Hello and welcome to the Computed Tomography section of the Biomedical Imaging course.
I am Dr Karine Mardon. In this video, we will cover a brief overview of the history of this technology.
The development of medical equipment such
as Computed Tomography scanners also called CT scanner happened in the mid-1950s. It has
initiated a big step forward in the field of diagnostic imaging. With this new technology,
we can look inside a human body, slice by slice, without using a scalpel.
The CT has benefited from the discovery of X-rays with the development of new mathematical
algorithms, allowing the reconstruction of an image of any given cross-section of a human
body. The accidental discovery of the radiation, known today as X-ray radiation, was made in
1895 by the German scientist Wilhelm Conrad Roentgen. He was a professor of physics at
University of Wuerzburg, and here is a photo of his lab where he discovered X-ray radiation.
He was awarded the Nobel Prize of physics in 1901.
Two years later, in 1897, William Morton was the first person to take a picture of a whole
skeleton using X-rays. However, the initial excitement surrounding the diagnostic possibilities
of X-ray did not last long. Scientists soon realised the limitations of body imaging in
two dimensions. In 1916, Doctor Karol Mayer obtained images
using a moving X-ray tube and a stationary film cassette, a method close to the process
of scanning by computed tomography. But the discovery of X-rays in itself was
not sufficient to the creation of computed tomography. CT invention was very much dependant
on the development of computational techniques. So without the combination of X-rays and the
progress in computer technology, computed tomography would not exist today.
In 1979, two scientists received the Nobel Prize of Physiology and Medicine. Allan MacLeod
Cormack and Godfrey Hounsfield created computed tomography.
In 1971, two neurologists James Ambrose and Louis Kreel, tested a prototype scanner, the
EMI Mark I scanner. This prototype was a head scanner. The system was installed at a hospital
in Wimbledon, in the UK. And the CT scanners at that time were known
as EMI-scanners. Two years later, in 1973, the first commercial
CT scanner was on the market. It was called the EMI CT 1000.
From 1974 to 1976, companies started to develop and sell CT scanners, and the competition
was fierce. For example Neurscan developed a head scanner, and Disco a whole body scanner.
Then bigger companies such as Technicare and General Electric, quickly took a major share
of the scanner market.
In Europe, manufacturers such as: Siemens and Philips also produced CT scanners at that
time. In 1976, the first fan-beam scanners was developed.
The fan-shaped radiation beam covered a larger part of the patient's body. The gantry this
part of the body here highlighted by an arrow, would spin 360 degrees in one direction and
take an image, then spin 360 degrees back in the other direction to take a second image.
However between each image, the gantry would stop. It would then reverse directions while
the patient table would be moved forward. So actually, scanning time would take very long.
In 1989, the first spiral or helical CT scanner
was developed. An innovation called the slip ring allows
electric power to be transferred from a stationary power source onto a gantry which now rotates non-stop.
CT scanners with the slip rings can rotate
constantly and do not have to start and stop. Scanning has become a lot faster.
From 1989 to 2004, a new type of CT scanner was developed again: the multi slices spiral CT scanner.
The beam of radiation took the shape of a cone. This was the start of three-dimensional
projection techniques. By combining the cone-beam and spiral motion,
scanning time was even shorter. With one major benefit: the artefacts caused
by patient motion such as breathing were greatly reduced.
If you are going for a CT scan, it is likely that you will be scanned with a CT scanner
using 64 rows of X-ray detectors, also called 64 Slice CT. However the newest scanner has
now 320 row detector, like this instrument. So Aquilion ONE is the world's first dynamic
volume CT imaging system that enables acquiring outer organs with one volume scan, one rotation.
Imaging a larger area of the body at one time is now possible, and the scan takes only 200
milliseconds. As you can see, the CT has really changed
in less than 40 years.