I'm a Senior Network Physician practicing at Dana-Farber Community Cancer Care in Weymouth. I am certified by the American Board of Internal Medicine in Hematology, Medical Oncology and Hospice and Palliative Medicine.  I received my BA from Oberlin College and my MD from Tufts University School of Medicine.  I did my training in Internal Medicine at Boston City Hospital and her Hematology-Oncology training at New England Medical Center. In my free time, I enjoy traveling, music and outdoor pursuits.

I graduated from Colegio Nacional de San Isidro in Buenos Aires, Argentina and completed my medical degree at Buenos Aires University School of Medicine. My surgical and urological residency were spent at the Hospital Italiano in Buenos Aires. I was an attending Urologist at Hospital Roffo in Buenos Aires until I came to the United States. At that point I was a Urology Fellow working on a research project at the Children’s Hospital and Harvard Medical School in Boston. I completed my American residencies in urology and surgery at the University of Massachusetts.

I enjoy spending time with my wife and three children.

William Tollefsen, MD is the EMS and MIH Medical Director for South Shore Health. Dual-boarded in Emergency Medicine and EMS Medicine, Dr. Tollefsen works clinically as an Emergency Physician at South Shore Health in addition to his role as EMS Medical Director.

One of few physicians in the country to receive the prestigious "FAEMS" recognition, Dr. Tollefsen is also the Medical Director for OEMS Region IV, serving 61 cities and towns of the Metro-Boston EMS Council. As the current EMS Medical Director for eight municipal and three private ambulance services on the South Shore, Dr. Tollefsen interacts and provides oversight for over 400 Paramedics.

Dr. Tollefsen graduated from New York Medical College and completed residency training in Emergency Medicine at Harvard University, Brigham and Women's, and Massachusetts General Hospital. He completed a fellowship in Emergency Medical Services and Critical Care Transport at the University of Massachusetts, where he worked as an Emergency Physician and Flight Physician for UMASS LifeFlight. He completed an MBA at the Isenberg School of Management at UMASS Amherst, and holds a Master of Medical Science degree from the Boston University School of Medicine.

A former pre-hospital provider, he is actively involved in EMS system design, paramedic education and Critical Care Transport Systems. He works closely with multiple EMS, Fire and Law Enforcement agencies throughout Massachusetts.

His research interests include systems of care, resuscitation, airway management, and paramedic education.

I grew up in Scituate and am a proud graduate of Scituate High School.  After graduating from Harvard-Radcliffe, I continued doing another year of diabetes research at Massachusetts General Hospital, then did two years of breast cancer research at the Dana-Farber Cancer Institute.  I graduated from the Boston University School of Medicine, went to UMass Worcester for residency, graduated from the Harvard School of Public Health, and then went to Brown for residency.  I began working at South Shore Medical Center in 2008.  I especially enjoy seeing patients who knew my father, a police officer in Scituate for 29 years and hearing their stories about him.  I try to motivate, encourage and work with my patients and it is an honor and a privilege to be able to care for them.  Outside of work, I love dancing, playing frisbee, and spending time with my family.