FINAL Qs (ALL TESTED Qs + REVIEW Qs) Flashcards
TRUE/FALSE
Technologists wear a TLD type personnel monitoring device.
FALSE
TRUE/FALSE
The common property of all electromagnetic (EM) radiation is frequency.
FALSE
The wavelength of an electromagnetic wave is:
inversely proportional to wave velocity
directly proportional to wave frequency
inversely proportional to wave frequency
usually designated by the letter c
inversely proportional to wave frequency
TRUE/FALSE
Time, Distance and shielding are the cardinal rules of radiation safety.
TRUE
Which of the following creates the most ionizations in air, and has a radiation weighting factor of 4?
x-ray
beta particle
alpha particle
they are equal
alpha particle
If the photon (x-ray) frequency is increased tenfold, then the:
velocity will increase times 10
velocity will decrease to 10
wavelength will increase times 10
wavelength will decrease to 1/10
wavelength will decrease to 1/10
A technologist is exposed to 10 mR of radiation at a distance of 50 cm . What distance would result in an exposure of 100mR?
5 cm
500 cm
16 cm
160 cm
16 cm
Background radiation accounts for 6 mSv of exposure, man mad sources account for ____mSv of that.
1
2
3
4
3
In the ionization process an electron is removed from an atom. In excitation the electron is moved to a/an ___ energy state.
lower
higher
incomplete
all of the above
higher
TRUE/FALSE
Air KERMA is an easily measured and comparable factor used for entrance skin exposure.
TRUE
Which of the following units of measure are used for patient absorbed dose?
R
Sv
Gy
Bq
Gy
The particles that distinguish one element from another are the
neutrons
protons
electrons
beta particles
protons
TRUE/FALSE
Thomas Edison discovered x-rays.
FALSE
A gamma ray is created in ___ and an x-ray is created in ___.
nucleus of an atom, x-ray tube
x-ray tube, nucleus of an atom
nucleus of an atom, image tube
none of the above
nucleus of an atom, x-ray tube
Visible light (moderate energy) acts like a ___ while x-rays(high energy) act like a ___.
particle, particle
wave, particle
particle, wave
wave, wave
wave, particle
If an electron is gained or lost from an atom, that atom becomes:
an ion
a new element
an isotope
unstable
an ion
TRUE/FALSE
0.05 Sv or 5 rem is the yearly occupational dose limi in the US.
TRUE
What unit of measure is used for the absorbed dose multiplied by the radiation weighting factor in the SI system
rem
Gy
Ci
Sv
Sv
The theory that electrons circulate in discrete circular paths was proposed by
Bohr
Einstein
Planck
Rutherford
Bohr
The maximum number of electrons found in any energy level (shell) at any point in time is
2
6
10
2n^2
2n^2
TRUE/FALSE
Stochastic effects of radiation require a threshold dose before they are detectable.
FALSE
WhIch of the following describes a product of the absorbed dose, the radiation weighting factor and the tissue sensitivity?
Effective dose
Equivalent dose
Absorbed dose
Tissue KERMA
Effective dose
The sum of protons and neutrons in a nucleus is called the
electron number
atomic weight
quantum number
atomic mass
atomic mass
Isotopes have ______ number of protons and ________ number of neutrons compared to a stable atom of a material.
the same, the same
the same, different
different, the same
different, different
the same, different
Frequency and the energy of electromagnetic waves have a ___ relationship, as explained by Plank’s equation. .
directly proportional
inversely proportional
exponential
indirect linear
directly proportional
Matter is measured in ____.
kilograms
joules
electron volts
rems
kilograms
Energy is measured in ____.
kilograms
curies
electron volts
becqurels
electron volts
Atoms and molecules are the fundamental building blocks of ____.
energy
radiation
matter
gravity
matter
Radio waves, light, and x-rays are all examples of ____ energy.
nuclear
thermal
electrical
electromagnetic
electromagnetic
What is the removal of an electron from an atom called?
ionization
pair production
irradiation
electricity
ionization
The energy of x-rays is ____.
thermal
potential
kinetic
electromagnetic
electromagnetic
The biggest source of man-made ionizing radiation exposure to the public is ____.
atomic fallout
diagnostic x-rays
smoke detectors
nuclear power plants
diagnostic x-rays
___ is a special quantity of radiologic sciences.
mass
velocity
radioactivity
momentum
radioactivity
Absorbed dose is measured in units of ____.
becquerel
sieverts
meters
grays
grays
Today, radiology is considered to be a(n) ___ occupation.
safe
unsafe
dangerous
high-risk
safe
What does ALARA mean?
All Level Alert Radiation Accident
As Low As Reasonably Achievable
Always Leave A Restricted Area
As Low As Regulations Allow
As Low As Reasonably Achievable
The smallest particle that has all the properties of an element is a(n) ____.
neutron
proton
electron
atom
atom
A positively charged nucleus surrounded by negatively charged electrons in well-defined orbits is the ___ model of the atom.
Bohr
Thomson
Rutherford
Dalton
Bohr
The chemical element is determined by the number of ___ in the atom.
protons
electrons
neutrons
nucleons
protons
An atom in a normal state has an electrical charge of ___.
one
zero
positive
negative
zero
The binding energies, or energy levels, of electrons are represented by their ____.
atomic numbers
atomic mass units
shells
isotopes
shells
When an atom has the same number of protons as another, but a different number of neutrons, it is called an ____.
isomer
isobar
isotone
isotope
isotope
TRUE/FALSE
KERMA is a measure only done in air.
FALSE
An atom that loses or gains one or more electrons is a(n) ____.
ion
molecule
isotope
isomer
ion
The maximum number of electrons that can exit in the 2nd electron shell is calculated with ____.
2*2
2*2^2
2/2
2/2^2
2*2^2
The absorbed dose for the PA view of the chest is 1 mrad, the absorbed dose for the lateral view of the chest is 4 mrad. What is the integral dose for this chest exam?
1
3
4
5
5
The atomic number of an element is symbolized by the letter ____.
A
X
Z
n
Z
Deterministic effects of radiation include all of the following except______?
skin burns
hairloss
sterility
cancers
cancers
During beta emission, an atom releases ____.
electrons
positrons
protons
neutrons
electrons
The only difference between x-rays and gamma rays is their ____.
energy
size
origin
name
origin
The ___ is the least penetrating form of ionizing radiation.
beta particle
x-ray
gamma ray
alpha particle
alpha particle
The three properties of photons are ___, ____, and ____.
size, shape, spin
frequency, mass, amplitude
frequency, wavelength, energy
refraction, velocity,amplitude
frequency, wavelength, energy
The theory of ALARA for health care workers supports which of the following practices for pregnant technologist?
No rotations through fluoroscopy
Limited rotations through portable examinations
No interventional or OR rotations
no modification to the work rotation
no modification to the work rotation
What is the velocity of all electromagnetic radiation?
8 x 10^3 m/s
2 x 10^8 m/s
3 x 10^8 m/s
4 x 10^3 m/s
3 x 10^8 m/s
The rate of rise and fall of a sine wave is called its ____.
amplitude
frequency
wavelength
velocity
frequency
A hertz (Hz) is equal to ___ cycle(s) per second.
103
102
10
1
1
If the wavelength of a beam of electromagnetic radiation increases by a factor of 2, then its frequency must ____.
double
increase four times
decrease by half
remain constant
decrease by half
The intensity of radiation ___ in ___ proportion to the square of the distance of the object from the source.
increases, direct
decreases, direct
increases, inverse
decreases, inverse
decreases, inverse
If the intensity of light from a flashlight is 4 millilumens (mlm) at a distance of 3 feet, what will the intensity be at 6 feet?
0.4 millilumens
1 millilumen
2 millilumens
16 millilumens
1 millilumen
The energy of a photon is directly proportional to its ____.
amplitude
frequency
velocity
wavelength
frequency
Photons with the highest frequencies have the ____.
highest velocity
lowest energy
longest wavelengths
shortest wavelengths
shortest wavelengths
The smallest unit of electrical charge is the ____.
electron
proton
neutron
neutrino
electron
Electrification occurs through the movement of ____.
protons only
protons and electrons
electrons only
electrons and neutrons
electrons only
Like charges ____ and unlike charges ____.
repel, repel
attract, attract
attract, repel
repel, attract
repel, attract
The charges on an electrified object are distributed ____.
in the center of the object
on the side nearest the charge
evenly on the surface of the object
on the side opposite the charge
evenly on the surface of the object
On the surface of an electrified object, the charges concentrate on the ____.
top side
underside
sharpest curvatures
smoothest curvatures
sharpest curvatures
A ___ is a source of direct current.
wall socket
battery
generator
spark
battery
What is the unit of electric potential?
watt
amp
volt
ohm
volt
An electric potential applied to a conductor produces ____.
an electric current
a magnetic field
an electric insulator
both A and B
both A and B
An alternating (AC) current is represented by a ____ line.
sinusoidal
horizontal
vertical
descending
sinusoidal
What is Ohm’s law?
I = V/R
V = I/R
R = VI
I = VR
I = V/R
A charged particle in motion creates a(n) ____.
negative charge
positive charge
magnetic field
electrostatic charge
magnetic field
Electrical power is measured in ____.
coulombs
amperes
volts
watts
watts
Rubber and glass are ___.
semiconductors
conductors
insulators
superconductors
insulators
When a group of atomic dipoles are aligned, they create ____.
a magnetic domain (a magnet)
paramagnetic material
magnetic induction
magnetic repulsion
a magnetic domain (a magnet)
What is the SI unit of magnetic field strength?
ampere
tesla
dipole
ohm
tesla
Methods of electrification are all of the following except
retention
friction
contact
induction
retention
Radiation protection practices, for example, shielding all patients and applying ALARA principles are based on the theory of ________, which has a non threshold relationship.
Deterministic
Stochastic
Erythema
Epilation
Stochastic
In diagnostic imaging (x-rays) 4.2 R of exposure is said to be equivalent to _________ absorbed dose.
- 2 rem
- 042 Rad
- 042 Air Kerma
- 042 Gy
0.042 Gy
Which of the following describes the type of radiation used, the tissue exposed and the amount absorbed, in other words, which tells us the most information regarding an exposure to radiation?
Integral dose
Air Kerma
Effective dose
Equivelent dose
Effective dose
TRUE/FALSE
AC current is required in the x-ray tube, and DC current is required in the transformers
FALSE
The filament in the x-ray tube requires ______ amperes to emit electrons, thermionic emission.
0.5-1
1-2
3-5
not enough information to answer
3-5
TRUE/FALSE
The high voltage generator consists of a high voltage transformer, rectifiers and an autotransformer
FALSE
no autotransformer
the most likely found incoming line current in a modern radiography system is
single phase power
three phase power
direct current
~ 60 volts
three phase power
The incoming power to a step up transformer is 100 V, 10 A with a turns ration of 250:1.
What is the resulting voltage in this transformer?
25,000 kV
25,000 V
- 4 kV
- 4 V
25,000 V
100 * 250
The voltage in the x-ray circuit is adjusted or fine tuned in the __________ for ease and safety.
filament transformer
high voltage transformer
rectifier circuit
autotransformer
autotransformer
An induction motor is used in what area of imaging?
rotor rotation
power increase
x-ray table movement
all of the above
rotor rotation
A filament transformer with a turns ration of 1:20 provides 3.1 amperes to the filament. What is the current flowing through the primary coil of the transformer?
62
- 2
- 55
.155
.155
.155 * 20
TRUE/FALSE
In single phase power systems, the potential never drops to zero.
FALSE
When full wave rectification is applied to three phase current, a varying (slight increases and decreases over time) ____ is produced.
current
star
double
voltage
voltage
The electrical device used to adjust the mA station is the
autotransformer
stator
switch
precision resistor
precision resistor
Nearly all hard wired equipment operates on incoming line voltage of
440 V
120 AC
120 Hz
210 A
440 V
All of the following are radiographer operated controls except
kVp selection
generator selection
rotor switch
mA selection
generator selection
A step down transformer has ______ windings in the secondary vs. primary side.
less
more
the same
none of the above
less
TRUE/FALSE
The basic x-ray circuit is divided into the main circuit and the anode circuit.
FALSE
A single phase full wave rectified system produces _____ pulses per cycle.
1
2
6
12
2
TRUE/FALSE
The mAs in a system controls the quality of the beam.
FALSE
At what point in the x-ray circuit is the rectification circuit located?
between the semiconductors and the valve tubes
between the step down transformer and the rheostat
between the step up transformer and the x-ray tube
between the thermionic diode tubes and the x-ray tube
between the step up transformer and the x-ray tube
Which of the following transformers has one winding?
Filament transformer
Hi voltage transformer
Autotransformer
none of the above
Autotransformer
Which of the following waveforms has the highest efficiency?
Three phase 6 pulse
three phase 12 pulse
single phase full wave
all are equal
three phase 12 pulse
An increase in kVp would ___ the ___ of the emission spectrum.
increase, position alone
increase, amplitude alone
increase, amplitude and position (shift to right)
not effect, amplitude and position
increase, amplitude and position (shift to right)
Voltage across the x-ray tube is most constant with ____.
high frequency generators
single-phase, half-wave rectification
single-phase, full-wave rectification
three-phase, full-wave rectification
high frequency generators
The quantity of bremsstrahlung radiation increases proportionately with increased ___.
kVp
mAs
filtration
rotor speed
mAs
Variations in power distribution to the x-ray machine are corrected by the ____.
line voltage compensator
high voltage autotransformer
full-wave rectifier
automatic exposure control
line voltage compensator
Cracking on the anode can occur from ___.
filament vaporization
a single excessive exposure
long exposure times
high kVp and low mA
a single excessive exposure
The efficiency of x-ray production increases as ___ increases.
mA
kVp
time
both A and B
kVp
A step-down transformer is located in the ___ circuit.
tube
timing
filament
rectifier
filament
The least accurate type of timer is the ____ timer.
mechanical
electronic
synchronous
mAs
mechanical
The external structure of the x-ray tube includes the support structure, the protective housing, and the ___.
anode
cathode
glass envelope
focusing cup
glass envelope
The x-ray beam generated by the circuit with the ___ voltage ripple has the ___ quantity and quality.
no correlation between V ripple and quality and quantity
highest, highest
lowest, highest
lowest, lowest
lowest, highest
Bremsstrahlung x-rays are produced by ___ at the target.
outer shell excitation
slowing electrons
K-shell interactions
L-shell interactions
slowing electrons
The ___ is/are outside the glass envelope.
stators
rotor
focal spot
filaments
stators
Full-wave rectified, three-phase units provide an x-ray beam at ___ pulse(s) per second.
