Giulio John D'Angio, 96, of Swarthmore, a Philadelphia radiation oncologist who was a pioneer in the treatment of children's cancers, died Friday, Sept. 14, at his residence on Rittenhouse Square.

Dr. D'Angio, known as "Dan," contributed to many advancements in pediatric oncology, publishing nearly 500 research papers in peer-reviewed journals. He was a professor of radiation oncology at the Hospital of the University of Pennsylvania beginning in the mid-1970s,  his family said.

At Children's Hospital of Philadelphia, where he treated many of his patients and collaborated on medical research, he was held in such esteem that the Giulio D'Angio Chair in Neuroblastoma Research was created. Neuroblastoma is an aggressive cancer of the nerves.

"He was an icon. He was amazing," said Dr. Joel Goldwein, his former protege, now director of medical affairs at Elekta, a radiation equipment firm. "He touched so many lives both directly, via what he did for his patients, and indirectly, via the many hundreds of his students whom he taught the craft and art of pediatric radiation oncology."

In the early days of cancer research, he was among the first to think of combining different cancer treatments for maximum effect.

To combat Wilms' tumor, a cancer of the kidneys, he suggested that instead of the then-accepted surgery followed by radiation, low doses of radiation be combined with chemotherapy as a follow-up to surgery. The survival rate during his career rose from 40 percent to 90 percent.

"It's one of the most satisfying things I've ever done," he told a 1999 meeting of the American Society for Therapeutic Radiation Oncology. He suggested that treatments being given for adult cancers could be harmful to children, and that separate treatments needed to be tailored to the young.

He pioneered the idea of cooperation among groups conducting clinical trials at various locations, and convinced his medical colleagues that it was important to look ahead and consider how medical treatments given to patients as children might affect them as adults.

His advances helped children with cancers such as Wilms' tumor, leukemia, medulloblastoma (a pediatric brain tumor), and neuroblastoma, according to the American Society for Therapeutic Radiation Oncology.

But his concern for children went beyond their physical ailments; he also helped introduce the notion of total care, or looking out for a child's overall needs, the society wrote in 1999.

While working with Sidney Farber, founder of the Children's Cancer Research Foundation, Dr. D'Angio learned that a physician seeing a sick child is actually seeing a sick family. He believed that the doctor must consider how a child's illness changes the family, how suffering is handled, and how expenses mount, said a 2017 article in a Harvard Medical School bulletin, the Environment.

"When parents would bring in their sick child with their other children, D'Angio says he would make a point of addressing the siblings first, complimenting them or showing an interest in something they were wearing or playing with," the article said. "He would also thank them for helping their parents care for their sick sister or brother."

Dr. D'Angio grew up in Brooklyn and Westchester County, N.Y., and graduated from Columbia University and Harvard Medical School. He trained at Boston City Hospital and Boston Children's Hospital, and later set up a practice in Philadelphia. He traveled widely to medical conferences, many of which he convened.

Son-in-law Greg Hinson said Dr. D'Angio was a warm, welcoming man. "He brought me into the family, as if I was just another child," Hinson said. "There were so many people that considered him a father figure, personally and professionally."

Dr. D'Angio's first wife, Jean Terhune D'Angio, died in 2004. In 2005, he married Dr. Audrey Evans, who survives. He is also survived by sons Carl T. and Peter D.; a brother; two grandchildren; and two great-grandchildren.

A memorial service will be held at 11 a.m. Saturday, Sept. 22, at St. Mark's Episcopal Church, 1625 Locust St. He donated his body to science. Burial will be private.

Memorial donations may be made to St. James School, 3217 W. Clearfield St., Philadelphia, Pa. 19132.