Image Apps Equations Flashcards
(20 cards)
How do you calculate the percent varience?
Percent variance: Measured value-set value/set value x 100
How do you calculate the minimum object size?
minimum object size=1/2(1/SF)
How do you calculate causal repeat rate?
Causal repeat rate=#of repeat images /Total # of repeats x100
How do you calculate total repeat rate?
Total repeat rate=Total # of repeat images/toatal # of images taken x 100
How do you calculate pitch?
Pitch=Couch movement per x ray tube revolution (mm)/beam width (mm)
How do you calculate the total amount of anatomy covered?
total amount of anatomy covered=Pitch x acquisition time x beam width/x ray tube rotation time
How do you calculate voxel size
Voxel size (mm2)=Pixel size (mm2)x slice thickness (mm)
How do you calculate pixel size?
Pixel size=FOV or DFOV/Matrix size
How do you calculate effective mAs?
effective mAs=mAs/pitch
How do you calculate CTDIw
CTDIw=2/3CTDI100(edge) + CTDI 100 (center)
How do you calculate CTDI vol?
CTDI vol=1/Pitch x CTDI w
How do you calculate DLP?
DLP=CTDI (vol) x scan length (cm)
Light field – X-ray field Congruency percentage deviation?
X+X+Y+Y=<2 %SID
How do you calculate SSDE?
SSDE = CTDIvol x conversion factor (which is based on the patient’s effective diameter).
The effective diameter is defined as the square root of the product of the AP and lateral patient diameters.
How do you calculate effective diameter
Effective diameter= The effective diameter is defined as the square root of the product of the AP and lateral patient diameters.
How do you calculate manual MPR?
Manual MPR=Slide thickness x incrementation of resulting images
How do you calculate the percentage of washout?
% of Washout=Enhanced-Delayed/Enhanced-Unenhanced x100 (talking about HU)
How do you calculate the total scan delay?
Total Scan Delay= Graph time at peak CE + Scan delay (talking about test bolus)
How do you calculate the AVID?
AVID=-Measurement of HU taken in the aorta-HU of the IVC
How do you calculate the contrast volume?
Contrast Volume = Injection Rate x Duration
