Dental Radiography - History & Physics (1) Flashcards
(151 cards)
1
Q
Who was the father of xrays
A
willhelm Roentgen
2
Q
when were X-rays first discovered
A
in 1895
3
Q
The X in xrays was used to name them due to
A
their unknown nature
4
Q
Dr Otto walkhoff took the
A
first dental X-ray (on himself) in 1896
5
Q
dr otto walkhoff subjected himself to how many minutes of radiation on one xray
A
25 minutes
6
Q
Dr c Edmund kells was the first to
A
take a dental xray on a patient in 1896
7
Q
The first hot cathode xray tube was developed by
A
William d Coolidge
8
Q
Ionizing radiation can
A
remove elections from atoms
9
Q
nonionizing radiation is able to ___ but docent have enough energy to
A
can heat things but not enough energy to remove electrons
10
Q
Radiation is
A
energy carried by waves of a stream of particles through space or matter
11
Q
X-radiation is
A
high energy radiation from the collision of electrons on a metal target in xray tubes
12
Q
Xradiation is AKA
A
ionizing electromagnetic radiation
13
Q
An Xray is known as a
A
beam of energy with power to penetrate through objects and record the shadows on a image receptor
14
Q
what is radiology
A
the study of radiation in medicine
15
Q
A radiograph is a
A
image produced on a receipt by exposing it to ionizing radiation
16
Q
radiography is the art and science of
A
making radiographs through exposure
17
Q
ALARA
A
as low as reasonably achievable
18
Q
alara is in place to
A
protect everyone and reduce exposure as much as possible without compromising the need for diagnostic records
19
Q
a radiation protection officer can only be the dentist and is responsible for
A
safe practice, ensures safety of equipment, and proper operation of it
20
Q
Matter is known as
A
anything occupying space and has a shape or form
21
Q
atoms are
A
basic form of matter containing energy
22
Q
sub atomic particles make up
A
an atom (electrons, protons, neutrons)
23
Q
molecules are
A
atom groupings - smallest particle of a substance that retains original state
24
Q
Capacity to do work is
A
energy
25
energy can't be destroyed or created but it can
change form
26
the central nucleus is composed of
protons and neutrons
27
electrons are negativley charged and ___ the nucleus
orbiting
28
Nuclear binding energy is responsible for
holding the nucleus together
29
electron shells are located where
a specific distance from the nucleus and each shell represents a different energy level
30
Shell L is the ___ and has the __ energy level
closest, energy
31
what is designated by letters l,m,n,o,p,q
electron shells
32
Mass number is
protons + neutrons
33
equal protons and neutrons are the
atomic number
34
Attraction between protons and electrons is the
electrostatic force
35
centrifugal force is what
pulls electrons away from nucleus
36
the balance of electrostatic force and centrifugal force keeping electrons in orbit is known as
biding energy
37
Radioactivity is the process of
unstable atoms undergoing spontaneous disintegration in order to become balanced
38
what is an ion
an atom that has gained or lost an electron
39
are ions electrically balanced
no
40
Ionization is the
production of ions / process if converting atoms to
41
if an atom gains a extra election it is now considered
more negative
42
what are the two types/categorys of ionizing radiation
particulate and electromagnetic
43
particulate ionizing radiation is
tiny particles (with mass) travelling in a straight line at high speeds
44
there are two sub types of particulate radiation called
beta particles and cathode rays
45
beta particles are
electrons from nucleus of radioactive atoms
46
a cathode ray is composed of
high speed electrons travelling from an xray tube
47
ionizing electromagnetic radiation is a
wavelike energy with no mass, travelling through space or matter
48
can electromagnetic radiation be ionizing or nonionzing
yes
49
photons make up
ionizing electromagnetic radiation
50
photons travel at the speed of light in a
straight line with a wavelike motion
51
do photons have mass
no
52
wave concept has 3 parts, what are they
velocity, wavelength, frequency
53
velocity is the
speed of the wave
54
wavelength is the
distance between the crests of two waves
55
what does wavelength determine
the energy and penetrating power of a ray
56
the shorter the wavelength, ____ penetrating power and energy
higher
57
frequency is the
number of waves that pass a certain point in a given time
58
a short wavelength results in a __ frequency
high
59
mA
milliamperage
60
mA is in control of
the quantity of electrons that are produced
61
mA is the electrical current coming from the
cathode - regulates temp of filament for production of electrons
62
What 3 factors impact density and contrast
mA, kVp, exposure time
63
What is the recommended setting of mA
7-15 mA, 10 is most common
64
increasing the mA will make the density ___
darker - less contrast
65
kV or kVp
kilovoltage
66
kVp controls the
quality of an xray beam (wave length size)
67
voltage rate for kVp
70-90 kVp
68
kV controls how ___ electrons move from the cathode to anode
fast
69
the faster an electron moves to anode the ___ the wavelength
shorter
70
a quality wave length is a
short wavelength
71
the speed of electrons is controlled by adjusting the
kVp
72
the amount of electrons is controlled by adjusting the
mA
73
if more electrons are produced the more wavelengths are produced leading to a ___ image
darker
74
if an image comes out to dense (dark) you would adjust the ___ to make it lighter and have more contast
mA
75
if adjustments to kVp and mA don't fix the image you would check what next
