Born in Baltimore and raised on West Fayette Street, he attended St. Martin's School and Calvert Hall Country School. He was a 1944 graduate of Calvert Hall College High School and served in the Coast Guard. He earned a bachelor's degree at the Johns Hopkins University and a medical degree at the Hopkins School of Medicine, with which he was associated for more than 60 years.
Dr. Wagner did research in imaging brain neuroreceptors. Hopkins colleagues said he was a pioneer in employing radioactive tracers for the rapid diagnosis of pulmonary embolism. They said he used himself as a human guinea pig in the first use of positron emission tomography, or PET scanning, to study brain chemistry.
"Considered one of the founders of the field of nuclear medicine as a scientific and medical specialty, the impact that Dr. Wagner had on our field is immeasurable," said Dr. Frederic H. Fahey, president of the Society of Nuclear Medicine and Molecular Imaging, who lives in Boston. "He was brilliant, visionary, jovial, generous and gracious."
Dr. Wagner trained more than 500 radiologists, internists, physicians and scientists, eight of whom later became presidents of the Society of Nuclear Medicine, a position that he also held. He held the posts of professor of medicine, professor of radiology and professor of environmental health sciences.
In 2002, the Hopkins School of Medicine created an endowed professorship in nuclear medicine in his name.
Dr. Wagner traveled the world to recruit students and also spent weekends at a home on the Chester River near Crumpton, where he grew grapes for wine. He also visited family in Hawaii and sang in a local ukulele group.
A Mass will be offered at 10 a.m. Friday at Shrine of the Sacred Heart Roman Catholic Church, 5800 Smith Ave., Baltimore.
Survivors include his wife of 61 years, the former Anne Barrett; two sons, Nick Wagner of Seattle and Mark Wagner of Baltimore; two daughters, Randy Wagner Rixey of Maui, Hawaii, and Anne Wagner Speed of Little Rock, Ark.; a brother, Albert Wagner of Columbia; a sister, Gertrude Stout of Timonium; and nine grandchildren.