Ch 19 & 21 Image Artifacts

Question 1

What is an image artifact?

Answer 1

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

Question 2

What is the problem with having artifacts in your image?

Answer 2

• Time
• Money
• Reexposure

Question 3

How do you determine the cause of artifacts?

Answer 3

By looking at the:

• Patient
• Processing
• Exposure
• Handling & Storage

Question 4

What are benefits of early detection of artifacts?

Answer 4

• Cost

- Patient dose

Question 5

What do you do when examining films for artifacts?

Answer 5

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

Question 6

What are some processor artifacts?

Answer 6

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

Question 7

What are Pi lines?

Answer 7

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

Question 8

What do dirty rollers cause?

Answer 8

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

Question 9

What are guide shoe marks?

Answer 9

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

Question 10

What is chemical fog?

Answer 10

• Over development of film

- Developer temp, time, pH too high

Question 11

What is another name for wet Pressure sensitization?

Answer 11

Entrance roller marks

Question 12

Chemical fog is typically ______ and across the entire image.

Answer 12

Uniform

Question 13

What is wet pressure sensitization?

Answer 13

Entrance rollers become wet before film is introduced

*Looks like a water spot

Question 14

What does a discolored film look like?

Answer 14

Sepia look

-Due to hypo (fixer) retention

Question 15

What is a Dichroic stain?

Answer 15

Curtain stain that shows up in (2) colors

Question 16

What causes a brown color in the dichroic stain?

Answer 16

Oxidized developer

Question 17

What causes a greenish yellow color in a dichroic stain?

Answer 17

Incomplete fixation

Question 18

What causes hypo retention?

Answer 18

• Incomplete washing

- Has a chalky appearance

Question 19

What is plus density?

Answer 19

Darker than the background (black)

Question 20

What is minus density?

Answer 20

Lighter than the background (white)

Question 21

What causes plus density?

Answer 21

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

Question 22

What causes minus density?

Answer 22

• 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

Question 23

When does plus density happen?

Answer 23

During development stage

Question 24

Motion

Answer 24

• Blurring of the image

- Caused by pt motion, x-ray source or IR

Question 25

Heat blur

Answer 25

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

Question 26

Double Exposure

Answer 26

IR is exposed more than once before processing

Question 27

Improper patient position

Answer 27

?

Question 28

Poor film to screen contact

Answer 28

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

Question 29

Grid lines

Answer 29

- 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

Question 30

Grid cutoff

Answer 30

- 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

Question 31

Moire Effect (zebra pattern)

Answer 31

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

Question 32

What are some artifacts caused by handling & storage?

Answer 32

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

Question 33

What is radiation fog caused by?

Answer 33

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

Question 34

What causes kink marks (crescent mark?)

Answer 34

- Improper handling of film | - Stacking film too high

Question 35

What causes static artifacts?

Answer 35

- Static electricity | - Temperature or humidity too low

Question 36

What does a Smudge static artifact look like?

Answer 36

Finger print

Question 37

What does a Crown static artifact look like?

Answer 37

Crown

Question 38

What does a Tree static artifact look like?

Answer 38

Brush marks

Question 39

Generally radiographic artifacts occur in what three areas?

Answer 39

1. Exposure 2. Processing 3. Handling

Question 40

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

Answer 40

1. Image receptor 2. Software 3. Object