the machine it self, could've been bumped and knocked out of place or broken
76
MPD
maximum permissible dose
77
what's the MPD for a worker
0.05 sv
78
for a pregnant worker the MPD is
2 msv
79
low contrast images would show lots of
grey shades
80
high contrast images would be primarily __
black and white shades
81
why would you increase the mA when taking xrays on a heavier person
the density of the individual effects the penetrating power of a beam - needs more to get through
82
the step down transformer sends low voltage electricity into the
cathode only
83
bremsstrahlung radiation is
breaking radiation - sudden stop of electrons when they hit the target
84
Exposure is measured in impulses/second - how Many impulses in 1 second
60 impulses per second
85
exposure time is the
interval of time in which xrays are produced
86
longer exposure time results in more waves created making the image
darker
87
if you increase the exposure time, you would need to do what to the kVp and mA
decrease both to compensate, and vice versa if shorter time
88
what factors effect the exposure time
length of PID, type of receptor, age of patient, type of tissue
89
if the PID is longer, you would have to increase what to compensate for the distance
exposure settings would need to increase
90
intensity is a combination of
quality and quantity
91
an ampere is
measurement of electrons flowing through cathode
92
TRD
target to receptor distance (longest)
93
TOD
target to object (tooth) distance
94
TSD
target to surface distance (skin)
95
Primary radiation is
the beam produced by target that exits tubehead
96
secondary radiation is
created when it interacts with soft tissue
97
scatter radiation
result of beam deflecting from path due to interaction with matter
98
background radiation
from normal objects (phones)
99
leakage radiation
produced by machines due to fault
100
how long is a quality assurance log book kept
6 years
101
a tubehead is equipped with what 3 things for patient protection
aluminum disks, lead collimater, PID
102
how much aluminum filtration is needed for a 70 kvp machine
1.5 mm
103
if machine is operating above 70 kvp how much filtration is needed
2.5mm
104
lead collimators are responsible for
restricting the size of the beam exiting
105
lead collar is only used for which type of xray
inta oral only
106
what is the fastest intra oral film
F speed film (insight)
107
what is used to prevent hand exposure to radiation
a film holding device
108
how far must you stand while xray in progress
3m or 9ft
109
asepsis protocol in radiology
all equipment must be disinfected after each patient, and barriers used when possible
film holders are sterilized after each use
universal standard precuations
110
cumulative effect
radiation can cause damage that is irreversible and tissues don't return
111
latent period is
the time between exposure and symptoms
112
total dose
amount of radiation absorbed
113
direct theory is damage occurring from radiation that
directly hits critical areas of cell
114
indirect theory is xray energy that
absorbs within a cell and causes toxin formation
115
what is the most sensitive cells
blood forming tissues (bone marrow)
116
erythema
radiation dermatitis, red rash
117
short term effects are
acute
118
long term effects are chronic and
are associated with small amounts of radiation in long periods of time
119
genetic effects damage
reproductive cells (ova and sperm)
120
somatic effects are damage to tissues not inherited and repair within
24 hours
121
the risk of damage to bone marrow cells is
development of leukaemia
122
extra oral xrays are
panoramic
123
intraoral xrays are
with tubehead
124
electrodes are
cathode and anode
125
why is the xray tube vacuum sealed
to allow electrons to flow with minimal resistance between electrodes
126
the cathode has 2 main components
the tungsten filament and molybdenum cup
127
the molybdenum cup is for
forcing electrons into a narrow beam towards anode
128
tungsten filament produces
electrons with heat
129
the anode has 2 components
the tungsten target and copper stem
130
the tungsten target is incasing a copper stem to
dissipate heat of the target
131
99% of electrons produced by cathode are converted into
heat
132
only 1% of electrons will
hit the target and become waves
133
central ray
xrays at the center of beam through collimater
134
melting point of tungsten is
3422 c
135
what shape is never used for PID's
square
136
SI
systeme internationale
137
what kind of rays are the most dangerous
gamma rays
138
what is the radiation pattern at the skin that should now be exceeded
2.75" or 7cm
139
Penumbra
a blurred or indistinct area surrounding an image
140
primary radiation is the most …
penetrating form of radiation
141
scatter radiation is a form of
secondary radiation - created by beam interacting with matter
142
a sensor is a __ with a chip and electrical current
solid state image receptor
143
what is the focal spot of the anode
the tungsten target
144
the step down transformer is responsible for
decreasing the voltage that is coming into the tube head from the extension arm. from 220>110>5>3 volts
145
how many volts are used to heat tungsten filament
3-5
146
thermionic emission is the
release of electrons from tungsten filament
147
radiolucent structures appear
dark on a radiograph
148
why do radiolucent structures appear dark
because radiation can easily pass through them
149
radioplaque structures appear how on a radiograph
white or light grey
150
why do radioplaque structures appear white or light grey
because radiation does now easily pass through them
151
the energy of a photon is knows as ___
quality
