Ch 19 & 21 Image Artifacts Flashcards Preview

Slockett's Rad Exposures > Ch 19 & 21 Image Artifacts > Flashcards

Flashcards in Ch 19 & 21 Image Artifacts Deck (40):
1

What is an image artifact?

Any undesirable OD on an image that does not properly show the anatomy being examined

2

What is the problem with having artifacts in your image?

-Time
-Money
-Reexposure

3

How do you determine the cause of artifacts?

By looking at the:
-Patient
-Processing
-Exposure
-Handling & Storage

4

What are benefits of early detection of artifacts?

- Cost
- Patient dose

5

What do you do when examining films for artifacts?

-Isolate artifact
-Identity the cause
-Make corrections to eliminate the cause

6

What are some processor artifacts?

-Emulsion pickoff
-Chemical fog
-Guide shoe marks
-Roller scratches
-Wet pressure sensitization
*water mark
-Chemical spots

7

What are Pi lines?

- Occur at 3.14 inch intervals
- Due to dirt or a chemical stain on a roller
- Artifact appears perp. to films direction of travel

8

What do dirty rollers cause?

Emulsion pick off and gelatin buildup resulting in sludge deposits on the film

9

What are guide shoe marks?

Seen at leading or trailing edge on film caused by improper positioning

10

What is chemical fog?

- Over development of film
- Developer temp, time, pH too high

11

What is another name for wet Pressure sensitization?

Entrance roller marks

12

Chemical fog is typically ______ and across the entire image.

Uniform

13

What is wet pressure sensitization?

Entrance rollers become wet before film is introduced
*Looks like a water spot

14

What does a discolored film look like?

Sepia look
-Due to hypo (fixer) retention

15

What is a Dichroic stain?

Curtain stain that shows up in (2) colors

16

What causes a brown color in the dichroic stain?

Oxidized developer

17

What causes a greenish yellow color in a dichroic stain?

Incomplete fixation

18

What causes hypo retention?

- Incomplete washing
- Has a chalky appearance

19

What is plus density?

Darker than the background (black)

20

What is minus density?

Lighter than the background (white)

21

What causes plus density?

- Caused by physical pressure on the film AFTER it was exposed
- Poor film handling
- Poor loading techniques
- Dropping or bending fo film

22

What causes minus density?

-Caused by physical pressure on film BEFORE it was exposed
- Artifact was caused before the fixing or washing stage
- Usually dust or dirt on cassette

23

When does plus density happen?

During development stage

24

Motion

-Blurring of the image
-Caused by pt motion, x-ray source or IR

25

Heat blur

Occurs when CR imaging plate is exposed to intense heat before processing with the CR reader system

26

Double Exposure

IR is exposed more than once before processing

27

Improper patient position

?

28

Poor film to screen contact

- Results in localized blurring of the image
- May appear smooth in the area of poor contact on the image

29

Grid lines

- Shadows of lead strips that appear due to failure of grid to move during the exposure
- Improper grid-focusing distance
- Improper centering
-improper angulation of CR w/respect to the grid lines

30

Grid cutoff

- A decrease in OD caused by primary radiation being absorbed by the grid
- Caused when patient is placed under the tube when the tube is not centered to the table or Bucky tray

31

Moire Effect (zebra pattern)

-Double set of grid lines caused by the placement of a grid cassette in a Bucky
-Biggest artifact in MRI

32

What are some artifacts caused by handling & storage?

-Light fog
-Radiation fog
-Static
-Kink marks
-Scratches
-Dirty cassettes

33

What is radiation fog caused by?

- Temperature or humidity too high
- Film bin not properly shielded from radiation
- Safelight too bright
- Film left in room during add. exposures

34

What causes kink marks (crescent mark?)

-Improper handling of film
-Stacking film too high

35

What causes static artifacts?

- Static electricity
- Temperature or humidity too low

36

What does a Smudge static artifact look like?

Finger print

37

What does a Crown static artifact look like?

Crown

38

What does a Tree static artifact look like?

Brush marks

39

Generally radiographic artifacts occur in what three areas?

1. Exposure
2. Processing
3. Handling

40

What are the (3) classification of artifacts in DR?

1. Image receptor
2. Software
3. Object