At this year’s Commencement ceremony, held May 21, graduating medical students were treated to words of wisdom from pediatric neurosurgeon Benjamin S. Carson Sr., M.D., who recounted the story of a dilemma he faced in 1985 as a young doctor.

In his Commencement address, Carson said he believed that a hemispherectomy—removal of half of the brain—was the best way to help one of his patients, a girl with severe epilepsy who was suffering constant seizures. But a senior physician, a distinguished neurologist, disagreed. Carson, a 1973 graduate of Yale College, decided to perform the surgery anyway.

“I risked my career because I asked myself why I became a neurosurgeon, and it was to give patients the best possible existence,” he told the 100 members of the Class of 2012. “When you tell someone their loved one is doing well,” Carson said, “that’s the best feeling in the world.”

Carson, director of pediatric neurosurgery at Johns Hopkins Medical Institutions, received national attention in 1987 for the first separation of twins joined at the back of the head.

Among his many awards is the Presidential Medal of Freedom, which he received in 2008. Carson’s belief in the power of education is such that he and his wife established the Carson Scholars Fund, which has awarded more than $4.5 million to scholars in 45 states.