Robert Ledley

Robert Ledley was born on June 28, 1926, in Flushing Meadows, Queens, New York City. 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. Ledley received a MS in physics from Columbia in 1950. In 1949, Ledley married Terry Wachtell (born 1926), a mathematics teacher at Queens College, and sister of Herbert Wachtell. The couple had two sons, Fred (born 1954) and Gary (born 1957). 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. 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. ==Early research career==

U.S. Army dental research 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. Work with Standards Eastern Automatic Computer (SEAC) at the National Bureau of Standards in the early 1950s. Robert Ledley learned to program on this computer, first via paper tapes Terry brought to him and then by using the machine extensively himself. 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. He recalled: “I had previously realized that although, conceptually, physics equations could be written to describe any biomedical phenomenon, such equations would be so complex that they could not feasibly be solved in closed form. Thus SEAC would be my panacea, because the equations would become tractable to numerical methods of solutions. Or so I truly believed at the time. That was to be my field, application of computers to biomedical problems.” When Ledley lost his job at the NBS in 1954 due to budget cuts, he turned down an offer to work for IBM (which hired Ledley’s colleagues en masse). Ledley’s main work for the RNA Tie Club was an effort to generate a set of contingency tables for the purpose of writing a computer program that would determine the correspondence between any three-letter sequence (triplet) of nucleotide bases and any amino acid (the building blocks of proteins). Sponsored by Gamow, Ledley published his work in 1955 in the Proceedings of the National Academy of Sciences. Though Ledley had produced a combinatorial table that could theoretically be used to determine which three-letter sequence of DNA bases corresponded to which amino acid, the problem required several thousand years of computation time on the world’s fastest computers (circa 1955) to produce a solution. Electrical engineering In 1956, Ledley was hired as an assistant professor of electrical engineering at the George Washington University School of Engineering and Applied Science. After the meeting, Lusted telephoned Ledley, and the two found that they shared a strong interest in using electronics and mathematics to improve medicine. The two men immediately began to collaborate on developing ways to teach physicians and biomedical researchers, who rarely had much training in electronics or mathematics, to use electronic digital computers in their work. In 1959, Ledley and Lusted published “Reasoning Foundations of Medical Diagnosis,” a widely read article in Science, which introduced operations research techniques to medical workers. Areas covered included: symbolic logic, Bayes’ theorem (probability), and value theory. In the article, physicians were instructed how to create diagnostic databases using edge-notched cards to prepare for a time when they would have the opportunity to enter their data into electronic computers for analysis. Within medicine, Ledley and Lusted’s article has remained influential for decades, especially within the field of medical decision making. Among its most enthusiastic readers was cardiologist Homer R. Warner, who emulated Ledley and Lusted’s methods at his research clinic at LDS Hospital in Utah. Warner’s work, in turn, shaped many of the practices and priorities of the heavily computerized Intermountain Healthcare, Inc., which was in 2009 portrayed by the Obama administration as an exemplary model of a healthcare system that provided high-quality and low-cost care. The article also brought national media attention to Ledley and Lusted’s work. Articles about the work of the two men ran in several major U.S. newspapers. A small demonstration device Ledley built to show how electronic diagnosis would work was described in the New York World Telegram as a “A Metal Brain for Diagnosis,” while the New York Post ran a headline: “Dr. Univac Wanted in Surgery.” On several occasions, Ledley and Lusted explained to journalists that they believed that computers would aid physicians rather than replace them, and that the process of introducing computers to medicine would be very challenging due to the non-quantitative nature of much medical information. NAS-NRC survey and computer advocacy In early 1957, Ledley was hired on a part-time basis by the National Academy of Sciences - National Research Council (NAS-NRC) to conduct a national survey of current and potential computer use in biology and medicine in the United States. Ledley published his survey findings in a November 6, 1959 Science article, “Digital Electronic Computers in Biomedical Science,” in which he called on biologists to train in mathematics and engineering in order to effectively use electronic digital computers. He predicted that in the long run, “perhaps the greatest utilization of computers will be in biomedical applications." Ledley’s survey and article also shaped the National Institutes of Health’s first major effort to encourage biomedical researchers to use computers. This effort began shortly after the Soviet launch of Sputnik in October 1957—in reaction to Sputnik, the U.S. Congress sought means boost U.S. scientific and technological productivity. Beginning in 1960, Congress allocated roughly $40 million to the NIH for the purpose of stimulating computer use in biomedical research. ==National Biomedical Research Foundation==

