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
X-rays are not electrically neutral
False, They made neither a positive nor a negative charge, therefore they cannot
be accelerated or made to change direction by a magnet or electrical field.
X-rays have mass
False, X-rays have no mass
They create no resistance to being put into motion and cannot produce
force.
X-rays travel at the speed of light in a vacuum
They move at a constant velocity of 3.0 x 108 m/s or 186,000 mi/s in a
vacuum.
True
X-rays canbe optically focused
False, cannot be, Optical lenses have no ability in focusing or refracting x-ray photons.
X-rays form a polyenergetic or heterogeneous beam
True, The x-ray beam that is used in diagnostic radiography is composed of
photons that have different energies. The maximum energy that a photon in
any beam have is expressed by the kilovoltage peak (kVp) that is set on the
control panel of the radiographic unit by the radiographer.
X-rays can be produced in a range of energies
X-rays can be produced in a range of energies that is useful for different
purposes in diagnostic radiography. The medically useful diagnostic range
of x-ray energies extend up to 25 to 150 kVp.
X-rays travel in a parallel line
False, X-rays travel in a straight line
X-rays used in diagnostic radiography form a divergent beam which each
individual photons travel in a straight line.
X-rays cause some substances to fluoresce
When x-rays strike substances, those substances produce light. These
substances are used in diagnostic radiography, in intensifying screens, and
in image intensifiers used in fluoroscopy.
True
X-rays does not cause chemical changes to occur in radiographic and photographic
film
False, X-rays are capable of causing images to appear in radiographic film and are
capable of fogging the photographic film.
X-rays cannot penetrate the human body
False, X-rays have the ability to pass through the body, based on the energy of the
x-rays and on the composition and thickness of the tissues being exposed.
X-rays cannot be absorbed or scattered (attenuated) in the human body
False, Depending on the energy of an individual x-ray photon, that photon may be
absorbed in the body or be made to scatter, moving in another direction.
X-rays can produce secondary radiation
True, When x-rays are absorbed as a result of specific type of interaction with
matter, the photoelectric effect, a secondary or characteristic photon will be
produced.
X-rays can cause chemical and biologic damage to living tissue
True, Through excitation and ionization of atoms comprising cells, damage to
those cells can occur.
