NMTCB-CT
Where are x-rays made? - answer in the electron shell structure of an atom
What is Bremsstrahlung radiation? - answer energetic electrons pass very near the
nucleus of an atom. The strong forces of th positive charged atom causes the negatively
charged electron to decelerate; the path of the electron is changed, and some of the
kinetic energy of the electron is lost, and converted into x-rays
what is characteristic x-ray radiation? - answer following the ionization of an atom that
leaves an inner shell, outer shell electrons drop down to refill the inner shell. As these
electrons drop down, they lose energy, which is released as x-rays.
What does pre-collimation do? - answer(used before x-rays enter the patient) defines
the beam shape and width (which is usually fan or cone shaped) and protects the
patient from excess radiation
What does post-collimation do? - answer(used to reduce scatter after leaving the
patient) is used before the radiation strikes the detectors
What are advantages of thinner collimation? - answerA: less volume averaging
B: increased spatial resolution
C: decreased spatial resolution
D: fewer artifacts
E: all of the above
F: a,b,d **
True or false: in CT, the gantry rotates continuously in one direction on a slip ring
system - answertrue
What is a scout imaged used for? - answerPositioning /localization
Pitch - answerthe ratio of patient's movements through the gantry during one 360
degree beam rotation relative to the beam collimation (in single slice CT)
The table distance traveled in 1 gantry rotation of 360o divided by the total thickness of
all acquired slices—in multi detector CT
How is pitch calculated? - answerpitch = table movement per rotation (mm)/ (number of
slices)(slices width in mm)
What happens when pitch is decreased? - answer--the number of views per linear scan
distance increases,
Where are x-rays made? - answer in the electron shell structure of an atom
What is Bremsstrahlung radiation? - answer energetic electrons pass very near the
nucleus of an atom. The strong forces of th positive charged atom causes the negatively
charged electron to decelerate; the path of the electron is changed, and some of the
kinetic energy of the electron is lost, and converted into x-rays
what is characteristic x-ray radiation? - answer following the ionization of an atom that
leaves an inner shell, outer shell electrons drop down to refill the inner shell. As these
electrons drop down, they lose energy, which is released as x-rays.
What does pre-collimation do? - answer(used before x-rays enter the patient) defines
the beam shape and width (which is usually fan or cone shaped) and protects the
patient from excess radiation
What does post-collimation do? - answer(used to reduce scatter after leaving the
patient) is used before the radiation strikes the detectors
What are advantages of thinner collimation? - answerA: less volume averaging
B: increased spatial resolution
C: decreased spatial resolution
D: fewer artifacts
E: all of the above
F: a,b,d **
True or false: in CT, the gantry rotates continuously in one direction on a slip ring
system - answertrue
What is a scout imaged used for? - answerPositioning /localization
Pitch - answerthe ratio of patient's movements through the gantry during one 360
degree beam rotation relative to the beam collimation (in single slice CT)
The table distance traveled in 1 gantry rotation of 360o divided by the total thickness of
all acquired slices—in multi detector CT
How is pitch calculated? - answerpitch = table movement per rotation (mm)/ (number of
slices)(slices width in mm)
What happens when pitch is decreased? - answer--the number of views per linear scan
distance increases,
