BBC Knowledge Asia Edition - December 2014

photographic plate in the next few
decades. The original Crookes tubes had
not been designed for such a purpose,
and the manufacture of specialised ‘cold-
cathode’ X-ray tubes began in earnest.
But these were fairly unreliable, would
stop working quickly, and scattered
X-rays in all directions.
In 1913 the US physicist William
Coolidge, who was working for General
Electric, was inspired by the work of a
colleague to develop the first hot-cathode
X-ray tubes, where the cathode from
which the electrons originate takes the
form of a heated filament. This led to
a more reliable and focused source of
X-rays, and the tube was boxed in with
lead, shielding everyone but the patient
from the rays. Versions of the Coolidge
tube design are still used today.
Glass photographic plates painted
with a light-sensitive mixture were used
to capture images until 1918, when
radiographic film was introduced by the
Eastman Kodak company. Today, film
has been replaced by digital detectors.

Clinical practice
While these technological changes were
occurring, so too were changes in the
clinical setup. The first X-ray department,
the New Electrical Pavilion at Glasgow
Royal Infirmary, was established in
1896 or 1897, and X-ray images soon
became part of everyday clinical practice.
Around the same time, a French doctor
called Antoine Béclère opened an X-ray
department in Paris and coined the
term ‘radiology’. He is credited with
introducing equipment such as lead
screens, aprons and gloves for people
taking X-ray images.
While early X-rays were useful to
surgeons looking to remove foreign bodies
or tumours, organs were harder to analyse.
Even as techniques improved, soft tissue
visualisation proved a challenge. This was
addressed by the use of contrast agents

• liquids that are opaque to X-rays and
  therefore make whichever organ they are
  in show up. In 1906 Béclère pioneered
  imaging of the digestive tract with the
  ‘barium meal’. It was barium sulphate
  mixed with water and swallowed
  to outline the oesophagus and

CAST OF

CHARACTERS

The minds that turned a harmful form of radiation

into a life-saving medical technology

Wilhelm Röntgen

(1845-1923) discovered

X-rays in 1895. The

German physicist won

the Nobel prize for his

discovery in 1901. He

died of a carcinoma, not

believed to be related

to his work, and all his

papers were burned

upon his death.

William Crookes

(1832-1919) was a

British researcher and

later spiritualist who

worked in physics and

chemistry. Inventor of

the Crookes tube, he was

an early investigator of

cathode rays.

Antoine Béclère

(1856-1939) was a

French doctor and

researcher who had

already established

himself in the field of

immunology when he

became fascinated with

X-rays. He pioneered

the use of barium for

imaging the digestive

tract and is credited

with both naming and

professonalising the

William Coolidge (^) field of radiology.
(1873-1975) is
best known for
his work carried
out at the General
Electric Research
Laboratories. The
American physicist
invented the
much-improved
X-ray ‘Coolidge tube’
and made important
contributions to light
bulb technology.
Godfrey Hounsfield
(1919-2004) was a British
electrical engineer who
produced the first CT
scanner for routine use
in hospitals in 1972 when
he worked at EMI. He
won the Nobel Prize in
1979, and spent some of
his prize money on
a home laboratory.
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