1
60
120
360
360
The heel effect is caused by the ___.
stator windings
anode angle
exposure times
induction motor
anode angle
What is the formula for heat units for a 3-phase, 6-pulse x-ray machine?
kVp x mA x seconds
- 35 x kVp x mA x seconds
- 41 x kVp x mA x seconds
- 66 x kVp x mA x seconds
1.35 x kVp x mA x seconds
The effective focal spot size is ___ the actual focal spot size.
equal to
larger than
equal to or larger than
smaller than
smaller than
Projectile electrons travel from ___.
anode to cathode
cathode to anode
target to patient
inner shell to outer shell
cathode to anode
The useful characteristic x-rays from tungsten targets are ___-shell x-rays.
K
L
M
N
K
Changes in ___ result in directly proportional changes in the amplitude of the emission spectrum.
mA
time
kVp
both A and B
both A and B
The ____ circuit (transformer) provides electrons for the cathode within the x-ray tube.
rectifier
autotransformer
high voltage
filament
filament
Extra-focal or off-focus radiation is produced from ___.
overheated anodes
scattered x-rays
non focused electrons
dual focus cathodes
non focused electrons
The x-ray intensity is lower on the anode side of the tube because of the ___.
line focus principle
heel effect
focusing cup
filament length
heel effect
Most of the x-rays produced at the target are ___.
bremsstrahlung
characteristic
gamma
beta
bremsstrahlung
Most of the heat generated at the target is due to ___.
inner-shell ionization
outer-shell excitation
nucleus bombardment
K x-rays
outer-shell excitation
The difference in the waveform between the primary and secondary sides of the high voltage transformer is ____.
frequency
velocity
amplitude
all of the above
amplitude
High capacity tube rotors revolve at ___ rpm.
2,000
3,600
6,000
10,000
10,000
Thermionic emission at the filament determines the ___ across the x-ray tube during an exposure.
kilovoltage
milliamperage
resistance
magnetism
milliamperage
The rotating anode is turned by a ___.
thermal cushion
rotating belt
magnetic field
mechanical pulley
magnetic field
The filament in an x-ray tube is about ___ cm in length.
1-2
3-4
8-10
10-20
1-2
Which of the following component receives power first in the x-ray circuit ?
mA meter
high voltage transformer
rectifier
autotransformer
autotransformer
The mAs timer is usually set to give the ___ mA at the ___ time.
highest, highest
highest, shortest
lowest, shortest
lowest, highest
highest, shortest
At 55 kVp, ___ of the useful x-rays produced are bremsstrahlung.
15%
80%
100%
none
100%
The x-ray generator with the lowest power rating is the ___ imaging system.
high frequency
three-phase, twelve-pulse
three-phase, six-pulse
single-phase
single-phase
Electron interactions at the inner-shell of the target atoms produce ___ radiation.
gamma
Bremsstrahlung
characteristic
all of the above kinds of
characteristic
Tube failure can occur from ___.
focal radiation
short exposure times
low kVp techniques
long exposure times
long exposure times
An exposure taken at 100 kVp would have a continuos emission spectrum with a maximum energy of ___ keV.
30
69
100
140
100
With half-wave rectification, the current flows through the x-ray tube during the ___ part of the cycle.
zero
positive or negative
positive
negative
positive
A single-phase waveform has ___ ripple.
1%
4%
14%
100%
100%
The automatic exposure control (AEC) terminates the exposure when ____.
the set time is reached
set radiation leaves the x-ray tube
sufficient radiation reaches the image receptor
the correct mAs is reached
sufficient radiation reaches the image receptor
The filament is made of ____.
graphite
tungsten
copper
molybdenum
tungsten
The high voltage generator contains the high voltage transformer, the ___, and the ___.
autotransformer, timer
timer, rectifiers
kVp meter, filament transformer
filament transformer, rectifiers
filament transformer, rectifiers
The three main parts of the x-ray imaging system are the x-ray tube, ____, and ____.
protective barrier, tabletop
operating console, high voltage generator
rectification circuit, operating console
crane assembly, tabletop
operating console, high voltage generator
Because of the line focus principal, the effective focal spot size decreases with decreasing ___.
target angle
rotor speed
window thickness
space charge
target angle
When electrons bombard the target, ___% of their kinetic energy is converted to heat.
10
25
50
99
99
As an x-ray tube ages, the inside can become coated with tungsten, which can cause ___ in the tube.
convection
anode pitting
on-focus radiation
arcing
arcing
At the target, the projectile electrons characteristically interact with ___ but are not useable radiation.
outer-shell electrons
inner-shell electrons
atomic nuclei
only A and B
outer-shell electrons
The following emission spectrum (SAME SHAPE, HIGHER # OF X-RAY PHOTONS) represents and increase in?
kVp
filtration
generator type
mAs
mAs
The ___ is the source of radiation in the x-ray tube.
filament
focal spot
focusing cup
stator
focal spot
Thermionic emission at the filament creates a ___.
space charge
grid control
line focus
heel effect
space charge
A diode allows electrons to flow from ____.
anode to cathode
cathode to anode
cathode to cathode
anode to anode
cathode to anode
An increase in mAs would ___ the ___ of the emission spectrum.
increase, position alone
increase, amplitude alone
increase, amplitude and position
not effect, amplitude and position
increase, amplitude alone
Which of the following changes are represented in the following emission spectrum (LOWER PHOTON INTENSITY, SLIGHT SHIFT INSIDE AND TO THE RIGHT)?
filtration
kVp
mAs
anode material
filtration
Characteristic x-rays are produced by ___.
braking electrons
excitation of outer shell electrons
nuclear fragmentation
released binding energy
released binding energy
The ___ of an x-ray beam is higher when the peak of the emission spectrum is further to the ___.
quality, right
quantity, right
quality, left
quantity, left
quality, right
The operating console contains circuits that are ____.
both high voltage and low voltage
high voltage only
low voltage only
non-voltage
low voltage only
Characteristic K-shell tungsten x-rays have an effective energy of ___ keV.
0.6
3
12
69
69
The cathode side of the tube should be directed toward the ___ part of the patient.
upper
lower
thicker
thinner
thicker
The negative side of the x-ray tube holds the ____.
filament
anode
target
rotor
filament
The production of heat at the anode is directly proportional to ___.
rotor speed
mAs
kVp
voltage ripple
mAs
The autotransformer has ____ winding(s).
one
two
three
four
one
TRUE/FALSE
A photoelectric interaction is more likely to occur when the x-ray photon energy and the electron binding energy are farther from one another.
FALSE
During photoelectric absorption, the ejected electron is called a/an
incident electron
photoelectron
characteristic electron
nuclear electron
photoelectron
The photon that exits the atom after a Compton scattering is called the Compton
scattered photon
scattered electron
recoil electron
photoelectron
scattered photon
TRUE/FALSE
During pair production, the positively charged electron is termed a negatron.
FALSE
When an x-ray photon with a slightly greater energy than the binding energy of the inner-shell electron interacts with that inner-shell electron, the following interaction results:
Compton scattering
coherent scattering
photoelectric absorption
characteristic radiation
photoelectric absorption
Which of the following interactions has a significant impact on the x-ray image?
Compton scattering
coherent scatter
pair production
photodisintegration
Compton scattering
During coherent scattering, the scattered photon possesses ___ as the incident photon.
the same energy, the same frequency, and the same wavelength
the same energy, the same frequency, and a different wavelength
the same energy, a different frequency, and the same wavelength
a different energy, the same frequency, and the same wavelength
the same energy, the same frequency, and the same wavelength
TRUE/FALSE
When a scattered photon is deflected back toward the source, it is traveling in the direction opposite to the incident photon and is called backscatter radiation.
TRUE
What is the total differential absorption in bone compared to fat?
bone Z# 13.8 and mass density 1900 kg/m3
fat Z# 6.8 and mass density 910 kg/m3
- 51
- 05
- 02
- 5
17.5
During which interaction with matter is the x-ray photon converted to matter in the form of two electrons?
pair production
Compton scattering
photoelectric absorption
coherent scattering
pair production
In which element are the inner-shell electrons more tightly bound to the nucleus?
mercury (Z = 80)
tungsten (Z = 74)
lead (Z = 82)
chromium (Z = 24)
lead (Z = 82)
Which of the following interaction has a significant impact on the x-ray image?
photoelectric absorption
coherent scatter
pair production
photodisintegration
photoelectric absorption
Which atomic shell possesses the highest binding energy?
K
L
M
all atomic shells possess the same binding energy
K
Which of the following interactions with matter results in a radiograph with a short scale of contrast (high contrast black and white image)?
Compton scattering
coherent scatter
photoelectric interactions
photodisintegration
photoelectric interactions
When x-ray photons interact with matter and change direction, the process is called
absorption
scatter
radiation
binding energy
scatter
Compton scattering occurs when an incident x-ray photon interacts with a ___ electron.
loosely bound inner-shell
tightly bound inner-shell
loosely bound outer-shell
tightly bound outer-shell
loosely bound outer-shell
Which of the following interactions with matter results in a radiograph with a long scale of contrast (low contrast gray image)?
Compton scattering
coherent scatter
photoelectric interactions
photodisintegration
Compton scattering
When an x-ray passes through matter, it undergoes a process called
radiation
filtration
attenuation
fluoroscopy
attenuation
TRUE/FALSE
During the photoelectric interaction, the incident x-ray photon must be greater than the binding energy of the inner-shell electron.
TRUE
Secondary radiation is created after a ________ interaction.
Pairs production
Photoelectric absorption
Photodisintegration
Compton’s scatter
Photoelectric absorption
TRUE/FALSE
As kVp increases, the total number of photons transmitted without interaction increases.
TRUE
During Compton scattering, the incident photon energy is divided between the
ejected electron and the scattered photon
incident photon and the scattered photon
incident photon and the recoil electron
recoil electron and the photoelectron
ejected electron and the scattered photon
The electron dislodged during Compton scattering is called the
photoelectron
recoil electron
incident electron
lost electron
recoil electron
TRUE/FALSE
Some x-ray photons may pass through matter and not interact with that matter at all.
TRUE
Secondary radiation energies are highest for which element?
hydrogen
carbon
barium
oxygen
barium
During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shell, energy is released in the form of
a characteristic photon
a primary radiation
an incident electron
an incident photon
a characteristic photon
During photoelectric absorption, a/an ___ shell electron is typically ejected.
inner-
middle-
outer-
all of the above
inner-
An interaction that occurs between very low energy x-ray photons and matter is called ___ scatter.
coherent
classical
unmodified
all of the above
all of the above
Unwanted densities caused predominantly by scattered photons are called
kilovoltage
radiation fog
amperage
pair production
radiation fog
During the process of attenuation, the x-ray photon may interact with
the nucleus
the entire atom
an orbital electron
all of the above
all of the above
The two primary forms of x-ray interaction in the diagnostic range are ____.
Compton scattering and pair production
photoelectric absorption and coherent scattering
Compton scattering and photoelectric absorption
coherent scattering and Thompson scattering
Compton scattering and photoelectric absorption
An incident x-ray interacts with an atom without ionization during ____.
photoelectric absorption
Compton scattering
coherent scattering
pair production
coherent scattering
An outer-shell electron is ejected and the atom is ionized during ___.
photoelectric interactions
Compton interactions
coherent scattering
pair production
Compton interactions
Which x-ray interaction involves the ejection of the K-shell electron?
photoelectric absorption
pair production
Compton interaction
coherent scattering
photoelectric absorption
The scattered x-ray from a Compton interaction usually retains ___ of the energy of the incident photon.
none
little
most
all
most
As kVp ___, the probability of photoelectric absorption ___.
increases, remains the same
increases, decreases
decreases, decreases
decreases, remains the same
increases, decreases
In ___, there is complete absorption of the incident x-ray photon
photoelectric interaction
Compton interaction
coherent scatter
none of the above
photoelectric interaction
____ occurs only at the very high energies used in radiation therapy and in nuclear medicine P.E.T. imaging.
photoelectric absorption
coherent scatter
pair production
Compton scatter
pair production
Only at energies above 10 MeV can ___ take place.
photodisintegration
pair production
Compton scatter
photoelectric absorption
photodisintegration
When the mass density of the absorber is ___, it results in ___ Compton scatter.
decreased, increased
increased, increased
increased, decreased
decreased, no change
increased, increased
K-shell binding energy increases with increasing ____.
mass density
kVp
atomic number
mAs
atomic number
Which has the greatest mass density?
soft tissue
bone
fat
air
bone
Differential absorption in diagnostic imaging is primarily caused by ___.
photoelectric absorption
Compton scatter
pair production
all of the above
photoelectric absorption
Differential absorption is dependent on (the) ___.
kVp of the exposure
atomic number of the absorber
mass density of the absorber
all of the above
all of the above
Barium is a good contrast agent because of its ____.
low atomic number
high atomic number
light color
low density
high atomic number
In the diagnostic range, rare earth scintillators are better absorbers than Calcium Tungstate. This is due to the phenomena know as ________.
