Robert S. Ledley, inventor of the whole-body CT (computerized tomographic) diagnostic x-ray scanners, was born in New York City on June 28, 1926. He earned a DDS from New York University in 1948 and an M.A. from Columbia University a year later. During the next twenty years, he served in a variety of academic and research positions at the National Institute of Standards and Technology (formerly National Bureau of Standards), Johns Hopkins University, and George Washington University, before becoming a professor of Physiology and Biophysics and Radiology at Georgetown University Medical Center.

With more than 20 patents to his name, Ledley is best know for developing the ACTA (Automatic Computerized Transverse Axial) diagnostic x-ray scanner, the first whole-body computerized tomography (CT) machine. The ACTA Scanner set the fundamental design of modern CT scanners, including the first use of the convolution method for CT image reconstruction, the first high-resolution digital TV display for medical imaging, and the tilting gantry. Many of the other features of the ACTA are still incorporated in all modern medical CT scanners.

Dr. Ledley used ACTA to revolutionize diagnostic medicine. With his scanner, he was the first to do medical imaging, three-dimensional reconstructions and to use CT in radiation therapy planning for cancer patients and in the diagnosis of bone diseases.

To take advantage of his invention, Ledley formed a company called DISCO (Digital Information Sciences Corporation), which manufactured the scanner, distributing it throughout the United Sates, Europe, Japan and the Far East. Ledley eventually allowed Pfizer, Inc. to take over DISCO's assets and continue manufacturing the machine. In return, Pfizer has provided ongoing support for Dr. Ledley's research.

Ledley has also patented the image processor. He wrote the first comprehensive textbook for engineers on digital computer engineering. He also developed the computational methods in Boolean algebra, used in digital circuit design. Dr. Ledley wrote the seminal paper for the field of Medical Informatics on computer use to aid in medical diagnosis.

Ledley is editor-in-chief of four scientific journals and has been the President and Research Director of the National Biomedical Research Foundation since 1960. He is also the author of numerous books on CT, pictorial pattern recognition, and the use of computers in biology and medicines.

The above information was supplied by the National Inventors Hall of Fame Foundation, Inc., Room 1D01-Crystal Plaza 3, 2021 Jefferson Davis Highway, Arlington, Virginia 22202. Videotapes and printed materials are currently available. For more information, visit the Foundation's web site at http://www.invent.org

      

         

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