Dental Radiology - Xray films (2) Flashcards by rebecca hannigan

what are the 4 components of a traditional xray film

film base, adhesive layer, film emulsion and protective layer

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Film base is made of a thin plastic (0.2mm) and is made to withstand what conditions

heat, moisture and chemical exposure

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the adhesive layer attaches emulsion to film base and is located where

on both sides of the base

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what is film emulsion made of

silver halide crystals and gelatin

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what is the purpose of silver halide crystals in film emulsion

to give it sensitivity to radiation in order to produce an image

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the protective layer is a thin transparent coating that protects from

physical manipulation and chemical processing

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what is the purpose of gelatin in film emulsion

to suspend and evenly dispute crystals over the film base

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what material absorbs processing solution to allow for chemicals to react with halide crystals

gelatin

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A chemical compound sensitive to light and radiation is known as

silver halide crystals

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Silver halide crystals are composed of

silver and a halogen (bromide or Iodide)

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what’s the percentage of silver bromide crystals in emulsion

80-99%

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what’s the percentage of silver iodide crystals in emulsion

1-10%

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How is a latent image created by halide crystals

the silver halide crystals absorb the radiation during exposure and store the energy from it. A pattern is then created by the stored energy

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Latent image

a image created by a pattern in the crystals that comes from stored energy

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an image that is existing but not yet developed is known as a

latent image

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Masking of a image prevents

crystals underneath the cover from being exposed to radiation

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what is the process chain of silver halide crystals

exposure> Processing > Visible/stable image

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What are the 3 types of xray film

intraoral, extra oral, duplicating film

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Intra oral film is placed where

inside the mouth

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Outer waterproof wrap, black paper wrapper, film, lead foil are all components of

traditional intra oral film

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what is the purpose of lead foil

to shield film from secondary radiation

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what is the purpose of a black paper wrapper

to shield film from light

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The identification dot (A) is used to

identify between right and left sides when mounting

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lead foil is considered __ and is ___

hazardous waste, properly disposed of

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Size 0 film is used only for

small children PA and BW's

Size 1 film is used for __ with the paralleling technique

adult anterior PA's

Which film size is considered standard film?

size 2

size 2 film is used on adults for

posterior PA's and BW's and anterior PA's with bisecting technique

can you use size 2 film on a child with a large mouth or for child occlusal films

yes

what is size 3 used for exclusively

extra long adult posterior bite wings

a size 3 film will cover __

one entire side of the mouth (max and mand)

what Is size 4 film used for

adult occlusal films

the mandible can continue growth until what age

20's

what is a prominent feature of maxillary occlusal films

the midsagital suture line

Periapical films are used to examine

the entire tooth, crown, root, and surrounding bone

Periapical also means

around - apex

root margins, infection/disease, decay and bone health are all aspects that a ___ film would show

periapicial

What sizes of film are used for PA's

0,1,2

3 types of intraoral film

Periapical, bitewings, and occlusal

what size film is used for PA anterior on an adult using the paralleling technique

size 1

what size film is used for PA bisecting adult anteriors and posterior

size 2

a size 0 film is used for PAs on

children

Bitewings are used to examine

crowns of max and mand, interproximal

overhangs, calculus, caries, height of crestal bone are all shown on what type of film

bitewings

what is a bitewing series

2-4 films of posterior teeth to detect and document internal structure of tooth

what is the minimum set of xrays you'd receive at a hygiene check up if any

bitewing series

sizes used for bitewings are

0, 1, 2, 3

occlusal films are used to

examine the maxilla and mandible

what sizes are used for occlusal films

size 4, and 2

the amount of radiation needed to produce a radiograph in relation to film is known as

film speed

film speed is determined by

the size of sliver halide crystal, thickness of emulsion and presence of radiosensitive dyes

the larger the halide crystal, the ___

faster the film speed

a faster film results in an image that is

less sharp

which film speed is the fastest

F speed

the speed requiring a 60% decrease in exposure from D speed film is

F speed

2 types of extra oral films

panoramic, cephalometric

extra oral films are used to examine

large areas of skull and jaw

when prepping a patient for a panoramic you would

explain the procedure, place double sided lead apron, and remove any object on the head that could compromise the quality of scan

How would you position a patient for a pan

spine straight, teeth on groove, midsagittal perpendicular to floor, Frankfort parallel to floor, lips around block, and tongue on roof of mouth

the midsagittal plane is

down the midline of face

the frankfort plane is

top of ear through to bottom of the eye and across

Cephalometric film is used to measure the

growth and development of the skull

2 types of extra oral films

screen films, nonscreen films

screen films are used with ___ to reduce radiation to pt

intensifying screens

nonscreen films are not recommended for dental radiography because they

require more exposure time

what are the two components of screen films

cassettes and intensifying screens

cassettes keep the light out so that the intensifying screen can

transfer energy to light and expose it to screen film

intensifying screens are made of

smooth plastic coated in small fluorescent crystals

fluorescent crystals are AKA

phorphors

fluorescence emit what color light

blue and green

Conventional calcium tungstate screen emits a

blue light

newer rare earth screens emit a

green light

which color emitted from the intensifying screens are more effective and require less radiation

green light

What is duplicating film

making a duplicate of a copy to send for insurance companies and specialists

duplicating film only has one side of

emulsion

is duplicating film exposed to xrays

no, made in dark room using a Lightbox

a double film packets creates

2 identical images from one dose of radiation

what is the ideal temp for film storage

50-70F or 10-21C

ideal humidity for film storage

30-50%

do films have an expiration date

yes, first in first out

what type of container is film store in

a lead lined/radiation resistant container to prevent film fog

what is film fog

caused by scatter radiation, it attaches to film making later exposure not stick

do edentulous patients need radiographs

yes

Radiolucent structures appear

dark or black, radiation passes through

radiopaque structures appear

light and white, radiation can't pass

enamel, bone, restorations are examples of

radiopaque structures

air, access, pulp are examples of

radiolucent

contrast is

degrees of blackness / shade of greys

low contrast images show _

lots of grey shades

high contrast images only show

black and white

which electrical factor has influence on contrast

Kvp

a low kip results in less adequate waves, meaning a ___ contrast

higher

long scale contrast is aka

low contrast

short scale contrast is aka

high contrast

the step wedge is a form of quality assurance that demonstrates

contrast scales produced by exposure

density is the overall

blackness of an image

what settings would give you a full range of grey shades

properly balanced kvp and ma

3 geometric influences

sharpness, magnification, distortion

what 3 things influence sharpness of an image

size of focal spot on target, size of halide crystals, movement

if you increase the length of your PID, the magnification of the image would ___

decrease

if the distance from the object being examined to the receptor is increased the magnification would also

increase

distortion is the

variation in size and shape from true form

if a receptor is placed to far or with an insufficient angle the image would be

distorted

quality + quantity =

intensity

inverse square law states that

the intensity of radiation is inversely proportional to the square of the distance from radiation source

inversely proportional means that when one variable increases, the other

decreases

if you changed a 8" PID out for a 16" PID the intensity would ___

be 1/4 as intense

changing from a 16" PID to an 8" PID would change the intensity to

4x as strong