Techniques

Question 1

x-ray film emulsion contents and purposes?

Answer 1

silver halide grains - sensitive to x-ray and light

vehicle matrix - absorb processing solutions

Question 2

base purpose in film?

Answer 2

structural

Question 3

intraoral x-ray film structure called? Advantage?

Answer 3

double-emulsion, less radiation needed

Question 4

Intraoral Rx sizes

• PA
• Bitewing
• Occlusal

Answer 4

PA: adult - 2
anterior - 1
child - 0

BW adult - 2
child -1

Occlusal - 4

Question 5

Size 4 is how many times larger than 2?

Answer 5

3x

Question 6

Direct exposure vs screen film which is more resolution?

Answer 6

DIRECT

Question 7

How do intensifying screens work?

Answer 7

absorb x-rays and produce visible light, exposes film

Question 8

Intensifying screens make how many times more sensitive?

What effect on dose?

Why not used intraorally?

Answer 8

10-60x

lowers

poor resolution

Question 9

Intensifying screens construction and purpose of each layer (3)

Answer 9

Base

phosphor layer - crystals with rare earth elements

protective coat - cleanable surface

Question 10

Green screen = what elements letters?

Blue/UV?

Answer 10

Green = GT

Blue = YNb

Question 11

What is the latent image?

Answer 11

Before processing, area with neutral silver

Question 12

Film processing flow: exposed film contains…
Developer converts…
Fixer removes…

Answer 12

Neutral silver atoms at latent image sites
Neutral silver bromide into black metallic silver grains
Unexposed silver bromide crystals

Question 13

Developer components (3) and their purposes
Developer
Activator
Preservative

Answer 13

developer - phenidone or hydroquinone - converts silver crystals
Activator - NaOH or KOH - keeps pH values around 10 and lets developing agents into film by swelling emulsion
Preservative - Sodium sulfite - preserves solution

Question 14

Developer should be replenished with replenisher how often?

Answer 14

each morning

Question 15

Rinsing between developing and fixing done for?

Answer 15

30s with agitation

Question 16

Fixing solution components and purposes? (4)
Clearing agents
Acidifier
Preservative
Hardener

Answer 16

Clearing agents - Ammonium thiosulfate - dissolves unexposed silver
acidifier - acetic acid buffer - 4.5pH, inactivates developer
Preservative - Ammonium sulfate - prevents oxidation of clearign agent
Hardener - Aluminum sulfate - reduces swelling and prevents damage when handling

Question 17

Excess clearing will result in?

Answer 17

loss of film density

Question 18

Temp of tanks should be?

Answer 18

60-75F

Question 19

Replenishing can let solutions last…

Answer 19

3-4 weeks

Question 20

Auto vs manual processing density, contrast, quality?

Answer 20

density and contrast same, but quality is lower for auto

Question 21

Primary things of concern when disposing is?

Answer 21

used fixer (silver) and lead foil in film packets

Question 22

Density vs...
mA
kVp
Exposure time
Distance focal spot to film?

Answer 22

up
up
up
down

Question 23

Film latitude is what?

more latitude means what for contrast?

Answer 23

range of exposures it can distinguish

Wide latitude = lower contrast

Question 24

What is noise?

Primary causes?

Answer 24

small areas of uneven density
mottle - bc structure of film/screen
artifacts - handling

Question 25

Sharpness is?
loss caused by?
Vs speed film? Intensifying screens?

Answer 25

ability to define edge
blur - receptor, movement, geometric
Low speed have finer grains - sharper
Intensifying screens hurt sharpness bc light spreads out