CT exam 1 2025 Questions and
Answers
Main advantages of CT over conventional radiography? - ANSWER✔✔-Elimination of
superimposed structures
Can tell difference in densities
Superior quality of images
CT image quality is evaluated by - ANSWER✔✔-1. Spatial resolution- ability to define
small objects
2. Low-contrast resolution- ability to differentiate objects with similar densities
3. Temporal resolution- speed that data can be acquired
What is attenuation? - ANSWER✔✔-The degree to which a beam is reduced
What is the most common matrix size? - ANSWER✔✔-512 or total number of 262,144
Black areas have ___ attenuation and white areas mean the beam has been ____ -
ANSWER✔✔-Low
Completely absorbed (high attenuation)
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, Density? - ANSWER✔✔-Mass of a substance per unit volume or degree to which matter
is crowded together
What is the linear attenuation coefficient? - ANSWER✔✔-Amount of X-ray beam that is
scattered or absorbed per unit thickness of the absorber
Attenuation coefficient ____ with ____ photon energy and ___ with ____ atomic number
and density - ANSWER✔✔-decreases with increasing photon energy and increases with
increasing atomic number and density
Air filled structures (low density) such as lungs appear as ___ areas on CT images -
ANSWER✔✔-black
What is given to create a temporary artificial density difference between objects to be
able to differentiate them on a image? - ANSWER✔✔-contrast
The number of photons that interact depends on... - ANSWER✔✔-Thickness
Density
Atomic number
What are Hounsfield units? - ANSWER✔✔-quantify the degree that a structure
attenuates an x-ray beam
What are the 3 general segments for the CT process? - ANSWER✔✔-Data acquisition,
Image reconstruction , and Image display
COPYRIGHT © 2025 ALL RIGHTS RESERVED
Answers
Main advantages of CT over conventional radiography? - ANSWER✔✔-Elimination of
superimposed structures
Can tell difference in densities
Superior quality of images
CT image quality is evaluated by - ANSWER✔✔-1. Spatial resolution- ability to define
small objects
2. Low-contrast resolution- ability to differentiate objects with similar densities
3. Temporal resolution- speed that data can be acquired
What is attenuation? - ANSWER✔✔-The degree to which a beam is reduced
What is the most common matrix size? - ANSWER✔✔-512 or total number of 262,144
Black areas have ___ attenuation and white areas mean the beam has been ____ -
ANSWER✔✔-Low
Completely absorbed (high attenuation)
COPYRIGHT © 2025 ALL RIGHTS RESERVED
, Density? - ANSWER✔✔-Mass of a substance per unit volume or degree to which matter
is crowded together
What is the linear attenuation coefficient? - ANSWER✔✔-Amount of X-ray beam that is
scattered or absorbed per unit thickness of the absorber
Attenuation coefficient ____ with ____ photon energy and ___ with ____ atomic number
and density - ANSWER✔✔-decreases with increasing photon energy and increases with
increasing atomic number and density
Air filled structures (low density) such as lungs appear as ___ areas on CT images -
ANSWER✔✔-black
What is given to create a temporary artificial density difference between objects to be
able to differentiate them on a image? - ANSWER✔✔-contrast
The number of photons that interact depends on... - ANSWER✔✔-Thickness
Density
Atomic number
What are Hounsfield units? - ANSWER✔✔-quantify the degree that a structure
attenuates an x-ray beam
What are the 3 general segments for the CT process? - ANSWER✔✔-Data acquisition,
Image reconstruction , and Image display
COPYRIGHT © 2025 ALL RIGHTS RESERVED
