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Current
Medical Scene
vol.17 No.2 April - June, 2002
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Radiology
has completely transformed the art and practice of medicine.
Nobody can lay greater claim to the birth of this speciality
than William C Roentgen after whom the humble x-ray or Roentgenogram
is named.
Roentgen was born in Prussia in 1845. He had an uneventful upbringing,
where the one talent that marked him out from the rest was his
marvellous skill in transforming glass, metal and rubber into
exquisite instruments with utmost subtlety. Soon after his graduation
he began to assist some leading physicists of Europe, designing
instruments that detected and measured physical phenomena.
THE CROOKES TUBE
Among Roentgen's important predecessors was Sir William Crookes,
England's most distinguished physicist. Having discovered thallium
in 1861, he became interested in investigating the possible
effects of electricity discharges on rare gases. For this he
constructed what is now called a Crookes tube - a glass cylinder
with air evacuated by means of a pump, thus creating a vacuum.
The cylinder also contained electrodes for the discharge of
a high voltage electric current. The passage of this current
was affected by the emission of what came to be known as cathode
rays.
Crookes occasionally placed wooden cassettes containing unexposed
photographic plates near the tube and often he found that some
of them were flawed by shadows. It never occurred to him that
they might have been exposed to a new type of ray.
Similarly, it never occurred to the distinguished scientist,
Philip Lenard to investigate why strips of paper covered with
barium platinocyanide salts and lying near this Crookes tube
began to fluoresce as soon as he produced cathode rays by running
a current through the cylinder.
THE ROENTGENOGRAM
Roentgen, although he could duplicate Lenard's findings, was
keen to know whether a window was necessary for the rays to
pass.
Meticulously and patiently, he covered the Crookes tube with
opaque cardboard and darkened the room completely so that any
fluorescence outside the tube could be differentiated from that
within the tube. He then electrically excited the tube to ensure
that it emitted no visible light. It did not. He was about to
begin his experiment when from the corner of his eyes he glimpsed
a mass of greenish yellow colour flickering very brightly in
the absolute darkness, about a yard from where he was standing.
Truly mystified, he lit a match and peered at the site where
the colours had appeared. He immediately spotted another screen
coated with barium platinocyanide that he had left on his bench.
Excitedly, he switched the current to the tube on and off. Each
time he switched the current on, the screen began to fluoresce.
Roentgen knew it could not possibly be cathode rays - such rays
could not travel more than several inches in ordinary air, and
the fluorescent screen was at least a yard away. On this momentous
evening - November 8, 1895 - Roentgen then placed a deck of
cards, followed by a two-inch thick book, between the tube and
his small screen. Regardless of these objects, when he excited
the tube the screen promptly began to flicker.
After November 8, Roentgen soon discovered that this wave, which
he now designated the x-ray, could not pass through lead at
all and was absorbed in great part by other metals, depending
on their density. It was sometime in early December, when he
held a small lead pipe before a photographic plate and exposed
the pipe to x-rays coming from the Crookes tube, that he became
awestruck and just a bit terrified. Although the plate showed
the dark shadow he expected the lead pipe to produce, it also
showed something he had never expected - the bones of two of
his fingers that had been holding the pipe.
He decided to share these findings with his wife Bertha. Inviting
her to his laboratory, he asked her to place her left hand on
an unexposed photographic plate, still lying in its wooden cassette.
Constantly reassuring his wife, Roentgen switched on the current
and let it continue for approximately six minutes. He asked
her to wait a while he developed the plate. Bringing back the
still-wet plate he handed it over to her saying: "Here's
the picture of your hand that my x-ray made," Roentgen
was overjoyed at Bertha's shocked astonishment.
After this incident, Roentgen decided to work in total secrecy.
A few weeks later, the Physical-Medical Society of Wurzberg
was to hold its December meeting and publish its proceedings
in the society's December journal. Roentgen desperately wanted
this issue to carry a preliminary report of his x-ray. Despite
his frantic rush, Roentgen took until December 28, 1895 to put
together even a preliminary report. By then the society had
already convened. Roentgen nevertheless begged the secretary
of the society to publish his article in December, even though
he had not actually presented the paper at the meeting. The
secretary read the report and was all set to reject the manuscript
until his eyes fell on the x-ray photograph of Bertha's hand.
Thus Roentgen's preliminary report, "On a new kind of ray:
A preliminary communication" appeared in the journal.
After publishing three papers on x-rays, Roentgen , published
only seven more papers till his death in 1923. He received hundreds
of prizes, medals, certificates, plaques, sculptures, honorary
degrees (over 50 honorary doctorates) and honorary membership
in scores of scientific and medical societies throughout the
world. In 1901, he became the first scientist to receive the
Nobel Prize in physics.
Prior to the x-ray, a physician was able to employ only four
of the five senses (hearing, smelling, touching and tasting)
in detecting an illness and its cause. Roentgen's discovery
allowed the doctor to employ the fifth sense (seeing) - not
only for detecting, but often enough for curing a disease. It
is difficult even today to think of a greater gift to the physician
(and of course the patient) than the discovery of x-ray. |
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