Ch 10 Radiographic Quality II Flashcards Preview

Slockett's Rad Exposures > Ch 10 Radiographic Quality II > Flashcards

Flashcards in Ch 10 Radiographic Quality II Deck (48):
1

What is film speed affected by?

-Immersion time
-Temperature
-Chemical activity

2

The longer the film stays in the chemical bath, the _______ the line becomes.

Straighter

3

If you increase your speed, what happens to your mAs?

It goes down

4

Speed and mAs are _______ proportional.

Inversely

5

A wide latitude, would have ____ shades of gray.

Many

6

A narrow latitude, would have a ______ scale of contrast

Short

7

Latitude and contrast are _______ proportional.

Inversely

8

What is Latitude?

Range of exposures that will produce densities within the diagnostic range

9

What is the formula for Latitude?

Latitude= E h - E I

10

E h=

High exposure point OD 2.50

11

E l=

Low exposure point OD 0.25

12

A narrow latitude film requires ______ exposure accuracy and produces short gray scales.

Greater

13

The _______ amount of magnification should be maintained.

Smallest

14

What is the ratio of image size to object size?

Magnification

15

Some magnification will _____ exist.
40"-?
72"-?

Always
40"- 1.1
72"- 1.05

16

What is SOD?

Source to object distance

17

What is OID?

Object to image distance

18

What is the acceptable magnification range?

?

19

How many cm are in an inch?

2.5

20

What are the (2) factors that effect image magnification?

1. SID
2. OID

21

What is distortion?

Unequal magnification of different portions of the same object

22

Distortion is dependent on...

-Thickness of object/ part
-Position
-Shape of the object

23

The thicker the object the _____ distortion present on the final radiograph.

More

24

We must compensate for object unsharpness with factors we can control, such as:

-Focal spot size
-SID
-OID

25

Fine detail=

Small focal spot

26

Smaller x-ray beam width will produce a _____ image.

Sharper

27

General radiology uses _____ focal spot

Large

28

The larger the focal spot the more ____ you get.

Penumbra

29

What is Penumbra?

Fuzzy border that appears outside the image

30

The greater the distance between tube and the cassette, the greater the image...

Sharpness

31

To reduce penumbra, use the _____ amount of SID.

Maximum

32

The closer the object to the film, the _____ the detail.

Sharper

33

When OID goes down, penumbra goes down and sharpness goes ____.

Up

34

When OID goes up, penumbra goes up and sharpness goes ____.

Down

35

Penumbra and Sharpness are _______ relational.

Inversely

36

Objects not on the central axis appear ______.

Distorted

37

If the object plane and the image plane are not parallel, image _______ will appear.

Distortion

38

What is Foreshortening?

Image size is reduced as the angle on inclination along the central axis increases

39

What is elongation?

The image size is lengthened as the inclination is increased

40

What is shape distortion?

The misrepresentation by unequal magnification of the actual shape of the structure being examined

41

The farther away the part of interest is from the CR of the image receptor, the greater the ______.

Distortion

42

What is focal spot blur?

Focal spot is not a point, but rather a rectangular source (0.1- 1.5mm)

43

What is the most important factor in determining resolution?

Focal spot blur

44

What is focal spot blur caused by?

-Large effective focal spot
-Short SID
-Long OID

45

What side of the tube is focal spot blur the greatest?

The cathode side

46

How do you minimize focal spot blur?

-Use small focal spots
-Decrease OID
-Increase SID

47

The difference between SID and OID =

SOD

48

Can you control subject factors?

No