CT registry- image production midterm exam 2026-
2027 /ACTUAL COMPLETE REAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) A+ GRADED.
As the tube rotates around the pt, the number of data samples is
essentially doubled bc
Of the electronic switching between the two focal spots. This
oversampling technology can be used to improve the systems temporal
and spatial resolution
Cooling of the tube
Oil and air cooling, increased anode diameter, and conduction by tube
rotation
Modern ct X-ray tube specific characteristics demanded by state of the
art MDCT
High heat rating- must have ability to absorb at while dissipating quickly
Small size, lightweight- must be capable of rotating within the ct gantry
at a high rate of speed
Stable and long lasting- must be capable of withstanding huge
centrifugal forces with an extended useful life
,Ma setting
Vary from 30 mA to 800 mA. Depends on study, pt size, SNR. Automatic
tube current modulation programs adjust the mA throughout an
acquisition to reduce pt radiation dose to a min according to a
predetermined noise index that is acceptable for appropriate image
quality
Exposure time
Varies and is determined by anatomic extent, detector configuration,
table speed, and so on.may reach up to 30-60 sec in length with total
scan scan times equal to the sum of all acquisitions occurring during the
study
The mas value directly controls the
Quantity of xradiation, or photon influence directed toward pt
,Photon flux
Rate at which the photon fluency passes through a unit of area
Mas value for a given acquisition is ____ proportional to pt dose and _____
proportional to image noise
Directly
Indirectly
Effective mAs can be described as:
Calculated mas value per acquired slice. Main controlling factor of
effective mas is table speed. The pitch selected for a given acquisition
determines the speed at which the pt translates through the gantry for
each tube revolution
Effective mas formula
Mas/ pitch. As pitch increase, the mas applied to each acquired slice
decreases
, Kvp controls the
Quality of the X-ray beam. Higher kvp settings produce X-ray beams
with greater penetrating power. Higher kvp used to decrease the streak
artifact that may occur as beam passes through very dense parts. Such
as posterior fossa. Kvp usually 70-150
Automated tube voltage selection (ATVS) is an
Advanced feature that may be available on some modern ct systems.
Software that automatically modulates the tube potential based upon
the changing pt attenuation along the scan acquisition range
Dual energy ct systems are capable of applying
Multiple X-ray energies during single ct acquisition. Transmission data
are acquired from soft tissue interaction with both high and low kvp
radiation. Differentiation and characterization of tissue composition are
made possible by the difference in attenuation between the two X-ray
spectra
Dual energy ct scanning
Complex voltage switching may be employed. As the single tube rotates
around the pt, the applied peak kvp is switched at an extremely high
rate for each successive projection
2027 /ACTUAL COMPLETE REAL EXAM QUESTIONS AND
CORRECT DETAILED ANSWERS WITH RATIONALES
(VERIFIED ANSWERS) A+ GRADED.
As the tube rotates around the pt, the number of data samples is
essentially doubled bc
Of the electronic switching between the two focal spots. This
oversampling technology can be used to improve the systems temporal
and spatial resolution
Cooling of the tube
Oil and air cooling, increased anode diameter, and conduction by tube
rotation
Modern ct X-ray tube specific characteristics demanded by state of the
art MDCT
High heat rating- must have ability to absorb at while dissipating quickly
Small size, lightweight- must be capable of rotating within the ct gantry
at a high rate of speed
Stable and long lasting- must be capable of withstanding huge
centrifugal forces with an extended useful life
,Ma setting
Vary from 30 mA to 800 mA. Depends on study, pt size, SNR. Automatic
tube current modulation programs adjust the mA throughout an
acquisition to reduce pt radiation dose to a min according to a
predetermined noise index that is acceptable for appropriate image
quality
Exposure time
Varies and is determined by anatomic extent, detector configuration,
table speed, and so on.may reach up to 30-60 sec in length with total
scan scan times equal to the sum of all acquisitions occurring during the
study
The mas value directly controls the
Quantity of xradiation, or photon influence directed toward pt
,Photon flux
Rate at which the photon fluency passes through a unit of area
Mas value for a given acquisition is ____ proportional to pt dose and _____
proportional to image noise
Directly
Indirectly
Effective mAs can be described as:
Calculated mas value per acquired slice. Main controlling factor of
effective mas is table speed. The pitch selected for a given acquisition
determines the speed at which the pt translates through the gantry for
each tube revolution
Effective mas formula
Mas/ pitch. As pitch increase, the mas applied to each acquired slice
decreases
, Kvp controls the
Quality of the X-ray beam. Higher kvp settings produce X-ray beams
with greater penetrating power. Higher kvp used to decrease the streak
artifact that may occur as beam passes through very dense parts. Such
as posterior fossa. Kvp usually 70-150
Automated tube voltage selection (ATVS) is an
Advanced feature that may be available on some modern ct systems.
Software that automatically modulates the tube potential based upon
the changing pt attenuation along the scan acquisition range
Dual energy ct systems are capable of applying
Multiple X-ray energies during single ct acquisition. Transmission data
are acquired from soft tissue interaction with both high and low kvp
radiation. Differentiation and characterization of tissue composition are
made possible by the difference in attenuation between the two X-ray
spectra
Dual energy ct scanning
Complex voltage switching may be employed. As the single tube rotates
around the pt, the applied peak kvp is switched at an extremely high
rate for each successive projection
