Invent Now | Hall of Fame | Search





			Robert S. Ledley Born Jun 28 1926 - Died Jul 24 2012 Diagnostic X-Ray System CAT Scan Patent Number(s) 3,922,552 Inducted 1990 Robert S. Ledley invented the whole-body CT (computerized tomographic) diagnostic X-ray scanner. The ACTA Scanner set the fundamental design for 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. Invention Impact Ledley used ACTA to revolutionize diagnostic medicine. He was the first to do medical imaging and three-dimensional reconstructions and the first to use CT in radiation therapy planning for cancer patients and in the diagnosis of bone diseases. Inventor Bio Born in New York City, Ledley earned a D.D.S. from New York University in 1948 and an M.A. from Columbia University a year later. During the next 20 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 of radiology at the Georgetown University Medical Center. With more than 20 patents to his name, Ledley is best known for developing the ACTA (Automatic Computerized Transverse Axial) diagnostic X-ray scanner, the first whole-body computerized tomography (CT) machine. In addition to the ACTA scanner, Ledley patented the image processor (originally called the Texture Analysis Computer or TEXAC). 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. 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 reviewed scientific journals and has been the president and research director of the National Biomedical Research Foundation since 1960.