Showing posts with label Head CT. Show all posts
Showing posts with label Head CT. Show all posts

Thursday, February 1, 2024

Pioneers; Hounsfield & Cormack

Godfrey Hounsfield (1919-2004) was a British electrical engineer who developed computed tomography (CT). 

In 1949, Hounsfield began working at EMI, Ltd where he researched guided weapon systems and radar.  At EMI, he became interested in computers and in 1958, he helped in the design of the first computer system in Great Britain. Shortly afterwork he started work on CT scanner.   

Hounsfield came up with the idea that one could determine what was inside a box by taking x-ray readings at multiple angles around an object.  He then built a computer that could take input from x-rays at various angles to create an image of the object in slices.  Applying this idea to the medical field led him to what is known today as computed tomography. The scale of units he used (HD), running from -1000 HD for air, 0 HD for water, and +1000 HD for cortical bone are the quantitive measures used in obtaining, depicting and evaluating a CT scan.

At that time, Hounsfield was not aware of the work and the two papers Allan Cormack (1924-1988) had published in 1956 on the theoretical basis of such a device when he worked at the University of Cape Town and Groote Schuur Hospital.

Hounsfield built a prototype head CT scanner and tested it first on a cadaver's brain and soon after on a cow's brain and finally on himself.  On October 1st 1971, CT scanning was introduced in medical practice with a brain scan performed on a patient and in 1975 Hounsfield built a whole body scanner. 

In 1979, Hounsfield and Cormack received the Nobel Prize in Physiology and Medicine.  Both received numerous awards in addition to the Nobel and Hounsfield was also knighted in 1981.


The above post is dedicated to Dr John Andreou and Professor A Gouliamos  prominent Greek radiologists whose expertise in computed tomography contributed in establishing it as a pre-eminent diagnostic method in Greece.  in addition to being a good colleagues I also thank them for being good friends to me for the past 50 years.

Friday, September 1, 2017

Head CT does not increase the risk for meningioma

A paper by Nordenskjold et al published in Radiology found that exposure to radiation from computed tomography of the head does not increase the risk of developing a meningioma.

The authors collected data from a cohort of 26 370 subjects from a radiology archive of CT examinations of the head performed from 1973 through 1992. For comparison, an age- and sex-matched cohort of 96 940 subjects who were not exposed to CT (unexposed cohort) was gathered.


Comparison of exposed and unexposed cohorts no statistically significant increase in the risk of meningioma was found among patients who were exposed to ionizing radiation from CT of the head compared to the unexposed control individuals.