National Biomedical Research Foundation. Georgetown University Search this
3 Cubic feet
Motion pictures (visual works)
The Robert Ledley Papers document the development of the first whole-body diagnostic imaging system, the Automatic Computerized Transverse Axial (ACTA) X-ray Scanner by Ledley in 1973. Also included is material relating to Ledley's company, Digital Science Information Corporation (DISCO), as well as the public and medical communities' reactions to the scanner.
Scope and Contents:
The Robert Ledley Papers document the development of the Automatic Computerized Transverse Axial (ACTA) X-ray Scanner, Ledley's company Digital Science Information Corporation (DISCO), as well as the public and medical communities' reactions to the scanner. The collection is arranged into nine series.
Series 1, ACTA Scanner I Schematics, 1973-1975; Series 2, ACTA Scanner I [Computer and Electronics], 1973; and Series 3, ACTA Scanner Tomograph Mechanics, 1973-1974 document the development and design of the ACTA scanner through drawings, notes, memoranda, and product information. More detailed information about these materials is located in the control file. All oversize drawings have been moved to flat storage for preservation concerns.
Series 4, ACTA Scanner Operating Instructions, 1975, is the operating manual created for the scanner used in Ledley's Georgetown lab.
Series 5, ACTA Articles, Clippings, and Press Releases, 1973-1979, is comprised of the aforementioned materials relating to the ACTA Scanner. Newspaper clippings illuminate the public's perception of the scanner, and scientific pieces highlight the medical community's reaction. Ledley's published articles on the scanner and related topics are included.
Series 6, Digital Information Science Corporation (DISCO) material, 1973-1981, documents Ledley's career and his company. A biographical sketch, list of articles, textbooks, and patents highlight Ledley's achievements. Invoices, receipts, contracts, and correspondence illuminate the financial situation at DISCO and the relationship between the company and Pfizer.
Series 7, Computer manuals, 1972-1975, documents the computer systems and software that were used with the ACTA Scanner.
Series 8, Photographic material, 1973-1978, includes an album of photographs depicting the ACTA Scanner and images of the scans it created. This album was disassembled due to preservation concerns. This series also includes a collection of slides featuring the scanner and related equipment in use and images of the scans it created. A detailed description of each photograph and slide is included in the control file.
Series 9, ACTA Scanner film, [1974?], is a 16mm narrated film describing the creation of the scanner, its components, the way they work, the scanner in use, and images of the scans produced.
This collection is arranged into nine series.
Series 1, ACTA Scanner I Schematics, 1973-1975
Series 2, ACTA Scanner I [Computer and Electronics], 1973
Series 3, ACTA Scanner Tomograph Mechanics, 1973-1974
Series 4, ACTA Scanner Operating Instructions, 1975
Series 5, ACTA Articles, Clippings, and Press Releases, 1973-1979
Series 6, Digital Information Science Corporation (DISCO) material, 1973-1981, undated
Series 7, Computer manuals, 1972-1975
Series 8, Photographic material 1973-1978
Subseries 1, Photographs, 19731978
Subseries 2, Slides, 1974
Series 9, ACTA Scanner film [1974?]
Biographical / Historical:
Robert Steven Ledley was born in Flushing Meadows, New York in 1926. He received a D.D.S. degree from New York University College in 1948. While attending dental school, he simultaneously studied at Columbia University; he earned a M.A. in Theoretical Physics in 1949. He volunteered for the army and was sent to the U.S. Army Medical Field Service School in Fort Sam Houston, Texas.1 After completing his service, Ledley held a wide variety of research and academic positions in physics, electrical engineering, and medicine.
Ledley was a physicist within the External Control Group of the Electronic Computer Laboratory of the National Bureau of Standards from 1953-1954. He was an operations research analyst within the Strategic Division of the Operations Research Office at Johns Hopkins University from 1954-1956. Ledley went on to become an associate professor in the Department of Electrical Engineering at The George Washington University from 1956-1960 while also serving as a consultant mathematician at the National Bureau of Standards Data Processing Systems Division, 1957-1960. At this time, Ledley also worked part time at the National Research Council's National Academy of Sciences from 1957-1961. Ledley became the president of the National Biomedical Research Foundation in 1960, a position he still holds today. He was an instructor of pediatrics at the Johns Hopkins University School of Medicine from 1960-1963. He returned to The George Washington University's Department of Electrical Engineering in 1968 where he was a professor until 1970. He then became a professor in the Department of Physiology and Biophysics at the Georgetown University School of Medicine in 1970. In 1974, Ledley also became a professor in the Radiology Department at the Georgetown University Medical Center. In 1975, he became the director of the Medical Computing and Biophysics Division at Georgetown University Medical Center.
In 1972, the British company Electric and Musical Industries Limited (EMI) released a medical imaging machine for use on smaller areas of the body that were positioned under a water tank. In 1973, Ledley developed the Automatic Computerized Transverse Axial (ACTA) X-ray Scanner (US Patent #3,922,552). This machine was a whole-body diagnostic medical imaging system. He was awarded a grant from the National Institutes of Health for an engineering equipment project, but the money was never received due to budget cuts. Ledley looked elsewhere for funding. He consulted with Georgetown staff and discovered a neurosurgeon had asked to buy a head scanning machine from EMI. Ledley did not think the images in EMI's brochure appeared clear, and he offered to create a similar machine for half the price. Georgetown agreed to fund this project for $250,000. Ledley secured the services of a machinist at a local machine shop, an electronic engineer, and a programmer/mathematician to assist in the project.2 The ACTA Scanner debuted in February, 1974 and did not require the use of a water tank.
