Renowned Radiologist Peter Callen Passes Away at 78

Dr. Peter W. Callen, a distinguished radiologist and educator, passed away on December 14, 2025, at the age of 78 in Mill Valley, California. His death marks the loss of a prominent figure in the field of obstetric and gynecologic ultrasound, where he made significant contributions that have shaped clinical practice for decades.

Born on August 8, 1947, Dr. Callen dedicated his life to medicine and education. He earned his medical degree from the University of California, San Francisco, in 1973, and completed his residency in Diagnostic Radiology and fellowship training at the same institution. Throughout his career, he remained at UCSF, impacting the lives of countless patients and students.

Dr. Callen was highly regarded for his expertise in ultrasound, particularly in improving sonographic detection of abnormalities and minimizing false positive diagnoses. His focused research on fetal imaging has had a lasting effect on the field. Over his career, he authored more than 200 peer-reviewed articles and 65 book chapters, sharing his knowledge with generations of clinicians. His textbook, Ultrasonography in Obstetrics and Gynecology, is considered a seminal resource and has become one of the most widely used references globally.

Beyond his professional achievements, Dr. Callen was known for his kindness, generosity, and engaging personality. Colleagues and students admired him not only for his academic contributions but also for his ability to connect with others. His humble nature allowed those around him to feel at ease, whether in clinical teaching or casual conversation.

He is survived by his wife, Karen Callen, and their children: Melanie, Brooke, Andrew, and Daniel Callen. He also leaves behind his grandchildren, Lula McMullin, Liam Callen, Jackson Callen, and Rory Callen, along with his older brother, John Callen.

Dr. Callen’s legacy endures not only in the advancements he brought to medical imaging but also in the spirit of generosity he exhibited throughout his life. His family plans to hold memorial services in Marin County, California, with further details to be announced.

In remembrance of Dr. Callen, those wishing to honor his memory may consider planting a living memorial or sending flowers. His profound impact on the field of radiology and the lives he touched will be remembered by many.