Diagnostic Rad

Front 1

INTENSIFYING SCREEN

Back 1

sheet of plastic in a CASSETTE that makes the x-ray beam STRONGER and FASTER

Holds film tight to screens

Front 2

Problem with old school radiology

Back 2

DIRECT EXPOSURE of film (great resolution), no screen, radiation!

Slow exposure, high dose

Front 3

To make x-ray film more sensitive, there is an ________________ on both sides of the cassette

Back 3

intensifying screen (Double emulsion)

Front 4

What directly exposes the film?

Back 4

FROM THE LIGHT DIRECTLY FROM INTENSIFYING SCREENS

Screens light up when I push the deadman button

Front 5

What exposes the film?

Back 5

the INTENSIFYING SCREENS

Front 6

Of the photons that make it through the screens, only 30% make it to the patient. What's the point?

Back 6

Reduce patient exposure
Lowers wear and tear on machine

Downside: lowers quality

Front 7

Cassettes are _________, so don't put it in backwards.

Back 7

UNIDIRECTIONAL
there is a front side and a back side so the front has low atomic number and therefore won't absorb all your x-rays. Backside has high atomic number to absorb x-ray.

Front 8

To prevent back scatter, what is on the back of the cassette?

Back 8

HIgh atomic number and thin protective layer

Front 9

Screens: Structures called Phosphor? (luminescence is something glowing in response to a stimulus)

Back 9

The structure that GIVES OFF THE LIGHT is the phosphor.

Front 10

2 types of lumenescent materials:

Back 10

Flourescent -
Phosphorescence -

Front 11

continues to emit light after the stimulus shuts off

Back 11

phosphorescence

Front 12

visible light is emitted only when the phosphor is emitted

Back 12

Fluorescence

ie, fluor light bulbs
x-ray screens

Front 13

Afterglow

Back 13

even fluorescent materials can have some phosphorescence (the green glow after the tv is turned off)

Front 14

By putting emulsion on both sides of the film, I cut the dose in ___

Back 14

1/2

Front 15

Cross section of intensifying screen - layer where all the magic happens?

Back 15

PHOSPHOR layer is where fluoresence happens

Front 16

1 xray hitting1 phosphor creates _____ photons

Back 16

1000

Front 17

Original material of screen

Back 17

calcium tungstate CaWO4

Front 18

Second kind of screen after calcium tungstate?

Back 18

RARE EARTH (mid 70's)

Gadolinium and yttrium

Front 19

What kind of screen should you NEVER UNDER ANY CIRCUMSTANCES USE?

Back 19

CALCIUM TUNGSTATE

Front 20

Phosphors emit light ____________

Back 20

ISOTROPICALLY
produced in all directions equally

Front 21

How to make screens better to offset isotropic effect?

Back 21

Add a REFLECTIVE LAYER to bounce photons back to the film and DOUBLES the efficiency

Front 22

Problem with reflective layer of screen?

Back 22

Light photons that travel in a straight path give exact image. Ones that bounce back still give exact image. What if taken at angle? DECREASED RESOLUTION because photon does not return straight angle.

Front 23

Isotropic light formation problem

Back 23

decreased radiation

Front 24

Isotropic light formation solution

Back 24

DYES in phosphor layer absorb photons with steeply angled path

decreases speed, increases resolution

Front 25

DYES

Back 25

increase resolution

Front 26

Number one reason screens get damaged?

Back 26

MECHANICAL WEAR AND TEAR

fingernails

Front 27

Screen characteristics

Back 27

speed
image noise
resolution

Front 28

screen speed

Back 28

depends of type of screen - the number of LIGHT photons that are released by each x-ray photon

decreases pt. dose and resolution

Front 29

Balance speed, patient dose, and _________

Back 29

resolution

high res = high dose

Front 30

PAR SPEED

Back 30

100 speed of screen

based on old CaWO4

Front 31

screen IMAGE NOISE

Back 31

images on old tv is pixelated - 'image noise' vs. HD tv resolution

FAST screens make NOISY screens

Front 32

high kVp, photoelectric effect decreases

what happens to compton effect

Back 32

decreases.

