T/F The number of photons in the beam is proportional to the radiation dose to the patient and the
exposure of the detectors? - correct answer ✔✔True
If beam intensity doubles, the patient dose HALVES/DOUBLES and the exposure to the detectors also
HALVES/DOUBLES - correct answer ✔✔doubles/doubles
The ___________ filament serves as the source of electrons - correct answer ✔✔cathode
The energy and intensity of the x-ray beam are controlled by the
technologist setting which three prime exposure factors? - correct answer ✔✔mA, kVp, & rotation time
varying of the mA based on the thickness (or density) of the anatomic section being scanned is known
as? - correct answer ✔✔Automated dose modulation
If rotation time is reduced by half, the mA must be doubled/halved to retain the same total photon
intensity - correct answer ✔✔Doubled
Filtration has the effect of increasing/decreasing the beam intensity while increasing/decreasing the
average beam energy - correct answer ✔✔decreasing/increasing
bowtie filter increases/reduces the intensity of the beam on the outer edges of the patient where less
radiation is needed - correct answer ✔✔reduces
Increasing mA in CT has the effect
of:
A. Increasing dose to the patient
B. Increasing exposure to the detector elements
C. Increasing the intensity of the beam
,D. All answers listed are true - correct answer ✔✔D
What technical change is expected to increase the penetrating
ability of an x-ray beam?
A. Increased kVp
B. Increased mA
C. Increased rotation time
D. Decrease mAs - correct answer ✔✔A
If the rotation time of a scan is increased, what other exposure
parameter should be changed to maintain the same total
exposure to the detector array?
A. Decrease mA
B. Decrease kVp
C. Increase scan length
D. Increase mA - correct answer ✔✔A
mA & time have NO effect on ______________ - correct answer ✔✔energy
kVp has an direct proportional relationship to ________ & ________ - correct answer ✔✔energy and
intensity
What effect on resolution does increasing rotation time have? - correct answer ✔✔Decreases resolution
The specific process that accelerates electron in an x-ray tube is:
A. Evacuation of air in the envelope
B. Themionic emission
C. Application of a voltage
, D. Bremsstrahlung electron interactions - correct answer ✔✔C. All options listed are valuable in the x-ray
production process, but only the voltage actually causes electrons to accelerate through the tube. A
"voltage" is the same as the kilovoltage potential (kVp).
Electrical power is supplied to the x-ray tube by a ________-__________
The incoming power supply to the x-ray system (220 V, alternating
current) is not capable of producing these technical settings, so the
electrical current must be changed. For the filament circuit, a ________-__________ transformer is used
to create the high-amperage necessary
for __________ emission - correct answer ✔✔step-down/thermionic
For the x-ray tube circuit, a _______-_______ transformer is used to create the high-voltage necessary
for x-ray production - correct answer ✔✔step-up
Dense materials (like bone) attenuate MORE/LESS radiation and result in a HIGHER/LOWER signal from
the detector. - correct answer ✔✔MORE/LOWER
Non-uniform detector arrays require MORE/LESS radiation dose, but the slices are THINNER/THICKER
and show MORE/LESS detail - correct answer ✔✔LESS/THICKER/LESS
Uniform detector arrays can produce very THIN/THICK slices of data for all detector rows, but a
LOWER/HIGHER radiation dose is required in order to INCREASE/REDUCE image noise - correct answer
✔✔THIN/HIGHER/REDUCE
________-__________ collimators are positioned before the patient and
shape the beam as it exits the tube housing. These collimators are adjusted to ensure the x-ray beam
width (geometry) is only as
wide as the activated detectors - correct answer ✔✔Pre-patient
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