Quantum mottle
Annihilation reaction
k-edge effect or absorption
Photoelectric effect
k-edge effect or absorption
X-rays transmitted without interaction contribute to ___.
photoelectric absorption
the radiographic image
the image fog
beam attenuation
the radiographic image
Compton interactions, photoelectric absorption, and transmitted x-rays all contribute to ___.
image fog (graying of image)
differential absorption (gray vs. Black and white)
patient dose
attenuation
differential absorption (gray vs. Black and white)
At energies below 40 keV, the predominant x-ray interaction in bone is ___.
coherent scatter
Compton scatter
photoelectric absorption
photodisintegration
photoelectric absorption
If 5% of an incident beam is transmitted through a body part, then 95% of that beam was ___.
absorbed
back-scattered
scattered
attenuated
attenuated
The main reason to use a scintillator or phosphor as a capture element is ________.
to increase detail vs. direct exposure film systems
to decrease exposure time vs. direct exposure systems
to decrease patient exposure (dose) vs. direct exposure systems
none of the above
to decrease patient exposure (dose) vs. direct exposure systems
The light-emitting efficiency (speed) of the intensifying screen is improved by the ___.
protective coating
reflective layer
added dyes
phosphor afterglow
reflective layer
Screen characteristics are determined by the ___.
size of the phosphor crystals
thickness of the phosphor layer
phosphor composition
all of the above
all of the above
A phosphorescent material emits light ___.
only from chemical stimulation
for less than a nanosecond
for a period of time after stimulation
only while it is stimulated
for a period of time after stimulation
Luminescent material emits light after its outer shell electrons are ___.
excited
ejected
removed
none of the above
excited
A screen that emits light after an exposure terminates is exhibiting ___.
conversion efficiency
image noise
screen lag
screen blur
screen lag
The intensification factor is a measurement of screen ___.
resolution
speed
noise
quality
speed
The ability of an intensifying screen to absorb x-rays is called ___.
intensification factor
quantum mottle
conversion efficiency
detective quantum efficiency
detective quantum efficiency
Image noise in increased with increased ___.
detective quantum efficiency (DQE)
conversion efficiency (CE)
both A and B
none of the above
conversion efficiency (CE)
Both the isotropic emission of light from screen phosphor crystals and the added reflective layer contribute to ___.
conversion efficiency
image blur
quantum mottle
detective quantum efficiency
image blur
As screen speed ______ image detail _______.
increases, increases
increases, decreases
decrease, decrease
decrease, no change
increases, decreases
A wrist x-ray required ________ detail and would be best imaged with a ______ speed phosphor.
lower, 100
lower, 400
higher, 400
higher, 100
higher, 100
Adding a light absorbing dye to the tube side of a phosphor ___________ the screen speed compared to phosphors with a reflective layer
does not change
decreases
increases
decreases
TRUE/FALSE
The tube side of a cassette should have a high Z# material, to prevent excessive attenuation.
FALSE
A scintillator can resolve 6 LP/mm, what is the smallest object we can resolve in that image?
0.1mm
.09mm
0.17mm
not enough information to answer
.09mm
TRUE/FALSE
The best method of reducing noise when using a very fast speed system, would be to increase the mAs.
TRUE
Energy is measured in _____.
a. kilograms
b. joules
c. electron volts
d. B or C
D
Energy is measured in joules or electron volts
Atoms and molecules are the fundamental building blocks of _____.
a. energy
b. radiation
c. matter
d. gravity
C
Atoms and molecules are the fundamental building blocks of matter.
The formula E=mc2 is the basis for the theory that led to the development of _____.
a. x-rays
b. electromagnetic radiation
c. nuclear power
d. cathode ray tubes
C
The formula E=mc2 is the basis for the theory that led to the development of nuclear power.
Radio waves, light, and x-rays are all examples of _____ energy.
a. nuclear
b. thermal
c. electrical
d. electromagnetic
D
Electromagnetic energy includes radio waves, light, and x-rays as well as other parts of the spectrum.
What is the removal of an electron from an atom called?
a. ionization
b. pair production
c. irradiation
d. electricity
A
The removal of an electron from an atom is called ionization.
The energy of x-rays is _____.
a. thermal
b. potential
c. kinetic
d. electromagnetic
D
X-rays are a form of electromagnetic energy.
The biggest source of man-made ionizing radiation exposure to the public is _____.
a. atomic fallout
b. diagnostic x-rays
c. smoke detectors
d. nuclear power plants
B
Medical x-ray exposure is the biggest source of man-made radiation.
The basic quantities measured in mechanics are _____, _____, and _____.
a. volume, length, meters
b. mass, length, time
c. radioactivity, dose, exposure
d. meters, kilos, seconds
B
The basic quantities measured in mechanics are mass, length, and time.
_____ is a special quantity of radiologic science.
a. Mass
b. Velocity
c. Radioactivity
d. Momentum
C
Radioactivity is a special quantity of radiologic science.
Exposure is measured in units of _____.
a. becquerel
b. sieverts
c. meters
d. grays
D
Exposure is measured in units of grays.
Today, radiology is considered to be a(n) _____ occupation.
a. safe
b. unsafe
c. dangerous
d. high-risk
A
Today, radiology is considered to be a safe occupation because of effective radiation protection practices.
What does ALARA mean?
a. All Level Alert Radiation Accident
b. As Low As Reasonably Achievable
c. Always Leave A Restricted Area
d. As Low As Regulations Allow
B
ALARA means As Low As Reasonably Achievable.
The smallest particle that has all the properties of an element is a(n) _____.
a. neutron
b. proton
c. electron
d. atom
D
The smallest particle that has all the properties of an element is an atom.
A positively charged nucleus surrounded by negatively charged electrons in well-defined orbits is the _____ model of the atom.
a. Bohr
b. Thomson
c. Rutherford
d. Dalton
A
A positively charged nucleus surrounded by negatively charged electrons in well-defined orbits is the Bohr model of the atom.
What are the fundamental particles of an atom?
a. quark, positron, negatron
b. nucleon, electron, proton
c. proton, neutron, quark
d. proton, electron, neutron
D
The fundamental particles of an atom are the proton, electron, and neutron.
An atom in a normal state has an electrical charge of _____.
a. one
b. zero
c. positive
d. negative
B
An atom in a normal state has an electrical charge of zero.
The binding energies, or energy levels, of electrons are represented by their _____.
a. atomic numbers
b. atomic mass units
c. shells
d. isotopes
C
The binding energies, or energy levels, of electrons are represented by their shells.
When an atom has the same number of protons as another, but a different number of neutrons, it is called an _____.
a. isomer
b. isobar
c. isotone
d. isotope
D
When an atom has the same number of protons as another, but a different number of neutrons, it is called an isotope.
An atom that loses or gains one or more electrons is a(n) _____.
a. ion
b. molecule
c. isotope
d. isomer
A
An atom that loses or gains one or more electrons is an ion.
The maximum number of electrons that can exist in an electron shell is calculated with the formula _____.
a. 2n
b. 2n^2
c. 2/n
d. 2/n^2
B
The number of electrons in an electron shell is calculated with the formula 2n^2.
The innermost electron shell is symbolized by the letter _____.
a. J
b. K
c. L
d. M
B
The innermost electron shell is symbolized by the letter K.
The atomic number of an element is symbolized by the letter _____.
a. A
b. X
c. Z
d. n
C
The atomic number of an element is symbolized by the letter Z.
Two identical atoms which exist at different energy states are called _____.
a. isotopes
b. isomers
c. isotones
d. isobars
B
Two identical atoms which exist at different energy states are called isomers.
During beta emission, an atom releases _____.
a. electrons
b. positrons
c. protons
d. neutrons
A
During beta emission, an atom releases electrons.
The only difference between x-rays and gamma rays is their _____.
a. energy
b. size
c. origin
d. name
C
The only difference between x-rays and gamma rays is their origin.
The four properties of photons are _____, _____, _____ and _____.
a. size, shape, spin, mass
b. frequency, mass, amplitude, wavelength
c. frequency, wavelength, velocity, amplitude
d. refraction, velocity, spin, amplitude
C
The properties of photons are frequency, wavelength, velocity, and amplitude.
The smallest quantity of any type of electromagnetic radiation is a(n) _____.
a. photon
b. electron
c. neutrino
d. quark
A
The smallest quantity of any type of electromagnetic radiation is a photon.
What is the velocity of all electromagnetic radiation?
a. 8 × 10^3 m/s
b. 2 × 10^8 m/s
c. 3 × 10^8 m/s
d. 4 × 10^3 m/s
C
The velocity of all electromagnetic radiation is 3 × 10^8 m/s.
The rate of rise and fall of a sine wave is called its _____.
a. amplitude
b. frequency
c. wavelength
d. velocity
B
The rate of rise and fall of a sine wave is called its frequency.
If the wavelength of a beam of electromagnetic radiation increases by a factor of 2, then its frequency must _____.
a. double
b. increase four times
c. decrease by half
d. remain constant
C
If the wavelength of a beam of electromagnetic radiation increases by a factor of 2, then its frequency must decrease by half.
The intensity of radiation _____ in _____ proportion to the square of the distance of the object from the source.
a. increases, direct
b. decreases, direct
c. increases, inverse
d. decreases, inverse
D
The intensity of radiation decreases in inverse proportion to the square of the distance of the object from the source.
If the intensity of light from a flashlight is 4 millilumens (mlm) at a distance of 3 feet, what will the intensity be at 6 feet?
a. 0.4 millilumens
b. 1 millilumen
c. 2 millilumens
d. 16 millilumens
B
If the intensity of light from a flashlight is 4 millilumens (mlm) at a distance of 3 feet using the inverse square law, it will be 1 millilumen at 6 feet.
The energy of a photon is directly proportional to its _____.
a. amplitude
b. frequency
c. velocity
d. wavelength
B
The energy of a photon is directly proportional to its frequency.
X-rays are usually identified by their _____.
a. energy
b. velocity
c. wavelength
d. hertz
A
X-rays are usually identified by their energy.
Photons with the highest frequencies have the _____.
a. highest velocity
b. lowest energy
c. longest wavelengths
d. shortest wavelengths
D
Photons with the highest frequencies have the shortest wavelengths.
The smallest unit of electrical charge is the _____.
a. electron
b. proton
c. neutron
d. neutrino
A
The smallest unit of electrical charge is the electron.
Electrification occurs through the movement of _____.
a. protons only
b. protons and electrons
c. electrons only
d. electrons and neutrons
C
Electrification occurs only through the movement of electrons.
Like charges _____ and unlike charges _____.
a. repel, repel
b. attract, attract
c. attract, repel
d. repel, attract
D
Like charges repel and unlike charges attract.
Electrostatic force is \_\_\_\_\_ proportional to the distance between charges, and \_\_\_\_\_ proportional to the product of the charges. a. directly, inversely b. inversely, directly c. inversely, inversely d. directly, directly
B
Electrostatic force is inversely proportional to the distance between charges, and directly
proportional to the product of the charges.
The charges on an electrified object are distributed _____.
a. in the center of the object
b. on the side nearest the charge
c. on the topside of the object
d. evenly throughout the object
D
The charges on an electrified object are distributed evenly throughout.
On the surface of an electrified object, the charges concentrate on the _____.
a. top side
b. underside
c. sharpest curvatures
d. smoothest curvatures
C
On the surface of an electrified object, the charges concentrate on the sharpest curvature.
A _____ is a source of direct current.
a. wall socket
b. battery
c. generator
d. spark
B
A battery is a source of direct current.
What is the unit of electric potential?
a. watt
b. amp
c. volt
d. ohm
C
The unit of electric potential is the volt.
An electric potential applied to a conductor produces _____.
a. an electric current
b. a magnetic field
c. an electric insulator
d. both A and B
D
When an electric potential is applied to a conductor, both an electric current and a magnetic field are
produced.
An alternating (AC) current is represented by a _____ line.
a. sinusoidal
b. horizontal
c. vertical
d. descending
A An alternating (AC) current is represented by a sinusoidal line.
A _____ uses direct current.
a. hair dryer
b. toaster
c. microwave
d. flashlight
D
A flashlight is battery operated, and batteries use direct current.
Alternating current is produced by a _____.
a. battery
b. generator
c. capacitor
d. semiconductor
B
Alternating current is produced by a generator.
What is Ohm’s law?
a. I = V/R
b. V = I/R
c. R = VI
d. I = VR
A
Ohm’s law is I = V/R.
A charged particle in motion creates a(n) _____.
a. negative charge
b. positive charge
c. magnetic field
d. electrostatic charge
C
A charged particle in motion creates a magnetic field.
Electrical power is measured in _____.
a. coulombs
b. amperes
c. volts
d. watts
D
Electrical power is measured in watts.
Rubber and glass are _____.
a. semiconductors
b. conductors
c. insulators
d. superconductors
C
Rubber and glass are insulators because they are nonconductors.
The rotation of electrons on their axis is the property called _____.
a. magnetic force
b. electron spin
c. unified field theory
d. magnetic induction
B
The rotation of electrons on their axis is the property called electron spin.
When a group of dipoles are aligned, they create _____.
a. a magnetic domain
b. paramagnetic material
c. magnetic resonance
d. a north pole
A
When a group of dipoles are aligned, they create a magnetic domain.
In the United States, alternating current goes through a complete cycle every _____ second.
a. 1/120
b. 1/100
c. 1/60
d. 1/30
C
In the United States, alternating current goes through a complete cycle every 1/60 second.
What is the SI unit of magnetic field strength?
a. ampere
b. tesla
c. dipole
d. ohm
B
The SI unit of magnetic field strength is the tesla or gauss.
The force between magnetic poles is proportional to the _____ of the magnetic pole strengths,
divided by the _____ of the distance between them.
a. square, sum
b. sum, square
c. square, product
d. product, square
D
The force between magnetic poles is proportional to the product of the magnetic pole strengths,
divided by the square of the distance between them.
What type of material can be made magnetic when placed in an external magnetic field?
a. diamagnetic
b. ferromagnetic
c. paramagnetic
d. nonmagnetic
B
Ferromagnetic material can be made magnetic when placed in an external magnetic field.
Like magnetic poles _____ and unlike magnetic poles _____.
a. attract, attract
b. repel, repel
c. repel, attract
d. attract, repel
C
Like magnetic poles repel and unlike magnetic poles attract.
Water is a _____ material.
a. paramagnetic
b. magnetic
c. diamagnetic
d. ferromagnetic
C
Water is a diamagnetic material.
The magnetic intensity of an electromagnet is greatly increased by the addition of a(n) _____ core.
a. wood
b. iron
c. aluminum
d. copper
B
The magnetic intensity of an electromagnet is greatly increased by the addition of an iron core.
The transformer changes:
A. on AC but not on DC B. on both DC and AC C. on DC but not on AC D. only above its critical current E. only on a constant voltage
A. on AC but not on DC
The output current in a step-up transformer is:
A. higher than the input current B. independent of the input current C. independent of the turns ratio D. lower than the input current E. the same as the input current
D. lower than the input current
If DC is applied to the primary coil of a step-up transformer, what is the result in the secondary coil?
