Mathematical foundations of computed tomography (CT) were developed in the early twentieth century. Due to the lack of powerful computing systems at that time, these algorithms were not used in medical practice. Allan McCormack, a mathematician from South Africa, was the first to propose the reconstruction of the three-dimensional structure of the object from its many projections in medicine. When working in the radiotherapy department of Groote Schuur hospital of Cape Town, he was the first to describe the principle of obtaining the cross-sectional images. In 1963, he published an article with mathematical calculations that allowed reconstructing the image of the brain after scanning it with a narrow beam of X-rays. Having studied these materials, a group of engineers of the English firm EMI (electric musical instruments) led by Godfrey Hounsfield was engaged in the creation of the first prototype of a computer tomograph for the study of the brain. They named the machine after the company. On this installation, the brain scanning took 9 hours, and each image consisted only of 4096 points. However, even such an imperfect and bulky machine, more like a tool of torture, could significantly improve the diagnosis of brain pathologies.
The first CT image was of a woman with a brain tumor. In 1972, at the British Institute of Radiology Congress G. Hounsfield and A. McCormack declared that "Radiology penetrates the brain". This moment became the starting point of explosive CT development. Following the increased demand, the leading manufacturers of medical equipment began to sell the first tomographs in 1973. Due to the rapid development of technology, there were 4 generations of computed tomographs by the end of 1979. By that time brain scan did not take 9 hours, but several minutes. In 1979, mathematician Allan McCormack and Godfrey Hounsfield were awarded a Nobel prize for medicine