeting ability of the proton beam is especially important to Dr. Buchsbaum because he specializes in treating complicated tumors of the brain, head and neck.

“Delivering 10 to 20 percent less radiation to critical structures can mean the difference between damage and no damage,” he says of the proton beam’s ability to spare healthy tissue within one millimeter away from cancer cells.

Once he visited the IU Health Proton Therapy Center, it didn’t take long for Dr. Buchsbaum – who has been affiliated with such prestigious institutions as St. Jude Children’s Research Hospital, Penn State Hershey Cancer Institute and the Cleveland Clinic – to decide that Bloomington was the perfect place for him to practice.

“As I walked the halls with John Kerstiens (IU Health Proton Therapy Center CFO and COO), I was amazed that he knew every patient by name,” says Dr. Buchsbaum. “That is unbelievable.”

“From how hands-on the physicists and nurses are to the precision of the treatment plan to the focus on the patient…everyone at the IU Health Proton Therapy Center is dedicated to creating the best possible plan and doing what is right for our patients without compromise,” he says.

Dr. Buchsbaum was also impressed by the cyclotron that produces the proton beam and the Indiana University Cyclotron Operations team dedicated to its operation.

“The IU Health Proton Therapy Center has an amazing top-of-the-line treatment machine,” he says. “This is a facility with the potential to be a unique national resource, especially for the Midwest.”

Having cycled competitively in Italy, Dr. Buchsbaum enjoys living in Bloomington, a city whose rich tradition of competitive cycling was depicted in the major motion picture “Breaking Away.”

“Bloomington is a wonderful place to live,” says Dr. Buchsbaum, who has relocated from Florida with his wife and two sons. “I’m thrilled to be a part of the IU Health Proton Therapy Center treatment team.”


  • AB and AM in physics, Dartmouth College, Hanover, N.H.
  • MD/PhD in molecular biophysics and biophysical chemistry, Johns Hopkins University School of Medicine, Baltimore, Md.
  • Board certified in radiation oncology
  • Author of seven book chapters as well as peer-reviewed papers and scientific abstracts, with national and international lecture presentations on proton therapy and pediatric radiation therapy
  • Previous faculty appointments at St. Jude Children’s Research Hospital, Radiation Oncology, Memphis, Tenn., and at Penn State Milton S. Hershey Medical Center, Radiation Oncology and Pediatrics, Hershey, Pa.
  • Active member in the Children’s Oncology Group, Paediatric Radiation Oncology Society, International Society of Paediatric Oncology, American Society of Radiation Oncology, American Association for Cancer Research and Radiological Society of North America 
  • Leadership roles in international protocols involving retinoblastoma, Hodgkins and medulloblastoma
  • Named as Top Doctor by Castle Connolly, and achieved the National Champion Radiation Oncologist Award in the Tournament of Top Doctors by HealthTap.

Mark McDonald, MDRadiation Oncologist

Radiation Oncologist, IU Health Proton Therapy Center; Assistant Professor of Radiation Oncology, IU School of Medicine

On staff since September 2009.

Specialties: Tumors of the skull base, head and neck, brain and spine



As the son of an oncologist and an oncology nurse, Mark McDonald grew up listening to his parents tell stories about the struggles and victories they shared with their patients. Now, Dr. McDonald is the story-teller.

“Having my parents relate stories about what they did for patients had a profound impact on me,” says Dr. McDonald, IU Health Proton Therapy Center physician and assistant professor of radiation oncology at Indiana University School of Medicine. “They instilled in me a strong sense of what a privilege it is to practice medicine and to take care of people.”

Today, Dr. McDonald considers it a privilege to be both a doctor and part of the treatment team at the IU Health Proton Therapy Center using state-of-the-art technology to treat cancer patients.

“We are very fortunate to have the physicians, medical physicists, dosimetrists, nurses and therapists that we have at the IU Health Proton Therapy Center,” says Dr. McDonald. “It is a great team.”

Dr. McDonald completed his internship and residency training at Emory University School of Medicine in Atlanta, which was an early adopter of new technologies including image-guided treatment and intensity-modulated radiation therapy (IMRT). As a result, Dr. McDonald worked extensively with the most advanced forms of X-ray radiation, earning awards from the Radiological Society of North America and the American Radium Society for his research on IMRT treatment of breast and head and neck cancers.

“IMRT is an impressive technology,” says Dr. McDonald, “But proton beam therapy has its advantages."