A. AC B. Increased current C. Increased magnetic field D. Increased voltage E. Nothing
E. Nothing
Power to the primary side of the high-voltage transformer comes from the:
A. Filament transformer B. Line-voltage compensator C. Primary side of the autotransformer D. Rectifier E. Secondary side of the autotransformer
E. Secondary side of the autotransformer
The autotransformer has only one:
A. Coil B. Meter C. Rectifier D. Switch E. Turns ratio
A. Coil
Line compensation:
A. Adjusts the line frequency to 60 Hz B. Compensates for rectification C. Is necessary for proper exposure timing D. Is necessary to convert AC to DC E. Is required to stabilize voltage
E. Is required to stabilize voltage
The filament transformer:
A. Has four windings B. Increases current C. Increases voltage D. Is an autotransformer E. Must have precision resistors
B. Increases current
The design of fixed mA stations requires the use of which of the following?
A. A center-tapped meter B. DC power C. Major and minor taps D. Precision resistors E. Primary and secondary windings
D. Precision resistors
A change in the voltage waveform from the primary side to the secondary side of the high-voltage transformer produces a change in:
A. Amplitude B. Frequency C. Phase D. Velocity E. Wavelength
A. Amplitude
Which of the following is an advantage of three-phase power over single-phase power?
A. Improved spatial resolution B. Increased kVp C. Increased mAs D. Increased x-ray intensity per mAs E. Lower capital cost
D. Increased x-ray intensity per mAs
Oil is used in the high-voltage section of an x-ray imaging system for which of the following functions?
A. Electrical insulation B. Reduction of rotor friction C. Reduction of voltage ripple D. Thermal conduction E. Voltage rectification
A. Electrical insulation
If 60 Hz AC power is full-wave rectified, output voltage consists of:
A. 60 pulses per second B. 90 pulses per second C. 120 pulses per second D. 70% ripple E. Zero ripple
C. 120 pulses per second
TRUE/FALSE
As the kinetic energy of the incident electron increases, so does the efficiency of the photon production.
TRUE
TRUE/FALSE
In the diagnostic range, the kinetic energy of the incident electrons is high enough to eject an outer-shell electron causing ionization.
TRUE
TRUE/FALSE
In a bremsstrahlung interaction, the closer the incident electron travels to the nucleus, the lower the energy of the resultant x-ray photon.
FALSE
TRUE/FALSE
The electron ejected during a characteristic interaction is also known as the x-ray photon.
FALSE
TRUE/FALSE
The creation of a characteristic photon is always the result of a K-shell electron ejection.
FALSE
TRUE/FALSE
The creation of a characteristic photon in the diagnostic range is always the result of a K-shell electron ejection.
FALSE
TRUE/FALSE
As the tube ages, the anode begins to pit and the glass envelope may gain a mild coating of vaporized metal. This will cause a decrease in inherent filtration.
FALSE
TRUE/FALSE
Inherent filtration is the filtration found within the tube design.
TRUE
TRUE/FALSE
In diagnostic radiology, filtration is typically added between the source and the patient.
TRUE
Almost all of the kinetic energy of the incident electrons is converted to:
a. a bremsstrahlung photon
b. a characteristic x-ray photon
c. light
d. heat
d. heat
What percentage of target interaction results in the production of x-ray photons?
a. 1 percent
b. 50 percent
c. 99 percent
d. 100 percent
a. 1 percent
The transfer of the incident electrons’ kinetic energy to the outer-shell electrons causing vibration of the outer-shell electron results in the emission of:
a. infrared radiation.
b. ultraviolet radiation.
c. light.
d. sound.
a. infrared radiation.
The energy of a bremsstrahlung photon is
a. equal to the kinetic energy of the entering electron.
b. equal to the kinetic energy of the exiting electron.
c. the sum of the entering and exiting kinetic energy of the electron.
d. the difference between the entering and exiting kinetic energy of the electron.
d. the difference between the entering and exiting kinetic energy of the electron.
Bremsstrahlung interactions may occur only when the incident electron interacts with:
a. an inner-shell electron.
b. an outer-shell electron.
c. the force field of the nucleus.
d. none of the above
c. the force field of the nucleus.
Characteristic interactions may occur only when the incident electron interacts with:
a. an inner-shell electron.
b. an outer-shell electron.
c. the force field of the nucleus.
d. none of the above
a. an inner-shell electron.
During a characteristic interaction, the energy of the incident electron must be ____ the electron it knocks from its orbit.
a. less than that of
b. greater than that of
c. proportional to that of
d. characteristic of
b. greater than that of
During a characteristic interaction, the dropping of a higher-energy state electron into a lower-energy state “hole” results in the emission of:
a. a photon of energy.
b. a high-energy electron.
c. a low-energy electron.
d. more than one of the above
a. a photon of energy.
The energy of a characteristic photon is:
a. equal to the binding energy of the entering electron.
b. equal to the binding energy of the exiting electron.
c. the sum of the binding energy of the outer and inner shells between which the electron dropped.
d. the difference between the binding energy of the outer and inner shells between which the electron dropped.
d. the difference between the binding energy of the outer and inner shells between which the electron dropped.
At the end of the characteristic cascade, the ____ shell is missing an electron.
a. innermost
b. K
c. outermost
d. characteristic
c. outermost
The K-shell can hold a maximum of ____ electrons.
a. 1
b. 2
c. 6
d. 8
b. 2
Filtration is the process of eliminating undesirable ____ by the insertion of absorbing materials into the primary beam.
a. high-energy x-ray photons
b. high-energy incident electrons
c. low-energy x-ray photons
d. low-energy incident electrons
c. low-energy x-ray photons
Filtration permits the radiographer to ____ the photon emission spectrum into a more useful beam.
a. narrow
b. widen
c. soften
d. There is no effect.
a. narrow
Filtration has what effect on patient dose?
a. It has no effect on patient dose.
b. It increases patient dose.
c. It decreases patient dose.
d. It increases occupational worker dose.
c. It decreases patient dose.
Which of the following materials is/are used as a filter?
a. glass
b. oil
c. aluminum
d. all of the above
d. all of the above
All filtration can be expressed in terms of the thickness of:
a. HVL.
b. Pb/Eq.
c. Al/Eq.
d. Sn/Eq..
c. Al/Eq.
The amount of material that will reduce the intensity of the primary beam to one-half its original value is the:
a. half-value layer.
b. radioactive half-life.
c. aluminum equivalency.
d. half-life equivalency.
a. half-value layer.
Which of the following is affected by half-layer value?
a. anode construction
b. image quality
c. target longevity
d. patient exposure
d. patient exposure
How many half-value layers must be added to the primary beam to reduce its intensity to less than 20 percent of its original value?
a. 1
b. 2
c. 3
d. 4
c. 3
Which one of these statements is true?
a. The thickest portion of the wedge filter is placed over the densest part of the patient.
b. The thickest portion of the wedge filter is placed over the less dense part of the patient.
c. The thinnest portion of the wedge filter is placed over the less dense part of the patient.
d. A wedge filter should not be used to compensate for unequal subject density.
b. The thickest portion of the wedge filter is placed over the less dense part of the patient.
True/False?
AC current is required in the x-ray tube, and DC current is required in the transformers
False
The filament in the x-ray tube requires ______ amperes to emit electrons, thermionic emission.
0.5-1
1-2
3-5
not enough information to answer
3-5
True/False?
The high voltage generator consistes of a high voltage transformer, rectifiers and an autotransformer
False
The most likely found incoming line current in a modern radiography system is:
single phase power
three phase power
direct current
~ 60 volts
three phase power
The incoming power to a step up transformer is 100 V, 10 A with a turns ration of 250:1.
What is the resulting voltage in this transformer?
25,000 kV
25,000 V
0.4 kV
0.4 V
25,000 V
The voltage in the x-ray circuit is adjusted or fine tuned in the __________ for ease and safety.
filament transformer
high voltage transformer
rectifier circuit
autotransformer
autotransformer
An induction motor is used in what area of imaging?
rotor rotation
power increase
x-ray table movement
all of the above
rotor rotation
A filament transformer with a turns ration of 1:20 provides 3.1 amperes to the filament. What is the current flowing through the primary coil of the transformer?
62
- 2
- 55
.155
155
True/False
In single phase power systems, the potential never drops to zero.
False
When full wave rectification is applied to three phase current, a varying(slight increases and decreases over time) ____ is produced.
current
star
double
voltage
voltage
The electrical device used to adjust the mA station is the
autotransformer
stator
switch
precision resistor
precision resistor
Nearly all hard wired equipment operates on incoming line voltage of
440 V
120 AC
120 Hz
210 A
440 V
All of the following are radiographer operated controls except
kVp selection
generator selection
rotor switch
mA selection
generator selection
A step down transformer has ______ windings in the secondary vs. primary side.
less
more
the same
none of the above
less
True/False?
The basic x-ray circuit is divided into the main circuit and the anode circuit.
False
A single phase full wave rectified system produces _____ pulses per cycle.
1
2
6
12
2
True/False?
The mAs in a system controls the quality of the beam.
False
At what point in the x-ray circuit is the rectification circuit located?
between the semiconductors and the valve tubes
between the step down transformer and the rheostat
between the step up transformer and the x-ray tube
between the thermionic diode tubes and the x-ray tube
between the step up transformer and the x-ray tube
Which of the following transformers has one winding?
Filament transformer
Hi voltage transformer
Autotransformer
none of the above
Autotransformer
Which of the following waveforms has the highest efficiency?
Three phase 6 pulse
Three phase 12 pulse
Single phase full wave
All are equal
Three phase 12 pulse
The voltage input to an x-ray transformer is most likely _____.
A. 60
B. 220
C. 660
D. >660
B. 220
A typical turns ratio in a step-up transformer is most likely _____.
A. 7:1
B. 70:1
C. 700:1
D. 7000:1
C. 700:1
Variation of x-ray tube voltage with time is best described as the:
A. ripple
B. pulse frequency
C. uniformity
D. nonlinearity
A. ripple
The percentage of ripple of a high-frequency generator is most likely:
A. 1
B. 5
C. 10
D. >10
A. 1
The number of pulses per cycle of a half-wave rectified single-phase generator is _____.
A. 1/2
B. 1
C. 2
D. 6
B. 1
Which generator has the lowest ripple?
A. single pulse
B. six pulse
C. twelve pulse
D. high-frequency
D. high-frequncy
Which generator is most likely to reduce the kVp during an exposure?
A. portable
B. dedicated chest
C. R/F unit
D. Interventional radiology
portable
The maximum distance (mm) energetic electrons travel to the x-ray tube tungsten target is most likely _____.
A. 0.05
B. 0.5
C. 5
D. 50
B. 0.5
The maximum Bremasstrahlung energy (keV) produced at 80 kVp is most likely _____.
A. 100
B. 80
C. 70
D. 35
B. 80
The percentage of Bremasstrahlung radiation at 120 kVp is most likely _____%.
A. 1
B. 10
C. 50
D. 90
D. 90
The average Bremsstrahlung energy (keV) produced at 100 kVp is most likely _____.
A. 100
B. 70
C. 55
D. 40
D. 40
Tungsten characteristic K-shell x-rays have an energy (keV) of _____.
A. 85
B. 65
C. 35
D. 18
B. 65
The percentage of K-shell characteristic x-rays at 55 kVp in a tungsten target is _____.
A. 0
B. 5
C. 10
D. >10
A. 0
An x-ray spectrum shows a graph of the number of photons on the vertical axis against _____ on the horizontal axis.
A. kVp
B. keV
C. mAs
D. mA
B. keV
The highest intensity in a spectrum from a tungsten target is most likely at the _____.
A. low energies
B. middle energies
C. high energies
D. low and high energies
B. middle energies
1 roentgen is approx. equal to _____ mGy.
A. 0.1
B. 1
C. 10
D. 100
C. 10
An x-ray tube current is a flow of:
A. electrons
B. protons
C. neutrons
D. ionized atoms
A. electrons
Doubling the x-ray tube current, and quadrupling exposure time, increases x-ray tube output by _____.
A. 2x
B. 4x
C. 8x
D. 16x
C. 8x
The most likely x-ray tube output (mGy/mAs) 100cm from the x-ray tube focus is most likely _____.
A. 0.05
B. 0.5
C. 5
D. 50
A. 0.05
Doubling the mAs increases x-ray production efficiency by ______%.
A. 0
B. 10
C. 50
D. 100
A. 0
Doubling the x-ray tube voltage would likely increase the x-ray tube output by _____%.
A. 50
B. 100
C. 200
D. 400
D. 400
Doubling the x-ray tube voltage would likely increase the x-ray tube output by _____%.
A. 50
B. 100
C. 200
D. 400
D. 400
Doubling the x-ray tube mAs is equivalent to increasing the x-ray tube voltage by _____%.
A. 5
B. 15
C. 50
D. 100
B. 15
Which x-ray component is most likely to store the heat generated during an x-ray?
A. anode
B. cathode
C. target
D. filament
A. anode
Anode heat capacity is most likely expressed in terms of:
A. heat units
B. watts
C. temperature
D. specific heat
A. heat units
How many heat units is 1J?
A. 0.35
B. 0.7
C. 1.35
D. 1.7
C. 1.35
Which of the following is not a method for heat dissipation?
A. conduction
B. radiation
C. convection
D. spallation
D. spallation
The length of an x-ray tube filament is most likely _____ mm.
A. 0.15
B. 1.5
C. 15
D. 150
B. 1.5
X-ray tube filaments are most likely made of:
A. moly
B. silver
C. tungsten
D. lead
C. tungsten
The most likely x-ray tube filament current is _____ A.
A. 0.04
B. 0.4
C. 4
D. 40
C. 4
The melting point of tungsten targets in x-ray tubes is most likely _____ °C.
A. 34
B. 340
C. 3,400
D. 34,000
C. 3,400
The material added to tungsten targets in x-ray tubes is most likely:
A. rhenium
B. silver
C. thorium
D. iron
A. rhenium
The target of a mammography x-ray tube is most likely:
A. moly
B. silver
C. aluminum
D. copper
A. moly
X-ray tube targets are most likely embedded in the:
A. anode
B. cathode
C. housing
D. focusing grid
A. anode
The most likely rotation speed of an anode in a chest radiograph x-ray tube is _____ RPM.
