CT Math || 100% Errorless Solutions.
how do you calculate in plane resolution correct answers divide DFOV by # of pixels along each
direction of the matrix
calculating th smallest object able to be imaged correct answers divide DFOV by # of pixels
along each direction of the matrix
if you decreases the DFOV what happens to the noise correct answers it increases
resolution can be expressed as correct answers DFOV divded by matrix
increase in matrix will affect the pixel how correct answers decreases the pixel size
if you increase the matrix, you ___the detail correct answers increase
if you increase the matrix, you _____ the noise correct answers increase
pitch for single row is expressed correct answers pitch= movement of the patient table in one
gantry rotaion/ slice thickness
pitch for MDCT is expressed by correct answers pitch= movement of the patient table in one
gantry rotation/ total slice volume
OR
pitch= movement of the patient table in one gantry rotation/ thickness of a single slice
how do you calculate the smallest line pair that can be resolved also known as the resolution of
the ct correct answers if the lines with 8 line pair per centimeter can just be resolved. the spatial
resolution is 10mm divided by 16 lines (each line equals 2. one for the line and one for the space
in between)
10mm (1 cm is 10 mm) divided by 16= 0.625
name the three factors for a detector efficiency correct answers absorbtion efficiency, capture
efficiency, and conversion efficiency
how do you calculate pixel size correct answers dfov/matrix size=
how do you calculate dfov correct answers matrix size x pixel (in mm)=
how do you calculate to get the CT number correct answers utisuue - uwater (then divide that
answer by uwater) and then multiply that by 1000
, how do you calculate to get the MSAD correct answers msad= ct dose index(slice
thickness)/table increment
if pitch is 1, then MSAD is _______ to CTDI correct answers equal to
the voxel dimension can be calculated by multiplying the pixel by correct answers first calculate
the dimension (divde dfov x matrix) then square the answer
how do you calculate the smallest object able to view if the limiting resolution is 15 lp/cm
correct answers first take the number and make it reciprical. 15lp/cm to 1/15 then to 10/15.
divide 15 in to 10 = 0.6. this will then be cut in half. because for every line there is a space. 0.3 is
the answer
voxel is equal to ________ x _______ correct answers pixel x section width
if the pitch is 1 and the slice thickness is 5mm, what is required per rotation correct answers the
gantry will turn 5 mm per rotation
if the pitch is 2 and the slice thickness is 5 mm what is required per rotation correct answers the
gantry will turn 10mm per rotation
in MDCT what would the pitch be if it has 4-slice MDCT and 1.25mm slice thickness and a table
feed of 6mm. correct answers 6/(4 x 1.25) = 6/5= 1.2
what is the formula in MDCT to calculate scan coverage correct answers pitch x total acquisition
x 1/rotation time x (slice thickness x slices per rotation) =anatomy covered
to determine the distance covered in SDCT helical what is the formula correct answers pitch x
total acquisition x 1/rotation time x slice thickness =anatomy covered
to determine the number of images in SDCT helical what is the formula correct answers pitch x
total acquisition x 1/rotation time =number of images
overscan is calculated by correct answers xray tube rotates more than half. it does the full 360
and adds the scan filed of view (40). this was used to overlap some of the scan and helps with the
inconsistencies
when measuring the lines on a phantom, you measure 20 lines in a space that is one centimeter
how would you write that correct answers 20 lines per 1p/cm
dose length product correct answers calculated dose per section mulitplied by the length of a CT
acquisition along the z-axis. DLP= CTDIv x scan length
how do you calculate Kev from kvp correct answers 30-40% of kvp
another name for hypopaque (ionic or nonionic) correct answers ionic, diatrizoate(gastrographin)
how do you calculate in plane resolution correct answers divide DFOV by # of pixels along each
direction of the matrix
calculating th smallest object able to be imaged correct answers divide DFOV by # of pixels
along each direction of the matrix
if you decreases the DFOV what happens to the noise correct answers it increases
resolution can be expressed as correct answers DFOV divded by matrix
increase in matrix will affect the pixel how correct answers decreases the pixel size
if you increase the matrix, you ___the detail correct answers increase
if you increase the matrix, you _____ the noise correct answers increase
pitch for single row is expressed correct answers pitch= movement of the patient table in one
gantry rotaion/ slice thickness
pitch for MDCT is expressed by correct answers pitch= movement of the patient table in one
gantry rotation/ total slice volume
OR
pitch= movement of the patient table in one gantry rotation/ thickness of a single slice
how do you calculate the smallest line pair that can be resolved also known as the resolution of
the ct correct answers if the lines with 8 line pair per centimeter can just be resolved. the spatial
resolution is 10mm divided by 16 lines (each line equals 2. one for the line and one for the space
in between)
10mm (1 cm is 10 mm) divided by 16= 0.625
name the three factors for a detector efficiency correct answers absorbtion efficiency, capture
efficiency, and conversion efficiency
how do you calculate pixel size correct answers dfov/matrix size=
how do you calculate dfov correct answers matrix size x pixel (in mm)=
how do you calculate to get the CT number correct answers utisuue - uwater (then divide that
answer by uwater) and then multiply that by 1000
, how do you calculate to get the MSAD correct answers msad= ct dose index(slice
thickness)/table increment
if pitch is 1, then MSAD is _______ to CTDI correct answers equal to
the voxel dimension can be calculated by multiplying the pixel by correct answers first calculate
the dimension (divde dfov x matrix) then square the answer
how do you calculate the smallest object able to view if the limiting resolution is 15 lp/cm
correct answers first take the number and make it reciprical. 15lp/cm to 1/15 then to 10/15.
divide 15 in to 10 = 0.6. this will then be cut in half. because for every line there is a space. 0.3 is
the answer
voxel is equal to ________ x _______ correct answers pixel x section width
if the pitch is 1 and the slice thickness is 5mm, what is required per rotation correct answers the
gantry will turn 5 mm per rotation
if the pitch is 2 and the slice thickness is 5 mm what is required per rotation correct answers the
gantry will turn 10mm per rotation
in MDCT what would the pitch be if it has 4-slice MDCT and 1.25mm slice thickness and a table
feed of 6mm. correct answers 6/(4 x 1.25) = 6/5= 1.2
what is the formula in MDCT to calculate scan coverage correct answers pitch x total acquisition
x 1/rotation time x (slice thickness x slices per rotation) =anatomy covered
to determine the distance covered in SDCT helical what is the formula correct answers pitch x
total acquisition x 1/rotation time x slice thickness =anatomy covered
to determine the number of images in SDCT helical what is the formula correct answers pitch x
total acquisition x 1/rotation time =number of images
overscan is calculated by correct answers xray tube rotates more than half. it does the full 360
and adds the scan filed of view (40). this was used to overlap some of the scan and helps with the
inconsistencies
when measuring the lines on a phantom, you measure 20 lines in a space that is one centimeter
how would you write that correct answers 20 lines per 1p/cm
dose length product correct answers calculated dose per section mulitplied by the length of a CT
acquisition along the z-axis. DLP= CTDIv x scan length
how do you calculate Kev from kvp correct answers 30-40% of kvp
another name for hypopaque (ionic or nonionic) correct answers ionic, diatrizoate(gastrographin)
