Fall 2012 - Radiology - Test 1 - Artifacts

Front 1

define radiographic artifacts

Back 1

anything that decreases the quality of the radiograph

any density not caused by proper shadowing of the object in the primary beam

Front 2

How do you evaluate film quality (what factors do you evaluate)

Back 2

exposure

positioning

labeling

centering

collimation

development/ processing

artifacts

Front 3

Back 3

This is an example of a non-diagnostic study due to overexposure

Front 4

Back 4

focal increased radioopacity in the disc space at L5-L6 IV disc space

due to debris on intensifying screen

Front 5

poor quality radiographs can result in

Back 5

non-dx study

missed or incorrect dx

excessive radiation exposure

increased cost to clinic & client

Front 6

What is the first thing you should look for when first evaluating an image

Back 6

evaluate film quality and identify artifacts

are the necessary items included?

is the film the correct density?

are the images clear?

Front 7

once you have identified an artifact, what should you ask yourself

Back 7

generalized or localized?

phase of image production
- prior to exposure
- during exposure
- during or after processing

Front 8

what are some of the common generalized artifacts

Back 8

decreased film density

poor contrast (film fog)

grid cutoff

off-collimation

image off-center

increased film density

motion

unevenly developed

kissing defect

double exposure

Front 9

Back 9

increased film density (film too dark)

overexposure
- technique too high (kVp, mA/ exposure time too long)
- use of grid technique w/o using a grid
- overestimation of thickness of the part to be examined

double exposures

decreased focal-film distance

increased developer time or developer temp too high

decreased focal-film dist
- decreasing the dist b/w the xray tube and the patient surface increases the concentration of radiation thus creating a darker radiograph

Front 10

Back 10

underexposure (decreased film density)

technique too low
- low kVp, mA
- exposure time too short

increased focal film dist

improper use of a slower film screen combination
- improper film for type of intensifying screen

underestimation of patient thickness or density

decreased developer time or low developer temp

failure to hold exposure switch closed for the length of the exposure time

loading 2 films in a cassette

Front 11

Back 11

loss of contrast (fog)

- pressure (stacking boxes in storage area)

- heat/ humidity (should be
stored <68 deg F; 30-50% humidity)

- light (safelight in darkroom might be too close to film, wrong spectrum of light for film, film exposed to safelight for too long, darkroom not light tight)

- chemical exposure (increased developing time due to exhausted developer, gasses such as formaldehyde in storage area)

- old film

- scattered radiation (storing cassettes in xray room, leaning on wall in room during second exposure with a diff cassette)

Front 12

how do you account for scatter radiation

Back 12

scatter increases with
- thickness of patient
- kVp setting
- field size

corrections
- use grid for anything over 10 cm
- use appropriate kVp
- collimate

Front 13

why does a properly positioned grid matter

Back 13

grid allows most of the primary radiation to reach the film and absorbs scatter radiation that is not parallel with the grid
- you have to increase mAs to compensate for decrease in primary beam

malpositioned grid
- blocks the primary beam to a greater degree than expected
- causes uniform loss of primary radiation across the entire surface of the grid
- lateral decentered grid
- off level grid

upside down grid
- extreme loss of primary radiation at the periphery, with near norm transmission at the center
- underexposure of edges

Front 14

Back 14

malpositioned grid

xray tube is off center in relation to grid

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Back 15

upside down grid

underexposed edges (notice the bands in the underexposed areas)

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Back 16

double exposure

2 separate images in the film with generalized overexposed, dark film

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Back 17

double exposure

2 separate images in the film with generalized overexposed, dark film

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Back 18

double exposure

due to accidental double click

2 images slightly overlapping each other
- more maxillary canines than norm
- really dark film

Front 19

Back 19

motion artifact

motion assoc with patient, tube, or cassette

SOLUTIONS

proper chemical &/or physical restraint
- buprenex can cause panting so hard to get good film

use fast screen film

avoid hand holding cassettes

shorter exposure time
- increase mA

Front 20

Back 20

film unevenly developed

chemicals not stirred

white streaky patter over the entire film

Front 21

Back 21

improper rinsing of film

Front 22

Back 22

chemical stains

developer not rinsed and streaks down film

Front 23

Back 23

kissing defect

Front 24

Back 24

localized area of increased density due to light leak

Front 25

Back 25

light leak

film exposed to light along the edge (likely while in storage bin)

check other films in that package

Front 26

Back 26

light leak

Front 27

Back 27

cassette not properly closed

allowed light to expose the corner of the film

also less image sharpness next to light leak

poor screen to film contact due to the cassette not being properly closed

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Back 28

localized artifact

bending film

Front 29

Back 29

mult crescent shaped artifacts caused by bending of the film

Front 30

Back 30

static electricity

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Back 31

static electricity
- smudge pattern

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Back 32

radioopaque material on left leg = surface debris

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Back 33

skin fold "artifact"

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Back 34

ET tube and esophageal stethoscope

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Back 35

ECG clips and lines

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Back 36

cast material causes a fuzzy appearance & decreases quality of the rad

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Back 37

malpositioning

Front 38

Back 38

malpositioning

Front 39

Back 39

how to fail 4th yr radiology

Front 40

how do you fail 4th year radiology

Back 40

Front 41

Back 41

improper LUT assignment

using abd setting when imaging thorax

Front 42

Back 42

quantum mottle

due to too few incident xrays striking the imaging plate
(not enough xray input or excessive attenuation - patient or grid)

result
- grainy, pixilated, mottled image

correction
- increase technique and retake image (provides the imaging plate with more info)

Front 43

Back 43

parital erasure

see previous image in background that remains due to incomplete erasure of the previous image from the digital plate

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Back 44

paradoxical overexposure

due to extreme overexposure

only most highly attenuated areas are displaced in norm gray scale

corrected by decreasing technique

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Back 45

Überschwinger artifact

this is norm with how the computer interprets the film (don't mistake for motion/ implant failure)

Thin black line along extremely radiopaque objects

Mimics lucent area seen with loosening/movement or infection around orthopedic devices

Decrease the artifact by controlling frequency spectrum of image

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Back 46

MOIRE

Results from using a low frequency grid with digital imaging