A. 50
B. 500
C. 5,000
D. 50,000
C. 5,000
The type of gas in an x-ray tube is most likely:
A. air
B. oxygen
C. nitrogen
D. none (vacuum)
D. none (vacuum)
Vaporized tungsten coated on the x-ray tube glass envelope is most likely to result in:
A. arcing
B. leakage radiation
C. gas leaks
D. secondary radiation
A. arcing
X-ray production in an x-ray tube is most likely to be emitted towards:
A. anode
B. cathode
C. filament
D. isotropically
D. isotropically
The area of an x-ray window is most likely _____ cm^2.
A. 5
B. 50
C. 500
D. 5000
A. 5
Radiation that escapes through the protective housing is most likely called:
A. primary
B. secondary
C. leakage
D. scatter
C. leakage
The most likely material between the protective housing and the x-ray tube is:
A. oil
B. water
C. air
D. acrylic
A. oil
The shape of an aperture diaphragm is least likely a(n):
A. circle
B. square
C. rectangle
D. ellipse
D. ellipse
Field size is most severely restricted by use of a(n):
A. cylinder
B. cone
C. diaphragm
D. alignment mirror
A. cylinder
The lead thickness of collimator leaves is most likely _____ mm.
A. 0.003
B. 0.03
C. 0.3
D. 3
D. 3
The minimum filtration required in a diagnostic x-ray tube is most likely _____ mm Al.
A. 1.0
B. 1.5
C. 2.5
D. 4.0
C. 2.5
Added filtration is most likely made of:
A. moly
B. rhenium
C. aluminum
D. silver
C. aluminum
The inherent aluminum equivalence of light mirror is most likely _____ mm.
A. 0.01
B. 0.3
C. 1
D. 3
C. 1
The small focal spot size in a conventional (W target) x-ray tube is most likely _____ mm.
A. 0.1
B. 0.3
C. 0.6
D. 1.2
C. 0.6
The limiting tube current on a small focal spot size is most likely _____ mA.
A. 3
B. 30
C. 300
D. 3000
C. 300
The maximum tube current for a typical diagnostic x-ray tube is most likely _____ mA.
A. 100
B. 1,000
C. 10,000
D. 100,000
B. 1,000
The maximum tube voltage for a typical diagnostic x-ray tube is most likely _____ kV.
A. 15
B. 150
C. 1,500
D. 15,000
B. 150
The most likely exposure time(s) for a synchronous timer would be _____ second.
A. 1/50
B. 1/60
C. 1/70
D. 1/80
B. 1/60
The lowest exposure time of an electronic timer is most likely _____ second.
A. 0.001
B. 0.003
C. 0.010
D. 0.030
A. 0.001
The most important factor affecting the heel effect is most likely the anode:
A. angle
B. rotation
C. size
D. density
A. angle
Which field size (cm x cm) is likely to show the highest heel effect?
A. 35 x 43
B. 30 x 35
C. 24 x 30
D. 18 x 25
A. 35 x 43
Off-focus radiation is best controlled by the use of:
A. high kVp
B. high mA
C. collimators
D. a grid
C. collimators
X-ray tubes that are used with reduced techniques are most likely to have:
A. longer lives
B. off-focus radiation
C. microprocessor failures
D. repeat rates
A. longer lives
Which target will result in the most x-rays, assuming a constant x-ray tube kVp?
A. Mo
B. Rh
C. W
D. no difference (all the same)
C. W
- The reduction in the number and energy of photons as radiation passes through matter is termed:
a. Irradiation
b. Deflection
c. Photoelectrolysis
d. Attenuation
d. Attenuation
- The production of scatter radiation wen x-radiation strikes an object principally results from:
a. Compton interaction
b. Brem’s event
c. Characteristic event
d. Photoelectric interaction
a. Compton interaction
- The type of interaction in the diagnostic range responsible for the radiographic contrast between soft tissue and bone is:
a. Compton interaction
b. Coherent scattering
c. Pairs production
d. Photoelectric absorption
d. Photoelectric absorption
- At photon energies above 1.02 MeV, the creation of a negatron and a positron may occur in an event termed:
a. Photodisintegration
b. Pairs production
c. Annihilation reaction
d. Van de Graff production
b. Pairs production
- The photoelectric interaction most commonly occurs when the incident photon strikes a/an:
a. Inner shell electron
b. Outer shell electron
c. Protons
d. Neutron
a. Inner shell electron
- The interaction of a x-ray photon and an orbital electron, which results in partial transfer of energy is
a. Photoelectric effect
b. Pairs production
c. Compton scatter
d. Thomas scatter
c. Compton scatter
- At 70 KeV photon strikes and inner shell electron, all of the photon energy is transferred to the electron. This describes:
a. Coherent scattering
b. Compton scattering
c. Photoelectric effect
d. Photodisintegration
c. Photoelectric effect
- The incoming photon before any interaction with matter takes place is called the :
a. Incident photon
b. Scatter photon
c. Inherent photon
d. Recoil photon
a. Incident photon
- Which of the following interactions contributes to image noise?
a. Brems
b. Characteristic
c. Compton
d. Photodisintegration
e. Photoelectric effect
c. Compton
- Compton scatter is:
a. Independent of Z#
b. Inversely proportional to Z#
c. Proportional to E
d. Proportional to Z#2
a. Independent of Z#
- The probability that a photon will undergo attenuation :
a. Decreases with increasing energy
b. Increases with decreasing electron energy
c. Increases with increasing electron energy
d. Increase with increasing x-ray energy
a. Decreases with increasing energy
- The photoelectric effect is principally associated with which of the following?
a. Absorption of an x-ray
b. Brems production
c. Characteristic production
d. Scattering of an x-ray
a. Absorption of an x-ray
- During photoelectric interactions:
a. An electron is emitted from an atom
b. An x-ray is emitted from the atom
c. Electron excitation results
d. The atom is made radioactive
a. An electron is emitted from an atom
- A 35 KeV x-ray will most likely undergo a k-shell PE interaction with which of the following?
a. Barium, BE of 37 keV
b. Calcium, BE of 4 keV
c. Iodine, BE of 33 keV
d. Tungsten, BE of 69 keV
c. Iodine, BE of 33 keV
- The probability of the PE effect varies as what function of x-ray energy?
a. E^-3
b. E^-2
c. E
d. E^2
e. E^3
a. E^-3
- A 39 keV photon interacts through PE absorption with a k-shell electron having a BE of 37 keV. Therefore:
a. The photoelectron will have 2 keV of energy
b. The photoelectron will have 37 keV of energy
c. The photoelectron will have 39 keV of energy
d. The scatter x-ray will have 2 keV of energy
a. The photoelectron will have 2 keV of energy
- Differential absorption between bone and soft tissue occurs principally for which of the following reasons?
a. The difference in Z#
b. The difference in mass density
c. The polychromatic x-ray beam
d. The monochromatic x-ray beam
a. The difference in Z#
The formula for computing the generator power is:
A. voltage + current
B. voltage • current
C. voltage / current
D. (voltage / current)^-1
B. voltage • current
Which of the following determines the type of element present?
Number of electrons
Number of protons
Number of neutrons
None of the above
Number of protons
Which of the following particles is mostly energy with very little mass?
Electron
Proton
Neutron
None of the above
Electron
Which of the following electron shells has the lowest binding energy?
K
L
M
N
N
Particulate radiation includes all of the following except?
Alpha particles
Beta particles
Electrons
All of the above are particulate radiation
All of the above are particulate radiation
The difference between gamma rays and x-rays are their______.
Speed
Energy
Mass
Origin
Origin
The total amount of background radiation received in the US is ______mSv.
- 5
- 0
- 5
- 0
6.0
Which of the following measures ionizations in air?
R
Air KERMA
Rad
Rem
R
A Gray measures which of the following?
Energy released in air
Absorbed dose
Effective dose
Equivalent dose
Absorbed dose
The best (most comprehensive information) descriptor of dose to a patient is the ______.
Absorbed dose
Effective dose
Equivalent dose
Integral dose
Effective dose
In the diagnostic imaging energy range, we are most concerned with ______ effects of radiation.
Stochastic
Deterministic
Threshold related injuries
None of the above
Stochastic
Cardinal rules of radiation protection include all of the following except?
Limiting views
Shielding
Distance
Time
Limiting views
Technologist in the US may receive up to _____ effective dose in a calendar year.
5 Sv
5 rem
5 Gy
5 rad
5 rem
All electromagnetic radiation travels at a constant _______.
Frequency
Wavelength
Velocity
Hertz
Velocity
As the frequency of x-ray increases, the wavelengths will _______ proportionally.
Increase
Decrease
Remain the same
Decrease
TRUE/FALSE
As the frequency of an electromagnetic wave increases, it will act more like a particle than a wave.
TRUE
At a distance of 100cm the intensity of radiation is 25 R, if the distance is decreased to 75 cm what will the intensity of radiation be, all other factors held constant?
- 017 R
- 75 R
- 3 R
- 4 R
44.4 R
TRUE/FALSE
Like charges repel and unlike charges attract.
TRUE
The law of electrostatics states that only _____ charges move along a solid conductor.
Positive
Neutral
Negative
None of the above
Negative
Methods of electrification include all of the following except?
Contact
Friction
Convection
Induction
Convection
In electric circuits, the quantity of electrons flowing is measured in ______ and the force at which they flow is measured in ______.
mA, kVp
mA, watt
watt, keV
mA, keV
mA, keV
TRUE/FALSE
Materials that are easily magnetized generally have poor retentivity.
TRUE
Which of the following materials would be prohibited from entering an MRI suite?
Ferromagnetic
Diamagnetic
Paramagnetic
None of the above
Ferromagnetic
TRUE/FLASE
Charged particles in motion create and opposing magnetic field, this theory is the basis for transformer function.
TRUE
The theory of mutual induction used in transformers relies on what type of power to create current flow in the secondary coil?
DC
AC
120 hz
120 watt
AC
A transformer with more coils in the secondary would be identified as a _________ transformer.
Filament
Step up
Step down
None of the above
Step up
The incoming line contains 120 V and 5 A of power, a transformer with a 100:1 turns ration will produce a secondary voltage of ________.
- 05 A
- 2 V
120 V
12000V
12000V
Which component in the x-ray circuit acts as a gatekeeper and only allows exposure to occur when incoming power is at the correct level?
mA meter
kV meter
rectifiers
line compensation
line compensation
Which of the following components of the x-ray circuit can function as a step up and step sown transformer?
Hi voltage transformer
Filament transformer
Manual transformer
Auto transformer
Auto transformer
The high voltage generator is composed of all of the following except_______.
High voltage transformer
Filament transformer
X-ray tube
Rectifiers
X-ray tube
The filament transformer must supply ____ Amperes for thermionic emission to occur.
1
2
4
None of the above
4
A single phase half wave rectified generator would produce ________.
1 % voltage ripple
2 pulses per cycle
A HU constant of 1.35
60 pulses per second
60 pulses per second
Which of the following is the most efficient generator?
Single phase half wave
Single phase full wave
3 phase 12 pulse
3 phase 6 pulse
3 phase 12 pulse
The best (shortest time possible) timer is the ______.
Electronic
Mechanical
Synchronous
mAs timer
Electronic
AEC will ensure the ___________ to get the best image quality.
Appropriate mA
Correct level of exposure
Appropriate kVp
All of the above
Correct level of exposure
Which of the following tube materials do we prefer due to the ability to ground it, thus reducing failures and increasing tube life.
Glass
Ceramic
Metal
None of the above
Metal
The focusing cup has a highly _______ charge during thermionic emission.
Positive
Negative
Neutral
Negative
The use of a small filament with a small focal spot will provide great detail, it is limited to ~ _____mA station.
50
100
300
400
300
The focal track in the anode is made of which of the following materials in diagnostic radiology?
Molybdenum
Rhenium
Rhodium
Tungsten
Tungsten
TRUE/FALSE
The main reason for a rotating anode vs. a stationary anode is increased heat capacity and dissipation.
TRUE
A tube with a 7degree target angle will have a ________ effective focal spot when compared with a tube having a 15 degree target angle, both having the same size actual focal spot.
Larger
Same size
Smaller
Smaller
When using anode heel effect to our advantage in imaging, one would place the cathode end of the tube over the _______ part of the patient.
Thinner
Less dense
Thicker
Has no effect
Thicker
Which of the following tube failures will occur, under normal use?
Pitting
Rotor imbalance
Cracking
Vaporization
Vaporization
A 3 phase 6 pulse unit using 100 kVp @ 20 mAs will create ______HU.
2000
2700
2820
12000
2700
In the diagnostic energy range _____ % of the kinetic energy used in production creates heat.
1
50
85
99
99
As the kVp is increased, the efficiency of production ______.
Increases
Decreases
Stays the same
Increases
Useful characteristic x-rays result from the ______ shell.
Inner shell
Outer shell
Either
Does not involve a shell
Inner shell
An incident electron has 71 keV of energy; it displaces an orbital electron with a binding energy of 50 keV. The vacancy is filled with an electron from a shell having a binding energy of 10 kev, what amount of energy (keV) does the displaced electron leave the atom with?
11
21
40
61
21
When 80 kVp is selected at the control panel, the majority of the resulting beam will be made of ______ radiation.
Characteristic
Bremsstrahlung
Neither
Bremsstrahlung
An incident electron enters the atom at the outer most shell. A small amount of attraction is realized between the incident electron and the nucleus. The resulting x-ray would have a relative energy that is_______.
High
Low
Not enough information to answer
Low
When the kVp is set at 100, the average energy for that beam is about ______.
20
40
75
90
40
In image A, what technical factor changed, thus changing the shape of the emission spectrum.
kVp
filtration
mAs
target material
mAs
Attenuation consists of all of the following except
PE absorption
Coherent scatter
Compton scatter
Transmission
Transmission
A material has a k shell binding energy of 42 keV. Which of the following photons would most likely be absorbed?
20 keV
40 keV
44 keV
60 keV
44 keV
Secondary radiation is the result of a characteristic production in the patient, resulting from a _____ interaction.
PE absorption
Coherent scatter
Compton scatter
Pairs production
PE absorption
Increasing the Z# of a material by a factor of 3, will increase PE absorption by _____.
