112 EXAM 3 Flashcards
Adjustments in mAs should be used to control IR
exposure.
All factors remaining constant, which of the following set of exposure conditions would yield the GREATEST image receptor exposure?
a. 100 mA, .75 sec, 40” SID
b. 300 mA, .25 sec, 44” SID
c. 600 mA, 125 ms, 40” SID
d. 400 mA, 200 ms, 40” SID
400 mA, 200 ms, 40” SID
All factors remaining constant, which of the following set of exposure conditions would yield an image with the HIGHEST image receptor (IR) exposure?
a. 100 mA, .75 sec, 40” SID, 70 kVp
b. 150 mA, .25 sec, 44” SID, 80 kVp
c. 300 mA, 125 ms, 40” SID, 70 kVp
d. 400 mA, 187 ms, 56” SID, 88 kVp
400 mA, 187 ms, 56” SID, 88 kVp
An increase in kVp by 15 percent will cause an approximate ____ in the exposure to the receptor
a. 15 percent increase
b. tripling
c. doubling
d. quadrupling
doubling
As the mA doubles, the number of electrons flowing from cathode to anode
a. increases fourfold.
b. increases twofold.
c. decreases twofold.
d. increases by 50 percent.
increases twofold
If kVp is doubled, the amount of x-ray photons created approximately increases
fourfold.
If the mAs of a radiograph is increased from 10 to 20, the result will be
a decrease in patient exposure.
In order to increase image receptor (IR) exposure by 40 percent, the radiographer would
change the mAs from 15 to 21 mAs.
Increasing the energy of an incident electron will result in the production of an x-ray photon with
greater energy.
Kilovoltage is the primary controlling factor of
x-ray beam quality.
Milliamperage-second (mAs) directly affects all of the following EXCEPT.
a. beam quantity.
b. beam intensity.
c. beam quality.
d. x-ray output.
beam quality.
The factors that affect x-ray emission under the direct control of the radiographer are called the ____ factors.
prime
The factors that directly affect x-ray quality are
kVp and beam filtration.
The length of the exposure time (S) for a radiograph, is used to primarily control
motion distortion.
The primary factor controlling x-ray beam quantity is determined by
mAs.
The prime factors include all of the following EXCEPT
a. filtration.
b. mAs.
c. kVp.
d. distance.
filtration
The product of tube current and exposure time is equal to
x-ray beam quantity.
The relationship between mAs and exposure is
directly proportional
The relationship between the intensity of radiation and distance is the
inverse square law
Total x-ray beam quality is numerically represented by the
HVL.
Which of the following sets of exposure factors would best control involuntary motion?
500 mA, 18 ms
X-ray beam penetrability is primarily controlled by
kVp.
A compensating wedge filter would be appropriate for
AP foot radiography.
A Thoraeus filter combines all of the following materials EXCEPT
a. silver.
b. copper.
c. tin.
d. aluminum.
silver.
All filtration can be expressed in terms of the thickness of _________ equivalency.
aluminum.
All of the following are true of K-edge filters EXCEPT
a. They are also called compound filters.
b. Copper and aluminum are the materials of choice.
c. They rely on photoelectric interactions and the production of characteristic radiation.
d. The x-ray beam traverses aluminum first, followed by the copper layer.
The x-ray beam traverses aluminum first, followed by the copper layer.
Beam filtration does what to patient dose?
It decreases patient dose.
Filtration is the process of eliminating undesirable ____ by the insertion of absorbing materials into the primary beam.
low-energy x-ray photons
Filtration permits the radiographer to ____ the photon emission spectrum into a more useful beam.
narrow
For an x-ray beam operated at 80 kVp,
the beam is harder than a 60 kVp beam.
For an x-ray beam operated at 90 kVp, the required minimum filtration must be
1.0 mm Al/Eq inherent plus 1.5 mm Al/Eq added.
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?
3
If the half-value layer of diagnostic radiographic equipment is too low, it may be corrected by
increasing the primary beam filtration.
In general, low-energy x-ray photons
are absorbed by the patient.
In mammography tubes, the glass window of the tube is replaced with __________ to reduce patient skin exposure.
beryllium
Most of the inherent filtration of a typical x-ray equipment comes from the
window of the glass envelope
The amount of material that will reduce the intensity of the primary beam to one-half its original value is termed the
half-value layer.
The build-up of tungsten deposits on the inside of an aged x-ray tube adds to the
inherent filtration
The collimator device is considered part of the ____ filtration.
added
The half-value layer is typically expressed in
Al/Eq.
The most common diagnostic x-ray beam filter material is
aluminum.
The problem of uneven image receptor exposure due the heel effect is solved by a
compensation filter.
Total beam filtration is equal to the sum of ____ filtration.
inherent and added
What term describes filtration that is part of the x-ray tube, the tube housing, and the collimation device?
inherent
When comparing two x-ray beams, one at 60 kVp and another at 85 kVp,
a. adding aluminum to the 60 kVp beam greatly reduces the skin dose to the patient.
b. the 85 kVp beam will offer a lower entrance skin exposure.
c. adding 0.5 mm of aluminum to the 85 kVp beam will require no additional mAs in order to maintain beam intensity.
all of them
When looking to purchase an x-ray tube, output of tubes can be measured by looking at the tube’s published
HVL
Which of the following are considered filter media as the beam traverses toward the patient?
a. glass
b. dielectric oil
c. aluminum
Which of the following filtrations would result in the lowest entrance skin exposure to the patient?
1.0 Al/Eq
Which of the following is affected by half-layer value?
patient skin exposure
Which one of the following compensating filters is used most commonly in the radiography of femur?
wedge
