Week 4 Flashcards
The path of the x-ray beam as it enters and exits the patient.
Projection
A path of an individual photon from the x-ray tube to the detector.
Ray
Individual measurement of beam attenuation
Ray sum
Combined attenuation properties of each ray sum cross-referenced with their respective positions.
Attenuation profile
A complete set of ray sums collected from multiple angles.
View
Information from all of attenuation profiles projected onto a matrix
Image
Interpolation is necessary because:
it allows the viewer to observe the images in a flat plan
a mathematical technique used to estimate the value of a function from known values on either side of the function.
Interpolation
Determines the total area scanned
Scan field of view (SFOV)
Ability to merge image data from overlapping acquisition data sets
Interlaced sampling
The relationship between DFOV and pixel size is:
Direct
The relationship between matrix and pixel size is:
Inverse
Adjusting the window width changes the ______ of an image.
Contrast
Adjusting the window level changes the ______ of an image.
Brightness
A disadvantage of performing image reformatting is the:
loss of image detail
MIPs, or maximum intensity projections, are created using only the ______ Housfield units and filtering out the rest
highest
T/F: Multiplanar reconstruction does not add additional information to the data set, just presents it in a new way.
True
The central database for receiving and storing image data is called:
PACS
T/F: The Hounsfield scale represents the range of contrast allowed to be administered in a scan
False
Subject scan data to mathematical processes
Kernels
Most modern CT scanners use ___ degree linear interpolation because:
180; increases spatial resolution
Difference from one slice to the next
Pitch
Size of reconstructed area on the monitor after the patient has been scanned
Display field of view (DFOV)
Scans requiring fewer shades of grey (brain)
Narrow WW
