From X-Rays to CT Scans to MRIs and Ultrasounds: medicine will never be the same again

Try and imagine a radical and untested new medical technique based on unexplained scientific principles becoming a mainstream tool mere weeks after being discovered.

In January 1896, only weeks after their discovery had made Wilhelm Conrad Röntgen a national celebrity in his native Germany, surgeons in Berlin were already exposing their patients to X-Rays.  Röntgen had named them X-rays since “x” – the traditional unknown quantity in mathematics – signified that he had no idea what constituted the rays he was producing.  His wife, Bertha, has the honour of having the world’s first X-ray; of her hand on 8 November 1895.

Röntgen had been fooling around with a cathode ray tube, subjecting it to various electrical stimuli and scaring himself with stories of producing ectoplasm.  The thin gas inside vacuum tubes would produce eerie luminous clouds. William Crookes, a contemporary of Röntgen become convinced that he was producing ectoplasm, much beloved of Victorian séances, and promptly turned to spiritualism.

Röntgen was made of sterner stuff and continued to experiment.  He noticed that, whenever he made sparks in the tube, a fluorescent screen at the other end of the table would light up.  The X-rays would pass through any material he placed in the way.  Experimenting with lead, he was pleased to note, stopped the rays.  As he was moving the lead he spotted his skeletal hand clasping the metal.  History was made.

X-rays are now part of the electromagnetic wave spectrum, shorter than light and of higher energy. Over-exposure is harmful as the results cause radioactive decay of DNA leading to cancer.  Which is why your doctor cowers behind a lead sheet prior to taking your picture.

Sadly basic X-ray technology hasn’t moved on much.  The resolution is slightly better but doctors still battle to tell exactly what is going on and would like to see what is happening in real time.

Along came the Second World War and the hideous injuries that one group of scientists were figuring out how to inflict, another group of scientists were figuring out how to fix.

RADAR, which had helped England win the war by spotting submarines and airplanes hiding away, was about to be put to a far better use. 

Quite a large number of people all over the world worked on ultrasound in the hopes that it could be used for imaging the body.  It wasn’t until the British got into it, though, that ultrasound became a commercial success.  Professor Ian Donald in Glasgow produced apparatus used in gynaecology in 1958 and soon moms and dads to be were watching a junior splotch kicking gamely on ultrasound screens.

Meanwhile X-rays were proving fertile soil for physicists who churned out Nobel Prizes:  Röntgen in 1901, Max von Laue in 1914 for X-ray crystallography, William and Laurence Bragg in 1915 for X-ray crystal structure analysis, Einstein in 1921 for the photoelectric effect (sure, they forgot entirely about relativity), and Arthur Compton in 1927 for explaining X-ray scattering.

In the 1960s the Beatles became an extremely popular band and made an awful lot of money for EMI, their producers.  Flush with cash, EMI endowed a chair of medical research at the Whittington Hospital.

Godfrey Newbold Hounsfield, working at the Whittington Thorn EMI Research Laboratory, conceived of an idea of computed axial tomography where a series of two-dimensional X-rays, taken about a single axis of rotation, could be spliced together to produce a three-dimensional image of the body.  This would become known as the CAT or CT scan.

Hounsfield conceived his idea in 1967, and it was publicly announced in 1972.

The original 1971 prototype took 160 parallel readings through 180 angles, each 1° apart, with each scan taking a little over five minutes. The images from these scans took 2.5 hours to be processed by algebraic reconstruction techniques on a large computer.

The first production X-ray CT machine (called the EMI-Scanner) was limited to making tomographic sections of the brain and required the use of a water-filled Perspex tank with a pre-shaped rubber "head-cap" at the front, which enclosed the patient's head. This wasn’t especially comfortable or pleasant for the patient.

The first CT system that could make images of any part of the body, and did not require the "water tank" was the ACTA scanner designed by Robert Ledley at Georgetown University.

CTs are still terribly radioactive – so you don’t want to spend too much time in them.

Around the same time Paul Lauterbur was hawking an academic paper to various journals about a nifty technique he had developed.  Nature turned him down on the basis that the pictures he included with his piece were fuzzy.  Never mind that they showed the difference between heavy water and ordinary water in a way that had never been seen before.  Never mind that the technique – nuclear magnetic resonance – would lead to the production of non-invasive pictures of brains and spinal cords at such a high resolution that it would revolutionise surgery.  In 2003 Lauterbur was awarded the Nobel Prize for medicine for his efforts in producing NMR.

NMR utilises the magnetic properties of atomic nuclei which are aligned in a strong magnetic field and then bombarded with radio waves which reflect and transmit information about the underlying structures of the body.  And it isn’t radioactive, although you don’t want to have any metal hanging around if you don’t want an unfortunate reaction.

Lauterbur died in March 2007 and there can be no greater thrill for any scientist than to see the fruits of your labours, not just recognised, but revolutionise the lives of millions of people around the world.