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Hounsfield, Sir Godfrey Newboldunlocked

  • Ian Young

Sir Godfrey Newbold Hounsfield (1919–2004)

by unknown photographer, 1979

Hounsfield, Sir Godfrey Newbold (1919–2004), engineer and inventor, was born on 28 August 1919 in Sutton-on-Trent, Nottinghamshire, the youngest child in the family of three sons and two daughters of Thomas Hounsfield, farmer, and his wife, Sophia Blanche, née Dilcock. His upbringing on a farm was a major factor in the way his life developed. From a very early age he began doing experiments using the sort of resources that can only be found on a farm. He exploited haystacks as the launch platforms for hang gliding investigations, and had access to barrels in which he performed some chemical experiments which, it is not unlikely, could have terminated his interest in science at a very early age. At Magnus grammar school, Newark, he was enthused only by physics and mathematics. He seems to have had an interest in electronics from a very early age, however, and many of his projects, such as the construction of his own audio recording system, involved this then embryonic subject.

When he left school Hounsfield worked for some time in a builder's design office before volunteering for the RAF in 1939, at the outbreak of the Second World War. His electronics experimentation led to his being accepted as a radio mechanic, passing the entry examination without taking the preparatory course. He received specialist radar training, and was sent first to the RAF-occupied Royal College of Science in London, then to Cranwell as a radar instructor, and promoted to corporal. While at Cranwell, he passed the City and Guilds radio communications examination in his spare time. In 1946 he was demobilized and, funded by a grant awarded on the recommendation of Air Vice-Marshal J. R. Cassidy, went to Faraday House Electrical Engineering College in London to study for the diploma in electronics which that college awarded. At the time electronics was regarded academically as a minor offshoot of physics, and was allocated very little course time by university departments. He graduated from Faraday House in 1951, and joined Electrical and Musical Industries Ltd (EMI) at Hayes, Middlesex.

EMI and the development of the CT scanner

EMI was an immensely innovative company, which had been responsible for many of the most important developments in sound recording and electronics in the period between the 1920s and the 1950s. Apart from the stereo recording of sound, the most significant was the development by Alan Dower Blumlein at the Central Research Laboratory, under the leadership of Isaac Shoenberg, of cathode ray tube-based television (which was chosen in preference to the mechanically scanned method proposed by John Logie Baird). It was predictable, therefore, that the company should become involved in the development of computers as soon as the potential significance of these devices became apparent. After some initial work on radar and guided weapons, Hounsfield headed a group developing the first British transistor-based computer, which was marketed as the EMIDEC 1100. Subsequently he worked on computer storage systems before moving on to investigate automatic pattern recognition in the Central Research Laboratory.

Hounsfield was asked to devise new topics for research, and suggested trying to reconstruct a picture by sampling it from a large number of different angles. As he studied this, he began to consider how one could determine the contents of an opaque box. Legendarily he developed the idea of computerized tomography (CT) during the long walks he took most weekends at Burnham Beeches, the nearest really attractive woodlands to Hayes. Initially he did not think of his problem in medical terms at all, but that may have evolved as he considered the kinds of radiation that might make it possible to achieve what he wanted, and it became apparent that an X-ray source was the most appropriate available. From that conclusion, it was only one more step to the idea of computerized tomographic (CT) X-ray imaging. The thoughts that he matured during these times led to a research proposal to the Central Research Laboratory in 1968. In this he suggested that highly accurate values might be expected for the absorption coefficients of various tissues, leading to high discrimination between them, and potentially useful diagnostic results. He requested £10,000 for the programme, which the company persuaded the Department of Health and Social Security (DHSS) to join it in providing. This funding was later increased, in spite of scepticism as to the idea's feasibility voiced by a leading academic mathematician who was asked to evaluate the concept.

The initial demonstration of the possibility of imaging using computerized tomography was based on an old lathe bed, which was modified to provide the mix of lateral translation and rotation necessary to obtain the huge number of individual 'edge' values needed for the reconstruction process. (The lathe bed is now in the care of the British Institute of Radiology, London.) Initial studies used a gamma-ray source and photomultiplier detector, but acquiring the data for a single image using this combination took nine days, and one of the funding increases that were sought (and agreed) was for an X-ray source with which the data for an image could be obtained in nine hours.

