Sir Godfrey Hounsfield invented computerized axial tomography scanning technology, commonly known as the CAT scan, a medical diagnostic tool that uses X-ray crystal detectors to photograph cross sections of the body that computer programs then compile and reconstruct into an image of internal organs and tissue. Doctors use this technology to diagnose previously undetectable diseases and conditions. Hounsfield defended the machine against early criticism of its seemingly exorbitant price, arguing that it ultimately saved money by preventing unnecessary surgical procedures. For his innovation, he received the 1979 Nobel Prize in physiology or medicine.
Godfrey Newbold Hounsfield was born on August 28, 1919, in the village of Newark in Nottinghamshire, England. He had two older brothers and two older sisters. His father was a steel-industry engineer who had become a farmer by the time Hounsfield was born. Hounsfield attended Newark’s Magnus Grammar School, but much of his formative education was self-initiated: he built his own electrical recording devices, experimented with flying in homemade gliders off haystacks, and investigated jet propulsion by lighting acetylene under tar barrels filled with water.
When World War II broke out, Hounsfield volunteered as a reservist in the Royal Air Force, which assigned him as a radar mechanic instructor at the Royal College of Science and then at Cranwell Radar School. At the same time, he advanced his own education at London’s City and Guilds College, where he passed the examination in radio communications and also received a certificate of merit for his construction of a large-screen oscilloscope. After the war, Air Vice-Marshal Cassidy recommended Hounsfield for a grant to London’s Faraday House Electrical Engineering College, where he earned a degree in electrical and mechanical engineering in 1951.
That year, EMI (Electrical and Musical Industries—now Thorn EMI) hired Hounsfield to work on radar systems and guided weapons and then appointed him to run a small design laboratory in Middlesex. In 1959, he and his design team built the EMI-DEC 1100, the first all-transistor computer constructed in Britain, made possible by Hounsfield’s innovation of a magnetic-core transistor to achieve a degree of speed equal to valve-driven computers.
EMI then transferred Hounsfield to its Central Research Laboratories in Hayes, where he designed and patented a high-capacity, immediate-access thin film computer-storage system that proved commercially unviable in the 1967 marketplace. Instead of immediately assigning him to a new project, EMI granted him latitude to formulate his own next undertaking. On a country stroll, inspiration struck him: he conceived the notion of a medical instrument that would take a series of X-ray cross sections, or "slices," that a computer program could compile to reconstruct a visual representation of internal physiology in much greater detail and clarity than achievable through X-ray photography alone. He called this technology tomography, or computerized transverse axial scanning, popularly known as "CAT scanning" (for "computerized axial tomography").
Hounsfield recruited the radiologists James Ambrose and Louis Kreel to work on the X-ray component of his proposed machine, while he worked to advance computer technologies capable of handling the demands of his complex conception. The British Department of Health and Social Services helped finance the project, which went into a trial phase in 1971 with the installation of a prototype at Atkinson Morely’s Hospital in Wimbledon. Doctors initially performed CAT scans on the brain exclusively; as head of the
Medical Systems section at EMI, Hounsfield continued to develop CAT technologies, leading to the introduction of the first "whole body scanner" in 1975. That year, the Royal Society inducted him into its prestigious fellowship.
In 1979, Hounsfield shared the Nobel Prize in physiology or medicine with Allan M. Cor-mack, an American nuclear physicist who in 1963 and 1964 had calculated and published mathematical formulae for computer reconstruction of images, thus establishing a theoretical basis for CAT scanning independent of Hounsfield. Interestingly, neither held a doctorate, and their degrees were not in the fields honored by the award. In addition to the Nobel, Hounsfield also received Britain’s highest engineering honor, the MacRobert Award, and in 1981, the Queen knighted him.
In 1977, EMI had promoted Hounsfield to the rank of senior staff scientist, and he continued to improve CAT scanning technology while also researching an alternative technology— nuclear magnetic resonance imaging. He retained this post until 1986, when he scaled back to consultant status with the company. A lifelong bachelor, Hounsfield committed himself wholeheartedly to his work and neglected even to establish a permanent residence until late in life, when he settled in Twickenham.
