equipment Flashcards
- The _______ is the source of radiation in the x-ray tube.
a. filament
b. focal spot
c. focusing cup
d. stator
b. focal spot
Because of the line focus principle, the effective focal spot size decreases with decreasing
a. target angle.
b. rotor speed.
c. window thickness.
d. space charge.
a. target angle.
High capacity tube rotors revolve at _________.
a. 2000 rpm
b. 3600 rpm
c. 6000 rpm
d. 10,000 rpm
d. 10,000 rpm
The x-ray intensity is lower on the anode side of the tube because of the
a. line focus principle.
b. heel effect.
c. focusing cup.
d. filament length.
b. heel effect.
The cathode side of the tube should be towards the ________ part of the patient.
a. upper
b. lower
c. thicker
d. thinner
c. thicker
What is the formula for heat units for a three-phase, six-pulse x-ray machine?
a. kVp × mA × seconds
b. 1.35 × kVp × mA × seconds
c. 1.41 × kVp × mA × seconds
d. 1.66 × kVp × mA × seconds
b. 1.35 × kVp × mA × seconds
Tube failure can occur from
a. extrafocal radiation.
b. short exposure times.
c. high kVp techniques.
d. long exposure times.
d. long exposure times.
The filament in an x-ray tube is about ______ in length.
a. 1–2 cm
b. 3–4 cm
c. 8–10
d. 10–20 cm
a. 1–2 cm
A dual focus tube has two
a. anodes.
b. filaments.
c. rotors.
d. stators.
b. filaments.
Each tube has its own tube rating chart to show
a. housing cooling times.
b. anode cooling times.
c. maximum exposure times.
d. maximum patient doses.
c. maximum exposure times.
The _________ is/are outside the glass envelope.
a. stators
b. rotor
c. focal spot
d. filaments
a. stators
Extrafocal or off-focus radiation is produced from
a. overheated anodes.
b. scattered x-rays.
c. rebounding electrons.
d. dual focus cathodes.
c. rebounding electrons.
The heel effect is caused by the
a. stator windings.
b. anode angle.
c. exposure times.
d. induction motor.
b. anode angle.
The effective focal spot size is __________ the actual focal spot size.
a. equal to
b. larger than
c. equal to or larger than
d. smaller than
d. smaller than
Localized pitting or cracking on the anode can occur from
a. filament vaporization.
b. a single excessive exposure.
c. long exposure times.
d. high kVp and low mA.
b. a single excessive exposure.
Projectile electrons travel from
a. anode to cathode.
b. cathode to anode.
c. target to patient.
d. inner shell to outer shell.
b. cathode to anode.
During an exposure most of the _________ energy of the projectile electrons is converted to __________.
a. kinetic, x-rays
b. x-ray, kinetic
c. kinetic, heat
d. heat, kinetic
c. kinetic, heat
At the target, the projectile electrons interact with
a. outer shell electrons.
b. inner shell electrons.
c. atomic nuclei.
d. Both a and b.
d. Both a and b.
The efficiency of x-ray production is ____________ the tube current.
a. indirectly proportional to
b. directly proportional to
c. not affected by
d. strongly affected by
D
Most of the heat generated at the target is due to
a. inner-shell ionization.
b. outer-shell excitation.
c. nucleus bombardment.
d. K x-rays.
b. outer-shell excitation.
The efficiency of x-ray production increases as ___ increases.
a. mA
b. kVp
c. time
d. Both a and b.
D. Both a and b
Approximately ____ of the kinetic energy of the projectile electrons is converted to x- target.
a. 1%
b. 10%
c. 50%
d. 99%
a. 1%
Electron interactions at the inner shell of the target atoms produce __________ radiation.
a. gamma
b. bremsstrahlung
c. characteristic
d. All of the above.
c. characteristic
The useful characteristic x-rays from tungsten targets are ______ x-rays.
a. K-shell
b. L-shell
c. M-shell
d. N-shell
a. K-shell
Characteristic K-shell x-rays have an effective energy of ______ keV.
a. 0.6
b. 3
c. 12
d. 69
d. 69
Most of the x-rays produced at the target are __________.
a. bremsstrahlung
b. characteristic
c. gamma
d. Beta
a. bremsstrahlung
At 55 kVp _____ of the x-rays produced are bremsstrahlung.
a. 15%
b. 80%
c. 100%
d. none
c. 100%
Bremsstrahlung x-rays are produced by ________ at the target.
a. outer shell excitation.
b. slowing electrons.
c. K-shell interactions.
d. L-shell interactions.
b. slowing electrons.
