Download History - Medical Imaging 1975-1980

The period from 1975 to 1980 was a transitional one in the field of medical imaging. In
the early 1970s, PET (Positron Emission Tomography), CT(Computed Tomography),
and MRI(Magnetic Resonance Imaging) technologies were just emerging. By the early
1980s, all were being deployed commercially in clinical settings for diagnosis.
CT
Tomography (the process of creating "slices" with x-rays) was originally (and not very
effectively) conducted via physical manipulation of x-ray machinery. Prior to
computerized tomography, there were only only had single plane films of the head
showing bones or angiography, showing masses only when vessels of the brain are
displaced. Very early versions of CT were incredibly slow, requiring overnight
processing and were extremely low resolution. The work of Hounsfield and Cormack
throughout the 1970s leveraged the rapidly developing potential of computer processors
to speed the processing of x-rays to render "slices" of the human body. Those slices
could then be assembled into 3-D images. Hounsfield adapted a mathematical method
called "Algebraic Reconstruction Technique (ART)" as the image reconstruction
machine in his first commercial CT scanner. Cormak's work drew on an even earlier
mathematical theory called "Radon Transform". Separately, but in similar time frames,
they each drew upon these mathematical theories to make transverse axial scanning
possible and launch the rise of the CAT scan as a diagnostic tool.
MRI
In 1971, Raymond Damadian published a paper in the journal Science that first
proposed that the technology behind NMR (Nuclear Magnetic Resonance) could be
used to distinguish between healthy and cancerous cells. This early paper did not
propose strategies, however, for converting the NMR data to images to make such
diagnosis possible. It simply posited that it should be possible.
In the years following, another scientist, Paul Lauterbur (a graduate of the University of
Pittsburgh) performed a series of tests with NMR machinery, proving that the rendering
of images from NMR data was possible. In particular, Lauterbur pursued techniques for
introducing gradients into the NMR data so that imagery could render much more
nuanced visual data. Early scans, however, were low quality and extremely slow to
produce.
Throughout the 1970s, another scientist, Peter Mansfield was working on several
mathematical techniques for improving the processing of MRI data. Mansfield was a
British physicist whose key contributions were in the development of mathematical
techniques for analyzing the radio signals produced in MRI. He also discovered a
protocol for speeding the imaging process called "echo-planar imaging". These
techniques dramatically improved the speed and quality possible in generating such
images, essentially the key piece in allowing MRI to be a commercially and clinically
viable diagnosis tool. It was these improvements to MRI that have eventually also
made functional magnetic resonance imaging (fMRI) possible.
While Lauterbur and Mansfield were working on techniques for processing NMR data
and rendering images, Raymond Damadian was concentrating on the construction of a
MRI machine that was capable of full-body scans. In 1977 he developed the first fullbody MRI scanner and completed the first full body scan of a human being on July 3,
1977.
The contributions of all three allowed for the rapid development of MRI technology in the
succeeding years (along with improvements to superconductors). MRI equipment was
quickly installed in hospitals and other medical facilities throughout the early 1980s and
quickly became a commonplace tool for evaluating soft-tissue.
In 2003, the Nobel Prize Committee awarded Paul Lauterbur and Peter Mansfield the
Nobel Prize in Physiology or Medicine for their work on MRI. The decision was
extremely controversial, as it completely ignored Raymond Damadian’s contributions to
the technology. Many of his supporters actually took out full page adds in the New York
Times following the announcement of the prize, decrying this oversight. The committee
argued that Damadian’s work didn’t substantively advance the understanding or
techniques behind MRI. Damadian’s followers argued that, instead, MRI would not
have been possible without him while Lauterbur and Mansfield simplied further
development of work that been done by others.