Generations of CT—the Evolution and Future Prospects

In the year 1972, at the British Institute of Radiology Annual Congress, a distinguished research scientist named Sir Godfrey Newbold Hounsfield declared the creation of a ground-breaking imaging method, he called “computerized axial transverse scanning.” This technique’s core idea was very straightforward: a pencil-sized x-ray beam was used to analyze a thin cross-section of the head, known as the tomographic slice, at various angles. The scintillation detector calculated the transmitted radiation, which was then entered into a computer for mathematical algorithm analysis and reconstruction as a tomographic image. There was an extraordinary feature on this tomographic image, that had never been observed on an x-ray image previously. With the help of computer analysis, the image demonstrated radiographical differences in various soft tissues, gray and white matter. This invention came to be known as computerized axial tomography (CAT), which now is popularly called computed tomography (CT). Like many great discoveries, CT was the end product of years of work put on by various investigators. Throughout the years, CT has undergone multiple improvements. In this chapter, we will deal with the development and generations of CT, its rapid technical advances that have brought dramatic changes in the field of biomedical imaging, and how these changes are having an impact on advancement today.