Robert Ledley

Robert Steven Ledley (June 28, 1926 – July 24, 2012), professor of physiology and biophysics and professor of radiology at Georgetown University School of Medicine, pioneered the use of electronic digital computers in biology and medicine.

Robert Ledley was born on June 28, 1926, in Flushing Meadows, Queens, New York City, US.

His father, Joseph Levy, was an accountant and his mother, Kate Levy, was a schoolteacher before becoming a homemaker.

Robert had a sister, Marion, and a half-brother, Ralph.

All three siblings were surnamed Ledley.

Among Ledley’s childhood friends in Flushing was Margaret Oakley Dayhoff, who would later spend most of her career working at the National Biomedical Research Foundation and who would become a founder of the field of bioinformatics.

Ledley attended the Horace Mann School, from which he graduated in 1943.

As an undergraduate student at Columbia University Ledley excelled in physics, taking undergraduate and graduate courses within his first two years as a student.

When, however, he informed his parents of his desire to become a physicist, they objected on the grounds that a career in physics would not be feasible for him given the scarcity of steady jobs in that field.

Instead, they urged him to make his living as a dentist.

Ledley attempted to follow both paths at once; he enrolled in the New York University College of Dentistry while continuing to pursue his education in physics at Columbia.

During the day, Ledley would take dentistry training courses at NYU, then he would take the subway to Columbia to take evening courses in physics.

After receiving his DDS from NYU in 1948, Ledley became a full-time physics graduate student at Columbia, where he took courses from many noted physicists including I.I. Rabi (who joked that Ledley was the only physicist who could pull a man’s tooth), Enrico Fermi, Hans Bethe, and J.A. Wheeler.

In 1949, Ledley married Terry Wachtell (born 1926), a mathematics teacher at Queens College, and sister of Herbert Wachtell.

Ledley received a MS in physics from Columbia in 1950.

When the couple moved to the DC area in the early 1950s, Terry was employed as a computer programmer until leaving work to raise their sons.

Both sons graduated from Georgetown University School of Medicine.

In 1950, shortly after the outbreak of the Korean War, Ledley was contacted by a U.S. Army recruitment officer, who offered him a choice: he could volunteer to join the U.S. Army Dental Corps as a first lieutenant or be conscripted into the infantry as a private.

Ledley promptly volunteered, and was sent to the U.S. Army Medical Field Service School for training.

Because Ledley was also trained in physics, he was assigned to a dental research unit at Walter Reed General Hospital, in Washington, D.C.

During his time in the army, Ledley was responsible for improving prosthetic dental devices (such as dentures) then widely used by Army personnel.

Notably, Ledley drew on his training in dentistry and physics to develop a system that optimized the process of fitting dentures by allowing dentists to determine the “angle of chew,” or the mean slope of each tooth relative to the surface of an object (e.g. a piece of food) being bitten.

Ledley presented this work to the American Physical Society in 1952, and it generated nationwide attention via an Associated Press newspaper story titled “Mathematics Used to Keep False Teeth in Place.”

Ledley's work on dental prosthetics brought him into collaboration with researchers based at the National Bureau of Standards Dental Materials Research Section, where he was offered a research job in 1952 following his discharge from the Army.

There he encountered the Standards Eastern Automatic Computer, one of the earliest stored-program electronic digital computers.

Ledley's first interaction with SEAC came via his wife, Terry, who worked as one of the machine's programmers – Robert taught himself to program by examining programs (on perforated paper tape) and manuals Terry brought home.

Ledley started to use SEAC himself for his dental research, but after proving an adept programmer and troubleshooter, he found himself working with SEAC (and later DYSEAC) full-time on a wide variety of projects, including a remote-controlled aircraft guidance system.

For Ledley, working with SEAC produced an epiphany, concerning both his career and the potential importance of computers to biomedical research.

The couple had two sons, Fred (born 1954) and Gary (born 1957).

In 1959, he wrote two influential articles in Science: "Reasoning Foundations of Medical Diagnosis" (with Lee B. Lusted) and "Digital Electronic Computers in Biomedical Science".

Both articles encouraged biomedical researchers and physicians to adopt computer technology.

In 1960 he established the National Biomedical Research Foundation (NBRF), a non-profit research organization dedicated to promoting the use of computers and electronic equipment in biomedical research.

At the NBRF Ledley pursued several major projects: the early 1960s development of the Film Input to Digital Automatic Computer (FIDAC), which automated the analysis of chromosomes; the invention of the Automatic Computerized Transverse Axial (ACTA) whole-body CT scanner in the mid-1970s; managing the Atlas of Protein Sequence and Structure (created in 1965 by Margaret O. Dayhoff); and the establishment of the Protein Information Resource in 1984.

Ledley also served as editor of several major peer-reviewed biomedical journals.

In 1990, Ledley was inducted into the National Inventors Hall of Fame.

He was awarded the National Medal of Technology in 1997.

He retired as president and research director of the NBRF in 2010.

Fred Ledley is Professor of Natural and Applied Sciences at Bentley University and is the author of numerous scientific papers as well as the novel, Sputnik’s Child (2011).

Gary Ledley is a practicing cardiologist associated with Drexel University.

Robert Ledley died of Alzheimer's disease in Kensington, Maryland, USA on July 24, 2012.