Godfrey Hounsfield

Sir Godfrey Newbold Hounsfield CBE, FRS, (28 August 1919 – 12 August 2004) was an English electrical engineer who shared the 1979 Nobel Prize for Physiology or Medicine with Allan McLeod Cormack for his part in developing the diagnostic technique of X-ray computed tomography (CT).

His name is immortalised in the Hounsfield scale, a quantitative measure of radiodensity used in evaluating CT scans. The scale is defined in Hounsfield units (symbol HU), running from air at -1000 HU, through water at 0 HU, and up to bone at +1000 HU.

Invention of the CT scanner
While on an outing in the country, Hounsfield came up with the idea that one could determine what was inside a box by taking X-ray readings at all angles around the object. He then set to work constructing a computer that could take input from X-rays at various angles to create an image of the object in "slices". Applying this idea to the medical field led him to propose what is now known as computed tomography. At the time, Hounsfield was not aware of the work that Cormack had done on the theoretical mathematics for such a device. Hounsfield built a prototype head scanner and tested it first on a preserved human brain, then on a fresh cow brain from a butcher shop, and later on himself. In September 1971, CT scanning was introduced into medical practice with a successful scan on a cerebral cyst patient at Atkinson Morley Hospital in Wimbledon, London, United Kingdom. In 1975, Hounsfield built a whole-body scanner.

Childhood and education
Hounsfield was born in Nottinghamshire, England in 1919. He was the youngest of five children.

As a child he was fascinated by the electrical gadgets and machinery found all over his parents' farm. Between the ages of eleven and eighteen, he tinkered with his own electrical recording machines, launched himself off haystacks with his own home-made glider, and almost killed himself by using water filled tar barrels and acetylene to see how high they could be waterjet propelled. He attended the Magnus Grammar School (now Magnus Church of England School) in Newark-on-Trent and excelled in physics and arithmetic.

Wartime
Shortly before World War II, he joined the Royal Air Force as a volunteer reservist where he learned the basics of electronics and radar. After the war, he attended Faraday House Electrical Engineering College in London, graduating with the DFH (Diploma of Faraday House). Faraday House was a specialist Electrical Engineering college that provided university level education and was established in 1890, before the advent of most university engineering departments. Faraday House pioneered the use of sandwich courses, combining practical experience with theoretical study.

The suggestion that Hounsfield lacked formal engineering education to the level of a Chartered Engineer does not reflect the nature of engineering education at the time when Hounsfield was a student, or the esteem in which Faraday House was held within the profession.

EMI and later years
In 1951, Hounsfield began work at EMI Ltd. where he researched guided weapon systems and radar. There, he became interested in computers and in 1958, he helped design the first all-transistor computer made in Great Britain: the EMIDEC 1100. Shortly afterwards, he began work on the CT scanner at EMI. He continued to improve CT scanning, introducing a whole-body scanner in 1975, and was senior researcher (and after his retirement in 1984, consultant) to the laboratories.

Hounsfield received numerous awards in addition to the Nobel Prize. He was appointed Commander of the British Empire in 1976 and knighted in 1981. In 1975, he was elected to the Royal Society.

He never married and died in 2004.