I grew up in a small town in Northern New York, and joined South Shore Hospital and Brigham and Women's Hospital in 2012. I completed my undergraduate and medical education as well as my general surgical training and surgical critical care fellowship at the University of Rochester in Rochester, NY. I am also fellowship trained in minimally invasive and bariatric surgery from Dartmouth Hitchcock Medical Center. I have had a long-standing passion in bariatric and weight-loss surgery and my goal in joining the South Shore Hospital team was to bring that expertise and opportunity to the South Shore community. The hospital has been very supportive in this endeavor and over the past few years we have created a collaborative team of providers from across institutions to start the South Shore Hospital Center for Metabolic and Bariatric Surgery. As medical director it has been my pleasure to help the program grow into a strong clinical component  of the department of surgery and create more outreach into the community. I am also actively engaged as a trauma surgeon and have a busy general surgery practice taking care of a variety of disease processes including the minimally invasive management of gallbladder disease, hernia, GERD, hiatal hernias, as well as the surgical management of a variety of other gastrointestinal disorders. When I am not working, I enjoy the simple things in life like relaxing by a large campfire or spending the day at the beach with my family. 

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.

Dr. O'Brien is Medical Director of Maternal-Fetal Medicine at South Shore Health. 

As a Maternal-Fetal Medicine physician, I am dedicated to caring for women and families navigating high-risk and medically complex pregnancies with expertise, compassion, and individualized attention. 

I strive to integrate evidence-based medicine with a holistic approach that recognizes the physical, emotional, and social factors that shape each patient’s experience. 

I am also committed to advocating for equitable healthcare and improving access and outcomes for marginalized and underserved communities.

I have been providing medical and surgical foot and ankle care to the greater South Shore community since 1996. I first joined the medical staff of South Shore Hospital in 1997 and have been working with South Shore Medical Center since 2004. Some of my clinical interests include Podiatric Surgery and Sports Medicine of the foot and ankle.

I am originally from Russia. I underwent undergraduate and medical school education in Texas, and moved to the Boston area for postgraduate training in 2001. 

I have practiced in Dorchester and Weymouth, Massachusetts since 2006. I joined South Shore Medical Center and South Shore Hospital in the Fall of 2017.

I am an experienced pulmonologist who provides care for multiple pulmonary diseases, including COPD, asthma, sarcoidosis, interstitial lung disease, lung nodules and lung cancer.
 

Establishing a good patient-physician relationship is crucial to help provide the best care. I believe in allowing ample time in a visit to listen to my patients' needs and thoroughly explain their diagnosis and treatment plan. Most podiatric issues can be treated with aggressive conservative therapy, although when surgical intervention is necessary, I will communicate that to the patient in a direct and concise manner. 

I strive to build a space where patients feel safe to discuss their health concerns and engage in shared decision-making.

Prior to joining South Shore Health, I had the privilege to train at UMass Family Medicine Residency and complete an additional year of fellowship to also care for patients living with HIV/viral hepatitis at the Family Health Center of Worcester.

Outside of work, I love spending time with my family, running, gardening, and camping/hiking.

I am honored to treat and work with my patients. When I am not working, I am running marathons or trails, skiing, biking or cooking. Health and wellness are some of my passions.