To illustrate his point, he describes a CT scan of a patient’s tumor overlaid with two treatment plans – one using IMRT and the other using proton beam therapy – that ‘map’ areas that will receive radiation. The proton therapy map shows a treatment area that is tightly focused on the tumor with a small margin around it, while the IMRT map shows radiation unnecessarily exposing a larger area surrounding the tumor.

“There’s no comparison in amount of normal tissue being radiated,” he says. “Proton therapy dramatically reduces the exposure of normal tissues to radiation.”

Having access to a variety of cancer treatment options – including both IMRT and proton therapy – is one of the things Dr. McDonald appreciates about his dual position at the Indiana University School of Medicine and the IU Health Proton Therapy Center.

“It is great to have the full arsenal of tools available to treat patients appropriately,” he says.

Dr. McDonald believes that the percentage of cancer patients treated with proton radiation will grow as the technology continues to evolve. For his part, he is focusing on increasing collaboration with Indiana University to explore areas where proton therapy will help improve cure rates, quality of life or both. He is particularly interested in the role of proton radiation in patients with tumors of the brain, head, neck or spine; and he is a supporter of the use of proton for children.

“Proton therapy is the most compelling treatment choice for many children who need radiation since they are so sensitive to radiation and can have more deleterious effects,” he says. “Anything we can do to minimize radiation exposure in children should be done, and proton therapy is often our best tool.”

The long- and short-term effects of radiation to the brain and cranial nerves also make proton therapy an ideal choice for treating cancers at the base of the skull or near the brain stem or spinal cord.

“With proton radiation, we can often take the untreatable or incurable and make it curable, and that’s the most exciting thing we can do in oncology,” says Dr. McDonald.

It also makes for a great story.


  • BA, summa cum laude, Xavier University, Cincinnati, Ohio
  • MD, The Ohio State University College of Medicine and Public Health, Columbus, Ohio
  • Board certified in radiation oncology
  • Author of numerous peer-reviewed publications, with national and international lecture presentations on on proton therapy and advanced imaging technologies
  • Active member in the American Society for Radiation Oncology, American Society for Clinical Oncology, American Radium Society and Children’s Oncology Group

Kevin McMullen, MDRadiation Oncologist

Radiation Oncologist, IU Health Proton Therapy Center; Associate Professor of Clinical Radiation Oncology and Indiana Lions Endowed Scholar in Cancer Survivorship, IU School of Medicine, IU Health Methodist Hospital Radiation Oncology

On staff since November 2011.

Specialties:  Pediatric cancers, intracranial/extracranial stereotactic radiotherapy/ radiosurgery, tumors of the central nervous system cancer of the reticulo-endothelial system, palliative care and quality of life/neuro-cognition


The Indiana University Health Proton Therapy Center welcomed Dr. Kevin McMullen to the physician team in November 2011. With over a decade of radiation oncology experience, the former U.S. Army flight surgeon and Wake Forest University School of Medicine faculty member focuses primarily on treating pediatric, adolescent, and young adult patients at the IU Health Proton Therapy Center.

Dr. McMullen brings with him diverse experiences within the field of oncology. While he has practiced in pediatric and adult radiation oncology, as well as radiosurgery for years, his passion lies in the area of survivorship with regard to the long-term effects of cancer therapy. Having published extensively about radiation therapy, he acknowledges that “second cancers, including those from radiation exposure of tissue during treatment, are a major cause of morbidity and mortality for cancer survivors.” His interests in survivorship issues and prevention of late effects of cancer therapies led him to the IU Health Proton Therapy Center because he believes proton therapy can have a major impact on the late effects of radiation treatments. “The opportunity to deliver proton therapy, while also helping to further develop the scientific basis for appropriate use of this technology was an exciting opportunity," he notes.

Dr. McMullen is also the Indiana Lions Endowed Scholar in Cancer Survivorship. The Indiana Lions Endowed Scholar in Cancer Survivorship was created at the generosity of the Indiana Lions to support research and efforts on behalf of cancer survivors. Cancer survivors suffer from late effects both from their cancer and from their therapy. About cancer survivors, Dr. McMullen notes, "The cancer survivor is never the same as they were before they got sick. They have literal scars and wounds suffered during their cancer treatment; but also bear hidden pain from the psychological and emotional trauma of their ordeal. Remission may seem like a glorious release to the outsider….but to the cancer patient, it’s not the same as true freedom. These patients need support in dealing with the global effects their treatments cause to the quality of their lives. As part of this position I’ve been given, my goal is to work towards improving the strategies we use for treatment to cause fewer late effects; and to work for creative supportive care strategies for survivors to address long term effects of their therapy."

