The computed tomography (CT) scanner has become an invaluable tool for surgeons, used in diagnosis, staging and characterisation, surveillance, operative planning, trauma assessment, and hybrid surgical procedures. It was the first imaging modality to reliably produce axial images and remains the most accessible and widely used form of cross-sectional imaging. The mathematical principles underpinning CT reconstruction were first described by Allan Cormack in the late 1950s. These concepts were independently advanced by Godfrey Hounsfield, who developed a practical system integrating X-ray acquisition with computer-based image reconstruction. The first clinical CT scan was performed in London in 1971 to assess intracranial pathology and, while primitive by modern standards, demonstrated the potential of cross-sectional imaging. Over the subsequent decade, rapid advances established CT as a cornerstone of neuroimaging, and improvements in image resolution and acquisition speed enabled effective whole-body imaging. CT was first incorporated into widespread surgical practice through trauma care, with guidelines recommending its use in haemodynamically stable patients during the 1990s. Also, around this time, CT became central to the assessment of suspected intracranial pathology and cancer staging. As access to CT scanners improved in the early 21st century, the technology became embedded as a default first-line investigation across numerous surgical guidelines and clinical pathways. Ongoing refinement has since extended its role beyond diagnosis, with contemporary applications including advanced angiography, three-dimensional reconstruction, and intraoperative use within hybrid operating theatres. The significance of CT was recognised with the awarding of the Nobel Prize to its creators, reflecting its status as a major medical innovation and its impact on surgical practice and patient outcomes.