FINAL RADIO Flashcards
Source to skin distance at 50kvp =
If >50kvp?
10cm
18cm
Ideal paralleling technique distance
12 inches
X ray field should have diameter of ___ or less
7cm
If exposure is longer than __, operator should be able to terminate it
0.5s
kvp and time need to be within __% accuracy
10%
Coefficient of variation for reproductibility of kvp, timing, and radiation exposure shall not exceed ___ for 4 consecutive exposures
0.05
Continuous dynamic process that can see things in real time
flouroscopy
Hand-held radiation can only be used for intraoral (T/F)
TRUE
If operating voltage (kVp) is from 50-70, total filtration is:
kvp in the 70s=
kvp in 80s=
kvp in 90s
50-70 = 1.5
70s= 2.1
80s=2.3
90s=2.5
Which film speed is the minimum
E-speed or faster!
What makes a detailed radiograph of a plane section of a solid object while blurring out the images of adjacent planes. What’s the focused area called?
panoramic
focal trough
Where is film in pan
film in FRONT of patient
Vertical magnification varies little with _____
object depth (focal spot to object distance)
Light, pale film is from
UNDERexposure
If anterior teeth look small (pic is very zoomed out), patient is biting..
too far onto rod (face is closer to film in front)
what plane is horizontal from tragus to the lower part of orbit of eye
frankfurt plane
If pano has exaggerated smile, patient chin is tipped ___
down
Pano is __% less dose than a full mouth series
20
Disadvantages of pano
poor definition
20-30% magnification
What produces non-superimposed images
CT (computed tomography)
What’s a Hounsfield unit
measurement of grey values in CT
Isotropic resolution:
Anisotropic:
boxes with all 4 sides equal (much clearer)
not all sides equal
Conebeam has between ____ sequential planar projection images of the field of view
150-600
Small field of view for cone beam=
medium=
large=
small 10
Difference of fan beam and cone beam with soft tissue
Fan beam shows all soft tissue. Cone only shows outline
MRI 3 steps
magnetic field
radio frequency pulse
relaxation
MRI signal is essentially a map of ____ion distribution in the body
hydrogen
What shows up black on MRI
What shows up white
black=air
white=fat
Which shows structure AND function of target tissues
Nuclear scintigraphy
3 ways to look at cone beam
3d volume rendering
2d multiplanar
3d curve MPR
Axial view of cone beam is look at occlusal surface of teeth (T/F)
TRUE
Caries are (increased/decreased) absorption of x-ray beam
decreased
Mach band is defined as a radiolucent (black) density difference between
enamel and dentin.
it’s an optical illusion! Can create false-positive
For periapical, rarefying osteitis is radio___
sclerosing is radio___
lucent
opaque
