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CNS Tumors

Thomas Merchant, DO, PhD

Member, St. Jude Faculty 
Chair, Radiation Oncology Department 
Baddia J. Rashid Endowed Chair in Radiation Oncology  
Chairman, Radiation Oncology Discipline, Children’s Oncology Group

Dr. Merchant is currently the Chair of Radiation Oncology at St. Jude Children’s Research Hospital in Memphis, Tennessee where he has practiced since 1996. The subject of his research has been the application of advanced radiotherapy methods in the treatment of children with cancer. His focus has been in pediatric neuro-oncology where he has designed new treatments for children with brain tumors and modeled radiation-related CNS effects. The broad long-term goal of his research has been to increase the cure rates for the most common brain tumors and reduce or eliminate the side effects of radiation therapy. His work in the area of conformal radiation therapy for pediatric CNS tumors has provided the basis for the dose, volume and normal tissue tolerance guidelines used in most of the national cooperative group brain tumor trials for children with medulloblastoma, ependymoma, low-grade glioma and craniopharyngioma. His work has recently been highlighted in a number of oncology journals including Lancet OncologyJournal of Clinical Oncology, and the International Journal of Radiation Oncology, Biology and Physics.

Anita Mahajan, MD

Mayo Clinic Rochester
Medical Director, Proton Therapy Center
Department of Radiation Oncology
Associate Professor, Department of Pediatrics. Section of Hematology-Oncology
Baylor College of Medicine

Dr. Anita Mahajan is a professor and​ the M​edical D​irector for the Proton Therapy Center in the Department of Radiation Oncology at the Mayo Clinic in Rochester, Minnesota​. Her areas of expertise are pediatric radiation oncology and adult CNS radiation oncology.  Dr. Mahajan has a particular interest in the application of advanced technologies, in particle proton therapy, in an effort to minimize radiation therapy associated side effects. Her recent publications and research have contributed to the understanding of the use of proton therapy for pediatric brain tumors. She is board certified by the American Board of Radiology and the Royal College Specialty Examination in Radiation Oncology.

Torunn Yock, MD

Director. Pediatric Radiation Oncology
Associate Professor, Harvard Medical School
Chair, Radiation Oncology Quality Assurance 

Dr. Yock completed her B.S. in genetics and ethics from Duke University on full academic scholarship as a National Merit and Angier B. Duke Scholar. She then acquired a Masters in Community Health as a Fulbright Scholar and from the University of New South Wales in Sydney, Australia and subsequently an MD from Harvard Medical School. Her residency was at Massachusetts General Hospital. She currently serves as the Chief of Pediatric Radiation Oncology at Massachusetts General Hospital and as an Associate Professor at Harvard Medical School, where she teaches residents, fellow, medical student and PhD students as well as lecturing in multiple continuing medical education classes.  She is an internationally recognized expert in pediatric radiation oncology and serves on multiple committees for the American Society for Therapeutic Radiation Oncology (ASTRO) and Children s Oncology Group (COG) and the American Board of Radiology in the certification process of new and tenured radiation oncologists.
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