Photoelectric effect happens faster so we see a lot more compton (scattered effect) = QUANTUM MODEL

Front 33

mass is too low then not enough photons to give me a distinct picture. This is when ______________ comes into play

Back 33

quantum model

Front 34

Screen spatial RESOLUTION

Back 34

depends on number of PIXELS per square

Similar to clinical concept of 2 point discrimination. Distinction down to a mm on finger but further apart on back. How small of a thing can we see?

Front 35

scaphoid
rib
radial head

Back 35

3 most commonly occult fx
can't see
need screen resolution

Front 36

Screen resolution is measured in

Back 36

LINE PAIRS PER MILLIMETER

Front 37

spine screen resolution vs. extremity screen

Back 37

spine fast 7 lp/mm
extremity detail 15 lp/mm

Front 38

small body part, use _______ focal spot

Back 38

small

to give high resolution

Front 39

the thicker the emulsion (silver), the ______ the film

Back 39

FASTER

Front 40

THE thicker the phosphor layer, the _____ the screen

Back 40

faster

bad because lower resolution

Front 41

Spatial resolution is affected by:

Back 41

focal spot size
film emulsion thickness
screen phosphor layer thickness
phosphor size

Front 42

System speed is a combination of

Back 42

film speed and screen speed

cassettes set the system speed!

Front 43

extremities 100 speed film, 100 speed cassettes = ____ speed.

Back 43

100 speed

Front 44

general spinal radiography recommendation 100 speed film, 400 speed cassette = ____ speed

Back 44

400 speed

Front 45

Obese pt. spinal radiography recommendation 100 speed film, 800 speed cassettes =

Back 45

800 speed

cuts mass in half
resolution goes down but is never high on obese patients anyway due to compton interaction

Front 46

Screens do not wear out from radiation/photons. Why do they wear out?

Back 46

mechanical wear and tear (fingernails)

Front 47

Film:
stores information from __________ x-rays

Back 47

attenuated

Front 48

Plain film radiography is identical to

Back 48

35 mm BW photographic film

camera film only has emulsion on one side but on x-ray film, DOUBLE EMULSION so either side goes up

Front 49

Original x-rays used glass plates. In WW1, changed to cellulose nitrate but that was _______

Back 49

flammable!

Front 50

Converted from cellulose nitrate to cellulose trinitrate (gunpowder) in 1920's then..

Back 50

in 1960's: POLYESTER

Front 51

Why use polyester?

Back 51

very rigid for emulsion
water resistant
DIMENSIONALLY STABLE -doesn't change shape during processing
TRANSPARENT -blue tint to decrease eyestrain

Front 52

Blue tint to polyester reduces

Back 52

eyestrain

Front 53

Emulsion is made from

Back 53

GELATIN

crystals are flat to max surface area

Front 54

based on FRANKEL defect (silver central, bromide peripherallly) and SENSITVITY SPECK

Back 54

GURNEY MOTT HYPOTHESIS

Front 55

poorly understood theory of photographic effect
describes conversion of halide crystal into metallic silver

Back 55

GURNEY-MOTT HYPOTHESIS

Front 56

allows Ag and Br movement

Back 56

FRANKEL EFFECT

Front 57

sulfur based small imperfection in silver halide crystal

Back 57

SENSITIVITY EFFECT

Front 58

DESCRIBE gurney-mott hypothesis

Back 58

atoms and ions are free to move (silver to inside, bromide to outside)
photon hits sensitivity speck and undergoes photelectric effect (photon absorption and photoelectric production)
THe photoelectron is captured by the sensitivity speck

Front 59

The negative charge of the sensitivity speck draws _________ ions

Back 59

Ag+

Front 60

Ag+ ions convert to metallic silver:
______ atoms of Ag+ are formed

Back 60

4-10

Front 61

Freed bromide and I migrate into the gelatin after Ag+ atoms are formed. This creates a _______________-

Back 61

LATENT IMAGE

Front 62

lUnexposed film appears identical to the film with the latent image. Difference can only be seen with an

Back 62

electron microscope

Front 63

Processing converts the entire crystal into _________ ________.

