Oral Radiology Test 2 Material Handout 1

Front 1

What are the two types of images created when performing an xray

Back 1

Aerial - invisible pattern in air that represents various x-ray photons as they exit the object

Latent - invisible image on film that is produced in film emulsion after exposure to x-rays

Front 2

What are the 4 types of receptors used in dental x-ray taking

Back 2

Conventional -
intra and extraoral

Digital -
CCD(charged couple devices) and PSP(storage phosphor systems)

Front 3

What is an image receptor

Back 3

recording medium that displays information about an object that has been exposed to xrays

Front 4

Describe some similar and differing qualities of the 2 types of conventional films

Back 4

Intraoral- is a DIRECT exposure film and can give higher resolution, Used for bitewings and PA's

Extraoral - is an INDIRECT or screen film in other words it uses an intensifying screen that emits light. Extraoral used for pans and cephs

Both are harmed by exposure to ambient light

Front 5

What is the functions of the lead foil layer in the film package

Back 5

protects from backscatter, adds rigidity to package.

MAKE SURE YOU PUT SIDE WITH FOIL AWAY FROM SUBJECT

IS SIDE OPPOSITE THE DOT

Front 6

What does the raised dot tell us

Back 6

its on the film side and goes towards the xray tube--- used for film orientation

Front 7

What is the function of the paper or plastic covering on the film package

Back 7

Moisture resistant and protection from visible light

Front 8

Should double film packages be processed at one time.

Back 8

No they should be processed individually

Front 9

What are the four parts of film composition

Back 9

Base, adhesive, emulsion and protective coating

Front 10

What are the base's functions in a film

Back 10

its a thin clear plastice that is flexible and gives blue tint for easy viewing and reduced eye strain, supports emulsion,

Front 11

describe the emulsion on a film

Back 11

Its radiosensitive and records the image by interaction of xray photons or light

Front 12

Why is emulsion coating on both sides of the film

Back 12

To increase film speed, reduce exposure time and radiation dose

Front 13

What is the main active ingredient of the emulsion

Back 13

Silver Halide granules -
AgBr in F speed
AgI in ultraspeed(D speed)

Front 14

Describe the vehicle matrix of the emulsion

Back 14

gelatinous and non-gelatinous materials that keep Ag halides dispersed and absorbs processing chemicals

Its transparent(transmission of xrays and light) and very porous(chemical penetration)

Front 15

What is the definition of film speed

Back 15

also called Film Sensitivity - the amount of radiation required to produce an image of standard density or the efficiency with which a film responds to xray exposure

Front 16

T or F Faster films need more radiation and longer exposure times

Back 16

False, faster films need less exposure time and less radiation

Front 17

What determines film speed

Back 17

Size of silver halide granules - Larger the granule size faster the film speed

Front 18

What are some of the benefits of faster films

Back 18

decreased patient dose, short exposure time and less chance of motion

Front 19

What are some of the characteristics of D speed films

Back 19

round grain technology that gives high contrast, fine detail but requires higher dose than F speed. Uses AgI instead of AgBr like F speed

Front 20

Describe F speed characteristics

Back 20

Its a flat or tubular T-grain technology that gives 50% or more reduction in exposure compared to D. it has larger crystals and greater amount of AgBr in emulsion. Gives comparable contrast and resolution to D speed
F speed also accomodates a wider range of processing conditions and is exceptionally tolerant of processing variations

Front 21

T or F film speed can be increased by processing at a slightly higher temp

Back 21

T
however its not recommended as it can create fog and graininess

Front 22

What can lower film speed

Back 22

processing in diluted processing solution

Front 23

Film fog is described as

Back 23

unwanted blackness by exposure to radiation other than primary beam

Front 24

What is film latitude

Back 24

Measure of range of exposures that can be recorded as distinguishable densities on a film

Front 25

Films with wide lattitude have what characteristics with respect to contrast

Back 25

Lower contrast

Front 26

What are the optimal storage conditions for xray film

Back 26

50-70 deg F or 10-21 deg C
30-50 % humidity

Front 27

What can storing film in dry conditions lead to

Back 27

artifacts or static electricity marks on the processed film

Front 28

When storing extraoral film boxes what should you take precaution in doing

Back 28

store it on side of box to prevent warping

Front 29

Open boxes should be stored in the xray room

Back 29

false, store outside the xray room

Front 30

What can storage of film in a refrigerator cause

Back 30

condensation on film and black marks

Front 31

What are some things that can cause film damage

Back 31

Heat, light, bending and pressure

Front 32

What are the four layers of the intensifying screen used for extra oral films

Back 32

Base, reflector, Phosphor layer and overcoat

Front 33

What is a synonym for extraoral film

Back 33

screen film

Front 34

What is the process that happens in an extraoral film which produces the image

Back 34

Energy of xray beam converts to light by the phosphors in the intensifying screen being exposed to radiation. this light exposes the film to form the image

Front 35

What are the properties of an intensifying screen

Back 35

sturdy, moisture resistant, chemically inert, flexible and contains no impurities

Front 36

What are the intensifying screen materials

Back 36

Calcium tungstate(blue)
Rare earth phosphors used as intens screens
1 Gadolinium oxysulfide(green)
2 lanthanum oxybromide(blue)
3 yttrium tantalate (blue)

Front 37

Why do manufactures recommend matching emission and absorption characteristics of intensifying screens and films

Back 37

Different intens screens have different emissions and different films have different absorption characteristics

Front 38

What are some of the effective doses of the different types of intensifying screens

Back 38

Calcium Tungstate - single panoramic 14 microsieverts

Rare earth Intensifying
single panoramic - 7 microsieverts

NOTE Poster - Anterior View 7-17 microsieverts but not sure if this is shows difference between 2 types or is an estimater for rare earth's

Front 39

Which type of intens screens require less radiation dose

Back 39

Rare Earth

Front 40

What are some advantages and disadvantages of extraoral film

Back 40

Advanatges
Reduced patient dosage
diagnostically acceptable image

Disadvantages
lack of fine anatomical detail

Front 41

What are some of the uses of extraoral films in dentistry

Back 41

Panoramic, Post-Ant or Lateral Cephalometric

Front 42

What are the most common causes of poor screen-film contact

Back 42

Worn contact area
loose or bent hinges
warped screens caused by moisture
warped cassette front
cracked cassette frame
foreign matter under the screen

Front 43

what are some function of grids

Back 43

used to reduce scatter radiation
placed betweem subject and film
only used when increased contrast is needed

Front 44

What is a disadvantage of grids

Back 44

Higher exposure is needed(approx double)