Editorial
Medical Historic Vignette: Sir Godfrey Hounsfield and CT Richard H. Daffner, MD, FACR
W
ilhelm Konrad Roentgen, a German physicist, discovered x-rays in November 1895 and reported his findings to the Würtzburg Physical Medical Society in December of that year1. Less than two months later, the first medical x-rays of a broken forearm were obtained at Dartmouth University. Over the next eighty years refinements in the practice of radiology resulted in improved safety for patients and operators of x-ray equipment as well as a wide variety of newer applications and techniques in the field. Radiographs (x-ray images) were (and still are) superb for diagnosing lung diseases as well as most fractures and bone lesions. However, when it came to studying the brain or the solid organs of the abdomen it was necessary to opacify those structures which could be opacified with either positive contrast or air to see if a disease process was displacing the normal organs. Physicians longed for the ability to see the body’s organs from the earliest days of radiologic practice. It would take the innovative thoughts of a British engineer, who like Roentgen was not a physician, to bring those desires to fruition. Sir Godfrey Hounsfield (Fig. 1) was born August 28th, 1919, in Suttonon-Trent, in Nottinghamshire, England. 12
As a child he was fascinated with electrical gadgets and machinery that he found on the family farm. While attending school he excelled in physics and mathematics. In 1939 he joined the Royal Air Force volunteer reservist squadron 89, where he learned the basics of electronics and radar, that would prove critical to the allied victory in World War II. Following the war, in 1946 he attended Faraday House Electrical Engineering College in London. There, he combined practical experience with theoretical study. In 1949 he began work at EMI (Electric and Musical Industries, Ltd - the same company that made the Beatles famous), where he researched guided weapon systems and radar and became interested in computers. In 1958, he helped design the first commercially available all-transistor computer in Britain, the EMIDEK 1100.
In 1960, Hounsfield had an idea that one could determine what was inside a box by taking x-ray readings at all angles around the object. He began constructing a computer that could take input from those x-rays at various angles to create an image of the object in “slices”. This led him to propose what we now know as computed tomography (CT). Hounsfield was unaware of the work Allan Cormack (1924–1998), a South African physicist had done on the theoretical mathematics for such a device. Hounsfield built a prototype scanner and tested it, first on a preserved human brain (Fig. 2), then on a fresh cow brain from a local butcher shop, and then on himself. On October 1st, 1971, the first successful CT brain scan was performed in London on a patient with a cerebral cyst. In 1975 he built the first whole body scanner for EMI.
Fig. 1. Sir Godfrey Hounsfield 1919–2004)
Fig. 2. Hounsfield’s prototype scanner with a section of brain www.acms.org