At the IU Health Proton Therapy Center, Dr. McMullen treats patients in all stages of treatment. He also works from an Indianapolis office where he can reach more patients in need of oncological treatment. He notes, “Not all pediatric and young adult patients need proton therapy, but for those who may benefit we would like to offer this option to as many patients as possible.”

The strategy of photon therapy (conventional radiation) and proton therapy can differ greatly depending on the case. "Although the goal, eradication of the tumor, is the same, technical issues from patient positioning to immobilization strategies to arrangement of beams is a different paradigm in thinking,” Dr. McMullen says, adding, “My favorite part of being a proton therapy oncologist is reviewing and creating plans for radiation that I could never have dreamt possible with even the best photon technology.”

With more physicians like Dr. McMullen moving to proton therapy treatment, the field will only continue to grow. Just as Dr. McMullen published articles and studies about his research in radiosurgery, he says he “wouldn't have come to the IU Health Proton Therapy Center without the opportunity to advance the science in addition to treating patients.”


  • BA, Biology, University of Colorado, Boulder, Col.
  • MD, Mayo Medical School, Rochester, Minn.
  • Board certified in radiation oncology
  • Author of five book chapters, more than 40 peer-reviewed publications, with national and international lecture presentations on cancer survivorship; adult and pediatric brain tumors; radiosurgery; pediatric radiation oncology; and proton therapy
  • Wake Forest University School of Medicine Attending Radiation Oncologist 2003 to 2011.
  • Radiation Oncology Residency Program Director, Wake Forest University, 2006 to 2011.
  • Member of the American Society of Therapeutic Radiology, Society for Neuro-Oncology and Children’s Oncology Group
  • Editor in Chief, Current Problems in Cancer 
  • Named as Top Doctor by Castle Connolly and HealthTap (formerly Avvo)

Teresa Oldham, MDRadiation Oncologist

Radiation Oncologist, IU Health Proton Therapy Center

On staff since August 2006.

Specialty: Prostate Cancer




As a radiation oncology resident, Dr. Teresa Oldham did not expect to end up practicing medicine in Indiana or to be treating her cancer patients exclusively with proton therapy.

“As residents, we learned about the physics of proton therapy but because the treatment was not widely available, it was not a large part of our curriculum,” says Dr. Oldham.

At the time – just earlier this decade – there were just two proton therapy centers in the United States – one in Boston at Massachusetts General Hospital and the other across the country in Loma Linda, California.

“Since proton therapy was only available at a handful of sites across the country, we thought of it as a treatment for unusual cases,” she says.

Proton therapy is especially beneficial for patients with specific cancers, including less common malignancies in the head, neck and brain. Because the proton beam can be contoured and programmed to stop at cancer cells – instead of traveling beyond them, as X-rays do – proton therapy is able to destroy cancer cells while sparing important organs and healthy tissue just a millimeter away.

“Proton therapy is an amazing form of treatment that is ideal for patients with certain cancers,” explains Dr. Oldham.

Proton therapy is also a highly advantageous form of radiation for a more common form of cancer – prostate cancer. Dr. Oldham has been using proton therapy to treat patients with prostate cancer at the IU Health Proton Therapy Center, which is the second leading cause of cancer deaths among men, affecting one of every six men throughout their lifetime.

“My prostate cancer patients have all done very well with proton therapy, with minimal side effects,” says Dr. Oldham. More and more men diagnosed with the disease are choosing the precision targeting ability of proton therapy because it minimizes the side effects that accompany other treatment options, such as incontinence and rectal complications.

“When I first started working with patients, most had learned about proton therapy through their own research,” she says. “But more and more, patients are hearing about proton therapy by word-of-mouth and former IU Health Proton Therapy Center patients.”

As for life in Southern Indiana, where the IU Health Proton Therapy Center is located, Dr. Oldham says her transition to Bloomington from Arkansas where she was born and raised was an easy one.

“I love living in Bloomington, and it is a comfortable and welcoming community,” she says. “My colleagues at the IU Health Proton Therapy Center are highly knowledgeable and extremely enjoyable people.”


  • BS, zoology, Arkansas State University
  • MD, University of Tennessee Center for the Health Sciences, College of Medicine, Memphis
  • Board certified in radiation oncology