EMI had many demands on its resources, and the possibility that it might stop funding scanner development was very real. Medical electronics was not part of the company's portfolio at the time, and the operating divisions felt that they had first claim on any available resources. The Central Research Laboratory, led by its then director of research, W. E. Ingham, approached the DHSS again seeking help to continue the work. They were fortunate in that the men who had charge of the appropriate department of the DHSS at the time were Cliff Gregory and Gordon Higson. The latter, in particular, had an appreciation of medical electronics and its potential which was many years ahead of his time. Higson was both a patriot, with a belief that British manufacturing industry was worth protecting and encouraging, and that the DHSS, through its support, could help with this aim, and a scientific administrator with an extraordinary ability to detect a good idea. Gregory and he were quickly persuaded that the case for supporting the development of the scanner was good, and they were largely instrumental in organizing the purchase on behalf of the DHSS of five of the new devices (one being for engineering development and the other four for installation in hospitals). EMI devised a specification for the machines against which their performance could be measured, and Higson ensured the order was placed. He also funded some of the research and development of the new scanner in return for a small royalty per machine to be paid to the DHSS. This research funding was critical in keeping the project going. In order to overcome scepticism about the value of the new equipment, Higson organized a group of three wise men—distinguished radiologists—to assess its clinical utility. Two of the three (James Ambrose and Louis Kreel) ultimately received respectively the first head and body CT scanners, while Frank Doyle, at the Hammersmith Hospital, would be charged nearly ten years later with the evaluation of the first clinical Magnetic Resonance Imaging (MRI) scanner, which had also been supported by Higson. At the same time as they developed the first group of machines EMI also designed and built a prototype machine for the American market. The whole project was implemented by a tiny team working very long hours, with Hounsfield involved in every aspect. The CT scanner was to an unusual degree the work and inspiration of one individual.

The first CT scanner was installed at Atkinson Morley's Hospital in Wimbledon for evaluation by James Ambrose of its potential for imaging the head and brain, with immensely promising results. The first patient, a lady presenting with a possible brain cyst or tumour, was scanned on 1 October 1971. The results of the initial clinical trials were startling. The many sceptics, who had expected computerized axial tomography (or CAT), as the method was by then known, to be no more than a somewhat distracting sideshow, were won over overnight, and when EMI formally unveiled the new machine at the annual congress of the British Institute of Radiology in April 1972 it was greeted with enthusiasm. Ambrose's presentation at the Radiological Society of North America's annual meeting in Chicago at the end of November, in which he described his initial clinical results, was given a standing ovation. American radiologists clamoured for machines, and, quite extraordinarily quickly by later standards, EMI began shipping machines to the USA by jumbo jet plane. The initial machines were sold as head scanners, but a whole body machine was launched by EMI in 1975.

Impact on radiology and consequences for EMI

The impact of the new machine on radiology was both extraordinary and fundamental. Patients benefited from the very beginning, with previous techniques (such as the very uncomfortable pneumoencephalography procedure) being discarded almost overnight, and with improved diagnosis and better patient care becoming ever more widely available. It was extraordinary, too, in the swiftness of the response of radiologists in all kinds of hospital to the opportunity it offered them. It was fundamental in that they demonstrated that they could generate the resources needed to acquire and operate the scanners, and that the additional knowledge and capability it gave them could raise their significance and power relative to those of other practitioners. The impact of the scanner on EMI was dramatic also. The company had thrived during the 1960s on the worldwide euphoria surrounding the Beatles. By the 1970s it needed an equally spectacular successor. EMI's managers certainly believed they had found it, and for some time the sale of CT scanners and licensing agreements with other manufacturers provided a steady stream of income, but they underestimated the determination of their competitors, their willingness to infringe the mass of patents EMI had accumulated, and the preparedness of governments to ignore the rules of free trade if it would benefit their own manufacturers. By the end of the 1970s, with both the record and medical companies in difficulties, the company was clearly vulnerable to being a takeover victim. It was bought in 1979 by Thorn Electrical—a supplier, predominantly, of domestic appliances.

Thorn-EMI (the result of the merger) began its withdrawal from the medical electronics business at once, and finally quit it in 1981. Hounsfield continued to work as a consultant at the rebuilt Central Research Laboratory after his retirement in 1986, involving himself in a variety of projects with medical imaging. In addition to his work on CT X-ray machines, Hounsfield had developed a great interest in MRI during the time EMI was actively investigating this imaging modality in the Central Research Laboratory, between 1974 and 1981. After his retirement he spent one or two days of every week working on MRI in the Cardiac MRI unit at the National Heart and Lung Institute at the Brompton Hospital. This unit had been founded, and was driven, by Donald Longmore, a charismatic and very able cardiac surgeon and physiologist with a voracious appetite for new things, and a willingness to invest huge energy in making them happen. Longmore was intensely interested in the use of MRI for cardiac investigations—with the real target being the replacement of X-ray based coronary angiography by its MRI equivalent. Hounsfield joined enthusiastically, inventively, and productively in the endeavour to achieve really good magnetic resonance images of the coronary arteries.

