CT Review || 100% VERIFIED ANSWERS!!
The ability to display small objects, or define small objects distinctly describes? correct
answers Spatial resolution
Tomography's root word "tomo" means? correct answers Cut, section, or layer
CT numbers are usually provided in the form of? correct answers Houndsfield units
The reduction in intensity of an x-ray beam as it interacts with matter is termed? correct
answers attenuation
The most current and proper name for CT is? correct answers Computed Tomography
What is a major limitation of conventional radiography when compared to computed
tomography?
-superimposition of tissues
-homogenous x-ray photon production
-increased radiation dose to the patient
-lack of digital imaging capabilities correct answers Superimposition of tissues
A CT scanner creates what type of images? correct answers cross-sectional
The thickness of a slice would be determined by what axis of the body? correct answers z-
axis
Given the window setting of window width = 1200, and window level = -300, what would be
the lowest value in the range? correct answers -900
A ct image is displayed in a window with a level of 0 and a width of 500. What would the
pixel values be? correct answers pixels with values between -250 and +250 HU are assigned
shades of grey
RIO measurements include what?
-the area selected
-the average HU
-the standard deviation correct answers all of the above
As the displayed field of view decreases
1. less anatomy is selected
2. spatial resolution increases
3. spatial resolution decreases correct answers 1 and 2
what CT number represents water? correct answers 0
Window width represents what? correct answers image contrast
to view a CT image on a LCD monitor, data must undergo what? correct answers digital-to-
analog conversion
, a 16 slice helical/spiral scanner produces how many images from a single slice of scan data?
correct answers 16
what operation forms the basis for CT reconstruction? correct answers Fourier transform
how do we solve for mAs correct answers mA x time
what is a common kVp for pediatric patients? correct answers 80 kVp
If we increase our matrix from 512 x 512 to 1024 x 1024, pixel size and spatial resolution do
what? correct answers pixel size decreases
spatial resolution increases
Increasing our mA in CT allows us to do what? correct answers allows us to lower our scan
time
Decreasing pixel size does what to the number of photons? correct answers decreases
Decreasing pixel size does what to noise? correct answers increases
Which matrix will have the most pixels?
a. 80x80
b. 256x256
c. 512x512
d. 1024x1024 correct answers 1024x1024
How many pixels would a 1024x1024 matrix contain? correct answers 1,048,576
When a matrix size is decreased from 1024^2 to 512^2 for the same field of view, which of
the following would be true?
1. the pixels will become larger
2. the pixels will become smaller
3. there will be a greater amount of volume averaging.
4. there will be less volume averaging correct answers 1 and 3
A two dimensional square created by the x and y axis of the matrix is called correct answers
picture element
The z axis runs along what? correct answers the length of the body
The atomic number of an object or tissue and the amount of x-ray beam attenuated
demonstrates what type of relationship? correct answers direct
When an object allows many x-ray photons to pass through it, the image will appear? correct
answers darker
The amount that an x-ray beam is attenuated per centimeter as it passes through a
tissue/object describes the? correct answers Linear attenuation coefficient
An average CT number for fat is correct answers -100 HU
The ability to display small objects, or define small objects distinctly describes? correct
answers Spatial resolution
Tomography's root word "tomo" means? correct answers Cut, section, or layer
CT numbers are usually provided in the form of? correct answers Houndsfield units
The reduction in intensity of an x-ray beam as it interacts with matter is termed? correct
answers attenuation
The most current and proper name for CT is? correct answers Computed Tomography
What is a major limitation of conventional radiography when compared to computed
tomography?
-superimposition of tissues
-homogenous x-ray photon production
-increased radiation dose to the patient
-lack of digital imaging capabilities correct answers Superimposition of tissues
A CT scanner creates what type of images? correct answers cross-sectional
The thickness of a slice would be determined by what axis of the body? correct answers z-
axis
Given the window setting of window width = 1200, and window level = -300, what would be
the lowest value in the range? correct answers -900
A ct image is displayed in a window with a level of 0 and a width of 500. What would the
pixel values be? correct answers pixels with values between -250 and +250 HU are assigned
shades of grey
RIO measurements include what?
-the area selected
-the average HU
-the standard deviation correct answers all of the above
As the displayed field of view decreases
1. less anatomy is selected
2. spatial resolution increases
3. spatial resolution decreases correct answers 1 and 2
what CT number represents water? correct answers 0
Window width represents what? correct answers image contrast
to view a CT image on a LCD monitor, data must undergo what? correct answers digital-to-
analog conversion
, a 16 slice helical/spiral scanner produces how many images from a single slice of scan data?
correct answers 16
what operation forms the basis for CT reconstruction? correct answers Fourier transform
how do we solve for mAs correct answers mA x time
what is a common kVp for pediatric patients? correct answers 80 kVp
If we increase our matrix from 512 x 512 to 1024 x 1024, pixel size and spatial resolution do
what? correct answers pixel size decreases
spatial resolution increases
Increasing our mA in CT allows us to do what? correct answers allows us to lower our scan
time
Decreasing pixel size does what to the number of photons? correct answers decreases
Decreasing pixel size does what to noise? correct answers increases
Which matrix will have the most pixels?
a. 80x80
b. 256x256
c. 512x512
d. 1024x1024 correct answers 1024x1024
How many pixels would a 1024x1024 matrix contain? correct answers 1,048,576
When a matrix size is decreased from 1024^2 to 512^2 for the same field of view, which of
the following would be true?
1. the pixels will become larger
2. the pixels will become smaller
3. there will be a greater amount of volume averaging.
4. there will be less volume averaging correct answers 1 and 3
A two dimensional square created by the x and y axis of the matrix is called correct answers
picture element
The z axis runs along what? correct answers the length of the body
The atomic number of an object or tissue and the amount of x-ray beam attenuated
demonstrates what type of relationship? correct answers direct
When an object allows many x-ray photons to pass through it, the image will appear? correct
answers darker
The amount that an x-ray beam is attenuated per centimeter as it passes through a
tissue/object describes the? correct answers Linear attenuation coefficient
An average CT number for fat is correct answers -100 HU