Back 63

metallic silver

Front 64

3 film types

Back 64

Direct exposure film
Screen film
Duplication (copy) film

Front 65

only common use is dentistry for bitewings. High exposure.

Back 65

DIRECT EXPOSURE FILM

Front 66

type of film we use for patients

Back 66

SCREEN FILM

light from the screens creates the x-ray film

Front 67

also called solarized film

Back 67

Duplication (copy) film

single emulsion film for copying originals
Starts black, turns white when exposed

Front 68

Faster the film, the ________ the resolution

Back 68

lower

Front 69

Describes film sensitivity to light

Back 69

SPEED

Given a value 50, 100, 200 (most common)

Front 70

MOst common type of film speed

Back 70

200

Front 71

100 speed is called

Back 71

full speed or per speed

Front 72

emulsion on both sides that cuts exposure in half

Back 72

DOUBLE EMULSION

Front 73

how efficient my emulsion is

Back 73

COVERING POWER

Front 74

DIFFERENCE between the black and white

Back 74

CONTRAST

Front 75

high contrast film = __________ latitude

Back 75

narrow latitude

Front 76

Contrast is inversely proportional to _______

Back 76

latitude

Front 77

gives me the ability to differentiate between different types of tissues

Back 77

contrast

Front 78

High contrast = _________ latitude

Low contrast = _________ latitude

Back 78

narrow

wide

Front 79

How do I know what kind of contrast of film I have?

Back 79

Ask to see the :
H&D curve
the CHARACTERISTIC curve
Hurter and Driffield curve

Front 80

Parts of the characteristic curve

Back 80

Base + Fog
Toe
Slope (linear portion)
Shoulder

Front 81

steep slope is _________ contrast film

Back 81

HIGH

Front 82

a shallow slope is ________ contrast film

Back 82

low

Front 83

minimal density of film

Back 83

toe

Front 84

the width of the slope

Back 84

LATITUDE

(narrow for high, wide for low)

Front 85

If I'm a little underexposed, I don't make the information. IF I'm a little overexposed, it's too dark. What kind of film is not as reactive as muculoskeletal film?

Back 85

chest film

Front 86

Steep slope
Narrow Latitude
High contrast

Back 86

MUSCULOSKELETAL FILM

the kind we want!

Front 87

When light crosses from one emulsion to the other

Back 87

CROSSOVER

Front 88

decreases film resolution by allowing light to crossover from one emulsion to the other = bad.

Back 88

CROSSOVER

Front 89

CROSSOVER CONTROL

Back 89

decreases patient dose*****
higher resolution*****


these things are usually inverse but with crossover control, you can get lower dose with better resolution

Front 90

Films are sensitive to either blue or green spectra of light. Green =

Back 90

ORTHOCHROMATIC

spectral mismatch
too light
grossly underexposed

Front 91

Mixing film and patient dosage

Back 91

SPECTRAL MISMATCH

bad! Mixing film and cassette colors increased patient dose up to 4x and reduces resolution

Front 92

If you use green sensitive film, use a ____ safelight

Back 92

red

Front 93

Buy a ______ filter because it works for both types of film.

Back 93

RED SAFELIGHT - GBX-2
works for both green and blue film

Front 94

People who buy safelights are genetically ________.

Back 94

inferior. You are a chiro. You work with your hands. Do it in the dark.

Front 95

Minimum distance of safelight is

Back 95

5'

inverse square law - closer it is, more photons hit film

Front 96

Store film in the _______ position

Back 96

upright

*because laying it flat will weight fog the lower half of the box

Front 97

Film ________, so buy only what you need.

Back 97

expires

Front 98

Store film away from

Back 98

heat, light and radiation.

Front 99

Using exposed film which is past its expiration date

Back 99

is a misdemeanor in most states

Front 100

Don't buy film in the

Back 100

summer

Front 101

Don't store film behind your

Back 101

bucky wall (unless it is made of lead)