Exam 5 Flashcards
mAs increases-
receptor exposure
mAs-
total exposure
kVp-
penetrating ability of the beam
kVp increases-
receptor exposure
kVp decreases-
contrast
kVp increases, the scale of contrast-
gets longer
kVp decreases, the scale of contrast-
gets shorter
kVp only affects-
visibility properties
motion caused by (2)-
voluntary & involuntary motion
voluntary motion-
breathing
involuntary motion-
heartbeat/peristalsis
motion increases-
-unsharpness
-penumbra/blur
-contrast only where motion occurs on img.
Motion decreases-
-spatial resolution
-image sharpness
focal spot size is confined ONLY to-
spatial resolution
focal spot size decreases-
spatial resolution
focal spot size increases
Unsharpness
SID increases-
spatial resolution
SID increases, spatial resolution increases, which results in-
less magnification (size distortion)
SID decreases-
-receptor exposure
-distortion
-intensity
OID increases-
-contrast
-size distortion
-magnification
OID decreases-
-spatial resolution
-receptor exposure
2 types of tube filtration-
inherent & added
added filtration-
intentionally added to image, can add compensating filter
added filtration filters (3)-
boomerang, wedge, & trough
wedge filter-
balances exposure, small on one end & large on other
tube filter/filtration increases-
contrast
tube filter/filtration decreases-
receptor exposure (the thicker the filter, the less exposure bec it absorbs x-ray beam)
beam restriction purpose-
decrease pt. exposure & dose & increase contrast
beam restriction/collimation increases-
contrast
beam restriction/collimation decreases-
-receptor exposure
-scatter
-quantity
beam restriction/collimation affects-
production of scatter
mA-
quantity being forced across x-ray tube
grids-
absorbs scatter before it reaches IR
Grid ratio increases-
-contrast
-mAs
Grid ratio decreases-
receptor exposure
when using a grid, you would increase mAs to-
maintain receptor exposure
when scatter increases, you get ______ contrast-
long scale of contrast
grids have no affect on-
-spatial resolution
-distortion
anode heel affect-
variation of intensity along longitudinal axis of IR
in anode heel affect, intensity increases toward _____ & decreases toward ______-
increases toward cathode & decreases toward anode
exams that utilize anode heel affect-
any exam w: short SID & large field size or coll. opened up to 14x17
elongation-
part & IR parallel to each other, but tube is angled
foreshortening-
x-ray tube perp. to IR, but part not parallel to IR
tube angle increases-
shape distortion
tube angle decreases-
-spatial resolution
-receptor exposure
patient factors-
-pt. size
-pathology
-casts
pt. factors increases-
magnification/distortion
pt. factors decreases-
-receptor exposure
-contrast
-spatial resolution