Public honours and private life

Recognition of the extent of Hounsfield's achievement came quickly. EMI received the MacRobert award for the development of the CT scanner in 1972. This was the most prestigious British engineering award, made to a company, represented by those involved, rather than to any individuals. Hounsfield himself was made a fellow of the Royal Society in 1975, was appointed CBE in 1976, and received (jointly with Allan M. Cormack, an American-based South African mathematician) the Nobel prize for physiology or medicine in 1979. He was knighted in 1981, and made an honorary fellow of the Royal Academy of Engineering in 1994. He received many other honours including six honorary degrees, and over forty awards from scientific institutions around the world.

Hounsfield never married, and lived very quietly all his life. His principal hobby was walking, both in the mountains and around the countryside nearer his home. He played the piano in, as he put it, a self-taught way. He lived very modestly, with few possessions. When, as in his later years, he did receive large prizes, he tried to invest them in further scientific studies. Indeed, he is said to have wished to use his Nobel prize to fund an MRI system for his own work, and was somewhat put out when it was pointed out to him that he had nowhere to put it, as he was then living in lodgings. As a result he was persuaded to buy a house (in Twickenham), one room of which he turned into a laboratory. Even then he spent little on himself, so that at one stage in his latter years he was diagnosed as suffering from malnutrition. He worked on consistently until ill health prevented it a couple of years before his death, at the New Victoria Hospital, Kingston upon Thames, on 12 August 2004, of heart failure. He left an estate valued for probate purposes at just over £1 million.


Godfrey Hounsfield was an unassuming electrical engineer, with an imagination, intuitive insight, and persistence that ultimately lifted him high above his peers, though his qualifications were superficially much less good then theirs. His working life was very simple. He worked for practically all his career for one company, and for most of his working life he lived in various forms of rented accommodation. By later standards he was something of an enigma—a self-contained man who was perfectly happy doing the job he was paid to do, and quite unimpressed by the fame that ultimately became his. He was a unique man, with unique working methods. His intuitive insights were invariably correct, even if he often could not explain rationally the process by which he reached the conclusions he had. He was genuinely interested in the things he was investigating, and widespread recognition with its requirements for travel, talks, and presentations seemed to him a slightly irritating distraction from things that were really important. He focused all his energies on what he was investigating at the time, and anything else simply got in the way of that. He wrote very few academic papers, and declined invitations to many events where he might have had to speak or receive an award, because they were all distractions that could be avoided. He was often quite vague about the details of what had happened in the past (as the American lawyers challenging EMI's patents in the latter part of the 1970s were to find out). He was always much more interested in the future, and, above all, in what he was currently working on.

By the time of Hounsfield's death CT scanners were part of the standard equipment of most hospitals in the developed world, and it has been estimated that the world market for CT scanners was by then valued at around £500 million annually. Nevertheless it can be argued that Hounsfield's impact on medicine extended far beyond the invention of the CT scanner, and was even more significant and had a much greater and more far-reaching effect than that huge achievement. Quite simply, he showed the medical community that computers could do things and deliver capabilities that were impossible without them. It is significant that, apart from traditional X-ray machines and ultrasound, all the other imaging modalities which were either in use or being investigated by the time of his death were first proposed in the three or four years after the announcement of the scanner. MRI, for example, was first described in recognizable form (actually using the same data acquisition strategy as the original CT scanner) in 1973, Positron Emission Tomography in 1974, and microwave and optical imaging soon after. Others (most notably John Mallard at Aberdeen, who developed a tomographic nuclear medicine system—later widely applied as the method known as SPECT) were working along parallel lines to Hounsfield, but it was his achievement that made people start to take all the other possibilities seriously. The 'all digital' hospitals which were emerging by the time of his death can truly be said to have had their genesis in Hounsfield's lathe bed rig in Hayes, Middlesex.


  • J. A. Lodge, ‘Thorn EMI Central Research Laboratories: an anecdotal history’, Physics in Technology, 18 (1987), 258–68
  • S. Webb, From the watching of shadows: the origins of radiological tomography (1990)
  • E. M. Tansey, D. A. Christie, and L. A. Reynolds, eds., Making the human body transparent: the impact of nuclear magnetic resonance and magnetic resonance imaging (1998), 1–66
  • Daily Telegraph (17 Aug 2004)


  • British Institute of Radiology, London


  • BL NSA, current affairs footage
  • British Institute of Radiology, London


  • British Institute of Radiology, London


  • photograph, 1979, Getty Images [see illus.]
  • obituary photographs

Wealth at Death

£1,081,874: probate, 17 Dec 2004, CGPLA Eng. & Wales

Biographical Memoirs of Fellows of the Royal Society
J. Burke, A general [later edns A genealogical] and heraldic dictionary of the peerage and baronetage of the United Kingdom [later edns the British empire] (1829–)