Characteristic x-rays are produced by
a. braking electrons.
b. excitation of outer shell electrons.
c. nuclear fragmentation.
d. released binding energy.
D. Released binding energy
The quantity of bremsstrahlung radiation increases proportionately with increased ______.
a. kVp
b. mAs
c. filtration
d. rotor speed
b. mAs
An exposure taken at 100 kVp would have a continuous emission spectrum with a maximum energy of ______ keV.
a. 30
b. 69
c. 100
d. 140
C. 100
The _____ of an x-ray beam is higher when the peak of the emission spectrum is further to the _____.
a. quality, right
b. quantity, right
c. quality, left
d. quantity, left
a. quality, right
An increase in mAs would _________ the ________ of the emission spectrum.
a. increase, position only
b. increase, amplitude only
c. increase, amplitude and position
d. not affect, amplitude and position
b. increase, amplitude only
An increase in kVp would ________ the ________ of the emission spectrum.
a. increase, position only
b. increase, amplitude only
c. increase, amplitude and position
d. not affect, amplitude and position
c. increase, amplitude and position
Changes in _______ result in directly proportional changes in the amplitude of the emission spectrum.
a. mA
b. time
c. kVp
d. Both a and b.
d. Both a and b.
The discrete portion of the x-ray emission spectrum would change position with a change in _________.
a. kVp
b. target material
c. voltage ripple
d. Both a and b.
b. target material
The amplitude of the emission spectrum is ________ with a _______ generator than/as with a three-phase generator.
a. lower, single-phase
b. lower, high frequency
c. higher, single-phase
d. the same, single-phase
a. lower, single-phase
A 15% increase in kVp is equivalent to
a. increasing the mAs 15%.
b. doubling the mAs.
c. Increasing the mAs 1½ times.
d. tripling the mAs.
b. doubling the mAs.
How does added filtration affect the emission spectrum?
a. increased amplitude and a shift to the right
b. increased amplitude and a shift to the right
c. reduced amplitude and a shift to the right
d. reduced amplitude and a shift to the left
c. reduced amplitude and a shift to the right
Roentgens (or grays) is the measurement for x-ray ________.
a. quantity
b. exposure
c. intensity
d. All of the above.
d. All of the above.
The number of useful x-rays in the beam defines x-ray
a. kVp.
b. quality.
c. quantity.
d. mAs.
c. quantity.
Standard x-ray machines produce about ____ mR/mAs at 70 kVp measured at 100 cm SID.
a. 2
b. 5
c. 10
d. 20
b. 5
X-ray quantity increases in direct proportion to increases in ______.
a. mAs
b. kVp
c. distance
d. filtration
a. 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?
a. It is increased 4 times.
b. It is doubled.
c. It is reduced by ½.
d. It is reduced by ¼.
a. It is increased 4 times.
If filter thickness is _______, then x-ray intensity is _______.
a. reduced, reduced
b. increased, reduced
c. reduced, increased
d. Both b and c.
d. Both b and c.
A 10% increase in kVp has ______ effect on x-ray intensity than/as a 10% increase in mAs.
a. the same
b. much greater
c. less
d. much less
b. much greater
If x-ray quantity is doubled, the optical density on the finished radiograph will be
a. reduced by half.
b. just slightly increased.
c. increased by a factor of two.
d. increased by a factor of four.
c. increased by a factor of two.
If a technologist changes the technique from 70 kVp @ 200 mAs to 70 kVp @ 400 mAs, then the x-ray intensity will ______ and optical density will __________.
a. double, double.
b. double, remain the same.
c. remain the same, will remain the same.
d. will remain the same, double.
a. double, double.
The inverse square law has the same effect on optical density and x-ray _______.
a. intensity
b. exposure
c. quantity
d. All of the above.
d. All of the above.
- The production of heat at the anode is directly proportional to
a. rotor speed.
b. filament current.
c. kVp.
d. tube current.
B. Filament current
An increase of 15% in kVp is equivalent to increasing mAs _____.
a. 15%.
b. 30%.
c. 50%
d. 100%.
d. 100%.
