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Godfrey HounsfieldNobel Prize in Physiology or Medicine, 1979, jointly with Alan Cormack
Date of Birth: 28.08.1919
Country:  Great Britain |
Content:
Biography of Godfrey Hounsfield
Early Life and EducationGodfrey Hounsfield was born in 1919 in Nottinghamshire, England. His father, Thomas Hounsfield, was an engineer who owned a small farm. Being the youngest of five children, Godfrey spent much of his time on the farm, turning it into a playground. Surrounded by agricultural machinery, he developed an interest in engineering from a young age. In his youth, Godfrey constructed a glider, a fountain powered by an acetylene engine, a gramophone, and a radio receiver. He attended Newark Grammar School, where he focused mainly on physics and mathematics. In 1939, he enrolled at City and Guilds College in London and then served as a radar instructor in the Royal Air Force during World War II. He also lectured at the Royal Air Force Radar School, where he developed technical teaching aids.
Career and Contributions
After being awarded a special commendation for his wartime service, Hounsfield received a subsidy to study at the Faraday Electrical Engineering College in London. Upon graduation in 1951, he joined the research company EMI, where he worked on electronics for commercial use. It was during his time in the Royal Air Force, dealing with radars and air tracking systems, that Hounsfield became interested in electronic computing. In 1958-1959, he was part of a team that constructed the first transistorized computer in England. However, early transistorized computers did not offer significant advantages compared to vacuum tube computers. Hounsfield managed to improve their speed and power by developing a system based on controlling transistors using magnetic fields.
In the early 1960s, Hounsfield worked on thin-film technology at several research laboratories in EMI with the aim of increasing the memory capacity of EMI computers. However, this project was abandoned due to commercial unprofitability. Hounsfield also participated in developing computer programs for identification purposes. These experiments led him to the idea of developing a computer that could determine the degree of X-ray absorption by biological tissues, maximizing their potential. Medical radiology as a science emerged in the late 19th century when Wilhelm Roentgen discovered X-rays and obtained the first images of various objects. Traditional X-ray images show the X-rays passing through the body and reaching the X-ray film. Since bones absorb more X-ray energy than soft tissues, which are less dense, bones appear as bright areas, called shadows, on the developed film. Soft tissues, overlapping one another, are poorly outlined. As a result, it was impossible to distinguish normal and altered soft tissues, such as tumors, using conventional X-ray imaging.
In the late 1950s and early 1960s, Alan Cormack, a specialist in medical physics at Tufts University, developed a mathematical method for determining the absorption of X-rays by biological tissues. Cormack's method was based on multiple measurements of the absorption of a thin X-ray beam passing through the body at different angles, which allowed for the creation of a thin cross-sectional image. Traditional X-ray examinations only determine the total absorption of the beam reaching the film. The tissues along the beam path are "overlaid" on top of each other. Cormack's method allowed for the reconstruction of internal details of the body based on the different X-ray absorption of each individual part. Although Cormack's work was published, it did not receive much attention from the scientific community, and his method remained a primitive laboratory technique rather than a means of studying biological tissues. Furthermore, fast computers capable of performing the necessary mathematical operations were not yet created, making Cormack's method time-consuming. The creation of X-ray images of body sections became known as tomography, derived from the Greek word "tomos," meaning "slice." With the development and availability of fast computers, the method became known as computerized axial tomography (CAT) or CAT scanning. In 1967, Hounsfield, independently of Cormack, began working on his own CAT system, starting with gamma rays, like Cormack, and developed a scheme very similar to Cormack's. The same principle applied to gamma rays as to X-rays. Hounsfield developed a slightly different mathematical model, using a large computer for data processing, and implemented the tomographic method into practice thanks to his engineering skills.
Initially, the scanning time took nine days due to the low-intensity gamma-ray source, which required long exposures. A powerful X-ray tube reduced the scanning time to nine hours. Successful images were obtained when scanning the human brain, the brain of a live calf, and the kidney area of a pig. The contrast of the images was clear, allowing for the evaluation of brain tissue and other organs. However, there was uncertainty about whether this method would distinguish between normal and abnormal tissues, such as detecting a tumor. In 1971, a fast and complex apparatus, the first clinical CAT scanner, was constructed and installed at Atkinson Morley Hospital in Wimbledon. In 1972, the first scanogram of a woman's brain suspected of having a lesion was obtained, clearly showing the presence of a dark, round cyst. Larger and faster scanners were gradually developed, reducing the scanning time to 18 seconds, and then to 3 seconds or less, providing high-resolution images of various organs. Hounsfield described the development of CAT devices in the proceedings of the annual conferences of the British Institute in London and wrote an article titled "Computerized Transverse Axial Scanning: Tomography" in December 1973, which presented the results of clinical studies with the first commercial EMI CT 1000 scanner. It quickly became evident that CAT scanning represented a significant advancement compared to other methods of obtaining images of biological tissues. This method allowed for detailed imaging of soft tissues that were previously inaccessible for examination, and it enabled more accurate identification of changes such as tumors, providing precise measurements of X-ray absorption by different tissues, which proved valuable for diagnosis and treatment. Hounsfield estimated that CAT scanning was hundreds of times more effective than traditional X-ray imaging since it used all the obtained information, whereas the latter only captured one percent of it. Additionally, the scanner was more sensitive and required less X-ray energy per frame than standard X-ray equipment, although they both resulted in similar levels of radiation exposure due to multiple exposures required for scanning.
An industrial CAT scanner consists of an X-ray source, a scanning device containing an X-ray tube, a detector, a computer for data processing, a terminal, and a printer for recording computed images. The scanning device moves around the head or body, making up to a million individual measurements of beam attenuation from different angles. (In some devices, the detectors are fixed, and only the X-ray source rotates.) From this tremendous amount of information, the computer reconstructs cross-sectional slices of the examined body parts. During the procedure, the patient moves along the longitudinal axis of the scanning device. By processing a series of consecutive cross-sectional scans, a spatial image of the organs is reconstructed.
Later Life and Legacy
In 1972, Hounsfield was appointed head of the Medical Systems Division at EMI, and from 1976, he served as a senior research scientist at the company. In 1978, he became a fellow of the Royal Society of Manchester University.
Hounsfield and Cormack were jointly awarded the Nobel Prize in Physiology or Medicine in 1979 for their development of computerized tomography. In his Nobel Lecture, Hounsfield explained that the "image reconstruction method was developed through practical steps. Most of the available mathematical methods at that time were abstract and not practical."
Hounsfield continued his work on improving CAT technology and related diagnostic methods, such as nuclear magnetic resonance, a recently developed imaging method that does not use X-rays.
Throughout his life, Hounsfield remained a bachelor. He enjoyed long walks, humorous conversations on abstract topics, and playing the piano. Biology never captured his attention, and he rekindled his passion for physics.
Among Hounsfield's many awards are the MacRobert Award from the Institution of Engineers (1972), the Barclay Prize from the British Institute of Radiology (1974), the Albert Lasker Award for Fundamental Medical Research (1975), the Duddell Medal and Prize from the Institute of Physics (1976), and the Gardner International Award (1976). He received honorary doctorates from the University of Basel and the University of London. Hounsfield was an honorary fellow of the Royal College of Physicians and the Royal College of Radiologists.