Following the creation of the ACTA Scanner, Ledley organized Digital Information Science Corporation (DISCO) in order to manufacture the system. DISCO began producing scanners as orders were received. Due to financial constraints, DISCO was forced to request $100,000 upon receipt of the order, $100,000 when the scanner was halfway completed, and the final $100,000 payment upon delivery3. In 1975, Pfizer purchased the rights to manufacture the ACTA Scanner from DISCO for $1.5 million.
Ledley is a Fellow of the American Association for the Advancement of Science and a senior member of the Institute of Electrical and Electronics Engineers. He has earned numerous awards and honors for his work. In 1997, he received the National Medal of Technology from President William Jefferson Clinton for his pioneering work on the whole-body CT diagnostic X-ray scanner. He also founded the Pattern Recognition Society and Computerized Tomography Society.
1 Ash, J., D. Sittig, and R. Ledley. "The Story Behind the Development of the First Whole-body Computerized Tomography Scanner as Told by Robert S. Ledley." Journal of the American Medical Informatics Association, 2006 Sep-Oct (2006), 465-469, http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1561796. (accessed June 24, 2009).
An ACTA Scanner and numerous accessories were donated to the Division of Medicine and Science in 1984.
This collection was donated by Robert S. Ledley on September 18, 1984.
The collection is open for research.
Collection items available for reproduction, but the Archives Center makes no guarantees concerning intellectual property rights. Archives Center cost-recovery and use fees may apply when requesting reproductions.
9 videotapes and 3 audiotapes. 11 digital video .wmv files and .rm files (Reference copies).
Motion pictures (visual works)
The Smithsonian Videohistory Program, funded by the Alfred P. Sloan Foundation from 1986 until 1992, used video in historical research. Additional collections have
been added since the grant project ended. Videohistory uses the video camera as a historical research tool to record moving visual information. Video works best in historical
research when recording people at work in environments, explaining artifacts, demonstrating process, or in group discussion. The experimental program recorded projects that
reflected the Institution's concern with the conduct of contemporary science and technology.
Smithsonian historians participated in the program to document visual aspects of their on-going historical research. Projects covered topics in the physical and biological
sciences as well as in technological design and manufacture. To capture site, process, and interaction most effectively, projects were taped in offices, factories, quarries,
laboratories, observatories, and museums. Resulting footage was duplicated, transcribed, and deposited in the Smithsonian Institution Archives for scholarship, education,
and exhibition. The collection is open to qualified researchers.
Ramunas Kondratas, curator at the Smithsonian's National Museum of American History (NMAH), interviewed Ledley, Homer Twigg, Robert Zeman, David Greigo, and Seong Ki
Mun about the history of CAT scanning in general, and the development and operation of the ACTA scanner in particular, as well as Ledley's more recent work in biotechnology
instrumentation. Kondratas also visually documented CAT scanning equipment, from the earliest model ACTA scanner to most recent CT scanners.
This collection consists of five interview sessions, totalling approximately 8:26 hours of recordings and 154 pages of transcript. Also included is one audio
interview, totalling approximately 4:30 hours of audiotape and 96 pages of transcript.
The ACTA (Automatic Computerized Transverse Axial) scanner was developed in 1973. The introduction of this first full-body CAT (Computer Assisted Tomography) -- or CT
(Computerized Tomography) -- scanner lead to advancement in medical imaging and diagnostic medicine, especially for non-invasive viewing of soft tissue inside the body. The
machine revolutionized diagnosis in cancer, heart disease, and soft tissue irregularities by transmitting X-ray beams through transverse axial slices of the body, resulting
in computerized cross-sectional images of the body part scanned. Robert S. Ledley, of Georgetown University Medical Center, designed the ACTA scanner, and it was first used
in clinical operation there in 1973.
Robert Ledley received a D.D.S. degree from New York College of Dentistry in 1948 and a M.A. degree in theoretical physics from Columbia University in 1950. Shortly thereafter
he worked for both the National Bureau of Standards (now the National Institute of Standards and Technology) and the Johns Hopkins University as 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 1960 he founded and
became president of the National Biomedical Research Foundation (NBRF). He joined the School of Medicine, Georgetown University Medical Center in 1970 as a professor in the
Department of Physiology and Biophysics. In 1974 he became a professor in the Medical Center's Department of Radiology and in 1975 was appointed director of the Medical Computing
and Biophysics Division.
Homer Twigg graduated from the University of Maryland Medical School in 1951 and entered the United States Public Health Service where he received training in radiology.
In 1957, he joined the Radiology Department of the Georgetown University Medical Center and was one of the first radiologists to work with Dr. Ledley in applying the ACTA
scanner to clinical situations.
Robert Zeman received his M.D. from Northwestern University in 1976. In 1977 he began his residency at Yale New Haven Hospital, in New Haven, Connecticut, and was appointed
assistant professor of Diagnostic Radiology at Yale University in 1981. The following year he joined Georgetown University School of Medicine as an assistant professor of
Radiology and held numerous other positions there until his appointment as Clinical Director of the Department of Diagnostic Radiology in 1986.
David Griego, Georgetown University Medical Center CAT scanning supervisor and radiology specialist, and Seong Ki Mun, director of the Division of Imaging Physics were
interviewed for their knowledge of current trends in the field of medical imaging.
Restricted. The permission of Ramunas Kondratas must be obtained for commercial reproduction or broadcast. Contact SIHistory@si.edu for more details.