If the intensity of a 70 kVp exposure at 20 mAs is 100 mR, what would it be at 5 mAs?
a. 25 mR
b. 50 mR
c. 200 mR
d. 400 mR
a. 25 mR
If an exposure is 50 mR at an SID of 40 inches, what would the exposure be at an SID of 60 inches?
a. 22.2 mR
b. 33.3 mR
c. 75 mR
d. 112.5 mR
a. 22.2 mR
X-ray intensity is proportional to ______.
a. distance
b. kVp
c. kVp2
d. filtration
c. kVp2
The penetrability of an x-ray beam is called x-ray _______.
a. quantity
b. quality
c. intensity
d. All of the above.
b. quality
An x-ray beam that could pass through dense tissue would have high _______.
a. penetrability
b. quality
c. quantity
d. Both a and b.
d. Both a and b.
A low quality beam would also have low
a. penetrability.
b. quantity.
c. mAs.
d. intensity.
a. penetrability.
Beam quality is affected by
a. mAs and distance.
b. kVp and mAs.
c. kVp and filtration.
d. filtration and mAs.
c. kVp and filtration.
The half value layer (HVL) of an x-ray beam is a measurement of beam ______.
a. intensity
b. quality
c. quantity
d. All of the above.
b. quality
Image contrast is affected by ________.
a. beam quality
b. kVp
c. mAs
d. Both a and b.
d. Both a and b.
The HVL is lowered by a decrease in _____.
a. kVp
b. mAs
c. distance
d. Both a and c.
A
X-ray beam quality is improved by
a. lowering kVp.
b. decreasing filtration.
c. increasing filtration.
d. increasing distance.
c. increasing filtration.
The main purpose of added filtration is to reduce
a. the HVL.
b. patient dose.
c. beam quality.
d. beam penetrability.
b. patient dose.
Added filtration will ________ beam quality and _______ beam quantity.
a. decrease, increase
b. decrease, decrease
c. increase, decrease
d. increase, increase
c. increase, decrease
A compensating filter is used to create _________ optical density with a body part of ___ thickness.
a. uniform, non-uniform
b. non-uniform, non-uniform
c. non-uniform, uniform
d. uniform, uniform
a. uniform, non-uniform
The two primary forms of x-ray interaction in the diagnostic range are
a. Compton scattering and photoelectric absorption.
b. Compton scattering and pair production.
c. photoelectric absorption and coherent scattering.
d. coherent scattering and Thompson scattering.
a. Compton scattering and photoelectric absorption.
An incident x-ray interacts with an atom without ionization during _____________.
a. photoelectric absorption
b. Compton scattering
c. coherent scattering
d. pair production
c. coherent scattering
An outer-shell electron is ejected and the atom is ionized with
a. photoelectric interactions.
b. Compton interactions.
c. coherent scattering.
d. pair production.
b. Compton interactions.
U
Which x-ray interaction involves the ejection of the K-shell electron?
a. coherent scattering
b. Compton interaction
c. pair production
d. photoelectric absorption
d. photoelectric absorption
The scattered x-ray from a Compton interaction usually retains ________ of the energy of the incident photon.
a. none
b. little
c. most
d. all
c. most
Compton scatter is directed at (a) _______ angle from the incident beam.
a. 180º
b. 90º
c. 0º
d. any
D. Any
As kVp _________, the probability of photoelectric absorption __________.
a. increases, remains the same
b. increases, decreases
c. decreases, decreases
d. decreases, remains the same
b. increases, decreases
There is complete absorption of the incident x-ray photon with
a. photoelectric effect.
b. Compton interaction.
c. pair production.
d. coherent scatter.
a. photoelectric effect.
_________ occurs only at the very high energies used in radiation therapy and in nuclear medicine PET imaging.
a. Coherent scatter
b. Compton scatter
c. Photoelectric absorption
d. Pair production
d. Pair production
Only at energies above 10 MeV can ___________ take place.
a. photodisintegration
b. pair production
c. Compton scatter
d. photoelectric absorption
a. photodisintegration
When the mass density of the absorber is __________, it results in __________ Compton scatter.
a. decreased, increased
b. increased, increased
c. increased, decreased
d. decreased, decreased
b. increased, increased
K-shell binding energy increases with increasing ________.
a. mass density
b. kVp
c. atomic number
d. mAs
c. atomic number
Which has the greatest mass density?
a. fat
b. soft tissue
c. bone
d. air
c. bone
Image fog in diagnostic imaging is caused by
a. photoelectric absorption.
b. Compton scatter.
c. pair production.
d. All of the above.
b. Compton scatter.