Radiographic Interp. 3A (Diag. Quality)

Front 1

A good radiograph should have (maximum/minimal) projection geometry

Back 1

minimal

Front 2

What are two things that cause motion unsharpness?

Back 2

moving BID or moving patient

Front 3

What is defined as "how well a boundary between two areas of differing radiodensity is revealed"?

Back 3

sharpness

Front 4

What is defined as "how well an image reveals small objects that are close to each other"?

Back 4

resolution

Front 5

If a radiograph is very dense, then it is (black/white)

Back 5

black

Front 6

The difference between the blacks, whites, and greys is known as what?

Back 6

contrast

Front 7

What is the useful range of radiographic density? (# value)

Back 7

0.3 (light) to 3.0 (dark)

Front 8

Increasing current will (increase/decrease) density

Back 8

increase

Front 9

Increasing voltage will (increase/decrease) density

Back 9

increase

Front 10

Increasing the distance of the x-ray source (tungsten block) will (increase/decrease) density

Back 10

decrease

Front 11

Increasing the development time will (increase/decrease) density

Back 11

increase (fog)

Front 12

What does the acronym SFD stand for?

Back 12

Source-image receptor distance (I'm guessing the "F" means "film" too)

Front 13

Beam intensity varies (directly/inversely) to the SQUARE of the SFD

Back 13

inversely

Front 14

Shorter distance between film and x-ray results in (higher/lower) density because of a (high/low) beam intensity

Back 14

higher; high

Front 15

Doubling the distance does what to the density?

Back 15

1/4th the density

Front 16

Halving the distance gives (2x/4x/8x) the density

Back 16

4x

Front 17

Underdevelopment produces (high/low) density images

Back 17

low

Front 18

(Over/under)development results in fog

Back 18

over

Front 19

Higher speed image receptor requires (more/less) mAs to produce a density change compared with slower-speed image receptors

Back 19

less

Front 20

Higher-speed intensifying screens require (less/more) mAs

Back 20

less

Front 21

True or False, fog has no effect on image contrast

Back 21

false

Front 22

Fog leads to (increased/decreased) density and (increased/decreased) contrast

Back 22

increased; decreased

Front 23

If you want to change the contrast, you need to change what parameter?

Back 23

kVp (Kontrast - Kvp)

Front 24

(High/Low) contrast has many shades of grey

Back 24

low

Front 25

Long scale contrast is synonymous with (high/low) contrast

Back 25

low

(Long = Low)

Front 26

High kVp = (low/high) contrast

Back 26

low

Front 27

Low kVp = (low/high) contrast

Back 27

high

Front 28

What is the range for high and low kVp?

Back 28

High = 80-90
Low = 60-65

Front 29

A radiograph with many shades of grey is considered (long/short) scale

Back 29

Long (remember, many greys is LOW contrast and Long = Low)

Front 30

PAs should have generally (higher/lower) contrast whereas bitewings should have generally (higher/lower) contrast

Back 30

lower, higher

Front 31

If you increase kVp, you must (increase/decrease) mAs or time to maintain density

Back 31

decrease

Front 32

Changes in density by changing mAs has what residual effect on contrast

Back 32

none

Front 33

Why will a change in CONTRAST also have an effect on DENSITY?

Back 33

Because to change contrast you must alter the kVp. When you alter the kVp, you also effect the density at the same time.

Front 34

You get better resolution and detail with a (small/large) focal pt.

Back 34

small

Front 35

When two distinct x-ray waves strike an object and travel in distinct lines, they hit the film in slightly different locations. The shadow-like distortion created by this is called what?

Back 35

Umbra (penumbra is the border of an umbra)

Front 36

With similar techniques, objects farther from the image receptor will always magnify (more/less) than objects closer to the image receptor

Back 36

more

Front 37

Divergent x-ray photon paths cause (enlargement/reducing)

Back 37

enlargement

Front 38

True or False, X-rays originate from an AREA and travel in diverging, but straight, lines that radiate from the source

Back 38

True

Front 39

Distance between focal spot and object should be as (long/short) as possible

Back 39

long

Front 40

Image receptor (film) should be as (close/far) as possible to the object

Back 40

close

Front 41

If you have the image receptor and object very close together, this will help to reduce what?

Back 41

magnification (this is like of you have a flashlight on your hand but the shadow is on a wall and you bring the wall in closer to your hand... now the shadow gets smaller and smaller until the wall is right up to your hand and the shadow and your hand are virtually the same size)

Front 42

True or False, it doesn't matter what angle the CR is to the film, as long as it's pointed at the middle

Back 42

False, it should be perpendicular

Front 43

Smaller focal spot = (larger/smaller) pneumbra

Back 43

smaller

Front 44

Geometric unsharpness can be minimized by having a (large/small) focal spot

Back 44

small

Front 45

Why are lingual cusps sharper?

Back 45

They are close to the image receptor

Front 46

To decrease magnification, we should (increase/decrease) the source to object distance

Back 46

increase (think about if you hold a flashlight close to your hand, the shadow will be large. Hold the flashlight far from your hand, and the shadow becomes much smaller [less magnified])

Front 47

Radiograph has anatomical accuracy when proximal contacts are (open/closed)

Back 47

open

Front 48

Radiograph has anatomical accuracy when buccal and lingual cusps of posterior teeth are (separated/superimposed)

Back 48

superimposed

Front 49

Radiograph has anatomical accuracy when buccal and lingual portions of alveolar crest are (separated/superimposed)

Back 49

superimposed

Front 50

If you are talking about the MANDIBLE, vertical OVERangulation is when the BID is pointed at the tooth from (above/below)

Back 50

below! for the maxilla, it would be above. the plane reverses when considering maxilla and mandible

Front 51

Radiograph has anatomical accuracy when the zygomatic arches (are/are not) covering the roots of the maxillary teeth

Back 51

are not

Front 52

In a bitewing, you can tell if it is right side up because the arch should slope (upward/downward) in the 3rd molar region

Back 52

upward

Front 53

*in class question
The size of the x-ray tube focal spot influences the image:
A. density
B. contrast
C. definition
D. distortion

Back 53

C. Definition

Front 54

*in class question
Which of the following does not control magnification of the object?
A. Focal spot-image receptor distance
B. Alignment of image receptor, object and BID
C. object-image receptor distance
D. Cathode size

Back 54

D. Cathode size

Front 55

*in class question
True or False: Radiographic fog will increase density and decrease contrast

Back 55

A. True

Front 56

*in class question
Why extending the source-image receptor distance by using a longer BID a necessary adjunct to intraoral paralleling technique?
A. To avoid unsharpness of the image
B. To avoid shape distortion of the image
C. To reduce scatter radiation
D. To avoid anatomical superimposition

Back 56

A. To avoid unsharpness of image (could also be B)

Front 57

*in class question
How do you change from a long scale contrast to a short scale contrast and still maintain the density?
A. Decrease kVp and increase mAs
B. Increase kVp and decrease mAs
C. Decrease kVp and decrease mAs
D. Increase kVp and increase mAs

Back 57

A. Decrease kVp and increase mAs (Low kVp = high contrast; high contrast = short scale contrast)