Fifty years ago on 1 October 1971, “Jamie Ambrose, a consultant radiologist at Atkinson Morley’s Hospital in Wimbledon, south London, made medical history by carrying out the first computed tomography (CT) scan on a live patient, revealing a detailed image of a brain tumour.” Eight years later, the Nobel Prize in Medicine was jointly awarded to Allan Cormack, a physicist who had published two seminal papers in 1963-64, and Godfrey Hounsfield, an engineer who had designed and built the first CT scanner used by Ambrose. In 2001, CT was ranked by physicians as the most important medical innovation of the 20^th century.

The figure above right illustrates the basic principles of CT scanning (© Physics Today). A series of X-ray images are first acquired over a range of angles θ, from 0^o to 90^o. The projection values P are a function of the distance x along the detector, and the angle θ. Then, using a process called filtered back-projection, a CT image of the four objects in the phantom can be reconstructed. This is the essence of all CT machines in use today.

Working for EMI, a company that manufactured stereophonic sound and radar equipment, Hounsfield was searching for a clinical collaborator who could help him bring his ideas to fruition. In 1969, he was introduced to Ambrose, by then an eminent radiologist who specialised in brain imaging, and they formed a formidable partnership. The two are seen standing next to one of their early CT scanners, with Ambrose in a white coat (© BMJ). In April 1972, they each contributed well-received papers to the British Institute of Radiology, while at year-end Ambrose’s presentation at the RSNA meeting in Chicago received a standing ovation.

Jamie Ambrose was born in Pretoria in 1923 – a year before Allan Cormack’s birth in Johannesburg – and signed up in 1941 at age 18 with the South African Air Force. Following training, he was posted to the Mediterranean as a fighter pilot where he was attached to the RAF, flying Spitfires in southern France, Italy and the Middle East.

Following demobilisation in 1945, Ambrose returned to South Africa and registered for a medical degree at the University of Cape Town (UCT). He graduated in 1952 and subsequently moved to the UK where he trained as a radiologist, later appointed a consultant at Atkinson Morley’s. Seen at right is that first CT image of his, revealing a tumour in the left frontal lobe (© Springer). It’s amazing to think that two UCT graduates made such an indelible mark on this breakthrough technology.