Innovations in Biotechnology and Medical Sciences

What is Computer Tomography?


From UPSC perspective, the following things are important :

Prelims level: Computer Tomography (CT) and its working

Mains level: NA

The first computed tomography image – a CT scan – of the human brain was made 50 years ago, on Oct. 1, 1971.

A few months back, almost all of us have heard about the High-resolution computed tomography (HRCT) scan being conducted on our relatives for diagnosing the damage of lungs caused due to the Wuhan Virus.

About Computer Tomography (CT)

  • A CT scan is a medical imaging technique used in radiology to get detailed images of the body noninvasively for diagnostic purposes.
  • The multiple X-ray measurements taken from different angles are then processed on a computer using reconstruction algorithms to produce tomographic (cross-sectional) images (virtual “slices”) of a body.

How does it work?

  • They use a narrow X-ray beam that circles around one part of your body. This provides a series of images from many different angles.
  • A computer uses this information to create a cross-sectional picture. Like one piece in a loaf of bread, this two-dimensional (2D) scan shows a “slice” of the inside of your body.
  • This process is repeated to produce a number of slices.
  • The computer stacks these scans one on top of the other to create a detailed image of your organs, bones, or blood vessels.
  • For example, a surgeon may use this type of scan to look at all sides of a tumor to prepare for an operation.

Its development

  • Since its development in the 1970s, CT has proven to be a versatile imaging technique.
  • While CT is most prominently used in diagnostic medicine, it also may be used to form images of non-living objects.
  • The 1979 Nobel Prize in Physiology or Medicine was awarded jointly to South African-American physicist Allan M. Cormack and British electrical engineer Godfrey N. Hounsfield “for the development of computer-assisted tomography”.


  • CT scans use X-rays, which produce ionizing radiation.
  • Such radiation may damage your DNA and lead to cancer.
  • The risk increases with every CT scan we get.
  • Ionizing radiation may be more harmful in children.


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