Establishment and goals of the NBRF (launched in 1984), 1990 was the NBRF's 30th year. Following his survey work for the NAS-NRC and the publication of his and Lusted’s articles in Science, Ledley sought federal government and university support his efforts to development computers and computer programs for use by biomedical researchers. With the support of the NAS-NRC, Ledley chartered in 1960 the National Biomedical Research Foundation (NBRF), a nonprofit organization, initially based in an NAS-NRC-owned building near Dupont Circle, Washington, D.C. Believing that his career as a university faculty member would ultimately constrain his research, Ledley left his position at GWU in order to dedicate his full-time to running the NBRF. Ledley would lead the NBRF until his retirement in 2010. Early employees included: Louis S. Rotolo (Ledley’s assistant in the NAS-NRC survey), James B. Wilson (Ledley’s former graduate student at GWU), and Margaret O. Dayhoff (a quantum chemist with a Ph.D. from Columbia and Ledley’s childhood friend from Flushing). Starting with an annual budget of under $100,000 and a half-dozen employees, the NBRF grew into a multimillion-dollar operation with more than 20 employees by the early 1980s. FIDAC was designed to scan a photograph into its memory and then send that information to a larger computer (e.g. IBM 360) in order to recognize patterns in the scanned image. Quickly trying to raise enough funds to cover the NBRF employee salaries, Ledley looked for projects the organization could undertake for Georgetown University. Aside from reducing cost, the NBRF team aimed to overcome the major constraint of the EMI-Scanner, namely that it required X-rays to be shone through a water tank enclosing the object being scanned—this constraint limited the use of the scanner to only patients’ heads and required physicians to place patients’ heads into a rubber bladder extending into a water tank. Later in 1975, DISCO sold the ACTA rights to Pfizer for $1.5 million in cash and $10 million in guaranteed research funding (paid out over 10 years) for the NBRF. Published annually by the NBRF, first on paper then (as the volume of information grew much larger) on magnetic tape and finally on CD-ROM, the Atlas served as an information clearinghouse for the growing community of protein sequencers. After Dayhoff died suddenly in 1983, Ledley and Winona Barker (who joined the NBRF in the late 1960s) took charge of the project. While at the NBRF, Ledley also carried out work related to computer design. In 1970, when Moore’s Law was still a relatively new idea, and when the most powerful computers had 1,000 to 2,000 logic gates, Ledley wrote a paper titled “Realization of a Billion-Gate Computer” in which he speculated on the capabilities of a transistorized computer that had 1,000,000,000 logic gates. He proposed that such a machine would: 1) have no fixed logic design; 2) be capable of redesign some of its own components; 3) be able to “self-heal.” Billion-transistor microprocessors have been commonplace in personal computers since 2010, though these machines are not as dynamic (in terms of logic structure) as Ledley had predicted. In the late 1980s, Ledley lead the team that developed the Bat, a three-dimensional mouse that allowed users to interact with objects in three-dimensional space (generated using stereo images). ==Scientific journals==

During his long career at the NBRF, Ledley served as editor of four major peer-reviewed journals. In 1969, he launched the Pattern Recognition Journal and Computers in Biology and Medicine. The former focuses on computerized approaches to pattern recognition, while the latter publishes articles, algorithms, and technical descriptions related to the use of computers in biomedicine. In 1972, Ledley started Computer Languages, Systems and Structures, the mission of which is to publish “papers on all aspects of the design, implementation and use of programming languages, from theory to practice.” In 1976, following the success of ACTA, Ledley initiated Computerized Tomography, which was renamed Computerized Radiology in 1977, and subsequently renamed Computerized Medical Imaging and Graphics in 1981. It serves as “a source for the exchange of information concerning the medical use of new developments in imaging diagnosis, intervention, and follow up.” Ledley served as editor of all four journals until his retirement in 2010. The journals are currently published by Elsevier. ==Honors, memberships, and affiliations==

• Morris F. Collen Award of Excellence, American College of Medical Informatics (AMIA) (1998) • National Inventors Hall of Fame (inducted 1990) • National Medal of Technology (1997) • Vicennial Gold Medal for Distinguished Service, Georgetown University (1990) • Member, Institute of Medicine, National Academy of Sciences (1999) • Distinguished Alumnus, New York University (1999) ==Publications==

• • • (General Books, 2010). • (xxiv+835+1 pages) • • • • • • ==Notes==