First CT Scanner Used
The first CT scanner produced a clinical image, revolutionizing diagnostic medicine
October 01, 1972
Seeing Inside Without Surgery
The first computed tomography (CT) scanner was developed by British engineer Godfrey Hounsfield at EMI Laboratories in the late 1960s. Hounsfield's machine used X-rays taken from many different angles around the body to create detailed cross-sectional images — essentially slices through the body — that traditional X-rays could not produce. The first clinical CT scan on a patient was performed on October 1, 1971 at Atkinson Morley Hospital in London. The patient had a suspected brain tumor, and the scan revealed it clearly without any surgery or risky procedures.
How CT Scanning Works
A CT scanner rotates an X-ray tube around the patient while detectors on the opposite side measure how much radiation passes through different tissues. Bone absorbs more radiation than soft tissue, and tumors or injuries may absorb differently still. A computer processes these measurements from hundreds of angles and reconstructs them into detailed images. Modern scanners can produce three-dimensional models of organs, blood vessels, and bones with remarkable precision in under a minute.
CT's Impact on Medicine
The CT scanner transformed diagnostic medicine. Doctors could now see brain hemorrhages, cancers, kidney stones, and lung disease without invasive procedures. Hounsfield shared the Nobel Prize in Medicine in 1979 with physicist Allan Cormack, who had independently developed the mathematical basis for the technique. Today, over 80 million CT scans are performed in the United States alone each year. The scan's ability to diagnose emergencies quickly — head trauma, pulmonary embolism, internal bleeding — has saved countless lives. Use our age calculator to see how long CT scanning has existed.