Dr Mohd Malik Afroz
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Properties of X-rays
There explanation in detail regarding the
understanding the use of x rays better.
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To understand the properties of x rays in
detail.
X rays are invisible, they cannot be seen, felt, smelled and heard
X rays travel in straight line, they can be deflected from there original
direction but there trajectory is linear
3.
They travel at the speed of light – 3X108m/sec
4.
X rays have a wider range of wavelength 0.01 – 0.05nm, in length
5.
X rays cannot be focused to a point, over the distance the beam
diverges as the light beam diverges
6.
Because of there extremely short wave lengths, they are able to
penetrate materials that absorb or reflect light.
7.
X rays are differentially absorbed by matter, this depends on the
atomic structure of matter – this creates an image on the film .
8.
X rays cause certain substances to florescence, that is to emit radiation
of longer wavelength. – use of intensifying screens.
9.
X rays produce biologic changes – use in radaition therapy.
10. X rays can ionize gases, that is, remove electrons from atoms to form
ions – used in measuring exposure.
1.
2.
Helps in defense of any country as it can
identify any harmful substances.
 They are invisible hence no body comes to
know whether it is being used.
 Disadvantages –
 It can be misused
 It is difficult to calculate the radiation
received by an individual.
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This property allows it to be focused in one
direction, though it cannot be seen but any
object kept in its focusing region gets
exposed.
Patient placement and film placement are
related to this property of travelling in
straight line.
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The x rays though they
travel in straight line,
they diverge and hence
cover a wider area.
If the x ray cone is kept
at a little farther distance
then a wider area can be
covered
This is used while taking
occlusal radiograph.
The same IOPA machine
can also be used in
exposing bigger films
 Disadvantage –
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As the distance between the x ray source and
film is increased the intensity (effect) of x ray
decreases
We can hence understand that wider area is
covered so more chances of people near to
the patient getting exposed.
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Though the x ray beam cannot be seen but
most of its properties are understood as it
travels with the speed of light.
Hence the ability of x rays to reach to the
point of interest can be assessed by the speed
of light.
As the light diverges so are the x rays.
Wave length
determines the length
between two peaks of
a range.
 The lesser the wave
length more is the
penetration power
 More is the
penetration power less
is the distance the
wave travels.
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Since x rays have higher wave
length they can penetrate to
all the materials
In an x ray machine we get
different wave lengths at a
time and hence we can
capture different densities
Disadvantage –
Since x ray tube generate
different wave lengths
unwanted x rays are also taken
by the body which is
detrimental.
X rays are absorbed by
different matter at a
different rate.
 Bone absorbs more of
x rays when compared
to the soft tissues.
 This make it easier to
see different tissues in
the same exposure.
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This can be best
understood by the
property of particulate
radiation – which means x
rays travel as a packet of
energy [ PHOTON].
Packets of energy are
absorbed at a different
rate, some die off within
the tissue while others
come out and cast an
image.
THE UNIT FOR MEASUREMENT OF
X RAY PHOTON IS ELECTRON VOLT
[Ev]
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Luminescence – Emission of
light from a substance that is
energized by various kinds of
stimuli like chemicals,
radiation etc
Flourescence – The ability of
certain inorganic salts like
phosphors to emit light
promptly (within 10-8 ) after
absorption
Phosphorescence – Is delayed
emission of light after
absorption of X ray photon.
This is seen in Flouroscopic
screen.
Radiation induced
cancer
 Radiation induced
caries
 Problems associated
with radiation therapy.
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Ionization is a process
of formation of an ion
pair.
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Any Questions?