3
9
27
None of the above
27
Coherent scattering involves __________.
Inner shell electrons
Outer shell electrons
The whole atom
The nucleus
The whole atom
Outer shell electrons partial credit
Pairs production requires which of the following energy levels?
- 51 MeV
- 02 MeV
10 Mev
None of the above
1.02 MeV
Which of the following interactions involves an outer shell electron?
PE absorption
Pairs production
Coherent scatter
Compton scatter
Compton scatter
Coherent scatter partial credit
TRUE/FALSE
As the kVp increases the overall attenuation in the beam increases.
FALSE
As kVp increases the percentage of the beam attenuated through _________ increases.
PE absorption
Coherent scatter
Compton scatter
None of the above
Compton scatter
Compton’s scatter causes a _______ in image contrast.
Increase
Decrease
No change
Decrease
When imaging a high Z# material with a low kVp, which interaction will predominate?
PE absorption
Compton’s scatter
Coherent scatter
Photodisintegration
PE absorption
Scintillators absorb______ and release _______.
Light, x ray
Light, light
X ray, xray
X ray, light
X ray, light
The use of scintillators decreases all of the following except_______.
Patient dose
kVp required
mAs required
detail
kVp required
All of the following are used currently as capture elements, except?
Gadolinium
Barium
Cesium Iodide
Calcium Tungstate
Calcium Tungstate
Capture elements that emit light while being stimulated and after are termed_____(be specific).
Fluorescent
Phosphorescent
Luminescent
None of the above
Phosphorescent
The greater the screen speed, the ____ the detail .
better
worse
no change in
worse
When using a screen with a high Conversion Efficiency (CE), which of the following will most likely result?
Over exposure
Over penetration
Improved contrast
Noise
Over exposure
Which of the following describes the percentage of x-rays absorbed by a screen?
CE
DQE
IF
Speed
DQE
The back cover of a scintillators is most likely what type of material?
Low Z#
Radiolucent
High Z#
None of the above
High Z#
A wide exposure latitude would result in an image described as _______.
Having high contrast
Having a short scale of contrast
Having low contrast
None of the above
Having low contrast
An isotope of boron has 5 protons and 6 neutrons. The atomic number of boron is
11
10
6
5
5
If an electron is gained or lost from an atom, that atom becomes
an ion
a new element
an isotope
unstable
an ion
Electric insulators
convert electrical energy into heat
consist of materials like silicon
inhibit movement of electrical charge
permit movement of electrical charge
inhibit movement of electrical charge
The electrons in an electrical current
all have the same velocity
flow from one end of the circuit to another
have a net motion in the direction opposite to the conventional current flow
none of the above
have a net motion in the direction opposite to the conventional current flow
An induced current in a wire loop
results from a constant magnetic flux
can result only from an alternatively expanding and contracting magnetic field
is in such a direction that its effects oppose the change producing the current
always decreases when the magnetic flux decreases
can result only from an alternatively expanding and contracting magnetic field
American generators operate at
220 V
120 AC
60 Hz
30 A
60 Hz
Backup time
cannot exceed the tube limit
is not needed for three-phase generators
should be set at 150 percent of expected manual mAs
both a and c
both a and c
The incoming line current in modern high cpacity x-ray units is supplied
in the form of a three-phase power cycle
in the form of a single-phase power cycle
as a direct current
at approximately 60 volts
in the form of a three-phase power cycle
Driving the thermionic cloud from the cathode to the anode requires
a large potential difference
a small voltage
a large amperage
a small amperage
a large potential difference
The focusing cup has a/an ___ charge.
neutral
atomic
positive
negative
negative
The only portion of the anode assembly placed outside the vacuum of the envelope is the
stator
rotor
rotating disc
molybdenum neck
stator
The types of target interaction that occur in the production of diagnostic-range x-ray photons are dependent upon
electron kinetic energy
nuclear binding energy
electron potential energy
both a and b
both a and b
The quantity of x-rays or gamma rays required to produce a given amount of ionization in a unit mass of air defines the
kerma
gray
roentgen
curie
roentgen
The annual effective dose limit for an occupational exposure to ionizing radiation is ___ rem.
1
0.1
5
0.5
5
Which atomic shell possesses the highest binding energy?
K
L
M
all atomic shells possess the same binding energy
K
During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shell, energy is released in the form of
a characteristic photon
a primary radiation
an incident electron
an incident photon
a characteristic photon
The radiation intensity from a diagnostic x-ray unit will vary in a/an
square of the kVp
inverse relationship with the
square of the distance
all of the above
all of the above
The speed of an imaging system depends on the
thickness of the phosphor or silver halide layer
crystal/phosphor size
efficiency of the crystal/phosphor
all of the above
all of the above
The line focus prinicple allows for a large _______ for maximum heat load and a small ________ for increaed detail in an image.
effective, actual
estimated, actual
actual, estimated
actual, effective
actual, effective
Photoelectric interactions are __________ related to the Energy of the beam
inversely
directly
inversely cubed
directly cubed
inversely cubed
Which of the following is placed between
grid
cone
collimator
cylinder
grid
The ratio of the height of the lead strips to the distance between the lead strips is the grid
pattern
ratio
frequency
speed
ratio
The density maintenance formula is a
reciprocity law
inverse square law
direct square law
15 percent rule
direct square law
As patient size increases a ______ in mAs is required for every 4cm increase in patient thickness.
halving
doubling
quadrupling
none of the above
doubling
Angulation across the long axis of a linear grid causes
grid shadow
cross-hatched impressions
grid cut-off
grid convergence
grid cut-off
Common mA stations found on dedicated tomographic machines may include each of the following except
10
30
40
100
100
A grid absorbs
light
incident electrons
scatter electrons
scatter radiation
scatter radiation
An asthenic patient may require _______mAs and _______kVp compared to the sthenic patient.
decrease in, increase in
increase in, no change
decrease in, decrease in
no change in, decrease in
decrease in, decrease in
Each of the following is considered a beam-restricting device except the
aperture diaphragm
cone
grid
collimator
grid
As a general rule, a grid is employed when the kVp exceeds
10
70
100
200
70
The tomographic ___ is the total distance traveled by the tube
arc
fulcrum
blur
thickness
arc
The exposure time must match the
fulcrum height
section thickness
length of time required for the x-ray tube to complete the tomographic amplitude
none of the above
length of time required for the x-ray tube to complete the tomographic amplitude
A factor that affects the amount of scatter produced is
kilovoltage
milliamperage
time
anode composition
kilovoltage
Photons that pass through the body unaffected produce
scatter radiation
radiographic contrast
secondary radiation
radiographic distortion
radiographic contrast
Which grid would have the greatest distance between lead strips?
15: 1
12: 1
8: 1
6: 1
6:1
As the volume of irradiated tissue ___, the amount of scatter ___.
increases, increases
increases, decreases
decreases, increases
no effect
increases, increases
When imaging a barium filled stomach, which of the following kVp selections is most appropriate when a standard abdomen requires 75kVp for good image quality.
110
90
75
55
110
The prime factors include each of the following except
filtration
mAs
kVp
distance
filtration
A variable kVp chart increases by 2 kVp for every ____cm of tissue.
4
3
2
1
1
The greatest source of scatter during a radiographic examination is the
patient
tube
image receptor
grid
patient
Milliamperage-second directly affects each of the following except
quantity
intensity
quality
x-ray output
quality
The object to be examined is placed at the
tomographic arc
fulcrum
exposure arc
image receptor level
fulcrum
The purpose of moving the grid is to blur the
unwanted density
unwanted contrast
motion
radiopaque strips
radiopaque strips
If kVp is doubled, the amount of x-ray photons approximately
doubles
triples
increases fourfold
decreases
increases fourfold
As a general rule, a grid is employed when the body part thickness exceeds ___ cm.
1
10
100
1,000
10
A high quality radiograph should always demonstrate ___.
high optical density ( O.D of 3.5 +)
high contrast
minimum magnification
all of the above
minimum magnification
Spatial resolution improves with decreased ___ blur.
scintilator
motion
geometric
all of the above
all of the above
___ is defined as the ability to image two separate objects and visually detect one from the other.
contrast resolution
spatial resolution
distortion
noise
spatial resolution
Radiographic ___ is random fluctuation in the optical density of a radiograph.
detail
contrast
noise
resolution
noise
An image can show objects as small at 0.5mm, the resolution would be expressed as _______.
MFT of 0.5
5 lp/mm
1lp/mm
MTF 0.1
1lp/mm
What is the formula for the magnification factor?
MF = SID/SOD
MF = SOD/SID
MF = (SID/SOD)^2
MF = SID^2/SOD
MF = SID/SOD
The three primary geometric factors affecting image quality are ___.
distortion, subject contrast, and mAs
patient thickness, distortion, and magnification
magnification, distortion, and focal spot blur
kVp, focal spot blur, and contast
magnification, distortion, and focal spot blur
Large objects with large interspaces are described as__________.
having high spatial frequency
having low spatial frequency
a low MTF
a high ESF
having low spatial frequency
Focal spot blur can be reduced by using ___.
a small focal spot
a shorter SID
a larger OID
all of the above
a small focal spot
The best way to minimize magnification is to use a ___.
long SID
small OID
large OID
both A and B
both A and B
Distortion can be reduced by ___.
placing the object plane obliquely to the image plane
placing the object plane parallel to the image plane
directing the central ray 15o from the object plane
increasing the SID and the OID
placing the object plane obliquely to the image plane
Patient thickness affects image quality by affecting ___.
magnification
radiographic constrast
focal spot blur
all of the above
all of the above
An image was taken with the following technical factors
SID 100 cm, SOD 80 cm and an EFSS 0f 0.7
What is the focal spot blur in the image?
- 175 mm
- 875 mm
- 8mm
- 5mm
0.175 mm
When reducing the field of view from 14 x 17 in to 10 x 12 in a decrease in scatter is realized. Which of the following factors should be increased to maintain IR exposure or image density?
SID
kVp
mAs
any of the above would be appropriate
mAs
The small focal spot will provide a ___.
I. higher quality x-rays beam
II. greater quantity of x-rays
III. finer detail of image
Selected Answer: Correct III only Answers: I only I & III Correct III only I, II & III The small focal spot will provide a \_\_\_.
I. higher quality x-rays beam
II. greater quantity of x-rays
III. finer detail of image
I only
I & III
III only
I, II & III
III only
An average patient is imaged at 70 kVp 40 mAs for a lumbar spine exam. patient measureing 15 cm larger than average would require which of the following?
320 mAs
160 mAs
80 mAs
80 kVp
320 mAs
Patient or part thickness has a direct effect on scatter in the resulting image. Which of the following parts would produce the most scatter?
wrist
foot
elbow
Femur
Femur
Which type of collimation (beam restrictor) reduces the blur seen in an image?
cone
cylinder
aperture diaphragm
variable collimators
cylinder
Subject contrast is affected by ___.
mA
focal spot size
patient thickness
time
patient thickness
The technologist primarily controls radiographic contrast by varying the ___.
image receptor
kilovoltage
voltage ripple
milliamperage
kilovoltage
Which kVp selection would result in the most scattered x-rays in the image-forming beam?
90 kVp
75 kVp
60 kVp
50 kVp
90 kVp
The three primary factors influencing the intensity of scatter in the exit beam are ___.
mAs, kVp, and collimation
mAs, filtration, and grids
kVp, field size, and patient thickness
filtration, patient thickeness, and mAs
kVp, field size, and patient thickness
The x-rays that are transmitted through the patient without interaction contribute to ___.
useful information
film fog
image noise
all of the above
useful information
The most commonly used beam restricting device is the ___.
extension cone
variable collimator
aperture diaphragm
compression device
variable collimator
The use of a compression device will increase ___.
film fog
patient dose
contrast
scatter
contrast
The use of ___ improves contrast and reduces patient dose, while maintaining image density..
collimation
high kVp
low kVp
less filtration
collimation
The positive beam limiting device (PBL) assures that the x-ray beam is collimated to ___.
the exact part size
2 cm inside image receptor size
the image receptor size
2 cm outside image receptor size
the image receptor size
Beam restriction with a(n) ___ is only accurate at a fixed SID.
aperture diaphragm
grid
collimator
PBL device
aperture diaphragm
Patient thickness should be measured with the ___ in a variable kVp chart.
caliper
eyes
hands
SID tape
caliper
In a fixed kVp system, a _______kVp and ____mAs are used compared to a variable kVp system.
lower , the same
lower, higher
higher, no change
higher, lower
higher, lower
In a variable kVp technique chart, the optimal mAs is set for each body part and there is a ___ kVp increase for each cm of thickness.
6
4
2
1
2
How can you improve image contrast with a heavy patient without increasing patient dose?
lower kVp and raise mAs
use tight collimation
raise kVp and lower mAs
do both A and B
use tight collimation
Decreasing the kVp while holding mAs constant will increase ___.
patient dose
image noise
Compton scatter
optical density
image noise
What are the four primary exposure factors?
kVp, mAs, filtration, and voltage ripple
mA, time, distance, and filtration
kVp, mA, time, and SID
mA, time, kVp controls, and focal spot size
kVp, mA, time, and SID
Optical density is primarily controlled by changing the ___.
kVp
mAs
film
SID
mAs
Changes in kVp affect ___.
optical density
image contrast
image noise
all of the above
all of the above
An increase in mAs causes ___ in beam quality and ___ in beam quantity.
an increase, a decrease
an increase, no change
an increase, an increase
no change, an increase
no change, an increase
There is a direct relationship between the quantity of x-rays and the ___.
milliamperage
kilovolt peak
filter thickness
voltage ripple
milliamperage
If mAs is increased from 20 mAs to 40 mAs, the patient exposure will ____.
not be affected
increase slightly
be halved
be doubled
be doubled
Beam penetrability is increased if ___ is/are increased.
mAs
SID
kVp
all of the above
kVp
A ___% increases in kVp has the same effect on optical density as doubling the mAs.
5
15
30
50
15
Which medical condition may require a lower technique?
atelectasis
emphysema
pneumonia
pleural effusion
emphysema
A radiograph is taken using 75 kVp @ 20 mAs. Which change in technique would increase contrast but maintain the same density?
