M13 Flashcards
were not developed; they were discovered, and quite by accidents.
X-rays
During the , many university physics laboratories were investigating
1870s and 1880s
the conduction of cathode rays, or electrons, through a large, partially evacuated glass tube. known as a
Crookes tube.
was an Englishman from a rather humble background who was a self-taught genius.
The tube that bears his name was the forerunner of modern fluorescent lamps and x-ray tubes. There were many different types of Crookes tubes; most of them were capable of producing x-rays.
Sir William Crookes
was experimenting with a type of Crookes tube when he
discovered x-rays.
Wilhelm Roentgen
On _______ Roentgen was working in his
physics laboratory at Wurzburg University in
Germany. He had darkened his laboratory and
completely enclosed his Crookes tube with black
photographic paper so he could better visualize the
effects of the cathode rays in the tube.
November 8, 1895,
The intensity of the glow increased as the plate was brought closer to the tube; consequently, there was little doubt about the origin of the stimulus of the glow.This glow is
fluorescence.
In ____ he received the first Nobel Prize in Physics. Roentgen
recognized the value of his discovery to medicine.
1901
He produced and published
the first medical x-ray image in ____. It was an image of his wife’s hand.
1896.
There are three general types of x-ray examinations:
radiography, fluoroscopy,
and CT.
Early radiographic procedures often required exposure times of _____ or
longer.
30 minutes
Long exposure time results in
image blur
One development that helped
reduce this exposure time was the use of fluorescent _______ in conjunction with the glass photographic plates.
intensifying screen
is said to have demonstrated the use of a radiographic intensifying screen in 1896, but only many years later did it receive adequate
recognition and use.
Michael Pupin
Radiographs during Roentgen’s time were made by exposing a _____ with a layer of photographic emulsion coated on one
side.
glass plate
found that by exposing two glass x-ray plates with the
emulsion surfaces together, exposure time was halved, and the image was
considerable enhanced. This demonstration of double-emulsion radiography
was conducted in 1904, but double emulsion film did not become commercially available until 1918.
Charles L. Leonard
Much of the high-quality glass used in radiography came from _______. This supply was interrupted during World War I;
therefore, radiologists began to make use of film rather than glass plates.
Belgium and
other European countries
The demands of the army for increased radiologic services made necessary a
substitute for the glass plate. The substitute was ______ and it quickly
became apparent that the substitute was better than the original plate.
cellulose nitrate
was developed in 1898 by the American inventor Thomas A.
Edison.
The fluoroscope
Edison’s original fluorescent material was ______, a widely-used laboratory material. He investigated the fluorescent properties of
more than 1800 other materials, including zinc cadmium sulphide and calcium
tungstate – two materials in use today.
barium platinocyanide
There is no telling what additional inventions Edison might have developed had
he continued his x-ray research, but he abandoned it when his assistant and
long-time friend,______ , experienced a severe x-ray burn that eventually required amputation of both arms.
Clarence Dally
Dally died in _____ and is counted
as the first x-ray fatality in the United States.
1904
In 1907, H.C. Snook introduced a substitute high-
power supply, an interupterless transformer, for the static machines and
induction coils then in use.
Although the Snook transformer was far superior to these other devices, its
capability greatly exceeded the capability of the Crookes tube. It was not until
the introduction of the ______ that the Snook transformer was widely
adopted.
Coolidge tube
X-rays are invisible
True
