Portal de Periódicos da CAPES

Godfrey Newbold Hounsfield

2005; AIP Publishing; Volume: 58; Issue: 3 Linguagem: Inglês

10.1063/1.1897571

1945-0699

E C Beckmann,

Nuclear Physics and Applications

The year 1972 will live in scientific history: On 21 April of that year, Godfrey Newbold Hounsfield presented the results of his development to an unexpecting audience. At the 32nd Congress of the British Institute of Radiology, he delivered his paper “Computerised Axial Tomography.” He described to the audience a new means of demonstrating some of the soft tissue structures of the brain without the use of contrast media. For that work, he and Allan M. Cormack received the Nobel Prize for Physiology or Medicine in 1979. Hounsfield died on 12 August 2004 in Kingston upon Thames, England.A quiet, unassuming person, Godfrey was born on 28 August 1919 in Newark, England, and grew up nearby on a farm in Sutton on Trent. Although he did not excel at school, he was known for experimenting with electronics and the farm’s mechanical and electrical machinery, and for building a homemade hang glider to test the principles of flight from haystacks. When World War II broke out in 1939, he joined the Royal Air Force (RAF) and found himself building an oscilloscope and carrying out radar R&D.Although Godfrey never received a PhD, he had enrolled in a college course just before the start of the war. Following his discharge from the RAF, he won a government grant to the Faraday House Electrical Engineering College in London, from which he graduated in 1951. That same year, he joined the research staff of Electric and Musical Industries (later known as EMI).Godfrey could well have been remembered for his significant contribution to the computer field, because in 1958 he was responsible for the development of the first solid-state computer in the UK, the EMIDEC 1100. After that effort, he was asked to add his intellect to the area of pattern recognition, in which EMI had a project team.One day around 1967, as he walked the countryside—an activity he was keen on doing—his work in the area of pattern recognition combined with his work in computers to spark the realization that if sufficient measurements were taken of an energy beam around an object, it should be possible to calculate the structure within the object.Following the initial theoretical calculations, Godfrey constructed a laboratory model using a lathe bed. His early model used a gamma source placed on one side of the specimen object and a detector on the other. The specimen object was rotated 1 inch at the end of each sweep. Each scan generated 28 000 measurements, which were digitized and recorded onto paper tape that was then fed into a computer system for processing.The early pictures were encouraging, but it took nine days to scan an object and 2-12 hours to process each scan on a computer. The result of the processing was paper-tape output that was used to modulate a spot of light on a cathode-ray tube in front of a camera to produce a photograph, a process that took an additional 2 hours.One of the first pictures using Godfrey’s model, an image of a human brain, was of a museum specimen and showed good gray-white matter differentiation. Unfortunately, further study showed that the formalin used to preserve the brain had caused the readings to be enhanced. Godfrey then took pictures of animal specimens and proved that differences within the brain could be clearly seen. He often recalled stories of traveling across London on the subway with bullocks’ brains and parts of pig bodies in a carrier bag.It was obvious that a long scan time would not be feasible for a clinical system. After some experimentation, Godfrey chose x rays as the energy source. He approached the Department of Health and Social Security in London for support in building the clinical prototype; Godfrey and his funding agency agreed on a scan time of 4 minutes and an accuracy of 0.5% in pixel density.In 1971 at the Atkinson Morley Hospital in South London, a woman with a suspected brain tumor was the first human patient to undergo a scan. The resulting picture clearly showed a dark lesion. Godfrey was still reserved; he feared that would just be the luck of the first clinical experiment. Not until he had scanned several patients and processed the pictures did he became convinced that the system was going to be sensitive enough to distinguish between normal and abnormal brain tissue. Godfrey’s model then evolved from being simply a brain scanner to the whole-body scanners with which we are familiar today. His R&D interests moved beyond computerized tomography to provide a significant contribution to the field of magnetic resonance imaging development.The invention of the CT scanner revolutionized x-ray investigation, which had remained virtually static since the turn of the 20th century, following Wilhelm Konrad Roentgen’s discovery of x rays. Certainly it was the most significant development in the field of neurological diagnosis since Walter Dandy’s air encephalography in 1918. In recognition of his contribution to CT scanning technology, Godfrey’s name was given to the absorption scale (Hounsfield units) that identifies the x-ray attenuation in CT images. Godfrey headed EMI’s medical systems section from 1972 to 1976, became a senior staff scientist in 1977, and retired from EMI in 1986. He received numerous awards, including a knighthood from Queen Elizabeth II in 1981.Godfrey was a keen lover of jazz and played it on the piano. He was also an eccentric; one particular example of his eccentricity was his insistence on remaining on UK time wherever he was in the world. He was even known to insist on presenting a lecture at 10am Greenwich Mean Time, even if it meant the audience attended at what was the middle of the night locally.He disliked lecturing, the publicity, and the public activities that the invention of CT gave him, and preferred instead to dedicate his time to his R&D projects. Whenever possible, he would decline requests for lecturing or find a colleague to fill in for him. He was passionate about his research and dedicated to increasing his knowledge and to looking for other areas in which technology could improve medicine. Godfrey Newbold Hounsfield PPT|High resolution© 2005 American Institute of Physics.