When Nancy Tarbell entered radiation oncology, almost no one in the room looked like her.

She was in a field dominated by men and went on to help transform how children with cancer were treated-pioneering approaches that made radiation more precise and helping spare young patients from some of its lifelong consequences.

Radiant is the story of what it takes to be a change maker and what it costs. Dr. Tarbell rose to the highest levels of academic medicine at Harvard Medical School while caring for children with devastating illnesses, mentoring generations of physicians, and opening doors for women coming behind her. At home, she was raising a family with her husband, Jay, navigating the tensions between ambition, caregiving, love, and loss.

Honest about sacrifice, grief, and the invisible labor of building something fairer, Radiant asks a larger question:

What endures?

Dr. Tarbell's answer lies not only in the patients she treated or the institutions she changed, but in the people she lifted along the way.

Nancy J. Tarbell, MD, is the C.C. Wang Professor of Radiation Oncology, Emerita, at Harvard Medical School. A pioneering pediatric radiation oncologist at Massachusetts General Hospital, she helped establish one of the nation's first hospital-based proton therapy programs for children. The first woman to serve as dean for Academic and Clinical Affairs at Harvard Medical School, she was the founding director of the MGH Office for Women's Careers and Center for Faculty Development and spent decades advancing women in medicine. Her clinical and scientific contributions have been recognized across ASTRO, ASCO, the Children's Oncology Group, and SIOP, and she continues to advise on advances in proton therapy. She is a member of the National Academy of Medicine and has received the prestigious ASTRO Gold Medal. She currently lives in Jupiter, FL and Boston, MA.

Smitha V. Gollamudi, MD, is a retired radiation oncologist and Brown University graduate who completed her residency at the Harvard Joint Center for Radiation Therapy under Dr. Tarbell's mentorship. She subsequently built a distinguished career at leading academic medical centers, including Memorial Sloan Kettering Cancer Center and Johns Hopkins Medicine. She currently lives in Washington, DC.