Robert S. Ledley (1926-2012)
AMIA and the field of informatics lost a pioneering contributor to our discipline when Bob Ledley passed away on July 24th at the age of 86. A founding fellow of ACMI, an early keynote speaker at the Annual Symposium, and a Collen Award recipient in 1998, Bob and his colleague Lee B. Lusted wrote a seminal 1959 paper in Science that many people cite as the publication that launched the field (Reasoning Foundations of Medical Diagnosis).
Dr. Ledley’s contributions extend well beyond informatics into a variety of other areas that reflect the breadth of his talents as an inventor and his drive to contribute to health care and science. He is often described simply as the inventor of the full-body Computer Tomography (CT) scanner, but he had a large number of other inventions to his name and was among the first to anticipate the role of computers in managing and analyzing the expanding but already substantial amounts of biomedical and clinical data.
Born in 1926 in New York City, he studied dentistry, receiving a D.D.S. from the New York College of Dentistry in 1948, and went on to earn an M.A. degree in theoretical physics from Columbia University in 1950.
He first worked for Washington D.C.'s National Bureau of Standards (now the National Institute of Standards and Technology) and later moved on to Johns Hopkins University where he was a physicist and research analyst. From 1968 to 1970, he was professor of Electrical Engineering in the School of Engineering and Applied Science at the George Washington University
In 1970 Ledley joined the School of Medicine, Georgetown University Medical Center, as a professor in the Department of Physiology and Biophysics. It was there, in 1973, that he developed the Automatic Computerized Transverse Axial (ACTA) x-ray scanner, known as the first whole-body CT machine.
The machine had a revolutionary impact on diagnostic medicine; it was able to generate visual models of internal organs not possible for conventional x-ray machines to produce. The three-dimensional reconstructions, created by transmitting X-ray beams through transverse axial slices of the body, allowed physicians to view soft tissue in the body with detail unlike any they had been able to see before, improving diagnosis of cancers, heart disease, bone disease and other irregularities. The technology was also used in radiation therapy planning.
In 1974 Ledley became a professor in the Medical Center's Department of Radiology. In 1975 he was appointed Director of the Medical Computing and Biophysics Division, and he maintained an emeritus role with Georgetown long after his formal retirement.
Ledley contributed to a number of areas within the field of diagnostic medicine. He patented the image processor (originally called the Texture Analysis Computer or TEXAC). He also wrote the first comprehensive textbook for engineers on digital computer engineering.
He developed computer systems for organizing the often very large volume of medical data required for precise diagnosis. He co-produced the first large-scale biotechnology databases, Protein Information Resources (PIR), to organize all known protein and DNA sequences. He also invented the instrumentation and computer algorithms used for automated chromosome analysis for prenatal diagnosis of birth defects. PIR is used by almost all in the field of molecular biology. Also, his vision of computers led to the early development of a genetics database, Genbank, the premier, universally used genetics database.
In the 1970s, he studied the use of computer technology in diagnosing and treating patients. Ledley’s research on cost containment in a concentrated care center was a” landmark study that led to the creation of critical care units in hospitals." In 1979-1980, Dr. Ledley developed the computerized electroneuro-ophthalmograph (CENOG), an integrated system for analysis of ocular motility, which helped in the diagnosis of seizure patients.
Over the course of his near-50-year career, Ledley earned more than 60 patents and numerous awards and honors, including induction into the National Inventor's Hall of Fame in 1990. In 1997, he received the National Medal of Technology from President Clinton. He was editor-in-chief of four scientific journals (including the informatics journal Computers in Biology and Medicine) and has been the president and research director of the National Biomedical Research Foundation since 1960.
Throughout his life, Ledley was a devoted husband to Terry and father to Fred and Gary, both physicians and graduates of Georgetown’s School of Medicine.
In lieu of flowers or gifts, donations can be made to:
The Dr. Robert Ledley Memorial Fund
Office of Advancement
P.O. Box 571404
Washington, DC 20057-1404