CT Scans 1967 – Computed Tomography

Shortly after physicist Wilhelm Röntgen discovered X-rays in 1895, X-ray machines were built to examine the inside of the human body. Important as this development was, X-ray images have limitations, because the body contains important anatomical features and tissues with only slightly different densities that cannot be distinguished on X-ray images. In addition, a conventional X-ray produces images of organs that overlap as the rays pass through the body, making them impossible to distinguish. Many of these shortcomings were overcome with the invention of computed axial tomography, or the CT scan (Tomography comes from the Greek “tomos,” meaning “slice” or “section”). For example, while a conventional head X-ray shows the skull, a CT scan shows both the skull and the brain in great detail.

A CT scanner uses a computer to combine many X-ray images of the human body into cross-sectional images. These images can also be combined to create three-dimensional reconstructions of organs and other structures. CT equipment includes a ring-shaped section that sends X-rays through the body from many different angles to detectors. CT scans represent one of the first major uses of information-processing technology in medicine.

The British electrical engineer Godfrey Hounsfield shared the Nobel Prize with the South African physicist Allan Cormack for their work on CT methods and theory. In 1967, while working for the British music and entertainment company EMI, Hounsfield began developing the first commercially usable CT scanner. In 1971, a prototype EMI scanner was first used to detect a brain tumor in a patient. 

Today, CT scans are useful for detecting tumors, ruling out coronary artery disease, and investigating bowel obstructions, complex fractures and damage to intervertebral discs. CT scanning helps surgeons plan reconstructive surgery and design components such as hip prostheses. In CT pulmonary angiography, pulmonary emboli (blockages in the pulmonary arteries) are visualized using CT scans with contrast-enhancing dyes. In helical or spiral CT machines, the patient moves continuously through the machine's X-ray ring.

About the Article Image: A historic EMI scanner

Historical Figures Mentioned in the Article: Sir Godfrey Newbold Hounsfield (1919–2004), Allan MacLeod Cormack (1924–1998)

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