85 kVp @ 10 mAs
85 kVp @ 40 mAs
65 kVp @ 20 mAs
65 kVp @ 40 mAs
65 kVp @ 40 mAs
A radiograph taken using 65 kVp @ 10 mAs is too light. Which technique would double the optical density while producing a wider scale of contrast?
75 kVp @ 10 mAs
75 kVp @ 20 mAs
55 kVp @ 20 mAs
55 kVp @ 40 mAs
75 kVp @ 10 mAs
When only the optical density needs to be changed, only the ___ should be adjusted.
mAs
kVp
SID
filtration
mAs
If the distance from the source to the image (SID) is reduced by half, how is the x-ray intensity at the image affected?
it is increased 4 times
it is doubled
it is reduced by 1/2
it is reduced by 1/4
it is increased 4 times
A 10% increase in kVp has ___ effect on x-ray intensity than/as a 10% increase in mAs.
the same
much greater
less
much less
much greater
X-ray intensity is proportional to ___.
distance
kVp
kVp^2
filtration
kVp^2
Beam quality is affected by ___.
mAs and distance
kVp and mAs
kVp and filtration
filtration and mAs
kVp and filtration
Image density is affected by ___.
SID
mAs
tube angle
both A and B
both A and B
An image was taken with the following technical factors
75 kVp, 100mAs, 40”SID 16:1 Grid (GCF 5)
The image will be repeated with an 8:1 grid, (GCF 3.5), to maintain image density, what is the correct mAS?
117
70
145
not enough information to answer
70
The distance at which a focused grid can be used is directly related to the :
grid ratio
grid frequency
convergence line
interspacing material
convergence line
The interspace material used in grids is said to be_______?
radiopaque
radiolucent
highly attenuating
none of the above
radiolucent
If the grid ratio is increased, and no technical factors are changed, the radiograph would show an increase in:
contrast
optical density
distortion
magnification
contrast
Which of the following grids would be best used for portable imaging?
focused 16:1
focused 10:1
parallel, 10:1
parallel, 16:1
parallel, 10:1
During tomography, all tissues _______ the focal plane will show a marked degree of blurring.
above
below
neither above or below
both above and below
both above and below
Tomography requires__________.
short exposure times
long exposure times
very high mA stations
very high kVp
long exposure times
TRUE/FALSE
The greater the tomographic arc, the thicker the slice.
FALSE
TRUE/FALSE
Trispiral is the greatest tube movement and results in the thinnest slice thickness.
FALSE
hypocycloidal
Using a typical fluoroscopy system (tube below table) a shield should be placed ___ the patient.
underneath
over
shielding is not needed in fluoroscopy
underneath
The number of fields per frame is ___ and the number of fields per second is _____
2, 30
1, 30
1, 60
2, 60
2, 60
Total brightness gain is
a measure of the increase in image intensity
determined by minification gain
determined by flux gain
all of the above
all of the above
Electrostatic lenses are used to accelerate and focus
light photons
x-ray photons
electrons
none of the above
electrons
The photocathode absorbs ___ and emits ___.
x-ray photons, light photons
light photons, electrons
light photons, x-ray photons
electrons, light photons
light photons, electrons
During fluoroscopic image intensification, the primary x-ray beam exits the patient and strikes the ___ of the image intensifier.
input screen
electrostatic lenses
photocathode
output screen
input screen
TRUE/FALSE
Conventional fluoroscopic systems work on a progressive scan pattern in the CRT monitor.
FALSE
What two tubes must be synchronized for fluoroscopic image production?
II and CRT
II and TV camera tube
TV camera tube and CRT
II and photospot
TV camera tube and CRT
Fluoroscopic mA range is commonly ___ mA.
- 5 to 5.0
- 0 to 10.0
- 0 to 100
100 to 500
0.5 to 5.0
TRUE/FALSE
Magnification with an Image Intensifier results in a decrease in flux gain, and a dimmer image, all other factors held constant.
FALSE
The shape of the input screen helps to control
distortion
OID
SOD
IOD
distortion
Which of the following artifacts are seen in fluorocopy due to light scattering within the II.
pincushion distortion
barrel distrotion
vignetting
veiling glare
veiling glare
The greater the voltage supplied to the electrostatic lenses, the ___ the acceleration and the ___ the focal point to the input screen (magnification mode) .
greater, farther
greater, closer
lesser, smaller
greater, larger
greater, closer
TRUE/FALSE
CRT monitors have a higher image resolution compared tot he Image intensifier output phosphor.
FALSE
The output screen absorbs ___ and emits ___.
electrons, light photons
electrons, x-ray photons
light photons, electrons
light photons, x-ray photons
electrons, light photons
Digital fluoroscopy uses which of the following techniques that are not used in traditional fluroscopy?
pulsed x-ray beam
1000:1 SNR
progressive scanning of TV camera tube and CRT
all of the above
none of the above
all of the above
Fluoroscopic resolution will vary according to
minification gain
electrostatic focal point
input and output screen diameter
all of the above
all of the above
The most commonly used fluoroscopic viewing system is
cine
real-time video
70 mm spot-film roll
none of the above
real-time video
Traditional fluoroscopy has a signal to noise ratio about _______.
1000: 1
1: 1000
200: 1
1: 200
200:1
TRUE/FALSE
The target is the photoconductive layer of the TV camera tube.
TRUE
Modern day computers use ___ to process information.
transistors
micro processors
array processors
macro processors
array processors
Computer hardware includes the ___.
keyboard
central processing unit
motherboard
all of the above
all of the above
A tape, diskette, hard disk or optical disk is used to ___.
archive files
process data
convert data
perform calculations
archive files
The ___ represents zero or one.
byte
bit
gigabyte
terabyte
bit
MAC-OS, Windows, and Unix are three different ___ systems.
hardware
printer
operating
output
operating
All of the below are examples of a type of computer storage except:
microprocessor
solid state drive
hard disk drive
flash drive
microprocessor
What is the form of radiology that allows for the transfer of images to remote sites for interpretation.
neuroradiology
interventional radiology
long distance radiology
teleradiology
teleradiology
The __________ controls receipt and retrieval of images and ______ actually stores them.
Image manager, Archive server
Archive server, Image manager
Image manager/ web based system
Archive server, client server system
Image manager, Archive server
TRUE/FALSE
Computed radiography cassettes may be used with the same equipment as film/screen cassettes, with minor modification to techniques.
TRUE
A photostimulable phosphor in a metastable state will emit light ___.
I. immediately
II. when stimulated by light
III. over time
I
II
II & III
I, II & III
I, II & III
Europium is the ___ of the photostimulable phosphor.
image buffer
scintillator
phosphor
activator
activator
The photostimulable phosphor screen is handled in a ___.
reader
darkroom
film processor
film changer
reader
The computed radiography reader is made up of ___, ___, and ___ modules.
I. mechanical
II. chemical
III. optical
IV. computer
I, II, III
II, III, IV
I, III, IV
I, II, IV
I, III, IV
The four steps of creating an image with computed radiography are ___.
metastable state, stimulate, read, and erase
erase, stimulate, metastable state, and read
read, erase, stimulate, and metastable state
metastable state, read, erase, and stimulate
metastable state, stimulate, read, and erase
Following the laser stimulation of the photostimulable phosphor, the excited electrons are ___.
completely (100%) stabilized
mostly (99%) stabilized
still excited
completely removed
mostly (99%) stabilized
The laser is one of the ___ features of the computed radiography reader.
computer
chemical
mechanical
optical
optical
Optical filters are used to filter out the ___ light and allow the ___ light to reach the photodetector.
stimulating, emitted
emitted, stimulated
emitted, monochromatic
stimulating, monochromatic
stimulating, emitted
The output signal from the photostimulable phosphor plate is converted from analog to digital by the ___.
optical system
computer controls
photodiode
drive mechanism
photodiode
Computed radiography and screen-film imaging both have a(n) ___.
image receptor response function
characteristic curve
digital image
latent image
latent image
TRUE/FALSE
Spatial resolution, contrast resolution, noise, and artifacts are identical in screen-film imaging and computed radiography.
FALSE
The principal source of reduced contrast resolution in computed radiography is ___.
scatter radiation
background radiation
computer noise
phosphor scatter
scatter radiation
TRUE/FALSE
The 800 speed film-screen systems are faster than computed radiography image receptors.
TRUE
With computed radiography the contrast is ___.
controlled by kVp
controlled by mAs
constant(LINEAR) regardless of radiation exposure
impossible to change
constant(LINEAR) regardless of radiation exposure
The computed radiography image has ___.
narrow exposure latitude
wide exposure latitude
improved contrast resolution
both B and C
both B and C
The laser beam must be less than 100 nm in diameter in order to maintain ___.
consistent beam shape
smooth image edges
high spatial resolution
high speed
high spatial resolution
___ is prevented by flooding the imaging plate with bright light after reading.
image fog
noise
overexposure
ghosting
ghosting
Fluoroscopy was developed so that radiologists could view ___ images.
static
dynamic
magnified
darkened
dynamic
What is the milliamperage used during fluoroscopy?
≤100 mA
≤50 mA
≤5 mA
≤1 mA
≤5 mA
X-rays that exit the patient and enter the image intensifier first interact with the ___.
output phosphor
input phosphor
photocathode
anode
input phosphor
The output phosphor of the image intensifier is composed of ___.
cesium iodide
antimony
zinc cadmium sulfide
graphite
zinc cadmium sulfide
The input phosphor converts ___ to ___.
x-rays, electrons
light, electrons
electrons, light
x-rays, light
x-rays, light
The ___ in the image intensifier emits electrons when it is stimulated by light photons.
input phosphor
output phosphor
photocathode
electron gun
photocathode
The number of light photons emitted within the image intensifier is ___ to the amount of x-ray photons exiting the patient.
equal
unrelated
inversely proportional
directly proportional
directly proportional
The kinetic energy of photoelectrons in the image intensifier is greatly increased by the ___.
mAs of the exposure
potential difference across the tube
cesium iodide at the input phosphor
zinc cadmium sulfide at the output phosphor
potential difference across the tube
Electrons hit the ___ after exiting the anode (fluoro).
output phosphor
tube housing
photocathode
focusing lenses
output phosphor
The ___ is the product of the minification gain and the flux gain.
horizontal resolution
brightness gain
contrast resolution
flux gain
brightness gain
The ratiio of x-rays incident on the input phosphor to light photons exiting the output phosphor is called ___ gain.
magnification
minification
brightness
flux
flux
An image intensifier tube is identified by the diameter of its ___.
input phosphor
glass housing
output phosphor
focusing lenses
input phosphor
Viewing the fluoroscopic image in magnification mode increases ___.
contrast resolution
spatial resolution
Entrance skin exposure
all of the above
all of the above
Automatic brightness control (ABC) maintains the brightness of the image by varying ___.
monitor settings
kVp and mA
monitor bandwidth
all of the above
kVp and mA
Digital fluoroscopy with a charge-coupled device has lower ___ and higher ___ than conventional fluoroscopy.
light sensitivity, patient dose
patient dose, light sensitivity
detective quantum efficiency, maintenance
signal-to-noise ratio, patient dose
patient dose, light sensitivity
Energy subtraction technique takes advantage of the difference in ___ during contrast injection.
tissue density
K-edge absorption
Compton scatter
patient thickness
K-edge absorption
Remasking due to a misregistration error s the result of ___.
noise artifacts
motion artifacts
technical factors
any of the above
motion artifacts
TRUE/FLASE
Digital fluoroscopic dose rate is lower than that for continuous analog fluoroscopy
TRUE
Conventional fluoroscopy creates images in using which of the following conditions?
progressive mode, 200:1 SNR
interlaced mode, 200:1 SNR
progressive mode 1000:1 SNR
interlaced mode, 1000:1 SNR
interlaced mode, 200:1 SNR
Which of the following languages is used for the image data, providing seemless transfer between types of equipment?
HL-7
DICOM
UNIX
DOS
DICOM
Which of the following PACS architectures is not network dependent?
Web based
Client/Server based
Distributed system
all of the above are network dependent
Distributed system
As the display field of view is increased in size, spatial resolution (sharpness) in the image:
increases
decreases
is unaffected
decreases
In a 12-bit analog-to-digital converter, each pixel will have how many possible values:
256
512
1024
4096
4096
Mottle is likely to appear in the computerized image any time the:
brightness is low
contrast is low
exposure indicator is low in a postive system
density is low
exposure indicator is low in a postive system
Which of the following types of DR uses a fan beam and a detector array?
a- Si indirect
a-Se direct
CCD
SPR
SPR
TRUE/FALSE
An indirect DR system with CsI is preferred over GdOS, due to its better spatial resolution from needle like phosphor crystals.
TRUE
Which of the following DR systems has the best spatial resolution?
CsI with a-Si
GdOS with a-Si
a-Se
CsI with CCD
a-Se
Which of the following choices will require the least image exposure for the same image quality/noise level.
25 % dead space
15 % dead space
5 % dead space
dead space has no effect on exposure factors
5 % dead space
Which of the following corrects for pixels that are not responding?
lag correction
Noise correction
Gain images
interpolation
interpolation
TRUE/FALSE
A radiography exam has a 1500 x 1200 matrix, and a 1 Byte grayscale. The image will require 1.8 MB
TRUE
Which of the following is not a form of image noise:
false images
mottle
artifacts
signal
signal
What size is the smallest object that can be resolved by an x-ray imaging system with a spatial frequency of 2.5 LP/mm?
.2 mm
0.4 mm
2 mm
2.5 mm
.2 mm
As the line pairs of a resolution test template become smaller and thus closer together, the overlapping of their penumbra in a radiographic image causes a loss of .:
width
umbra
contrast
noise
contrast
When the hardware pixels of a digital imaging system are smaller than both the object and the focal spot, what becomes the primary limiting factor for spatial resolution?
the hardware pixel size
the focal spot size
the size of the object being imaged
the subject contrast of the object being imaged
the focal spot size
Which of the following is not a variable affecting image noise:
mAs
Part thickness
OID
Exposure time
Exposure time
For radiography, the brightness of a particular pixel within the image matrix of a digital image is related to the:
percentage of hydrogen in the tissue
radionuclide uptake of the tissue
attenuation coefficient of the tissue
interface reflectivity of the tissue
attenuation coefficient of the tissue
In a 12-bit analog-to-digital converter, each pixel will have how many possible values:
256
512
1024
4096
4096
The larger the number of pixels in an image matrix, the:
greater the resolution in the image
greater the number of gray shades in the image
shorter the acquisition time
none of the above
all of the above
greater the resolution in the image
The general term for making changes in the brightness and contrast of a digital image is:
automated re-scaling
image enhancement
windowing
histogram analysis
windowing
The term preprocessing
is best used to describe all those computer algorithms which are designed to:
prepare the image for display according to the parameters of the human eye
refine the characteristics of the image
prepare the acquired data for entry into the computer system
correct for flaws and limitations in the image acquisition system being used
correct for flaws and limitations in the image acquisition system being used
In the active matrix array of a DR receptor plate, variations in alignment for multiple electronic amplifiers and differences in resistance for varying lengths of wires coming from the hundreds of detector elements cause:
data clipping
gain offsets
pixel drop-out
light guide variations
gain offsets
Which of the following flaws is unique to the CR reader or processor, (not shared by DR)?
Light guide variations
Electronic response offsets
Electronic gain offsets
The anode heel effect
Light guide variations
Background exposure to a CR cassette, and small amounts of electrical current flowing through a DR detector system when no exposure is taking place, are examples of:
Mottle
The heel effect
Light noise
Dark noise
Dark noise
In a digital image histogram graph, the vertical height of any data point along the plotted curve (measured against the y axis of the graph), indicates the:
pixel value (brightness)
number of pixels possessing the value
S1
image contrast
number of pixels possessing the value
Which of the following systems requires the greatest amount of preprocessing functions?
direct digital radiography (DR)
computed radiography (CR)
digital fluoroscopy (DF)
conventional screen/film radiography (S/F)
direct digital radiography (DR)
On an image histogram, an unusual spike to the left of the main bell-shaped lobe of the curve most likely represents:
bone disease
a large metallic object
air in the lungs
background density
a large metallic object
An algorithm designed to accentuate soft tissue densities will locate the volume of interest (VOI) on the histogram:
higher
lower
farther to the left
farther to the right
farther to the right
The computer distinguishes the anatomy of interest from background densities during:
automated exposure field recognition
automated rescaling
exposure
field uniformity corrections
automated exposure field recognition
For a large abdomen which completely covers the image receptor plate, the expected shape of the original histogram will appear:
with no spikes, only the main lobe
with a single spike to the left of the main lobe
with a single spike to the right of the main lobe
with spikes both on the left and the right of the main lobe
with no spikes, only the main lobe
Exposure field recognition is normally done as part of:
histogram analysis
rescaling
noise reduction
gradation processing
histogram analysis
Many systems present the histogram with an “S”-shaped exposure response curve overlying the histogram. The steeper the slope of this curve, the:
darker the image
lighter the image
higher the image contrast
longer the image gray scale
higher the image contrast
The bins of data from an acquired image to be used for rescaling are labeled as ___ values:
S
QP
I
D
S
Because the range of the Q scale is far beyond the discernment of the human eye, this allows for _____ of the image:
data clipping
normalizing
windowing
noise reduction
windowing
Rescaling the image is primarily a process of __________ the acquired data set:
geometrically sorting
numerically counting
algebraically re-labeling
electronically amplifying
algebraically re-labeling
Histogram analysis can fail to identify key landmarks when a bizarre data set results in an unexpected ________.
Histogram shape
Histogram position
Pixel count
Volume of interest
Histogram shape
All of the following are general domains in which a digital image can be processed except:
intensity
amplitude
frequency
spatial
amplitude
Sorting an image by the location of its pixels results in a(n):
LUT
frequency distribution
histogram
matrix
matrix
Point, area, and global operations are all subcategories within the ________ domain:
intensity
amplitude
frequency
spatial
spatial
An example of an area operation would be:
a window width adjustment
darkening the image overall
translating the image left-for-right
zoom (magnification)
zoom (magnification)
Whenever a displayed image is windowed, which of the following default processes is re-applied:
Band-pass filtering
Uniformity correction
Gradation processing
Dynamic range compression
Gradation processing
If the dynamic range of a digital processing system is too limited, it is possible for ________ to occur when the displayed image is later windowed:
Quantum mottle
Image reversal
Data clipping
Excessive contrast
Data clipping
From a selected mid-point in the various gray levels of a digital image, lighter areas in the image are progressively darkened, while darker areas are progressively lightened. This describes:
multi scale processing
normalization
dynamic range compression
rescaling of brightness
flat-field uniformity correction
dynamic range compression
For the gradation processing curves developed early on by Fuji, the shape of a particular curve which a particular algebraic formula generates is represented by the parameter:
GT
GS
GA
GC
GT
Noise in the image caused by electronic malfunctions is normally periodic, occurring at regular intervals across the image, (rather than random, such as quantum mottle). This periodic type of noise is best eliminated from a digital image using:
processing in the frequency domain
processing in the spatial domain
gradation processing
histogram analysis
processing in the frequency domain
A smaller “core” matrix of mathematical values which is passed through the entire image matrix, multiplying the value of each image pixel sequentially by the numbers in it, is called a(n):
region of interest
look-up table
kernel
Fourier transform
kernel
High-pass filtering only allows to pass through processing to the final displayed image:
high frequencies
low frequencies
high pixel values
low pixel values
high frequencies
The mathematical method by which a complex wave form representing one line of a digital image can be broken down into a set of the different individual wavelengths that make it up is known as:
pyramidal decomposition
the Fourier transform
the calculus
dual-energy subtraction
the Fourier transform
What “across-the-board” adjustment in radiographic techniques is recommended to allow for CR operation at the 400-speed class, reduce patient exposure, and avoid image mottle?
double all mAs values
cut all mAs values in half
increase all kVp levels by 15 per cent
reduce all kVp levels by 15 per cent
increase all kVp levels by 15 per cent
Which of the following statements is true regarding CR systems:
They are “mAs-driven,” adjust only the mAs
Never use less than 70 kVp
Grids cannot be used
Digital processing is able to compensate for scatter caused during the exposure
Digital processing is able to compensate for scatter caused during the exposure
Which of the following statements is false:
Digital processing cannot compensate for insufficient penetration of the original
remnant x-ray beam
Digital processing cannot always compensate for very extreme (10 times) overexposure in the original remnant x-ray beam
Scatter radiation in the original remnant x-ray beam always results in a dark image after digital processing
Digital processing cannot always compensate for inadequate signal-to-noise ratio
(SNR) in the original remnant x-ray beam
Scatter radiation in the original remnant x-ray beam always results in a dark image after digital processing
When exposing multiple fields on a single CR receptor plate, which of the following assists the computer in avoiding exposure field recognition errors:
keep the anatomy centered within each field
keep the fields parallel to each other
keep the fields equidistant from each other equalization
a, b & c only
a, b & c only
For CR, as a rule-of-thumb, at least ___ per cent of the receptor plate must be exposed to avoid histogram errors:
25%
33%
50%
75%
33%
Which of the following has the least dramatic effect on scatter radiation:
large body parts
large field sizes
grids
kVp
kVp
Which of the following affects the displayed image contrast for a digital image:
windowing
gradation processing
rescaling
all of the above
all of the above
The increased exposure latitude afforded by digital imaging includes all of the following options except:
Using high kVp levels
Performing more procedures non-grid
Not using compensating filters except for the most extreme cases
Using low kVp levels
Using low kVp levels
When a department changes a particular room from film/screen to CR, the AEC for that x-ray unit must be recalibrated according to the:
final density of the image
final brightness of the image
exposure indicator readings
measured primary beam radiation
exposure indicator readings
In the digital age, for final displayed image contrast, the kVp is best described as:
the only controlling factor
the primary controlling factor
one contributing factor among many
not related at all
one contributing factor among many
For all digital imaging systems, a strict lower limit for exposure to the receptor is imposed by:
the appearance of quantum mottle
images turning out too light
the appearance of fog density
images turning out with excessive contrast
the appearance of quantum mottle
Mottle is likely to appear in the computerized image any time the:
brightness is low
contrast is low
exposure indicator is low in a postive system
density is low
exposure indicator is low in a postive system
Anything that can result in a histogram error can result in:
improper technique
mottle
blank image
exposure indicator error
exposure indicator error
Which of the following is a possible ill effect of edge enhancement?
excessive noise
segmentation failure
saturation
excessive overall brightness
excessive noise
The use of low-pass filtering (smoothing) will tend to:
increase the sharpness of the edges of the image border
improve the alignment of images during subtraction
increase the appearance of noise when excessive data is available
eliminate the appearance of high-attenuation artifacts from the image
eliminate the appearance of high-attenuation artifacts from the image
Which of the following is determined by the computer by finding the mid-point between S-MIN and S-MAX in the main lobe of the generated histogram for the image?
the exposure indicator
the average gray scale
the dynamic range
the volume of interest
the exposure indicator
Mottle in a CR or DR image can result from:
insufficient kVp
insufficient mAs
improperly calibrated AEC
all of the above
none of the above
all of the above
For a quality digital image, the highest possible _______ should be achieved:
brightness
contrast
gray scale
signal-to-noise ratio
magnification
signal-to-noise ratio
The exposure indicator is _________ related to the brightness of the image displayed on the monitor screen:
directly
inversely
exponentially
not
not
For each image in the PACS, the exposure indicator is to be permanently stored as part of the DICOM:
Header
Tag
Menu
Viewer
Header
The speed of a digital imaging system is _____ to the amount of exposure required to
produce adequate signal for processing:
Not related
Directly proportional
Inversely related
Exponentially related
Inversely related
The only prominent disadvantage of the liquid crystal diode (LCD) monitor is related to its:
compactness
image sharpness
reflective glare
viewing angle
viewing angle
In a liquid crystal diode (LCD) screen, in order to shut a pixel “off” so that it appears dark:
electrical current is applied to the pixel
electrical current is blocked from reaching the pixel
an LED is energized behind the pixel
two light-polarizing plates are turned perpendicular to each other
electrical current is applied to the pixel
electrical current is blocked from reaching the pixel partial credit
A 5-megapixel LCD screen presents much higher than a 3-megapixel LCD:
brightness
contrast
resolution
viewing angle
resolution
TRUE/FALSE
Detail processing in the spatial domain includes multi scale processing (used different matrix sizes in the layers) and bandpass filtering (removes layers for improved quality).
FALSE
TRUE/FALSE
Edge enhancement is sharp mask filtering, we find large objects and only add them to the mask, the mask is inverted and then subtracted from the original.
FALSE
TRUE/FALSE
Dynamic range compression is also known as tissue equalization.
TRUE
TRUE/FALSE
the S-ave is calculated and will determine the brightness of our image. If we send a histogram into the computer that is not the shape its expecting ( like there is no raw in our data but raw in the histogram) an error will occur and our image quality will suffer.
TRUE
TRUE/FALSE
Only those values between S-min and S-max are used for analysis, VOI and will be feed into the LUT.
TRUE
TRUE/FALSE
Image analysis includes exposure field recognition (EFR), it identifies the raw radiation area, finds Smax
TRUE
Mammography utilized a magnification of 1.8 to allow assessment of ____________.
skin margins
tumor margins
soft tissue margins
microcalsifications
microcalsifications
The Focal Spot Size in mammography is ________ as compared to diagnostic radiography.
larger
smaller
the same
smaller
Mammography has multiple target materials available, which of the following will provide a beam with the appropriate kVp for fatty breasts (lowest kVp)?
Rhodium
Tungsten
Silver
Molybdenum
Molybdenum
Which of the following prevents anatomical iinformation at the chest wall from being “cut off” or missed?
cathode at chest wall
anode at chest wall
CR at chest wall
none of the above
CR at chest wall
Compression in mammography does all of the following except?
allows for a decreased exposure
increases the penetration needed for good image quality
decreases superimposition
increases detail in the image
increases the penetration needed for good image quality
Which of the following mammography system has the best spatial resolution?
CsI with a Si
GaOS with a Si
a Se
CR
CR
Thrombolysis performed in the IR suite _________.
uses a balloon to open an vessel
places a metal tube to maintain an open vessel
terminates blood supply to an area
dissolves a clot with pharmaceuticals
dissolves a clot with pharmaceuticals
IR x-ray tubes require a larger ____________ than diagnostic due to the amount of heat created with long exposure times.
anode
focal spot size
SID
cathode
anode
TRUE/FALSE
CR/DR systems are faster than traditional film systems and therefore require less exposure for equal image quality.
FALSE
TRUE/FALSE
When an image is under penetrated (too low kVp) the computer processing can correct the image to proper quality.
FALSE
When changing from a film system, speed 400, to a CR system speed 200, which of the following changes in technique would be the best choice?
increase mAS by 2x
increase kVp by 15%
decrease SID by 20%
decrease grid ration used
increase kVp by 15%
Scatter radiation is a concern with image quality, which of the following factors is the main cause of scatter?
high kVp
high mAs
large FOV
large patient size
large patient size
TRUE/FALSE
In CR/DR imaging scatter is less of a concern than in film imaging, due to the computer processing ability to remove the scatter digitally.
TRUE
If a CR cassette is allowed to gather background radiation (prefogging) which part of the histogram will be effected?
the very dark black shades
the very light, almost white shades
the mid gray levels
none will be affected
the very light, almost white shades
TRUE/FALSE
Utilizing the 15 % rule to adjust technique compared to increasing the mAs by a factor of two will save 33% in exposure.
TRUE
All of the following are influencing factors for contrast except?
LUT
window width
window level
kVp
window level
TRUE/FALSE
Dose creep occurs because over exposure in CR/DR generally does not negatively effect image quality .
TRUE
When using a CR system, you may need to purchase new grids to prevent which of the following __________.
grid cut off
veiling glare
barrel distortion
moire patterns
moire patterns
TRUE/FALSE
The signal values between S-min and S-max are known as our VOI and represent the anatomical information in our image.
TRUE
TRUE/FALSE
Information above S-max and below S-min are not included in the VOI and are not included in the final image.
TRUE
In the attached histogram a prosthetic a nd lead shield are present. The S-min has been placed too far to the left, how will this skew the S-ave and our exposure indicator?
it will be increased
it will be decreased
will not affect it
it will be decreased
The histogram displayed represents which of the following body parts?
abdomen
extremity
chest
chest
